急性失血对老年自发性高血压大鼠术后认知功能的影响

Effect of acute hemorrhage on cognitive function of aged spontaneously hypertensive rats

目的研究围术期老年自发性高血压大鼠(SHR)血容量对术后认知功能的影响。方法 40只老年雄性SHR随机分为假失血组(A,n=13)、失血量20%组(B,n=13)和失血量40%组(C,n=14)。经股动静脉建立急性失血模型,补液量按失血量:乳酸钠林格液为1∶3的比例进行。采用Morris水迷宫测试大鼠的空间记忆及学习能力,之后断头取脑,观察大鼠海马区的病理变化。结果C组参考记忆中逃逸潜伏期较术前显著延长(P=0.002)。各组工作记忆无差别。与A组比较,B、C组海马CA1区免疫组化结果分析显示p-CREB的表达量无明显差别。C组CA1区部分椎体神经元体积缩小。结论不同程度急性失血对术后认知功能的影响是有差异的,急性失血至全身血容量的40%时可影响老年SHR的参考记忆,但不影响工作记忆和学习能力。

Objective To investigate the effect of acute blood loss on postoperative cognitive function of aged spontaneously hypertensive rats（SHRs）. Methods Forty aged male SHRs were randomized into sham hemorrhage group（group A, n=13）,20% hemorrhage group（group B, n=13） and 40% hemorrhage group（group C, n=14）. The rats were subjected to acute loss from the femoral artery and subsequent fluid replacement with lactated Ringer＇s Solution（3 folds of the blood loss volume）.All the rats underwent Morris water maze test to assess the visuospatial memory and learning ability, and were then decapitated to observe the pathological changes of the hippocampus. Results The latency of reference memory in group C was significantly prolonged after the operation（P=0.002）, but the working memory and learning capacity showed no significant differences between the 3 groups. Immunochemistry did not reveal significant differences in p- CREB expressions in the hippocampal CA1 region among the groups, but volume reduction of some neurons was noted in the CA1 region in group C.Conclusion Varying degrees of acute hemorrhage can result in different effect on postoperative cognition in aged SHR. Acute hemodilutional anemia to 40% of baseline can cause reference memory impairment with cell volume reduction of the neurons in the hippocampal CA1 region but does not affect the working memory and learning capacity or p-CREB expression.