Objective: To investigate the expression of RhoA/Rho-kinase (ROCK) in penile corpus cavernosum smooth muscles in rats of hyperlipidemia-induced erectile dysfunction and its molecular mechanism.
Methods: Forty male Sprague-Dawley rats were randomly divided into control and experimental groups using a random number table. Rats in the control group (n=20) were fed with regular diet for 24 weeks and those in the experimental group (n=20) with high-fat diet for the same period of time. The serum lipids profile was detected before and after the diet treatment. The ratio of intracavernosal pressure (ΔICP)/mean arterial pressure (MAP) was measured, and Western blot was used to detect the expression of total RhoA, ROCK1, and ROCK2 in penile corpus cavernosum smooth muscles, and RhoA protein in cell membrane and cytoplasm of smooth muscles after 24 weeks.
Results: After 24 weeks, the levels of cholesterol, triglyceride, and low-density lipoprotein were significantly higher in the experimental group compared with those before diet treatment and the control group (all P<0.01). ΔICP/MAP in the experimental group was greatly lower than in the control group (P<0.01). The protein expression of ROCK2 in penile corpus cavernosum smooth muscles was higher in the experimental group than in the control group (0.77±0.10 vs 0.27±0.08, P<0.01) after 24 weeks, while no statistically significant differences were observed in total RhoA and ROCK 1 protein expression between the two groups (both P>0.05). RhoA expression in cytoplasm was lower in the experimental than in the control group (1.66±0.09 vs 1.79±0.15, P<0.05). The ratio of RhoA expression in menmbrane/cytoplasm was higher in the experimental than in the control group (0.33±0.09 vs 0.26±0.07, P<0.05).
Conclusion: Up-regulation of RhoA/ROCK may be involved in hyperlipidemia-induced erectile dysfunction in rats.