Differential Expression of Proteins Related with Penile Apoptosis in a Rat after Cavernous Nerve Resection

Abstract

Purpose: The mechanism including changes of proteome within cavernosal tissue after cavernous nerve injury were not evaluated. We performed proteomics and functional analysis to identify proteins of penile corpus cavernosum whose expression was or was not altered by cavernous nerve resection (CNR). Materials and Methods: Using 8-week-old male WKY rats, sham and CNR operation under microscope were performed. After 8 weeks, penile tissues of sham and CNR group were harvested. We used 2-DE and MALDI-TOF/TOF (AB 4700) to identify of differently expressed penile proteins. 2-DE gels were stained with silver nitrate and the gels were analyzed with PDQuest. Results: We isolated more than 950 proteins on silver-stained gels of whole protein extracts from normal rat penile corpus cavernous. Of these proteins, 48 prominent proteins were identified using MALDI-TOF/TOF. Protein characterization revealed that the most prominent penile corpus cavernous proteins were those with antioxidant, chaperone, or cytoskeletal structure. Moreover, 11 proteins having levels elevated by CNR were annexin proteins, endoplasmic reticulum protein 29, glutathione s-transferase w-1, and others. In addition, Rho-GDP dissociation inhibitor (RhoGDI), a regulator of Rho proteins, was also increased in CNR rats compared with sham-operated control rats. Conclusions: The apoptotic signals observed in penile tissues was greatly increased in CNR rats than in sham-operated rats. These results suggest that RhoGDI is one of the proteins regulated by CNR in penile smooth muscle strips, and has a crucial role in the early stage of penile apoptosis.