Acute effects of hypercholesterolemic diet on erectile responses in rats

The aim of this study was to evaluate the acute effects of a high cholesterol diet (HCD) on erectile and endothelial functions in Sprague-Dawley rats.

Sprague-Dawley rats were divided into 2 groups as control and HCD groups. The control group was fed on a normal diet and the hypercholesterolemia group was fed a 1% cholesterol-enriched diet daily for 2 weeks. Total cholesterol levels were measured at the end of 2 weeks in both groups. To examine the effect of HCD on erectile function, electric cavernous nerve stimulation (CNS) at 20 Hz with a pulse duration of 1 ms for 1 min at 5 V was performed. During CNS, we measured intracavernous pressure (ICP), mean arterial pressure (MAP), detumescence time and area under the curve (AUC). To evaluate the endothelial responses, acetylcholine (Ach) was applied cumulatively (1 nM to 1 microM) to thoracic aorta tissues contracted with 60 mM KCl.

In the HCD group total cholesterol levels were significantly higher than in the control group (148.1 +/- 18.9 vs. 55.7 +/- 8.1 mg/dl, p = 0.002). The detumescence time was significantly decreased after HCD compared to the control diet (19.3 +/- 3.6 vs. 78.6 +/- 12.8 s, p < 0.001). The decreases in the HCD group were also significant in terms of ICP (53.4 +/- 4.5 vs. 35.6 +/- 5.5 mm Hg; p < 0.05), ICP/MAP (55.9 +/- 3.9 vs. 38.2 +/- 5.2%; p < 0.05) and AUC (1,404 +/- 197.1 vs. 2,250 +/- 253.7, p < 0.05) values. There were no significant changes in maximum relaxation responses of the thoracic aorta to Ach.

These results suggest that erectile functions were significantly damaged early in HCD rats. However, endothelial functions, evaluated in the thoracic aorta, were not affected simultaneously with erectile functions in rats fed a low concentration of HCD.