氯沙坦对小鼠前脑缺血再灌后期脑损伤的保护作用研究

发布时间：2018-04-21 21:33

本文选题：小鼠 + 前脑缺血　；参考：《山西医科大学》2014年硕士论文

【摘要】：目的：脑缺血是脑卒中的一种主要类型，严重危害病人的健康，至今并无良好的治疗手段。降压药AT1受体阻断剂可以通过控制高血压这一脑卒中的高危因素，而减少脑卒中的发生。研究还发现脑缺血后脑内血管紧张素系统发生了变化，而且改变脑内血管紧张素系统成分也相应对脑缺血的损伤产生作用。众多动物实验证实了AT1受体阻断剂对脑缺血再灌的保护作用，并探讨了其在神经元凋亡、氧化应激反应、炎症反应等方面的可能机制，但研究局限于再灌前期。本实验为进一步探讨AT1受体阻断剂氯沙坦对小鼠前脑缺血再灌后期有无保护作用。由于星形胶质细胞在脑缺血再灌后期对神经再生和功能恢复有抑制作用，，相关研究也提示AT1受体对星形胶质细胞有抑制作用。故本实验将对这一作用进行研究。方法：将正常小鼠随机分为多个组，选择0.5mg/kg、1mg/kg和5mg/kg三个剂量的氯沙坦钾经腹腔注射给药，对照组给予生理盐水。通过阻断双侧颈总动脉60min建立前脑缺血模型。给药的第15d，给予脑缺血或假手术处理，手术后仍给药；比较再灌后各组的体重和运动功能的变化；再灌16d时对各组存活小鼠进行水迷宫学习记忆实验；再灌21d时，对各组小鼠灌流取脑、冰冻切片、甲苯胺蓝染色、免疫荧光染色，观察纹状体、海马CA1区神经元损伤情况及海马CA1区星形胶质细胞的改变。结果：再灌1d后前脑缺血组小鼠体重即出现下降，给予1mg/kg氯沙坦在再灌3、7、14及21d后显著提高小鼠的体重恢复程度。但0.5mg/kg和5mg/kg两个剂量无明显改善。假手术组小鼠给药前后体重增加的程度无显著差异。再灌3d及21d后，前脑缺血组小鼠在旋转棒上停留的时间显著低于对照组，给予1mg/kg氯沙坦显著提高小鼠在旋转棒上停留的时间。0.5mg/kg和5mg/kg两个剂量并无明显改善。假手术组小鼠给药前后在旋转棒上停留的时间增加，但组间增加的程度无显著差异。再灌16d进行水迷宫实验。训练第3d和第4d时，前脑缺血组小鼠相比于对照组找到平台的潜伏期显著延长，给予1mg/kg氯沙坦显著缩短小鼠找到平台的潜伏期，而给予5mg/kg氯沙坦仅在训练第4d显著缩短小鼠找到平台的潜伏期。0.5mg/kg剂量无明显改善。给予1mg/kg氯沙坦的假手术组小鼠在训练阶段找到平台的潜伏期与对照组无显著差异。再灌21d后，前脑缺血组小鼠相比于对照组在纹状体和海马CA1区可见明显损伤。前脑缺血组小鼠相比于对照组，纹状体和海马CA1区神经元密度都有显著下降，给予1mg/kg氯沙坦显著逆转了纹状体和海马CA1区神经元的损伤，而0.5mg/kg则仅显著逆转海马CA1区神经元的损伤。Bccao+Los(5mg/kg)组对神经元密度没有显著改善作用。另外，再灌21d后，前脑缺血组相比于对照组，显著增加海马CA1区GFAP的表达和GFAP阳性细胞密度，给予1mg/kg氯沙坦显著抑制了这一增加。结论：氯沙坦能够促进小鼠前脑缺血再灌后体重与运动功能的恢复，并改善再灌后期空间学习记忆能力的降低和神经元的缺失。氯沙坦对再灌后期星形胶质细胞激活和增殖的显著抑制，可能是其在再灌后期发挥神经保护作用的靶点之一。
[Abstract]:Purpose :

Cerebral ischemia is one of the main types of cerebral apoplexy , which is a serious harm to the health of patients . It has not been used to treat cerebral ischemia .

Method :

Normal mice were randomly divided into a plurality of groups , 0.5 mg / kg , 1 mg / kg and 5 mg / kg of losartan potassium were injected intraperitoneally to the control group .
comparing the weight of each group and the change of exercise function after re - irrigation ;
water maze learning and memory experiment was carried out on the survival mice of each group at the time of reperfusion ;
Twenty - two days later , the brain , frozen section , methylene blue staining and immunofluorescence staining were performed on each group of mice to observe the damage of neurons in the striatum and hippocampus CA1 region and the changes of astrocytes in CA1 region of hippocampus .

Results :

After reperfusion , the weight of mice in the cerebral ischemia group decreased , and the weight recovery of mice was significantly improved after 3 , 7 , 14 and 21 days after reperfusion . However , the dosage of 0 . 5mg / kg and 5 mg / kg did not improve significantly .

After 3 d and 21 d reperfusion , the time of stay on the rotating rod was significantly lower than that of the control group , and the dose of 1 mg / kg losartan significantly increased the stay time of the mice on the rotating rod . The dose of 0.5 mg / kg and 5 mg / kg did not improve significantly . The time of stay on the rotating rod was increased before and after the administration of the sham operation group , but there was no significant difference between the groups .

At the 3rd and 4th day of training , the latency of the platform was significantly shortened compared with the control group , and the latency of the platform was significantly shortened compared with the control group .

Compared with the control group , the density of neurons in the striatum and the CA1 region of the hippocampus decreased significantly compared with the control group , and 1 mg / kg losartan significantly reversed the damage of the neurons in the striatum and the CA1 region of the hippocampus , while 0.5 mg / kg only significantly reversed the damage of the neurons in the CA1 region of the hippocampus .

In addition , compared with the control group , the expression of GFAP and GFAP - positive cell density in the CA1 region of the hippocampus were significantly increased after 21 days of reperfusion , and the increase was significantly inhibited by the administration of 1 mg / kg losartan .

Conclusion :

losartan can promote the recovery of body weight and exercise function after cerebral ischemia reperfusion in mice , and improve the reduction of spatial learning and memory capacity at the later stage of reperfusion and the loss of neurons , and losartan can inhibit the activation and proliferation of astrocytes in the later stage of reperfusion , and may be one of the targets in which the nerve protection function is exerted in the later period of reperfusion .

【学位授予单位】：山西医科大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R743.3

【参考文献】