HoxB5在高体积分数氧致慢性肺疾病新生大鼠肺组织中的动态表达及其意义

Dynamic Expression of HoxB5 in Lung Tissue of Neonatal Rats with Hyperoxia-Induced Chronic Lung Disease and Its Significance

目的探讨生长调控基因HoxB5对正常肺泡发育的调控及其在肺泡损伤修复过程中的作用。方法新生大鼠80只,随机分为高体积分数氧(高氧)组和对照组。高氧组吸入850～900 mL/L氧气,建立慢性肺疾病(CLD)模型;对照组吸入空气,余控制因素相同。分别于实验第1、3、7、14、21天留取大鼠肺组织,应用免疫组织化学法测定二组大鼠肺组织HoxB5动态表达部位及强度,RT-PCR测定二组大鼠肺组织HoxB5 mRNA的动态表达,原位杂交技术测定HoxB5 mRNA在其肺组织的动态表达部位。SPSS 11.5软件进行统计学分析。结果对照组新生大鼠出生第21天肺泡发育逐渐完成,而高氧组自第7天始肺泡发育受阻,随着时间的延长肺泡发育障碍明显加重。二组新生大鼠肺组织HoxB5蛋白在第1、3天表达均无差异(Pa>0.05),但高氧组在第7天后表达逐渐减少,对照组在第7天达高峰之后平稳表达,第14、21天对照组肺组织HoxB5均明显高于高氧组(Pa<0.05),HoxB5 mRNA高氧组在第7天后表达逐渐减少,对照组在第7天后平稳表达,均明显高于高氧组(Pa<0.05)。免疫组织化学和原位杂交检测结果显示,对照组HoxB5蛋白及mRNA主要表达于肺泡上皮,且在肺泡连接处、肺泡拐角处及肺泡嵴表达更明显,而高氧组在上述部位表达明显减弱。结论高氧肺损伤新生大鼠肺泡上皮HoxB5随着肺泡化障碍及肺损伤的加重表达明显减少,HoxB5表达减少可能在高氧肺发育障碍和肺泡上皮细胞损伤修复中发挥重要作用。

Objective To explore the control of normal alveolus development with growth controlling gene HoxB5 and the role of HoxB5 in lung damage and reparation of alveolar epithelium. Methods Eighty neonatal rats were randomly divided into model group and control group. The neonatal rats in model group inhaled highly concentrated oxygen （850 -900 mL/L）, while the neonatal rats in control group were exposed on room air. The lung tissue of the 2 groups on the first, third,7^th, 14^th and 21^ st, day after exposure were obtained, the site and intensity of expression of HoxB5 protein was detected by using immunohistochemical method, the dynamic expression of HoxB5 mRNA was detected by using in situ hybridization method and RT - PCR. Results The alveolaration were finished on the 21^st day in control group, while the lung development of neonatal rats in model group was disturbed from the 7^th day. The gene and protein expression of HoxB5 had no significant difference on the first and third day between the 2 groups （P 〉 0.05 ） , and the expression of HoxB5 in the model group tapered after the 7^th day,but the expression of HoxB5 increased and reached the peak on the 7^th day and expressed in a stable level in the control group and were significantly higher than those of model group （P, 〈 0.05 ）. Hybridization in situ results showed that HoxB5 mRNA expressed obviously in the alveolar septum and cristae in the control group, while the expressions were significantly increased in the model group. Conclusions The expression of HoxB5 decreased gradually in chronic lung disease rats with lung injury,and the quantity of HoxB5 decrease might play an importaut role in the development of pulmonary dysplasia and reparation of epithelium impairment in hyperoxia - induced chronic lung disease.