高体积分数氧致A549细胞肺表面活性物质蛋白-A表达的变化

目的探索高体积分数氧(高氧)致A549细胞肺表面活性物质蛋白(SP)-A表达的变化规律。方法将A549细胞分为高氧组和常氧组。高氧组细胞置于含950 mL·L-1氧气和50 mL·L-1二氧化碳的条件下培养,常氧组以空气替代氧气,于0 h、12 h、24 h、48 h、72 h、96 h在倒置相差显微镜下观察细胞生长状况,提取细胞内总蛋白,采用硫代巴比妥酸比色法检测其丙二醛(MDA)水平,Western blot检测其SP-A表达水平。结果高氧48 h可导致A549细胞生长明显减慢,72 h后细胞生长停滞,可见较多漂浮死亡细胞,96 h后漂浮死亡细胞明显增多。高氧组各时间点A549细胞SP-A表达水平均高于常氧组,高氧24 h SP-A表达增多最显著,此后增多的幅度逐渐减小,高氧48 h后细胞内MDA水平显著高于常氧组,随时间延长,MDA水平进一步升高。结论高氧可导致A549细胞损伤,SP-A表达在细胞高氧损伤早期代偿性增加,晚期降低,推测SP-A表达降低可能与细胞损伤加重有关,增加SP-A的表达可能有助于减轻高氧引起的细胞损伤。

Effect of Hyperoxia on Expression of Pulmonary Surfactant Protein-A in A549 Cells

Objective To evaluate the expressional alterations of pulmonary surfactant protein(SP)-A in A549 cells after hyperoxia challenge. Methods A549 cells were divided into hyperoxia group and normoxia group.The cells in hyperoxia group were exposed to 950 mL·L-1O2 and 50 mL·L-1CO2,and the O2 was substituted by the air in normoxia group.The cell growth was observed by inverted phase contrast microscope at 0 h,12 h,24 h,48 h,72 h and 96 h after hyperoxia challenge,then the total protein of the cells was extracted.The malondialdehyde(MDA) level of the protein was determined by the thiobarbituric acid reactive substance test and the SP-A was detected by Western blot. Results The A549 cells in hyperoxia group proliferated obviously slowly at 48 h and didn′t proliferate after 72 h.Quite a little dead cell floating emerged at 72 h and more emerged at 96 h.The expression of SP-A in A549 cells increased after hyperoxia challenge.Among the 12 h,24 h,48 h,72 h and 96 h time points,the increasing expression of SP-A in A549 cells after hyperoxia challenge was most at 24 h time point,then the increasing expression cut down gradually.The MDA level in A549 cells in hyperoxia group was significantly higher than that in normoxia group.With the time of hyperoxia challenge prolonging,the MDA level increased gradually. Conclusions Hype-roxia can cause the injury of A549 cells.The expression of SP-A in A549 cells increases compensatively at the early stage of hyperoxia-induced cell injury,and decreases at the later stage.The depression of SP-A may be related to the aggravation of hyperoxia-induced cell injury,and increasing the expression of SP-A probably help to alleviate the injury.