Shortened elastase infusion time in the elastase-induced rat aneurysm model

Objective. This study was performed to determine whether it would be possible to shorten the elastase infusion time in the elastase-induced rat aneurysm model, Methods, The abdominal aortas of 76 male Sprague-Dawley rats were dissected and infused for 10, 20, 30, 60, or 120 min with a solution containing 14 U of elastase or for 30 min with saline solution (control). After infusion, the rats were evaluated every day: for calculation of the mortality rate. On day 7, the surviving rats underwent laparotomy. The diameter of the aorta was measured, and the aortic tissue was excised for histologic examination. Results. There were no deaths among the rats infused for 10, 20, or 30 min. The mortality rate was 64% in the 60-min and 90% in 120-min groups. There were no significant differences in the diameters of the 30-min saline-infused aortas and the 10- or 20-min elastase-infused aortas. The diameter of the 30-min elastase-infused aortas (6.2 +/- 2.1 mm) was significantly larger (P < 0.01) than the diameters of the 10-and 20-min elastase;infused aortas. There were no significant differences between the 30-min and the 60-and 120-min elastase-infused aortas. Microscopically, there was total or subtotal loss of elastic tissue and marked inflammatory cell infiltration of the aortic wall in the 30-, 60-, and 120-min elastase-infused aortas. Conclusions. It is possible to shorten the elastase infusion time from 120 to 30 min in the elastase-induced rat aneurysm model. This shortening of infusion time reduces the experimental time and mortality rate. (C) 1999 Academic Press.