Src激酶在机械通气性牵张致肺泡上皮细胞损伤中的作用

Role of Src tyrosine kinase in damage to alveolar epithelial cells caused by mechanical stretch

目的 评价Src激酶在机械通气性牵张致肺泡上皮细胞损伤中的作用.方法 采用随机数字表法,将体外培养的MEL12细胞分为3组：机械通气性牵张组（S组）、二甲基亚砜对照组（D组）和Src激酶抑制剂PP2组（P组）.D组和P组分别加入二甲基亚砜30 μl/ml和Src激酶抑制剂PP2100 μmol/L（用二甲基亚砜溶解）孵育30 min,然后3组给予20％应变率的机械牵张,频率0.5 Hz.分别于机械牵张即刻、2、4和8h时,每组取3孔 MLE-12细胞,测定细胞凋亡情况,计算细胞凋亡率,采用Western blot法测定Occludin蛋白的表达.结果 与S组比较,D组各时点细胞凋亡率和Occludin蛋白表达差异无统计学意义（P＞0.05）,P组机械牵张2、4和8h时细胞凋亡率降低,Occludin蛋白表达上调（P＜0.05）.结论 Src激酶激活参与了机械通气性牵张致肺泡上皮细胞损伤.

Objective To evaluate the role of Src tyrosine kinase in damage to alveolar epithelial cells caused by mechanical stretch.Methods MLE-12 cells cultured in vitro were randomly divided into 3 groups using a random number table：mechanical stretch group （group S）,dimethyl sulfoxide control group （group D）,and Src tyrosine kinase inhibitor PP2 group （group P）.In D and P groups,dimethyl sulfoxide 30 μl/ml and PP2 100 μmol/L were added to the culture medium,respectively,and the cells were then cultured for 30 min.The cells underwent mechanical stretch for 8 h with frequency of0.5 Hz and amplitude of 20％ in the three groups.At 0,2,4 and 8 h of mechanical stretch,MLE-12 cells in 3 wells of each group were collected for determination of cell apoptosis with flow cytometry and expression of occludin using Western blot.The apoptosis rate was calculated.Results Compared with S group,no significant changes were found in the apoptosis rate and expression of occludin at each time point in group D,and the apoptosis rate was significantly decreased,and the expression of occludin was up-regulated at 2,4 and 8 h of mechanical stretch in group P.Conclusion The activation of Src tyrosine kinase is involved in damage to alveolar epithelial cells caused by mechanical stretch.