RESUMEN
<p><b>OBJECTIVE</b>To investigate the mechanism of erectile dysfunction (ED) in rat models with chronic renal failure (CRF).</p><p><b>METHODS</b>Chronic renal failure was induced by adult male Sprague-Dawley rats, which were subjected to an excisional 5/6 nephrectomy. The rats in NCRF group and CRF group were divided into three groups randomly. Injected with apomorphine(APO, 80 microg/kg), penile erections of three groups were observed and noted by the 2nd week, 4th week respectively and 6th week from the 14th day of 5/6 nephrectomy and experimental models of ED with CRF were selected; NOS activity was examined and the microstructures of penile were observed under optical microscope with computer configuration image analysis system in selected rat models.</p><p><b>RESULTS</b>Compared with the controls, the areas of smooth muscle and NOS activity in the penile cavernous tissue of ED rats with CRF decreased significantly (P < 0.01 or P < 0.05) , and collagen fibers slightly increased, and these alterations had close correlations with the duration of CRF. The</p><p><b>CONCLUSIONS</b>Penile erection is seriously affected in rats with CRF. The decreases of areas of blood sinus had no obvious changes. the number of smooth muscles and NOS activity might be the most important factors.</p>