Ramos colaterais viscerais da aorta abdominal em coelhos da raça Nova Zelândia (Oryctolagus cuniculus)

Abstract

Background: Rabbits (Oryctolagus cuniculus) are lagomorphs belonging to the Leporidae family. They are widely used in laboratory experiments and are an important source for humans feeding industry. In the biomedical investigation fi eld, the rabbit contributes for the production of several scientifi c studies. Since studies about the rabbit’s morphology is rare, especially what refers to abdominal vascularization, this work had the objective to systematize and describe the visceral collateral branches of the abdominal aorta in New Zealand rabbits. Materials, Methods & Results: Fourteen male and sixteen female New Zealand young adult rabbits (Oryctolagus cuniculus) were used. Animals were euthanized with T 61, administered via an intrapulmonary injection. Skin was removed, thoracic cavity opened in plastron, thoracic aorta cannulated, according to blood fl ow, and the two cranial and caudal cava veins sectioned near the heart. System was washed with saline solution and heparin and fi lled with red latex. Animals remained immersed in running water, for 90 min, and the trunk was transversally sectioned, near the last thoracic vertebra. The abdominal cavity remained closed and formaldehyde was administered via an intraperitoneal injection. Samples were fi xed in formaldehyde for seven days, the abdominal cavity opened, the viscera removed in block and the arteries dissected. Schematic drawings of every preparation were made-up and the visceral branches of the abdominal aorta systematized. Statistical analysis of the results was performed using percentage values. The celiac artery was the fi rst direct visceral collateral branch, followed by the cranial mesenteric artery, and they were given off from the ventral surface of the abdominal aorta. The renal arteries were originated from the lateral side of the abdominal aorta, and the right vessel was originated more cranial than the left. Near the entrance of the pelvic cavity, the abdominal aorta emitted from its ventral surface the caudal mesenteric artery, and near this latter, the aorta abdominal originated the right and left gonadal arteries. The adrenal arteries were found as being indirect visceral collateral branches, which in most of the cases originated from the caudal phrenic artery. It was also observed that the right and left umbilical arteries were indirect visceral collateral branches, but from the internal iliac artery on its respective antimere. Discussion: In nutria, the celiac and the cranial mesenteric arteries were the fi rst and second direct visceral collaterals branches, respectively, and they were given off from the ventral surface of the abdominal aorta, as observed in rabbits. In moco, the cranial mesenteric artery could be given off in a common trunk with the caudal mesenteric artery, which was not observd in rabbit. As opposed to nutria, in which the renal artery was double in 3,3% of the animals, on the rigth and left antimeres, in the rabbit was observed its absence in one sample, to the left, due to left kidney agenesis. The gonadal artery, in chinchilla, was branch of the correspondent renal artery and in nutria, was a branch of umbilical artery. It was noticed in this study that the gonadal artery in rabbit was originated directly from the abdominal aorta. The caudal mesenteric artery, in nutria, was usually emitted from the aorta abdominal ventral surface, near its bifurcation, and could be absent, while in rabbit it was double in 3,3% of the animals.