慢性肺疾病早产鼠肺组织转化生长因子β_1基因及蛋白表达的动态变化(英文)

Expression of transforming growth factor-β_1 mRNA and protein in premature rats with chronic lung disease

目的近年来研究发现慢性肺疾病(CLD)早产儿支气管肺泡灌洗液中转化生长因子-β1(TGF-β1)水平明显升高,但其表达在CLD发生、发展中动态变化规律及与CLD的肺泡发育障碍的关系尚不明确。该研究探索高氧致CLD肺组织TGFβ1基因及蛋白表达特点及对其肺发育的影响。方法采用高浓度氧诱导早产鼠CLD模型,应用反转录聚合酶链反应(RTPCR)、免疫组织化学及图像分析等技术,动态观察肺系数、放射状肺泡计数(RAC)的变化,并同时测定肺组织TGF-β1mRNA及蛋白表达水平。结果生后1d,3d,两组肺系数、RAC无差异(P>0.05),7d和14d时实验组肺系数、RAC低于对照组(P<0.05),21d时RAC明显降低(P<0.001),但两组肺系数无差异;实验组肺组织TGFβ1mRNA水平3d高于对照组(P=0.005),14d达高峰(P<0.001),21d稍有下降,但仍高于对照组(P=0.005);实验组肺组织TGFβ1蛋白表达7d增高(P=0.036),21d达高峰(P<0.001);肺组织TGF-β1蛋白表达与RAC呈显著负相关(P=0.003)。结论暴露高氧环境中早产鼠肺组织TGF-β1蛋白表达的动态变化与其肺发育障碍的程度相一致,TGF-β1是抑制肺泡发育的重要因子。

Objective To investigate the dynamic changes of transforming growth factor-β_1 (TGF-β_1) mRNA and protein expression and their effects on lung development in premature rats with chronic lung disease (CLD).Methods CLD was induced by hyperoxia exposure (FiO_2=0.90) in neonatal premature rats. The dynamic changes of lung coefficient and radical alveolar counts (RAC) were observed; and the expressions of TGF-β_1 mRNA and protein were assayed with reverse transcription polymerase chain reaction (RT-PCR), immunohistochemical and image processing technique on days 1, 3, 7, 14 and 21 after birth. For comparison analysis, 30 premature rats exposed to air were used as the Control group.Results There were no differences in the lung coefficient and the RAC between the CLD and the Control groups within 3 days after birth. However on the 7th and 14th days, the lung coefficient and the RAC of the CLD group were significantly lower than those of the Control group. The RAC decreased to the nadir on the 21st day, but the lung coefficient was not different from the Control group. In the CLD group, the expression level of TGF-β_1 mRNA increased on the 3rd day, peaked on the 14th day and remained higher on the 21st day; the higher expression of TGF-β_1 protein was detected on the 7th day and peaked on the 21st day; and the TGF-β_1 protein expression was negatively correlated with RAC(P =0.0027).Conclusions The over-expression of TGF-β_1 in lung tissues is associated with the lung development disorder. The TGF-β_1 expression level may be an index for the assessment of lung development.