The results suggested that chinchilla corneal endothelium undergoes age-related changes. Moreover, with advancing age, the mean cell area increased and cell density decreased.

Ramos colaterais do arco aórtico e suas principais ramificações em nutria (Myocastor coypus)Collaterals branches of the aortic arch and its main rami in nutria (Myocastor coypus) ABSTRACT Background: Nutria (Myocastor coypus), also known as Swamp Beaver, is a medium-sized semiaquatic rodent that belongs to the Capromyidae family. Originally from the southernmost part of South America, the species is distributed in several parts worldwide such as Europe and United States, where it has been used for commercial purposes due to the excellent quality of its fur and meat. Information about the nutria morphology is rare. Only a few articles about its abdominal aorta branches can be found, but nothing exists regarding its aortic arch. Consequently, other rodents such as chinchillas, agoutis, guinea pigs capybaras, pacas and rats will be used in the discussion. Therefore, this study aims to obtain morphological information that could justify such discussions in a functional point of view, and that could result in support for a better understanding of the physiology of this animal. Materials, Methods & Results:Thirty-two Myocastor coypus were used in the study, originated from a breeding facility in the town of Caxias do Sul, RS and authorized by IBAMA. The animals were put to sleep by means of an anesthetic overdose administrated intraperitoneally, and kept in formaldehyde for seven days to be subsequently dissected. After having their arterial system flushed with saline solution, the aorta of thirty specimens received an injection containing latex 603 through the left ventricle, for later observation of the arteries of the cranial mediastinal space and neck. Dental resin was injected in two specimens, for subsequent manufacture of molds by means of maceration. Schematic drawings of all parts were made with the help of a magnifying glass, for posterior composition of results. The brachiocephalic trunk and the subclavian artery arose in sequence from the aortic arch of the nutria in 60% of the samples, whereas the brachiocephalic trunk, left common carotid artery and left subclavian artery arose from the arch in 40% of the samples. The branching sequence of the collateral branches of the subclavian arteries showed a great variation, presenting isolated vessels and forming trunks among the arteries identified (according to the tables). The thoracic vertebral, vertebral, internal thoracic, dorsal scapular arteries and the superficial-deep cervical trunk aroused medially from the right subclavian artery towards a lateral direction, as main collateral branches of highest prevalence. On the other hand, the left subclavian artery also gave off the vertebral artery as its first vessel, followed by the internal thoracic and thoracic vertebral arteries, and its last collateral branch was a common trunk between the dorsal scapular artery and the superficial-deep cervical trunk. Discussion: Other rodents in the study presented the same aortic arch sequence as observed in nutrias i.e., the brachiocephalic trunk and the left subclavian...

RESUMOA capivara é um mamífero roedor, de origem sul-americana, herbívoro, semi-aquático, da família Hydrochoeridae. No presente trabalho foram utilizados sete espécimes de capivara (Hydrochoerus hydrochaeris), todas fêmeas. Após o preenchimento do sistema arterial com látex 603 corado em vermelho, procedeu-se à dissecção das peças com o objetivo de observar a disposição dos ramos colaterais do arco aórtico determinando o padrão e as variações ocorridas nessa espécie. Em todos os espécimes originou-se do arco aórtico apenas um tronco braquiocefálico, o qual distribuiu-se da seguinte forma: em quatro peças (57,1%) originaram-se do tronco braquiocefálico primeiramente a artéria subclávia esquerda, após a artéria carótida comum esquerda e em seguida o tronco braquiocarotídeo, o qual emitiu as artérias carótida comum direita e subclávia direita. Em duas preparações (28,6%) o tronco braquiocefálico originou a artéria subclávia esquerda e após trifurcou-se originando as artérias subclávia direita, carótida comum direita e carótida comum esquerda. Em uma observação (14,3%) originaram-se do tronco braquiocefálico primeiramente a artéria subclávia esquerda, logo após a artéria subclávia direita e em seguida um tronco bicarotídeo, que emitiu as artérias carótidas comuns direita e esquerda. O arco aórtico da capivara emitiu, como único ramo colateral, o tronco braquiocefálico. ABSTRACTCapybara is a rodent mammal, from South America, herbivorous, semiaquatic, of Hydrochoeridae family. In this research 7 specimens of capybara (Hydrochoerus hydrochaeris), were used, all of them were females. After performing the injections with neoprene-látex stained with specif pigment, the animals were dissected. Only the brachiocephalic trunk originating from de aortic arch in all cases. The brachiocephalic trunk was first originate the left subclavian artery after the left common carotid artery and afterwards emerged the brachiocarotid trunk originating the right common carotid artery and the right subclavian artery in 4 cases (57,1%). In 2 cases (28,6%) the brachiocephalic trunk originating the left subclavian artery and after divided into three branches, the right subclavian artery, the left and right common carotid arteries. In one case (14,3%) were first originated from the brachiocephalic trunk the left and the right subclavian artery and after the bicarotid trunk that originated the left and right carotid arteries. The aortic arch in capybara emited, as the only one collateral branch, the brachiocephalic trunk.

Background: This member of the Didelphidea family, commonly known as opossum, is widely distributed in the American territory, with species found from southern Canada up to northern Argentina. Similarly to all marsupials, they are characterized by a short gestational period, followed by a long development period. Opossums are arboreal, terrestrial slow animals of lonely and nocturnal habits. They are omnivore animals, eating from small rodents, birds, eggs and amphibians to fruits and vegetables. These general characteristics have drawn in the interest and curiosity of the scientific community to this animal, which is now the object of study in several knowledge areas. In order to find morphological information that could assist in discussions from a functional point of view and that could offer support for measures that aim at protecting opossums in their natural environment, the objective of the present study is to divulge the anatomical behavior of their celiac artery and its branches, including its distribution areas, considering the importance of these vessels in the blood supply of several digestive organs. Materials, Methods & Results:In this study, the celiac artery of 24 opossums (Didelphis albiventris), of which 17 were females and 7 were males, was systematized. For the purpose, their arterial system was filled with colored latex 603. The abdominal aorta gave off its first visceral collateral branch, the celiac-mesenteric trunk, which originated the celiac artery and the cranial mesenteric artery in 87.5% of the samples, but in 12.5% of the samples, the abdominal aorta gave off these arteries individually. The celiac artery gave off the lienal and hepatic arteries. The lienal artery gave off the left gastric artery to the lesser curvature of the stomach, supplying its parietal and visceral side, also giving off esophageal branches. The lienal artery reached the splenic hilum, giving off several pancreatic branches during its path. Once it reached the splenic hilum, it gave off its own lienal branches and then continued as left gastroepiploic artery towards the greater stomach curvature. The hepatic artery was projected cranially, giving off the gastroduodenal artery and cranial pancreaticoduodenal artery reaching the portal fissure, where hepatic branches arose towards the liver. The gastroduodenal artery gave off the right gastroepiploic artery towards the greater curvature of the stomach, also giving off the right gastric artery towards the lesser curvature of the stomach and then became divided into one branch to the visceral side and one branch to the parietal side, also giving off esophageal and pyloric branches. The cranial pancreaticoduodenal artery branched to the cranial duodenum and right lobe of the pancreas. Discussion: In the majority of opossums (87.5%), the celiac artery had origin in a common trunk with the cranial mesenteric artery, but in 12.5% of the animals, this origin took place separately. In opossums (Didelphis albiventris), regardless of its origin, the celiac artery was a sing...

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