Min Chul Cho1, Kwanjin Park2, Soo Woong Kim2, Jae-Seung Paick3. 1. Department of Urology, Dongguk University College of Medicine, Goyang, Republic of Korea. 2. Department of Urology, Seoul National University College of Medicine, Seoul, Republic of Korea. 3. Department of Urology, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address: jspaick@snu.ac.kr.
Abstract
PURPOSE: We determined whether Rho-kinase inhibition would improve corporal veno-occlusive dysfunction by suppressing apoptosis and fibrosis via normalization of the Rho-kinase driven pathways related to the 2 structural alterations in a rat model of cavernous nerve crush injury. MATERIALS AND METHODS: A total of 30 male 10-week-old male Sprague Dawley® rats were equally divided into 3 groups, including sham surgery, cavernous nerve crush injury and cavernous nerve crush injury treated with fasudil. The treated group received fasudil (30 mg/kg) daily for 4 weeks starting day 1 postoperatively. Electrostimulation and dynamic infusion cavernosometry were performed 4 weeks postoperatively. Penile tissue was processed for imm unohistochemistry, double immunofluorescent and Masson trichrome staining, TUNEL, caspase-3 activity assay and Western blot. RESULTS: The cavernous nerve crush injury group showed significantly lower intracavernous pressure/mean arterial pressure, and higher maintenance and drop rates than the sham surgery group. Rho-kinase inhibition in the injury plus fasudil group restored erectile responses and dynamic infusion cavernosometry parameters. Increased apoptosis, decreased immunohistochemical staining of α-SMA and increased caspase-3 activity were noted in the injury group. In that group densitometry revealed increased ROCK1 expression, increased MYPT1 phosphorylation, decreased Akt phosphorylation, decreased Bad phosphorylation and a decreased Bcl2-to-Bax ratio. A significantly decreased smooth muscle-to-collagen ratio and increased fibroblast pCofilin were also observed in the injury group, as was increased phosphorylation of cofilin, a downstream effector of LIMK2. Rho-kinase inhibition in the injury plus fasudil group alleviated the histological and molecular dysregulation. CONCLUSIONS: Our data suggest that early inhibition of Rho-kinase after cavernous nerve crush injury may prevent corporal apoptosis and fibrosis by suppressing the Akt/Bad/Bax/caspase-3 and LIMK2/cofilin pathways, preventing corporal veno-occlusive dysfunction and erectile dysfunction.
PURPOSE: We determined whether Rho-kinase inhibition would improve corporal veno-occlusive dysfunction by suppressing apoptosis and fibrosis via normalization of the Rho-kinase driven pathways related to the 2 structural alterations in a rat model of cavernous nerve crush injury. MATERIALS AND METHODS: A total of 30 male 10-week-old male Sprague Dawley® rats were equally divided into 3 groups, including sham surgery, cavernous nerve crush injury and cavernous nerve crush injury treated with fasudil. The treated group received fasudil (30 mg/kg) daily for 4 weeks starting day 1 postoperatively. Electrostimulation and dynamic infusion cavernosometry were performed 4 weeks postoperatively. Penile tissue was processed for imm unohistochemistry, double immunofluorescent and Masson trichrome staining, TUNEL, caspase-3 activity assay and Western blot. RESULTS: The cavernous nerve crush injury group showed significantly lower intracavernous pressure/mean arterial pressure, and higher maintenance and drop rates than the sham surgery group. Rho-kinase inhibition in the injury plus fasudil group restored erectile responses and dynamic infusion cavernosometry parameters. Increased apoptosis, decreased immunohistochemical staining of α-SMA and increased caspase-3 activity were noted in the injury group. In that group densitometry revealed increased ROCK1 expression, increased MYPT1 phosphorylation, decreased Akt phosphorylation, decreased Bad phosphorylation and a decreased Bcl2-to-Bax ratio. A significantly decreased smooth muscle-to-collagen ratio and increased fibroblast pCofilin were also observed in the injury group, as was increased phosphorylation of cofilin, a downstream effector of LIMK2. Rho-kinase inhibition in the injury plus fasudil group alleviated the histological and molecular dysregulation. CONCLUSIONS: Our data suggest that early inhibition of Rho-kinase after cavernous nerve crush injury may prevent corporal apoptosis and fibrosis by suppressing the Akt/Bad/Bax/caspase-3 and LIMK2/cofilin pathways, preventing corporal veno-occlusive dysfunction and erectile dysfunction.