[Phenotype modulation of smooth muscle in corpus cavernosum in penis tunica albuginea in diabetes mellitus with erectile dysfunction: experiment with rats]

Abstract

Objective: To investigate the phenotype modulation of smooth muscle of corpus cavernosum in diabetes mellitus with erectile dysfunction.

Methods: Thirty SD rats were randomly divided into 2 equal groups: 4-week group and 7-week group, injected with streptozocin to cause diabetes mellitus (DM), and then subdivided into DM group [with DM and without erectile dysfunction. (ED)], DM + ED group (with DM and ED), and group of failure to cause DM (Group None) according whether DM was induced. Another 10 rats without STZ injection were divided into 4-week and 7-week control groups. The penis was resected and immunohistochemistry and color image analysis were used to observe the expression of alpha-actin and desmin in the corpus cavernosum. In situ hybridization was used to detect the mRNA expression of osteopontin (OPN), characteristic of noncontractil phenotype.

Results: The alpha-actin expression of smooth muscle in corpus cavernosum in the DM + ED group was significantly lower than those of the other groups (all P < 0.05). No significant difference existed between the 7 week group and 4 week group (F = 3.801, P = 0.62), and there was significant interaction (F = 1.549, P = 0.225). There was no significant difference in the desmin expression of smooth muscle in corpus cavernosum among different groups (F = 0.045, P = 0.987) and there was not significant interaction (F = 0.572, P = 0.639). The OPN mRNA expression of smooth muscle in corpus cavernosum of the DM + ED group was significantly higher than those of the other subgroups (F = 156.439, P = 0.000). No significant difference existed between the 7 week group and 4 week group (F = 1.288, P = 0.266), and there was no significant interaction (F = 1.819, P = 0.168).

Conclusion: Phenotype modulation of smooth muscle in corpus cavernosum can be caused by DM. ED can be caused by phenotype modulation of smooth muscle in corpus cavernosum.