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目的探讨低氧预适应对缺氧缺血性脑损伤(HIBD)大鼠脑保护作用及相关机制。方法选用生后7dSD大鼠48只,随机分为对照组(6只)、假手术组(6只)、HIBD组(18只)和HIBD+低氧预适应(HPC)组(18只)。用湿化的氧浓度为8%的氮氧混合气体以0.3L/min的流量灌入建立HPC模型。用免疫荧光和激光共聚焦显微镜技术,分别行大脑皮层和海马神经细胞凋亡、Bcl-2和Caspase-3表达强度的检测。结果HIBD、HIBD+HPC组TUNEL染色阳性细胞较假手术组明显增多(P<0.05);HIBD+HPC组较HIBD组明显减少(P<0.05)。对照组和假手术组大脑皮层、海马可见极少量Bcl-2和Caspase-3表达,两组比较差异无统计学意义(P>0.05);HIBD、HIBD+HPC组Bcl-2和Caspase-3表达明显高于假手术组,HIBD+HPC组Bcl-2表达高于HIBD组,Caspase-3表达低于HIBD组(P均<0.05)。结论低氧预适应过程中,HIBD大鼠大脑皮层和海马区通过Bcl-2的高表达和Caspase-3的低表达,抵御神经细胞凋亡,参与脑保护机制。
Objective To investigate the protective effects of hypoxic preconditioning on hypoxic-ischemic brain damage (HIBD) in rats and its related mechanisms. Methods Forty-eight SD rats were randomly divided into control group (n = 6), sham operation group (n = 6), HIBD group (n = 18) and HIBD + hypoxic preconditioning group (n = 18). The HPC model was filled with a nitric oxide gas mixture humidified at an oxygen concentration of 8% at a flow rate of 0.3 L / min. Immunofluorescence and confocal laser scanning microscopy were used to detect the apoptosis of cerebral cortex and hippocampal neurons, and to detect the expression of Bcl-2 and Caspase-3. Results The number of TUNEL-positive cells in HIBD and HIBD + HPC groups was significantly higher than that in sham operation group (P <0.05). HIBD + HPC group was significantly lower than HIBD group (P <0.05). The expression of Bcl-2 and Caspase-3 in the cerebral cortex and hippocampus of the control group and the sham operation group was very low (P> 0.05). The expressions of Bcl-2 and Caspase-3 in HIBD and HIBD + The expression of Bcl-2 in HIBD + HPC group was significantly higher than that in HIBD group and Caspase-3 expression was lower than that in HIBD group (all P <0.05). Conclusions During hypoxic preconditioning, the high expression of Bcl-2 and the low expression of Caspase-3 in the cerebral cortex and hippocampus of HIBD rats can resist neuronal apoptosis and participate in the mechanism of cerebral protection.