Hyperlipidemia impairs erectile function in rats by causing cavernosal fibrosis

Men with hyperlipidemia are more likely to have erectile dysfunction (ED) than those without hyperlipidemia, but the mechanisms are not fully understood. The aim of this study was to investigate the underlying mechanism of ED caused by hyperlipidemia. Fourteen 8-week-old Sprague-Dawley rats were randomly divided into two groups: a control group and a hyperlipidemia group (fed chow containing 4% cholesterol and 1% cholic acid). After 6 months, we assessed erectile function by performing cavernous nerve electrostimulation followed by intracavernosal pressure/mean arterial pressure measurements, as well as plasma lipid profile assessment in all rats. A transferase-mediated nick end labeling (TUNEL) assay, immunohistochemical staining and Western blotting were performed to determine the levels of apoptosis, autophagy and fibrosis in the penile tissue. Compared with the control group, the hyperlipidemia group exhibited: (i) increased plasma lipid levels; (ii) decreased erectile function; (iii) a decreased smooth muscle/collagen ratio; (iv) increased fibrosis; (v) increased apoptosis and decreased autophagy. Overall, hyperlipidemia may attenuate erectile function in rats by causing of cavernosal fibrosis.