The impact of rosiglitazone, a PPAR agonist, on the cavernous tissue in a hyperlipidemic environment

OBJECTIVEHyperlipidemia is one of the leading controllable risk factors of cardiovascular disease and erectile dysfunction. The reverse cholesterol transport (RCT) plays an important role in carrying increased cellular cholesterol out of the cell in hyperlipidemic environment and maintaining the function of the endothelium. In our study, we investigated the impact of oral rosiglitazone on CC tissue in a hyperlipidemic environment.METHOD21 New Zealand male rabbits were divided into control, hypercholesterolemia and treatment groups with 7 rabbits each. For 6 weeks the control group was fed regular feed, while hypercholesterolemia and treatment groups were given a diet of 2% cholesterol. The treatment group was also administered 3mg/kg/day rosiglitazone. At the end of the 6 weeks, plasma cholesterol levels were measured. PCR method was used to check mRNA expressions of ABCA-1 and Caveolin-1 in RNAs obtained from the CC tissue.FINDINGSThe total cholesterol and LDL levels of the hypercholesterolemia and treatment groups were significantly higher than the control group (p<0,001). At the end of the 6 weeks, the plasma HDL concentration of the treatment group was higher than the hypercholesterolemia and control groups (p<0.05). The LDL level of the treatment group was lower than the hypercholesterolemia group (p<0.001). Caveolin-1 mRNA expression decreased in the hypercholesterolemia group compared with the control group, while it elevated significantly in the treatment group. ABCA-1 mRNA expression elevated in the hypercholesterolemia group compared with the control group, while it decreased in the treatment group (p=0.07).CONCLUSIONBy increasing the RCT, rosiglitazone exerts a positive impact on the plasma lipid profile. This study has been the first study to show ABCA-1 in the CC tissue. Caveolin-1 has also been shown for the first time at molecular level in the CC tissue. Protein expressions must be checked to see how CC tissue is affected by ABCA-1 and caveolin-1 that play important roles in the RCT. Further studies are also needed on their relationships with eNOS enzyme.