孕鼠叶酸缺乏对幼鼠肺发育及其SP-A变化的研究

Effects of maternal deficiency of folic acid during pregnancy on pulmonary development and SP-A expression in newborn rats

摘要:

目的：研究孕鼠叶酸缺乏对幼鼠肺发育的影响及幼鼠SP-A基因表达的变化，探讨孕鼠叶酸缺乏引起幼鼠肺发育障碍的发病机制。方法：成熟雌性Sprague-Dawley大鼠36 只随机分为实验组和对照组（各18只），分别喂以缺乏叶酸和添加叶酸的纯合饲料。2 周后与雄性大鼠交配，分别于生后1、7、14 d留取幼鼠肺组织标本。苏木精-伊红染色观察肺组织病理改变，免疫组化检测肺组织SP-A蛋白表达，实时荧光定量RT-PCR技术检测SP-A mRNA表达。结果：与对照组比较，实验组幼鼠肺组织结构紊乱。实验组幼鼠SP-A阳性的Ⅱ型细胞免疫组化染色平均光密度从第1天到第14天逐渐减少，与对照组第1天至第14天比较差异有统计学意义（P<0.05）。RT-PCR检测表明实验组幼鼠SP-A mRNA从第1 天到第14 天逐渐减少，与对照组第1 天至第14天比较差异有统计学意义（P<0.05）。结论：孕期叶酸缺乏能影响新生大鼠肺组织SP-A的表达，从而可能导致肺成熟障碍。

Abstract:

OBJECTIVE: This study examined the effects of maternal deficiency of folic acid during pregnancy on pulmonary development and protein A (SP-A) expression in newborn rats in order to explore the possible mechanism of lung developmental disorders. METHODS: Thirty-six adult Sprague-Dawley female rats were randomly assigned into two groups: control and study (n=18). The study and the control groups were fed with fodder containing folic acid or not respectively. Two weeks later, the female rats in the two groups copulated with normal male rats. Newborn rats were sacrificed at 1, 7 and 14 days after birth (8 pups at each time point). Lung sections were stained with hematoxylin and eosin for histological examination. SP-A expression of protein and mRNA were determined by immunohistochemistry and real-time quantitative RT-PCR, respectively. RESULTS: The newborn rats from the study group showed damaged lung tissue structures. The mean optical density of type II cells with positive expression of SP-A decreased significantly from 1 to 14 days in newborn rats of the study group compared with the control newborn rats (P<0.05). The real-time quantitative RT-PCR showed that the expression of lung SP-A mRNA also decreased significantly from 1 to 14 days in newborn rats of the study group compared with control newborn rats (P<0.05). CONCLUSIONS: Maternal deficiency of folic acid during pregnancy can decrease the expression of SP-A in lung tissues of newborn rats, which might lead to the disorder of lung development maturation.