Rho激酶可能介导模拟失重所致大鼠肾动脉收缩功能的变化

Rho kinase may mediate impaired vasoconstriction of renal artery induced by hindlimb unweighting in rats

目的观察模拟失重对大鼠肾动脉收缩功能的影响及Rho相关蛋白激酶(Rho-associated protein kinase,ROCK)与其关系。方法以大鼠尾部悬吊4周建立模拟失重模型,采用离体血管环功能实验检测大鼠肾动脉收缩反应变化,通过免疫蛋白印迹技术检测大鼠肾动脉ROCK蛋白的表达,采用ROCK活性试剂盒检测ROCK活性。结果模拟失重大鼠肾动脉苯肾上腺素(Phenylephrine,PE)与氯化钾(KCl)诱导的收缩反应均明显降低(P<0.05),ROCK特异性抑制剂Y-27632显著缩小模拟失重大鼠与正常大鼠动脉收缩反应之间的差异(P<0.05);蛋白印迹结果显示,模拟失重大鼠肾动脉ROCK蛋白表达增加(P<0.05);ROCK活性检测结果显示,模拟失重大鼠肾动脉ROCK活性降低(P<0.05)。结论模拟失重大鼠肾动脉收缩反应明显降低,抑制ROCK的作用可减小模拟失重大鼠与正常大鼠肾动脉收缩功能的差异,ROCK活性改变可能在模拟失重大鼠肾动脉收缩功能降低中发挥一定作用。

AIM To investigate the relationship between impaired vasoconstriction of renal artery and altered Rho-associated protein kinase （ROCK） induced by simulated microgravity in rats. METHODS Four-week hindlimb unweighting （HU） rats were adopted as animal models. Isometric force was measured by isolated tissue bath with or without Y-27632, a specific ROCK inhibitor. Protein expression and activity of ROCK were examined by Western blot and ROCK activity assay. RESULTS Compared with those in the control group, phenylephrine （PE）- and KCl-induced contractions were significantly decreased in the HU group （P 〈 0. 05 ） and inhibition of ROCK with Y-27632 significantly reduced the decrement of vaso- constriction between the control group and the HU group （P 〈 0. 05 ）. The protein expression of ROCK was up-regulated （ P 〈 0. 05 ）, whereas ROCK activity was decreased （P 〈 0. 05 ） in renal arteries of the HU group. CONCLUSION Renal artery vasoconstriction is decreased under simulated microgravity. Inhibition of ROCK may diminish the vasoconstrictive difference between control and simulated microgravity rats. The reduced activity of ROCK may be an important mechanism accounting for the impaired vasocon-striction in renal arteries induced by simulated microgravity in rats.