大鼠原发性脑损伤伴低血压对脑子肿形成时相的影响

目的探讨脑外伤和伴发低血压的脑外伤对于大鼠脑水肿形成时间和程度的影响。方法利用组织比重法测定创伤后大鼠顶叶皮层和纹状体含水量的变化。通过联合使用氯醛糖和潘龙诱发脑外伤后低血压。结果改良的加速性脑创伤模型大鼠病死率为48．6%,而颅骨骨折的发生率为6．4%。创伤后8 h和24 h存活大鼠,其脑组织含水量与对照组比较无明显差别；但创伤后24 h较8 h大鼠,其顶叶皮层含水量[(79．1±0．5)%vs．(78．6±0．5)%,P＜0．05]增加0．5%。然而,创伤后合并低血压大鼠,创伤后8 h就已出现明显的脑水肿。与创伤后8 h存活大鼠相比,其顶叶皮层含水量[(81．5±0．9)%vs．(78．6±0．5)%,P＜0．01]和纹状体含水量[(78．5±0．9)%vs．(75．5±0．9)%,P＜0．01]均明显增加,即,创伤后合并低血压使大鼠脑组织含水量增加了2．9%。结论无低血压的颅脑外伤大鼠,其脑水肿形成晚且程度轻；而合并有低血压的脑外伤大鼠,其脑水肿出现早且严重。

Effects of primary cerebral injury with hypotension on the development and severity of brain edema in rats

Objective To study the effects of traumatic brain injury with or without hypotension on the development and severity of brain edema using the impact- acceleration model.Methods Brain tissue water content (BWC) was measured by the gravimetric technique in the cortex and striatum following traumatic brain injury (TBI) . The hypotension was induced by the combination of α - chloralose and pavulon after TBI.Results The mortality of this improved model of TBI was 48.6 %, but the rate of skull fracture was 6.4 %. Within the first 24 hours after TBI, the BWC of cortex and striatum in the survival rats showed a slight decrease at first, and then an increase. There appeared no difference in BWC between the two groups of TBI and the control. Nevertheless, the BWC in the area of parietal cortex at 24 hours after impact injury slightly increased by 0.5 % in comparison with that at 8 hours after impact [ (79.1 ± 0.5) % vs. (78.6 ± 0.5) %, P ＜ 0.05]. Meanwhile,the BWC of striatum didn't show the difference. However, while TBI was associated with hypotension, the BWC of both parietal cortex [ (81.5±0.9)% vs. (78.6±0.5)%, P＜0.001] and striatum [ (78.5±0.9)% vs. (75.5±0.9)%, P＜0.001) were significantly increased, by comparison with survival rats at 8 hours after impact. Moreover, the amplitude of increase in BWC achieved about 2.9 %.Conclusion The rats, suffering TBI without hypotension, presented the slight brain edema at the relatively late stage; by contrast, the rats,suffering from TBI with hypotension, had severe brain edema at the early stage.