Effect of insulin on acute experimental cerebral ischemia in Gerbils

Abstract

We studied the effects of insulin with and without food deprivation on experimental cerebral ischemia in 197 gerbils. Ischemia was induced by unilateral common carotid artery occlusion for 4 hours. Gerbils were divided into four experimental groups and were studied for up to 1 week of survival: Group A (n=50) was fed but received no insulin, Group B (n=50) was deprived of food for 24 hours before surgery but received no insulin, Group C (n=49) was fed and received daily injections of 0.1 IU lente insulin for 3 days before surgery, and Group D (n=48) was deprived of food and received daily insulin injections. Insulin treatment was continued in Groups C and D after surgery. Blood glucose levels of all gerbils were determined before treatment (overall mean±SEM 88.0±12.4 mg/dl) and before carotid artery occlusion (Group A 92.2± 18.3 mg/dl, Group B 81.4±11.7 mg/dl [p<0.05 different from before treatment], Group C 92.8±22.3 mg/dl, and Group D 66.1 ±24.0 mg/dl [p<0.001 different from before treatment]). Among the four groups, 52 gerbils died within 1 week. Neurologic deficits were scored and histologic evidence of the infarcts was graded in survivors at 1 week. Group C gerbils had the best stroke index scores. Histologic evaluation revealed that 35.9% of Group A, 21.1% of Group B, 13.9% of Group C (p<0.05 compared with Group A), and 28.1% of Group D survivors developed cerebral infarcts. Our results indicate that Group C, with daily insulin injections but without hypoglycemia, had the most favorable outcome in this study, which suggests that insulin may be beneficial in ischemic stroke. © 1989 American Heart Association, Inc.