间歇低氧对大鼠肺组织RhoA/ROCK通路及肺血管新生肌化的影响

Effect of intermittent hypoxia on Rho A/ROCK pathway in lung and on the muscularization in pulmonary vascular in rat model

目的探讨间歇低氧（IH）对大鼠肺组织RhoA/ROCK通路及肺血管新生肌化的影响。方法将40只Wistar雄性大鼠随机分为对照组和IH组各20只,对照组：间歇正常氧暴露（21%O2）;IH组：IH暴露（5%-21%O2）,持续4周。暴露结束后,2组均采用Real-time PCR和Western blot检测肺组织RhoA、ROCK mRNA和蛋白表达情况,免疫组化法测定肺组织和肺动脉的增殖细胞核抗原（PCNA）及α-平滑肌肌动蛋白（SM-α-actin）的表达情况。结果IH组肺组织RhoA mRNA（0.463±0.067 vs 0.182±0.040）、ROCK mRNA（0.384±0.062 vs 0.192±0.052）、RhoA蛋白（0.827±0.065 vs 0.424±0.075）及ROCK蛋白（0.488±0.088 vs 0.336±0.102）表达水平均高于对照组（均P〈0.05）;IH组肺组织PCNA[（54.67±1.80）%vs（9.14±0.91）%]、肺动脉PCNA[（49.40±1.21）%vs（8.38±1.13）%]、肺组织SM-α-actin[（42.66±1.63）%vs（35.44±1.41）%]与肺动脉SM-α-actin[（62.62±2.53）%vs（45.54±2.58）%]表达水平均明显高于对照组（均P〈0.05）。结论 RhoA/ROCK传导通路在IH所致肺动脉高压发病机制中可能起着重要作用;IH可通过促进肺动脉的新生肌化进一步促进肺动脉压力升高。

Objective To explore the effect of intermittent hypoxia（IH） on RhoA/ROCK pathway in lung and on themuscularization in pulmonary vascular in rat model. Methods Wistar rats（n=40） were randomly divided into two groups：the normal oxygen control group（n=20） and the IH group（ n=20）. For 4 weeks, rats in control group and IH group were ex-posed to intermittent normal oxygen（21% O2） or IH（5%-21% O2） respectively. Then, mRNA transcription and protein trans-lation levels of RhoA/ROCK were examined by Real-time PCR and Western blot. Expression of proliferation cell nuclear an-tigen（PCNA） and α-smooth muscle actin（SM-α-actin） of lung and pulmonary artery were detected by immunohistochemis-try. Results RhoA mRNA transcription level（0.463±0.067 vs 0.182±0.040）, ROCK mRNA transcription level（0.384±0.062 vs 0.192±0.052）, RhoA protein expression level（0.827±0.065 vs 0.424±0.075）and ROCK protein expression level（0.488±0.088 vs 0.336±0.102）were higher in IH group than those in control group（P〈0.05）;Levels of PCNA in lung tissue[（54.67±1.80）% vs（9.14±0.91）%], PCNA in pulmonary artery [（49.40±1.21）% vs（8.38±1.13）%], SM-α-actin in lung tis-sue [（42.66±1.63）% vs（35.44±1.41）%] and SM-α-actin in pulmonary artery [（62.62±2.53）% vs（45.54±2.58）%] were alsohigher in IH group than those in control group（P〈0.05）. Conclusion Rho/ROCK pathway may play an important role indeveloping pulmonary hypertension（PH） associated with IH; and IH can promote the muscularization in pulmonary vascularto accelerate PH.