Factors influencing mortality in the rat elastase-induced-aneurysm model.
BACKGROUND
Intraarterial infusion of elastase has been used to create an experimental model of aortic aneurysm in rats. Unfortunately, the utility of this model is limited by a high mortality rate among experimental animals. This study examined the factors influencing mortality to help refine this model.


METHODS
A total of 126 Wistar rats were divided into six groups. A 1.0-cm segment of infra-renal abdominal aorta was clamped (n = 21), clamped and cannulated via the femoral artery (n = 21), infused with saline (n = 21), or infused with solution containing 25 U of elastase from three different lots (each group, n = 21). Clamping or infusion was performed for 30 (n = 7), 60 (n = 7), and 120 min (n = 7). The mortality rates were calculated at 7 days.


RESULTS
There were no deaths in the clamp group, but 29% of the rats that underwent cannulation with clamping or saline infusion for 2 h died. The mortality rate for a 30-min elastase infusion ranged from 0 to 71%. Mortality for a 60-min infusion ranged from 14 to 100%. Mortality for a 2-h infusion ranged from 43 to 100%. The mortality rate was dependent on the treatment time and the elastase lot number.


CONCLUSIONS
Aortic cannulation, elastase infusion, and prolonged infusion times all increase the mortality rate in the elastase-induced rat aortic aneurysm model. Mortality is also dependent on the elastase lot number.
Yamaguchi
T
T
First Department of Surgery, Toyama Medical and Pharmaceutical University, Toyama, Japan. surg1@ms.toyama-mpu.ac.jp
Yokokawa
M
M
Suzuki
M
M
Higashide
S
S
Katoh
Y
Y
Sugiyama
S
S
Misaki
T
T
D000818:Animals; D017544:Aortic Aneurysm, Abdominal / Q000139:chemically induced / Q000401:mortality / Q000473:pathology*; D003250:Constriction; D004195:Disease Models, Animal; D007261:Infusions, Intra-Arterial; D008297:Male; D010196:Pancreatic Elastase / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D010196:Pancreatic Elastase