缺氧/复氧后星形胶质细胞AQP5表达的变化及亚低温的干预效应

目的观察缺氧/复氧条件下大脑星形胶质细胞水通道蛋白5(AQP5)的表达变化以及亚低温对其表达的影响。方法利用新生24 h内的SD大鼠,进行原代、传代培养,将星形胶质细胞分为对照组、常温组及亚低温组。用台盼蓝染色法测定37℃及32℃时,缺氧/复氧不同时间点星形胶质细胞的存活率,作为细胞受损指标,用倒置相差显微镜对细胞进行形态学观察,应用细胞免疫化学技术检测星形胶质细胞缺氧/复氧各个时间点AQP5的表达变化及亚低温的干预效果。结果 (1)缺氧4、8 h细胞形态变化不明显,随着复氧时间的延长,可见活化逐渐明显,而亚低温干预的细胞形态及细胞存活力变化均较相应的常温组明显减轻;(2)缺氧及复氧早期AQP5的表达水平降低,复氧后6 h随着时间延长AQP5表达明显增多,在复氧≤8 h常温组及亚低温组的表达水平均低于对照组(P<0.05或0.01),而复氧后10、12 h AQP5蛋白表达水平均明显高于对照组(P<0.05或0.01);(3)在复氧后各时间点亚低温组AQP5的表达水平均明显低于常温组(P<0.05或0.01)。结论亚低温可以减轻缺氧/复氧后星形胶质细胞的损伤,通过降低AQP5的表达水平,可能是亚低温减轻缺血性脑水肿的作用机制之一。

Influence of the expression of aquaporin5 in astrocytes and the intervention effect of mild hypotherma under the condition of hypoxia/regoxygenation

Objective To observe the change of the expression of AQP5 in astrocytes and the influence of mild hypothermia under the condition of hypoxia/regoxygenation. Methods The primary and subculture cells from the cortex of SD fetal rat(less than 24 hours),were divided into three groups:control group,common temperature and mild hypotherma group.Trypan blue staining was used to detect the astocytes survival rate of all time points after hypoxia/reoxygenation in 37℃ and 32℃ as cellular damage index.Morphology observation of the cells was used as celluler damage index inverted phase contrast microscopy was used.Immunocytochemistry was used to examine the expression change of AQP5 in the astrocytes at every indicated time points after hypoxia/reoxygenation and intervention effect of mild hypothermia. Results(1)The cell morphology,survival rate weren’t impacted by hypoxia for 4 and 8 h.However,reoxygenation made a damage obviously.The longer time of reoxygenation,the greater damage to the shape and the survival rate of astrocytes was observed.There were lesser damage in mild hypotherma group at corresponding time points.(2)The expression of AQP5 showed a tendency to decrease at early phase but rised after reoxygenation for 6 h and showed a tendency to increase as time extension.The expression of AQP5 in common temperature and mild hypotherma group in less than or equal to 8h was significantly lower than that in the control group(P<0.05 or 0.01),and higher than that in the control group 10 h and 12 h after reoxygenation(P<0.05 or 0.01).(3)The expression degree of AQP5 in mild hypothermia group were significantly lower than that in common temperature group at all time points after reoxygenation(P<0.05 or 0.01). Conclusions Mild hypothermia can relieve the deterioration of astrocytes after hypoxia and reoxygenation and can restrain the expression of AQP5.One of the mechanisms that mild hypothermia restrains brain edema might be to reduce the expressions of AQP5.