Microscopy of the Umbilical Cord of Rock Cavies—Kerodon rupestris Wied, 1820 (Rodenta, Caviidae) MARCIO NOGUEIRA RODRIGUES, 1 * GLEIDSON BENEVIDES DE OLIVEIRA, 2 VAL  ERIA VERAS DE PAULA, 2 ALEXANDRE RODRIGUES SILVA, 2 ANTONIO CHAVES DE ASSIS NETO, 1 MARIA ANGELICA MIGLINO, 1 AND MOACIR FRANCO DE OLIVEIRA 2 1 Department of Surgery, Faculty of Veterinary Medicine and Animal Science (FMVZ-USP), S~ ao Paulo University (USP), Cidade Universit aria, Av. Prof. Dr. Orlando Marques de Paiva 87, S~ ao Paulo SP, 05508270, Brazil 2 Department of Animal Science, Federal Rural of Semi Arid University, Mossor o, Rio Grande do Norte-Brazil. Av. Francisco Mota, 572, costa e silva, 59625900, RN Mossor o, Brazil KEY WORDS umbilical cord; rock cavies; Kerodon; animal model; stem cells; morphology ABSTRACT The rock cavies (Kerodon rupestris) are rodents belonging to family Caviidae, with habitat restricted to northeastern Brazil. Current studies have shown that blood cord has stem and hematopoietic cells both with a high regenerative potential, microscopic studies about the description in rodents and other mammals are scarce. The aim of this study was to describe the structural components of the umbilical cord of rock cavies. Rock cavies embryos at different stages of pregnancy were used, three in the first third, five in middle third, and six in the final third of gestation. They were obtained at the Centre for Wild Animals Multiplication of Federal Rural University of Semi-Arid. In rock cavies was observed that the number of vessels involved in the transport of maternal substances was represented by two major arteries, veins and an allantois duct. The umbilical cord was delimited by amniotic epithelium, formed by a layer of squamous cells, connective tissue with characteristic of the mucosal tissue, corresponding to the Wharton jelly (fetal mesenchyme), where elastic fibers were observed and intercellular spaces were arranged in concentric blades. The morphology observed in rock cavies is similar to that described in the literature for other mammals, including man. The rock cavies are well adapted to captivity and are docile, which makes this animal an important model for study within the field of regenerative medicine. The knowledge of the umbilical cord morphology represents a base point for using this animal as a model for culture and cell therapy. Microsc. Res. Tech. 76:419–422, 2013. V C 2013 Wiley Periodicals, Inc. INTRODUCTION The rock cavies are mammals rodents belonging to family Caviidae with habitat restricted to northeast- ern Brazil. These are characterized by presenting the dorsal surface of the body with light gray color mixed with black and white and the posterior part of the limb with staining brown-ferriginosa (Moojen, 1962; Rood, 1979). Adults’ measure 410 mm and can reach 1 kg of body weight. They are gregarious with twilight habits, spending the day sheltering in rocks holes, leaving in the evening and at dawn to feed of trees branches, shrubs and small branches of some climbing plants’ species (Mendes, 1987). The umbilical cord has origin from the embryonic stem, which connects the bladders of the yolk sac and amniotic. It is shifted ventrally and is called abdominal stalk, having an important role in the transport of maternal nutrients to the developing fetus and the elimination of excreta from the fetus to the mother (Keeth et al., 2000). Current studies have shown that blood cord has stem cells, hematopoietic with regenerative potential of solid organ and stem cells. The mesenchymal cells derived from Wharton’s jelly from the stromal cells have great potential for use in engineering tissues and may contribute in the regeneration of cartilage, fat, bone, muscle, and stroma (Jiang et al., 2007). The umbilical cord is a structure discarded after the birth and the transplant of their cells may present less risks of causing immune reactions, resulting in mini- mum risk for the recipient of its cells (Bydlowsk et al., 2009). The use of stem cells from umbilical cord has created scientific expectations for its use in cell ther- apy and regeneration of organs affected by the so called incurable diseases (Zucconi et al., 2009). The rock cavies represent an excellent biological model since they are wild rodents well adapted to cap- tivity. Microscopic studies about the umbilical cord description of rodents and other mammals are not common. The aim of this study was to describe the structural components of the umbilical cord of rock cavies emphasizing its importance in the transport of substances between mother and fetus and as a poten- tial source of stem cells. *Correspondence to: Marcio Nogueira Rodrigues, Av. Prof. Melo Morais, 1235, Bl. C Apto 206. Zip Code: 05508030, Butanta, S~ ao Paulo, SP, Brazil. E-mail: marcio_medvet@hotmail.com Received 22 November 2012; accepted in revised form 7 January 2013 DOI 10.1002/jemt.22182 Published online 11 February 2013 in Wiley Online Library (wileyonlinelibrary.com). V V C 2013 WILEY PERIODICALS, INC. MICROSCOPY RESEARCH AND TECHNIQUE 76:419–422 (2013)