Analysis of the characteristic changes in cerebral infarction and cerebral edema induced by middle cerebral artery occlusion in rats / 中华急诊医学杂志

ABSTRACT

Objective To investigate the characteristic changes in cerebral infarction and brain edema. Method A total of 122 Healthy adult male Spraque-Dawley rats were randomly (random number) divided into three groups normal group ( n = 12), sham operated group (n=12) and cerebral ischemia group ( n = 98). Cerebral infarction and brain edema were induced by a permanent occlusion of right middle cerebral artery (POM-CA) with ligature. According to the duration of POMCA, the rats of cerebral ischemia group were further divided into seven sub-groups, 2 h, 4 h, 6 h, 12 h, 18 h, 24 h and 30 hours. The hemispheric ratio was detected by staining with 2% 2,3,5-triphenyltetrazolium chloride solution, and brain water content was assayed by dry/wet ratio 2 h, 4 h, 6 h, 12 h, 18 h, 24 h and hours after POMCA. Results There was a focal cerebral infarction in the rats of cerebral ischemia group 4 hours after POMCA. There was no significant difference in hemispheric ratio between 4 hours and 6 hours after POMCA by One-way ANOVA (P = 0.091). Compared with 6 h sub-group, the hemispheric ratio increased significantly in 12 h, 18 h, 24 h and 30 h sub-groups (P < 0.01), and the peak was in the 24 h sub-group. The brain water content began to increase 4 hours after POMCA and aggravated 6 hours later, and reached the peak 24 hours after POMCA. The brain water content of the non-ischemic hemisphere increased 18 h,24 h and 30 hours after POMCA. Furthermore, there was a significant correlation between the hemispheric ratio and brain water content ( r = 0.834, P < 0.01). Conclusions The critical point of cerebral infarction and brain edema aggravated is 6 hours after POMCA. Both brain edema and cerebral infarction reach the most serious degree 24 hours after POMCA. It is an important experimental evidence for evaluating the milieu conducive to the pathogenesis, and choosing the suitable time window for the treatment of cerebral infarction and brain edema.