锂对沙土鼠脑缺血后热休克蛋白70表达的影响

目的：观察氯化锂预处理对沙土鼠脑缺血一再灌注损伤后海马和脑皮质区热休克蛋白70（HSP70）表达的影响。方法：夹闭沙土鼠双侧颈总动脉5min，制备全脑缺血性脑损伤模型。36只沙土鼠随机分为实验组和对照组。实验组手术前连续5天给予氯化锂5mmol／kg腹腔注射；对照组以等渗盐水代替氯化锂。分别于术后第1、3和7天将动物处死，取海马齿状回互包段制成石蜡切片，进行HSP70的免疫组化分析。结果：全脑缺血后1天，与对照组相比，实验组海马CA1区HSP70表达明显减少（P〈0．05）；相反，在脑皮质HSP70表达增加（P〈0．01）。结论：锂的神经保护作用机制涉及基因表达的改变。

The effects of preconditioning with lithium on the expressions of heat shock protein 70 in gerbil after global ischemia

Objective: To investigate the effects of preconditioning with lithium on the expressions of HSP70 in gerbil after global ischemia. Methods: The transient ischemia model of gerbil global was established by clamping the bilateral common carotid arteries for 5 min.36 gerbils were randomly divided into group lithium(n=18) and group control(n=18).Gerbils in group lithium were injected with lithium intraperitoneally,5 mmol/kg,once a day for 5 consecutive days.Normal saline was used instead of lithium in group control as vehicle control.Both group lithium and control underwent ischemia after preconditioning,and were then further divided into three subgroups(n=6,in each subgroup).The garbles in lithium 1 or control 1 subgroup were sacrificed 1 day after ischemi;lithium 3 or control 3 sacrificed in 3 days;and lithium 7 or control 7 were sacrificed in 7 days.The brains were made into paraffin sections and were used for immunohistochemistry against HSP70. Results: Compared with the vehicle control,the HSP70 expression in subgroup lithium1 was inhibited in the hippocampus CA1(P<0.05) while upregulated in the cortex(P<0.01). Conclusion: The mechanisms underlying the neuroprotective effects of lithium might involve with the regulation of HSP70 expression.