Phenotypic modulation of corpus cavernosum smooth muscle cells in a hyperlipidemic rat model

Objective: The aim of this study was to determine the changes and underlying mechanisms of erectile organ structure and function in hyperlipidemic rats. Materials and Methods: Sixteen male rats were fed a normal diet to serve as controls, and the other sixteen rats were induced to develop hyperlipidemia with a high fat diet. After 4 months, the penile tissues were harvested and assessed for smooth muscle content. Molecular markers of phenotypic modulation were examined by qRT-PCR and western blotting. Results: Serum total cholesterol, triglyceride, and low density lipoprotein cholesterol levels were significantly higher in hyperlipidemic rats than those in control rats (P<0.01 for all). However, the high density lipoprotein cholesterol level was significantly reduced (P<0.01). Erectile function was significantly lower in hyperlipidemic rats than in control rats. There was no significant difference in the content of smooth muscle cells between the hyperlipidemic group and the control group. The expression of CCSMC phenotypic markers, such as calponin, smooth muscle myosin heavy chain 11, and myocardin was markedly lower, whereas osteopontin protein expression was significantly higher in hyperlipidemic rats than in control rats. Conclusion: CCSMCs possesses the ability to modulate the phenotype under hyperlipidemic conditions, which could have a key role in the pathogenesis of erectile dysfunction.