高氧对早产大鼠肺表面活性蛋白C表达的影响

Effect of hyperoxia on the expression of surfactant protein C in premature rats

目的探讨高氧对早产大鼠肺表面活性蛋白C(SP-C)表达的影响。方法孕21dSD早产大鼠,生后12～24h内随机分为空气组、高氧组。于空气或高氧暴露后1、4、7、10和14d提取肺组织,采用RT-PCR测定SP-C mRNA表达,免疫组化和Western-blot检测SP"C蛋白表达。结果早产大鼠生后肺组织SP-C表达1d时最高,4d后表达渐减弱,其阳性染色信号主要定位于Ⅱ型肺泡上皮细胞。高氧暴露1d,肺组织SP-C mRNA及蛋白表达显著低于空气组,以后增加,高氧7d增加最明显,高氧14d时SP-C表达较空气组又减弱。结论SP-C参与了早产大鼠肺发育及高氧肺损伤的生理与病理过程,高氧暴露导致SP-C表达下调或功能障碍是促使高氧肺损伤发生发展的重要因素。

Objectives To explore the effect of hyperoxia on expression of surfactant protein C （SP-C） in premature rats. Methods Sprague-Dawley （SD） newborns of 21-day gestational age were randomly assigned to air group and hyperoxia group within 12 h - 24 h after birth. After 1 to 14 days exposure, SP-C mRNA in lung tissues of these rats were detected by RT-PCR. Immunohistochemistry and Western-blot were used to detect SP-C protein. Results The SP-C expression in premature rats of air group was highest on day 1 and began to decrease after day 4. The positive staining was restricted to the type Ⅲ alveolar epithelial cells. Compared with air group, the SP-C mRNA and protein were significantly lower on day 1 in hyperoxia group but gradually increased and achieved a peak on day 7, then decreased again. Conclusions Hyperoxia exposure lead to a down regulation or functional impairment of the SP-C expression, this may be an important factor which influences the development of hyperoxia lung injury.