Pravastatin improves the impaired nitric oxide-mediated neurogenic and endothelium-dependent relaxation of corpus cavernosum in aged rats

Abstract

Aim: The aim of this study was to investigate the effect of pravastatin treatment on diminished corpus cavernosum (CC) function associated with aging.

Methods: Male rats were divided into three groups as adult rats (12–14 weeks old), aged rats (72–80 weeks old) and aged rats given 10?mg/kg/d pravastatin in drinking water for six weeks. Blood pressure was measured by tail-cuff method. Total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, triglycerides and testosterone levels were estimated in blood. Changes in expression levels of endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (p-eNOS) (Ser-1177), neuronal nitric oxide synthase (nNOS), NADPH oxidase subunit gp91^phox, Rho A and Rho kinase (ROCK2) in CC were assessed by immunohistochemistry. Nitric oxide (NO)-mediated endothelium-dependent and neurogenic CC relaxation were evaluated by acetylcholine (ACh, 0.1?nM–100?µM) and electrical field stimulation (EFS; 30?V, 5?ms, 2–32?Hz), respectively.

Results: In aged rats, NO-mediated, both endothelium-dependent and neurogenic CC relaxation, were significantly impaired as compared to adult rats. Besides, eNOS, p-eNOS and nNOS expressions decreased significantly in CC from aged rats, while gp91^phox, RhoA and ROCK2 expressions increased significantly. The diminished relaxation in response to ACh or EFS as well as the changes in expression of these proteins in aged rats were significantly improved by pravastatin treatment.

Conclusion: Pravastatin improves NO-mediated CC relaxations of aged rats probably by inhibiting NADPH oxidase/Rho kinase pathways, and this effect does not seem to be associated with lipid lowering effect of this drug.     

两种训练对乳酸脱氢酶、肌酸激酶活性的影响

为了探讨同属有氧训练的短期耐力、力量性耐力训练对男大学生血清乳酸脱氢酶、肌酸激酶活性影响,本研究分别在训练前后测试了18名男大学生血清乳酸脱氢酶、肌酸激酶活性.结果表明:血清乳酸脱氢酶、肌酸激酶活性在短期耐力、力量性耐力训练过程中变化不敏感,这提示乳酸脱氢酶、肌酸激酶不宜选作评价有氧训练效果的指标.     

信号转导蛋白的调节性结合结构域研究进展

在具有蛋白激酶活性的信号转导蛋白上,信号是以部分氨基酸残基磷酸化的形式向下传递的,而这些信号转导蛋白不仅具有催化位点,更重要的是还具有结合位点。对这些结合位点的进一步研究,发现了三个同源序列区,分别被称为SH2、SH3和PH结合性结构域。这些结构域通过介导蛋白与蛋白或蛋白与脂质间的相互联结作用,调节信号转导蛋白在细胞内的定位,从而特异地决定信号转导的途径。这些结构域所介导的信号传递过程在细胞增殖、分化甚至凋亡中起着重要作用。本文就它们的结构与功能的研究现状作一简要概述。     

短期耐力、力量性耐力训练对血清CK活性的影响

为了探讨同属有氧训练的短期耐力、力量性耐力训练对血清ＣＫ 活性的影响，本研究分别在训练前后测试了１８ 名男大学生血清ＣＫ 的活性．结果表明：血清ＣＫ 的活性在短期耐力、力量性耐力训练过程中变化不敏感；ＣＫ 不宜选作评价有氧训练效果的指标．