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

Objective. This study was performed to determine whether it would be possib le to shorten the elastase infusion time in the elastase-induced rat aneury sm 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. O n 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-infus ed aortas and the 10- or 20-min elastase-infused aortas. The diameter of th e 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 12 0-min elastase-infused aortas. Microscopically, there was total or subtotal loss of elastic tissue and marked inflammatory cell infiltration of the ao rtic 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 in fusion time reduces the experimental time and mortality rate. (C) 1999 Acad emic Press.