Abstract in English:
Leishmaniasis is a parasitic disease with a worldwide distribution, transmitted to animals and humans through the blood meal of sand flies, caused by protozoa of the genus Leishmania. This report aims to describe the clinical, pathological, and molecular findings of mucocutaneous leishmaniasis caused by Leishmania enriettii in a guinea pig (Cavia porcellus). The animal presented ulcerated skin lesions in the right pinna. Samples from the lesion were evaluated by cytology, revealing the presence of amastigote forms of Leishmania spp. Histopathology showed a dermal inflammatory infiltrate consisting of macrophages, multinucleated giant cells, lymphocytes, plasma cells, and heterophils. The foam cells contained parasitophorous vacuoles filled with amastigotes. Molecular characterization identified the species as L. enriettii. The diagnosis of mucocutaneous leishmaniasis was based on morphological findings (macroscopic and microscopic) associated with molecular biology tests that allowed defining the etiological agent of the disease.
Abstract in Portuguese:
A leishmaniose é uma doença parasitária com distribuição mundial, transmitida a animais e humanos através do repasto sanguíneo de flebotomíneos, causada por protozoários do gênero Leishmania. Este relato tem como objetivo descrever os achados clínicos, patológicos e moleculares da leishmaniose mucocutânea causada por Leishmania enriettii em cobaias (Cavia porcellus). O animal apresentava lesões cutâneas ulceradas no pavilhão auricular direito. Amostras da lesão foram avaliadas por citologia, revelando a presença de formas amastigotas de Leishmania spp. A histopatologia mostrou um infiltrado inflamatório dérmico composto por macrófagos, células gigantes multinucleadas, linfócitos, plasmócitos e heterófilos. As células espumosas continham vacúolos parasitóforos cheios de amastigotas. A caracterização molecular identificou a espécie como L. enriettii. O diagnóstico da leishmaniose mucocutânea foi baseado em achados morfológicos (macroscópicos e microscópicos) associados a testes de biologia molecular que permitiram definir o agente etiológico da doença.
Abstract in English:
Three domestic guinea pigs (Cavia porcellus) from Ampére, Paraná State, Brazil, presenting crusted nodular lesions on the pinnae, snout, and digits of all limbs were examined at the University Veterinary Hospital of the Federal University of the Southern Border in February 2023. Cytological evaluation by fine-needle aspiration revealed Leishmania amastigotes within macrophages. Two animals were euthanized for further histopathological, immunohistochemical, parasitological, and molecular investigations. Skin samples exhibited a diffuse mixed inflammatory infiltrate, predominantly histiocytic, with macrophages densely parasitized by amastigotes. Immunohistochemistry (IHC) using an anti-mTXNPx monoclonal antibody confirmed the abundant presence of amastigotes in the skin, providing key diagnostic support. Liver sections showed mild lymphocytic infiltrates, with specific IHC labeling in pericentral hepatocytes indicating antigenic presence despite the absence of visible parasites. Kidneys, lungs, and spleen exhibited mild architectural changes with no detectable amastigotes on microscopy. Promastigote forms were successfully isolated in NNN/LIT medium from one liver sample. Molecular analysis using hsp70-targeted PCR and sequencing confirmed the presence of Leishmania DNA in the skin, spleen, and liver, identifying the species as Leishmania (Mundinia) enriettii. The absence of microscopically visible amastigotes in tissues, despite molecular and immunohistochemical evidence, underscores the value of a multimodal diagnostic approach. This study expands the known geographic distribution of L. enriettii in Paraná State and reinforces the guinea pig’s role as the only confirmed reservoir of this parasite in Brazil.
Abstract in Portuguese:
Três porquinhos-da-índia domésticos (Cavia porcellus), provenientes de Ampére, no estado do Paraná, Brasil, apresentando lesões nodulares crostosas no pavilhão auricular, focinho e dígitos de todos os membros, foram examinados na Unidade Hospitalar Veterinária da Universidade Federal da Fronteira Sul em fevereiro de 2023. A avaliação citológica por punção aspirativa com agulha fina revelou formas amastigotas de Leishmania no interior de macrófagos. Dois animais foram eutanasiados para realização de exames histopatológicos, imuno-histoquímicos, parasitológicos e moleculares. As amostras de pele apresentaram infiltrado inflamatório misto difuso, predominantemente histiocítico, com macrófagos densamente parasitados por amastigotas. A imuno-histoquímica (IHQ), utilizando anticorpo monoclonal anti-mTXNPx, confirmou a presença abundante de amastigotas na pele, contribuindo significativamente para o diagnóstico. As seções hepáticas revelaram infiltrado linfocitário discreto, com marcação IHQ específica em hepatócitos pericentrais, indicando presença antigênica mesmo na ausência de parasitos visíveis. Rins, pulmões e baço apresentaram alterações arquiteturais leves, sem detecção de amastigotas à microscopia. Formas promastigotas foram isoladas com sucesso em meio bifásico NNN/LIT a partir de uma amostra de fígado. A análise molecular por PCR direcionada ao gene hsp70, seguida de sequenciamento, confirmou a presença de DNA de Leishmania em amostras de pele, baço e fígado, com identificação da espécie como Leishmania (Mundinia) enriettii. A ausência de amastigotas nos tecidos viscerais, apesar da imuno-histoquímica e positividade molecular, reforça o valor de uma abordagem diagnóstica multimodal. Este estudo amplia a distribuição geográfica conhecida de L. enriettii no estado do Paraná e reforça o papel do porquinho-da-índia como único reservatório confirmado desse parasito no Brasil.
Abstract in English:
In the last decade, there has been a significant increase in the demand for small rodents such as hamsters, guinea pigs, rats, and mice to be kept as pets. Consequently, the veterinary care provided to these animals has also increased. The aim of this study was to describe gross, histopathological and immunohistochemical findings of 26 spontaneous neoplasms diagnosed in 25 pet rodents in Northeastern Brazil. A retrospective study was carried out from 2014 to 2022 in two veterinary diagnostic laboratories to identify cases of tumoriform lesions in these species. Hamsters represented the most frequent species in this study (60%, 15/25), followed by rats (28%, 7/25), guinea pigs (8%, 2/25), and mice (4%, 1/25), with a mean age of 17.63 months. The anatomical regions of the face/head and thoracic region were the most affected. The most affected tissues were the skin/subcutaneous/mucosal (65%, 15/26) and mammary gland (23%, 6/26). Eighteen different types of neoplasms were diagnosed, and T-cell lymphomas and mammary adenocarcinomas were the most diagnosed tumors, each corresponding to 12% (3/26) of the cases. Leiomyosarcoma, myxosarcoma and mammary adenocarcinoma metastases were also noted. Immunohistochemistry was essential for the diagnosis of certain malignant mesenchymal and round-cell neoplasms. Pet rodent neoplasms in Northeastern Brazil are common, especially in hamsters, and immunohistochemistry can be a useful tool for the definitive diagnosis of these tumors.
Abstract in Portuguese:
In the last decade, there has been a significant increase in the demand for small rodents such as hamsters, guinea pigs, rats, and mice to be kept as pets. Consequently, the veterinary care provided to these animals has also increased. The aim of this study was to describe gross, histopathological and immunohistochemical findings of 26 spontaneous neoplasms diagnosed in 25 pet rodents in Northeastern Brazil. A retrospective study was carried out from 2014 to 2022 in two veterinary diagnostic laboratories to identify cases of tumoriform lesions in these species. Hamsters represented the most frequent species in this study (60%, 15/25), followed by rats (28%, 7/25), guinea pigs (8%, 2/25), and mice (4%, 1/25), with a mean age of 17.63 months. The anatomical regions of the face/head and thoracic region were the most affected. The most affected tissues were the skin/subcutaneous/mucosal (65%, 15/26) and mammary gland (23%, 6/26). Eighteen different types of neoplasms were diagnosed, and T-cell lymphomas and mammary adenocarcinomas were the most diagnosed tumors, each corresponding to 12% (3/26) of the cases. Leiomyosarcoma, myxosarcoma and mammary adenocarcinoma metastases were also noted. Immunohistochemistry was essential for the diagnosis of certain malignant mesenchymal and round-cell neoplasms. Pet rodent neoplasms in Northeastern Brazil are common, especially in hamsters, and immunohistochemistry can be a useful tool for the definitive diagnosis of these tumors.
Abstract in English:
We describe an outbreak of leishmaniasis in seven guinea pigs (Cavia porcellus) in which nodular ulcerated skin lesions of varying sizes were observed in the nasal cavity, upper lip, pinnae, vulva, and periarticular region of the limbs. Cytologic exam of collected samples of the lesions in the auricle of one of the animals revealed macrophages containing parasitophorous vacuoles of approximately 4.0μm in diameter in their cytoplasm with morphology suggestive of Leishmania sp. Although skin lesions spontaneously regressed in two of the Guinea pigs, only one survived. All six animals that died were necropsied. Grossly, all animals showed bloody nodular cutaneous lesions with crusts. One of the guinea pigs had distended dark red and firm lungs. Histopathology of the skin lesions revealed histiocytic interstitial acanthotic dermatitis associated with a myriad of Leishmania organisms within macrophages cytoplasm. In the lung, the lesions were characteristic of broncho-interstitial pneumonia with focal infiltrates of neutrophils, epithelioid macrophages, and multinucleated giant cells containing 2µm basophilic amastigotes with morphology compatible with Leishmania spp. A focal granulomatous lesion ,associated with the causal agent in the lung is a novel description of leishmaniasis in guinea pigs caused by L. enriettii. The polymerase chain reaction (PCR) technique with mini-exon primer performed in samples of lesions from two affected guinea pigs was positive and equal to the reference strain, identifying Leishmania enriettii. The cytological, macroscopic, and histological lesions associated with the PCR technique allowed the diagnosis of leishmaniasis and the identification of the specie L. enriettii.
Abstract in Portuguese:
Descrevemos um surto de leishmaniose em sete cobaias (Cavia porcellus), com lesões cutâneas nodulares ulceradas de tamanhos variados observadas na cavidade nasal, lábio superior, pavilhões auriculares, vulva e região periarticular dos membros. No exame citológico foram encontrados macrófagos contendo vacúolos parasitóforos no citoplasma de aproximadamente 4.0μm em diâmetro com morfologia sugestiva de Leishmania sp. Apesar de regressão espontânea das lesões cutâneas terem ocorrido em duas das sete cobaias, apenas um sobreviveu. Seis dos sete animais afetados morreram e foram necropsiados. Macroscopicamente, todos os animais apresentaram lesões cutâneas nodulares, crostosas e sanguinolentas. Uma das cobaias tinha pulmões vermelho-escuros, distendidos e firmes. A histopatologia das lesões cutâneas revelou dermatite acantótica intersticial histiocítica associada a miríades de organismos de Leishmania no citoplasma de macrófagos. Nos pulmões as lesões eram características de pneumonia bronco-intersticial com infiltrado focal de neutrófilos, eosinófilos, macrófagos epitelioides e células gigantes multinucleadas contendo amastigotas basofílicos de 2µm com morfologia compatível com Leishmania spp. Lesões granulomatosas focais associadas ao agente no pulmão são um achado inédito na leishmaniose causada por L. enriettii em cobaias. A técnica de reação em cadeia da polimerase (PCR) com primer mini-exon realizada em amostras de lesões de duas cobaias afetadas foi positiva, identificando Leishmania enriettii. Os aspectos macroscópicos, citológicos, e histológicos associados à técnica da (PCR), permitiram o diagnóstico da leishmaniose e a identificação da espécie L. enriettii.
Abstract in English:
Guinea pigs are animal models widely used in research related to developmental biology. The objective of this work was to demonstrate the process of formation and differentiation of urinary organs in females of the species in the prenatal period. Four females were used at 25, 30, 45 and >65 DG (days of gestation). The animals were dissected, and then macroscopic and microscopic descriptions of the urinary organs were performed. At 25 DG metanephros were present in the urogenital crest into the abdominal cavity. Collecting ducts and glomerular precursor cells could be visualized. After this period, metanephros underwent microstructural modifications to form the kidneys at the end of the prenatal period. After 30 DG, the renal parenchyma already had a cortex, where the glomerulus and proximal convoluted tubules were present; and the medulla, where distal convoluted tubules, collecting ducts, and pelvis were present. The pelvis of each kidney was drained by the ureters. The ureters also underwent tissue differentiation to be differentiated (mucosa with transitional epithelium and lamina propria of connective tissue, muscular, and adventitia) at the end of the prenatal period. The urinary vesicle also underwent tissue changes to form the tunics similar to those found in the ureters, with emphasis on the greater volume of the muscular tunica and the lamina propria that constituted the submucosa in this organ. The pelvic urethra was evidenced by a mucosa lined by transitional epithelium, submucosa, muscular and adventitia. Finally, a partial clitoral urethra and a urethral meatus in the prepuce of the clitoris were also evidenced. The urethral channel began to form with the emergence of the urethral plate and the urethral groove at 30 DG and thereafter with the fusion of the urethral folds to form a partially channeled urethra in the clitoris. A urethral meatus was observed in the most distal portion of the clitoral tissue, formed by the fusion of the prepuce. It is concluded that the urinary organs of guinea pig have similar development to that described in domestic animals, except for the partial clitoral urethra and evident urethral meatus.
Abstract in Portuguese:
Os porquinhos‑da‑índia são modelos animais amplamente utilizados em pesquisas relacionadas a biologia do desenvolvimento. O objetivo deste trabalho foi demonstrar o processo de formação e diferenciação dos órgãos urinários em fêmeas da espécie no período pré-natal. Foram utilizadas quatro fêmeas aos 25, 30, 45 e >65 DG (dias de gestação). Os animais foram dissecados e então, realizaram-se descrições macroscópicas e microscópicas dos órgãos urinários. Aos 25 DG os metanefros estavam presentes na crista urogenital da cavidade abdominal. Podiam ser visualizados ductos coletores e células precursoras glomerulares. Após este período, os metanefros sofreram modificações microestruturais para formar os rins ao final do período pré-natal. Após os 30 DG, o parênquima renal já apresentava um córtex, onde estavam presentes os glomérulos e túbulos convolutos proximais, e a medula onde estavam presentes túbulos convolutos distais, ductos coletores e a pelve. A pelve de cada rim era drenada pelos ureteres. Os ureteres também sofreram diferenciação tecidual para estarem com suas túnicas diferenciadas (mucosa com epitélio de transição e lâmina própria de tecido conjuntivo; muscular; e, adventícia) ao final do período pré-natal. A vesícula urinária também passou por modificações teciduais para formar as túnicas semelhantes as dos ureteres, com destaque para o maior volume da túnica muscular e a lâmina própria que constituiu a submucosa neste órgão. Uma uretra pélvica foi evidenciada por uma mucosa revestida por epitélio de transição, submucosa, muscular e adventícia. Por último, uma uretra parcialmente clitoriana e um meato uretral no prepúcio do clitóris também foi evidenciado. O canal uretral começou a se formar com o aparecimento da placa uretral e do sulco uretral aos 30 DG e posteriormente com a fusão das pregas uretrais para formar uma uretra parcialmente canalizada no clitóris. Observou-se um meato uretral na porção mais distal do tecido clitoriano, formado pela fusão do prepúcio. Conclui-se que os órgãos urinários do porquinho-da-índia possuem desenvolvimento semelhante ao descrito em animais domésticos, com exceção da uretra parcialmente clitoriana e do meato uretral evidente.
Abstract in English:
Animal models are essential to understand healthy human placentation. Guinea pig related rodents became on focus for such purposes. In particular, processes of trophoblast invasion are similar. The latter is associated with a specialized area, the subplacenta. Since previous results showed differences between the guinea pig and its close relative Galea spixii, we aimed to study subplacental development with more detail. We investigated 16 pregnant females of 14 to 55 days of gestation by means of histology, morphometrics, immunohistochemistry and electron microscopy. The overlap between the fetomaternal blood systems resulted as intimate, suggesting some exchange processes. Proliferation was revealed by three independent methods, being most active in early and mid-gestation, which was in accordance to former results. Though degeneration of tissues took place, the subplacenta was maintained towards term with access to the fetal vascularization, supporting a hypothesis about the release of substances to the fetal unit in advanced gestation. In contrast to other species, the extraplacental trophoblast showed a shift from syncytial streamers to giant cells during mid-gestation. Views on placentation in caviomorphs were influenced by the guinea pig, but our data supported recent studies that the subplacenta had a much greater placidity. In regard to subplacental grow, degeneration and likely also exchange processes, Galea and other species showed a more basal pattern of caviomorphs than the guinea pig. Such differences should be considered, when choosing most adequate animal models for special purposes in comparison to human placentation.
Abstract in Portuguese:
Animal models are essential to understand healthy human placentation. Guinea pig related rodents became on focus for such purposes. In particular, processes of trophoblast invasion are similar. The latter is associated with a specialized area, the subplacenta. Since previous results showed differences between the guinea pig and its close relative Galea spixii, we aimed to study subplacental development with more detail. We investigated 16 pregnant females of 14 to 55 days of gestation by means of histology, morphometrics, immunohistochemistry and electron microscopy. The overlap between the fetomaternal blood systems resulted as intimate, suggesting some exchange processes. Proliferation was revealed by three independent methods, being most active in early and mid-gestation, which was in accordance to former results. Though degeneration of tissues took place, the subplacenta was maintained towards term with access to the fetal vascularization, supporting a hypothesis about the release of substances to the fetal unit in advanced gestation. In contrast to other species, the extraplacental trophoblast showed a shift from syncytial streamers to giant cells during mid-gestation. Views on placentation in caviomorphs were influenced by the guinea pig, but our data supported recent studies that the subplacenta had a much greater placidity. In regard to subplacental grow, degeneration and likely also exchange processes, Galea and other species showed a more basal pattern of caviomorphs than the guinea pig. Such differences should be considered, when choosing most adequate animal models for special purposes in comparison to human placentation.
Abstract in English:
Nerium oleander is an ornamental cardiotoxic plant found in tropical and subtropical areas of the World. Its toxicity is related to the content of cardioactive glycosides, mainly oleandrin, found throughout the plant. The present study aimed to describe a new and improved method for oleandrin detection in tissue samples. The determination of oleandrin was made after extraction with a modified QuEChERS technique and measurement by UFLC-MS/MS. A total of 36 guinea pigs (Cavia porcellus) were distributed into 3 groups (n=12): control group that received only water orally (CON), and two treated groups that received hydroalcoholic oleander extract at doses of 150mg.kg-1 (OLE 150) and 300mg.kg-1 (OLE 300) in single oral dose. After three hours, fragments of heart, kidneys, liver and brain were collected for determination of oleandrin levels. The extraction and chromatographic procedures were effective for oleandrin detection and quantification in tissues, with retention time of 1.2 min and detection limit of 0.001µg g-1. The chromatographic analysis of treated guinea pigs indicated that oleandrin is distributed equally among the analyzed tissues. The developed methodology is a reliable, effective and rapid form of diagnosis of N. oleander poisoning based on necropsy tissue samples.
Abstract in Portuguese:
Nerium oleander é uma planta cardiotóxica ornamental encontrada em áreas tropicais e subtropicais do mundo. Sua toxicidade é relacionada á presença de glicosídeos cardioativos, principalmente a oleandrina, encontrada em toda a planta. O presente estudo objetiva descrever um novo e aprimorado método para detecção da oleandrina em amostras de tecido. A determinação da oleandrina foi feita após extração utilizando técnica modificada de QuEChERS e mensuração por UFLC-MS/MS. Um total de 36 cobaios (Cavia porcellus) foi distribuído em três grupos (n=12): grupo controle que recebeu apenas água por via oral (CON), e dois grupos tratados que receberam extrato hidroalcóolico de oleander nas doses de 150mg.kg-1 (OLE 150) e 300mg.kg-1 (OLE 300) em uma única dose oral. Após três horas, fragmentos do coração, rins, fígado e cérebro foram coletados para determinação dos níveis de oleandrina. A extração e procedimentos cromatográficos foram eficientes na detecção e quantificação da oleandrina nos tecidos, com tempo de retenção de 1,2min e limite de detecção de 0,001µg g-1. A análise cromatográfica dos animais tratados indicou que a oleandrina é distribuída de forma equalizada pelos tecidos analisados. A metodologia desenvolvida representa uma forma de diagnóstica segura, efetiva e rápida da intoxicação por N. oleander a partir de amostras de tecidos de necropsia.
Abstract in English:
ABSTRACT.- Fonseca E.T., Galindo L.T., Porcionatto M.A. & Miglino M.A. 2016. Culture, characterization and differentiation of neural precursors from the central nervous system of guinea pigs (Cavia porcellus Linnaeus, 1758). Pesquisa Veterinária Brasileira 36(Supl.1):71-78. Escola de Medicina Veterinária e Zootecnia, Universidade Federal do Tocantins, BR-153 Km 112, Rural, Araguaína, Tocantins, TO 77804-970, Brazil. E-mail: erikafonseca@uft.edu.br
Potentially neurogenic areas were initially identified by incorporation of bromodeoxyuridine (BrdU) in cells underlying the subventricular zone (SVZ) of the lateral ventricles wall, hippocampus and olfactory bulbs of newborn guinea pigs. Neural precursors from the SVZ were cultured in suspension, generating neurospheres (NSFs), which, upon dissociation were able to generate new NSFs. Upon culture in the absence of growth factors, cells dissociated from NSFs displayed evidence for neural differentiation, giving rise to cells from neural lineage. Flow cytometry analysis for of NSFs-derived cells after differentiation revealed approximately 13.3% nestin positive, 5.5% Beta-III-tubulin positive, 9% GFAP positive and 7.8% mGalC positive. Functional assays by measurement of calcium influx upon gamma butiric amino acid (GABA) and glutamate stimuli, revealed stimulation in differentiated cells, an indicator of neuronal differentiation. The ability of guinea pig SVZ cells to originate functional neurons in vitro is promising for research and towards a future use of neural stem cells in the therapy of neurological disorders.
Abstract in Portuguese:
RESUMO.- Fonseca E.T., Galindo L.T., Porcionatto M.A. & Miglino M.A. 2016. Culture, characterization and differentiation of neural precursors from the central nervous system of guinea pigs (Cavia porcellus Linnaeus, 1758). [Cultura, caracterização e diferenciação de precursores neurais do sistema nervoso central de guineas pig (Cavia porcellus Linnaeus, 1758).] Pesquisa Veterinária Brasileira 36(Supl.1):71-78. Escola de Medicina Veterinária e Zootecnia, Universidade Federal do Tocantins, BR-153 Km 112, Rural, Araguaína, Tocantins, TO 77804-970, Brazil. E-mail: erikafonseca@uft.edu.br
Áreas potencialmente neurogênicas foram identificadas por incorporação de bromodeoxiuridina (BrdU) na zona subventricular (SVZ) dos ventrículos laterais, hipocampo e bulbos olfatórios de cobaias neonatos. Precursores neurais provenientes da SVZ foram cultivados em suspensão, resultando na geração de neuroesferas (NSFs), que quando dissociadas foram capazes de proliferar e gerar novas NSFs. Quando cultivadas na ausência de fatores de crescimento, as células provenientes de NSFs dissociadas apresentaram evidências de diferenciação neuronal, dando origem a células da linhagem neural. Citometria de fluxo em células das NSFs após a diferenciação revelou aproximadamente 13,3% positivas para nestina, 5,5% positivas para Beta-III-tubulina, 9% positivas para GFAP e 7,8% positivas para mGalC. Testes de funcionalidade pela mensuração de influxo de cálcio após estímulo com ácido gama amino butírico (GABA) e glutamato revelaram a estimulação de células diferenciadas, um indicador de função neuronal. A capacidade de células da SVZ de fetos de cobaias originarem células neurais funcionais in vitro é promissora para a pesquisa e eventual uso terapêutico de células tronco em disordens do sistema nervoso.
Abstract in English:
ABSTRACT.- Simões L.S., Rici R.E.G., Favaron P.O., Sasahara T.H.C., Barreto R.S.N., Borghesi J. & Miglino M.A. 2016. Ultrastructural analysis of the spermatogenesis in the guinea pig (Cavia porcellus). Pesquisa Veterinária Brasileira 36(Supl.1):89-94. Departamento de Cirurgia, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Dr. Orlando Marques de Paiva 87, Cidade Universitária, São Paulo, SP 05508-270, Brazil. E-mail: phelipe.favaron@yahoo.com.br
Understanding of the reproductive function is essential for both, the establishment of appropriate management systems, and for the use of new species as animal models. In this study, we used light and electron microscopy to characterize the sexual development stages of the guinea pig (Cavia porcellus) in specimens of 30, 45 and 90 days of age. We observed the differentiation of spermatocytes only through transmission electron microscopy in the leptotene, zygotene and pachytene phases of meiosis, in 30-day-old animals. During puberty, there was differentiation of the germinative epithelium and formation of the acrosome. Spermatozoa, however, were not detected. Thus, we could infer that puberty happens after 45 days of age. Sexual maturity was evident in 90-day-old specimens. Our results showed that changes in the testicular germinative epithelium during the postnatal sexual development in guinea pig led to morphological changes, including the ones related to the development of Leydig and Sertoli cells, which are directly related to puberty. In this work, we provide new morphological subsidies for a better understanding of reproductive parameters of this species, enabling its use as an animal model in the field of the reproductive biology.
Abstract in Portuguese:
RESUMO.- Simões L.S., Rici R.E.G., Favaron P.O., Sasahara T.H.C., Barreto R.S.N., Borghesi J. & Miglino M.A. 2016. Ultrastructural analysis of the spermatogenesis in the guinea pig (Cavia porcellus). [Análise ultraestrutural da espermatogênese do porquinho-da-Índia (Cavia porcellus).] Pesquisa Veterinária Brasileira 36(Supl.1):89-94. Departamento de Cirurgia, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Dr. Orlando Marques de Paiva 87, Cidade Universitária, São Paulo, SP 05508-270, Brazil. E-mail: phelipe.favaron@yahoo.com.br
A função reprodutiva é um fator de vital compreensão tanto para o estabelecimento de sistemas apropriados de manejo, quanto para o uso de novas espécies como modelos animais. Neste estudo através da microscopia de luz e eletrônica caracterizou-se a fase de desenvolvimento sexual do porquinho-da-Índia (Cavia porcellus) em espécimes de 30, 45 e 90 dias de desenvolvimento. Nos animais de 30 dias, a diferenciação dos espermatócitos foi visualizada somente na microscopia eletrônica de transmissão em leptóteno, zigóteno e paquíteno. Durante a puberdade, houve diferenciação do epitélio germinativo, formação do acrossoma, porém não foram evidenciados espermatozóides, assim, infere-se que a puberdade acontece a partir dos 45 dias de idade. A maturidade sexual foi evidente aos 90 dias de idade. Nossos resultados mostraram que ao longo do desenvolvimento sexual pós-natal do porquinho-da-Índia, mudanças no epitélio germinativo testicular levam há alterações morfológicas, inclusive com relação ao desenvolvimento das células de Sertoli e de Leydig, as quais estão diretamente relacionadas com a puberdade. Assim, novos subsídios morfológicos são fornecidos para um melhor entendimento dos parâmetros reprodutivos desta espécie, a fim de viabilizar sua utilização como modelo animal no campo da biologia reprodutiva.
Abstract in English:
ABSTRACT.- Botelho A.F.M., Oliveira M.S., Soto-Blanco B. & Melo M.M. 2016. Computerized electrocardiography in healthy conscious guinea pigs (Cavia porcellus). Pesquisa Veterinária Brasileira 36(12):1203-1208. Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Presidente Antônio Carlos 6627, Belo Horizonte, MG 31275-013, Brazil. E-mail: anaflaviamabo@gmail.com
The purpose of this study is to evaluate healthy conscious guinea pigs as a model for electrophysiology assessment and to describe normal electrocardiographic patterns in controlled laboratory environment, establishing the best QT formula for this method. Electrocardiographic recordings of fifty adult conscious guinea pigs were obtained using a computerized electrocardiography. The electrocardiographic measurements of three different tracings were analyzed. The results obtained established normal mean and range values for the parameters: heart rate, waves and intervals of P-QRS-T deflections, as well as the mean cardiac axis. Groups were separated by body weight: group 1 gathered animals with 500-699g and group 2 with animals 700-900g. No differences were found when measurements were compared between groups, showing no significant difference between weight/body sizes to the electrocardiographic parameters (P<0.05). The mean corrected QT values (QTc) obtained using diverse formulae were significantly different (P<0.05), were the most consistent was Van der Water (QTcV). QTcV values were strongly correlated (r=98) and 95% confidence interval 185.7 to 195.2ms.Considering its simplicity and reliability, the QTcV was deemed the most appropriate to be used for the correction of QT interval in conscious guinea pigs.The results of this study also suggest that the values found can be used as reference for the species.
Abstract in Portuguese:
RESUMO.- Botelho A.F.M., Oliveira M.S., Soto-Blanco B. & Melo M.M. 2016. Computerized electrocardiography in healthy conscious guinea pigs (Cavia porcellus). [Eletrocardiografia computadorizada em cobaios (Cavia porcellus) saudáveis e conscientes.] Pesquisa Veterinária Brasileira 36(12):1203-1208. Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Presidente Antônio Carlos 6627, Belo Horizonte, MG 31275-013, Brazil. E-mail: anaflaviamabo@gmail.com
O objetivo desse estudo foi avaliar cobaios hígidos e conscientes como modelos para estudos de eletrofisiologia e descrever os padrões eletrocardiográficos normais em ambiente laboratorial controlado, estabelecendo a melhor fórmula QT para esse método. Gravações eletrocardiográficas de cinquenta cobaios adultos conscientes foram obtidas usando eletrocardiografia computadorizada. As medidas eletrocardiográficas de três trechos diferentes foram analisadas. Os resultados estabeleceram média e desvio padrão para os parâmetros: frequência cardíaca, ondas e intervalos P-QRS-T, assim como o eixo cardíaco médio. Grupos foram separados de acordo com o peso: grupo 1 incluiu animais com 500-699g e o grupo 2 animais de 700-900g. Nenhuma diferença foi encontrada quando as medidas foram comparadas entre os grupos, mostrando que não há diferença significativa entre peso/tamanho corporal com os parâmetros eletrocardiográficos (p<0.05). As médias corrigidas dos valores do QT (QTc) obtidas usando diferentes fórmulas foram significativamente diferentes (p<0.05), sendo a mais consistente a de Van der Water (QTcV). Valores de QTcV fortemente correlacionam com o QT (r=98), com intervalo de confiança a 95% de 185.7 a 195.2 ms. Considerando a simplicidade e confiabilidade, o QTcV foi considerado apropriado para correção do intervalo QT em cobaios conscientes. Os resultados do presente estudo também sugerem que os valores encontrados possam ser utilizados como referência para essa espécie.