低氧预适应对小鼠急性脑缺血性损伤保护作用的研究

目的 探讨低氧预适应对小鼠急性脑梗死致脑缺血性损伤的保护作用.方法 将Blb/c近交系小鼠按照随机数字表法分为正常对照组(N组),不做任何处理;假手术组(C组),仅行冷光源照射,不注射玫瑰红;急性脑梗死组(CI组),光化学法诱导制作小鼠脑皮层梗死模型;低氧预适应+急性脑梗死组(HP+CI组),低氧预适应后光化学法诱导制作小鼠脑皮层梗死模型.利用行为学、免疫荧光和激光共聚焦等实验方法.分别行神经功能评定、脑梗死体积测定、细胞凋亡检测.结果 (1)脑梗死体积比较:N组、C组未发现梗死灶,CI和HP+CI组均见明显缺血梗死灶,其中HP+CI组脑梗死体积较CI组明显减小,差异有统计学意义(P<0.05);(2)神经功能评分比较:N组、C组无神经功能缺损症状,CI组和HP+CI组出现明显神经功能缺损症状,神经功能评分明显降低,其中HP+CI组神经功能评分比CI组明显增加,差异有统计学意义(P<0.05);(3)细胞凋亡比较:N组、C组小鼠大脑皮层偶见TUNEL阳性细胞,CI组和HP+CI组TUNEL阳性细胞数明显增多,其中HP+CI组TUNEL阴性细胞数较CI组减少,差异有统计学意义(P<0.05).结论 低氧预适应可能通过减小小鼠急性脑梗死体积、减少细胞凋亡两个方面发挥脑缺血性损伤的保护作用.

Protective effect of hypoxic preconditioning against cerebral ischemic injury induced by acute cerebral infarction in mice

Objective To observe the protective effect of hypoxic preconditioning against cerebral ischemic injury induced by acute cerebral infarction in mice. Methods Blb/c mice were randomized into normal control, sham-operated, acute cerebral infarction (CI), and hypoxic preconditioning with CI (HP+CI) groups. In the latter two groups, acute cerebral cortical infarction was induced photochemically by cold light exposure of the brain tissue following intravenous Rose Bengal injection. The mice in the sham-operated group received only cold light exposure without Rose Bengal injection. Behavioral test, immunofluorescence assay and confocal laser scanning microscopy were performed to evaluate the neurological deficits of the mice and assess the cell apoptosis, and the cerebral infarction volume was measured. Results No infarct was found in the normal control and sham-operated groups, whereas obvious isehemic infarction foci were found in CI and HP+CI groups, but the infarction volume was significantly smaller in HP+CI group (P<0.05). The mice in the normal control and sham-operated groups presented with no neurological impairment, but in CI and HP+CI groups, obvious symptoms of neurological impairment were observed with lowered neurological scores. The neurological scores were significantly higher in HP+CI group than in CI group (P<0.05). Occasional apoptotic cells were found in the normal control and sham-operated groups, while in the other two groups, the TUNEL-positive cell number increased significantly. The apoptotic cell number was significantly smaller in HP+CI group than in CI group (P<0.05). Conclusion Hypoxic preconditioning may protect against cerebral ischemic injury induced by acute cerebral infarction in mice possibly by reducing the cerebral infarction volume and cell apoptosis.