控制性降压的时间对大鼠神经功能和脑水含量的影响

Effects of hypotension duration on neural function and brain water content in rats

目的探讨SD大鼠在安全阈值低血压下暴露不同时间的安全范围。方法将30只实验大鼠随机平均分为5组:不进行控制性降压(A组);控制性降压的目标血压为平均动脉压50 mm Hg,降压的药物选用艾司洛尔(ESM)和硝普钠(SNP),分成B1、B2、B3、B4组(B组),降压持续时间相应为0.5、1、2、4 h。记录大鼠的血气分析、生命体征,降压结束24 h后大鼠的生存率,神经行为功能,脑海马组织HE染色,脑组织的含水量(BWC)。结果 A组和B组的24 h生存率均为100%。B4组与A组的神经行为功能比较差异有统计学意义(P<0.05),B3和B4组与A组的脑组织含水量比较差异有统计学意义(P<0.05),海马组织HE染色,B3组见细胞核固缩,B4组可见较多空泡细胞,细胞间隙扩大,组织结构存在。结论艾司洛尔联合硝普钠将平均动脉压降至50 mm Hg,持续低血压2 h有脑损伤表现,持续低血压4 h出现明显脑损伤临床症状。把控制性安全阈值低血压持续时间限制在2 h内比较合理。

Objective To study the safety duration of hypotension in rats. Methods Thirty rats were randomly divided into 5 groups.Group Awas control group without controlled hypotension, group B1, B2,B3 and B4 were controlled hypotension at MAP 50 mmHg andmaintaining for 0. 5, 1, 2 and 4 h respectively. Controlled hypotension was induced with sodiumnitroprusside and esmolol. The vital signs and arterial blood gas analysis were recorded. The nerve behavior function, survival rate, brain tissue wapathology were studied 24 h after hypotension. Results The 24 h survival rates in all groups were 10neurobehavioral function in group B4 changed significantly （ R 〈0.05 ）, the brain water content in group B3 and B4 increased significantly（R 〈0. 05） . In hippocampus HE staining, there was nuclear pyknosis in group B3 and more vacuolated cells and cell gap expanding in group B4. Conclusion The rats with controlled hypotension at MAP 50 mmHg for 2 h developed signs of brain injury. The safety dura-tion of hypotension should be limited to 2 h in rats.