氯化锂预处理对沙土鼠前脑缺血保护作用的病理观察

A Pathological Survey of the Neuroprotective Effect of Preconditioning with Lithium on the Gerbil Forebrain Ischemia

目的:观察氯化锂预处理对沙土鼠脑缺血-再灌注模型的神经元保护作用。方法:夹闭沙土鼠双侧颈总动脉5 min,制备前脑缺血性脑损伤模型。48只沙土鼠随机分为2组:实验组(A组,n=24)和对照组(B组。n=24),A组手术前连续5天给予氯化锂腹腔注射,B组以生理盐水代替氯化锂。每组又分为两个亚组:假手术组(Ash,Bah,n均为12)和缺血组(Ais,Bis,n均为12),分别于术后3天(Ash3,Ais3,Bsh3,Bis3,n均为6)和7天(Ash7,Ais7,Bah7,Bis7,n均为6)断头取脑,制成石蜡切片,光镜下观察。结果:海马CA1区锥体细胞数目(每0.04 mm2中含有的细胞数)分别为:Ais3组15.8±3.31、Ais7组13.54±5.22、Bis3组11.81±4.58、Bis7组1.48±1.55、Ash3组28.17±4.02、Ash7组28.11±4.14、Bah3组29.64±5.99、Bsh7组30.21±2.95。Ais3组、Ais7组显著多于相应的Bis3组、Bis7组(P<0.01)。Ais3组、Bis3组显著多于相应的Ais7组、Bis7组(P<0.01)。结论:氯化锂预处理能明显减少沙土鼠脑缺血再灌注后海马CA1区延迟性神经元死亡。

Objective:To investigate the neuroprotective effect of lithium on the gerbil forebrain ischemia. Methods: The gerbil forebrain transient ischemia model was established by clamping the bilateral common carotid arteries for 5 min. Forty-eight gerbils were randomly divided into group A (n = 24) and group B (n=24). Gerbils in group A were injected intraperitoneally with lithium, 5' mmol/kg, once a day for 5 days. Saline was used instead of lithium in group B as control. Both group A and B were further divided into 4 subgroups respectively according to whether the animals underwent ischemia and when they were killed. The subgroups in group A were: Ais3, undergoing ischemia and killed 3 days after operation; Ash3, sham-operated and killed 3 days after operation; Ais7, undergoing ischemia and killed 7 days after operation; Ash7, sham-operated and killed 7 days after operation. Similarly, the subgroups in groupB were: Bis3, Bsh3, Bis7, Bsh7; n = 6 in each subgroup. All the gerbils were perfusion-fixed and made into paraffin sections. Neurons in the hippocampal CA1 subfield were counted under light microscopy blindly. Results:The numbers of the pyramidal cells(cells/0. 04mm2) in the CA1 sudfield were: 15.8±3.31 in Ais3, 13.54±5.22 in Ais7, 11.81 ±4.58 in Bis3, 1.48± 1.55 in Bis7, 28. 17±4. 02 in Ash3, 28. 11±4. 14 in Ash7, 29. 64±5. 99 in Bsh3, 30.21 ±2.95 in Bsh7. The living neuron density in the CA1 area of subgroup Ais3 was significantly higher than that of subgroup Bis3 (P < 0. 01) . Similarly the living neuron density of subgroup Ais7 was significantly higher than that of Bis7 (P < 0. 01). Conclusion: Preconditioning with lithium can protect the gerbil forebrain from the delayed neuron death induced by ischemia.