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abstract

abstract

035

The mechanisms of stress-induced erectile dysfunction; a focus on regulators of contraction and relaxation in the corpus cavernosum by using a rat model of water immersion-restraint stress

Mori, T1; Hotta, Y1; Nakamura, D1; Yahagi, R1; Kataoka, T1; Maeda, Y1; Kawade, Y1; Kimura, K1

1: Nagoya City University, Japan

Objectives: Stress is known as a risk factor for erectile dysfunction (ED), but the mechanisms of stress-induced ED have been unknown yet. In this study, we aimed to investigate the mechanisms of stress-induced ED by using a rat model of water immersion-restraint stress, focusing on regulators of contraction and relaxation in the corpus cavernosum.

Materials and Methods:Ten-week-old male Wistar-ST rats were divided into three groups as follows: control, stress, stress+fasudil (Rho-kinase [ROCK] inhibitor) groups (each group with n=6 rats). The rats in the control group were kept in a normal tip cage for 5 days. The rats in the stress group were kept in a cage filled with water to a height of 2.0 cm for 5 days. The rats in the stress+fasudil group were kept in a cage filled with water and were administrated 10 mg/kg fasudil chloride once a day for 5 days. Erectile function was evaluated on the basis of intracavernousal pressure (ICP)/ mean arterial pressure (MAP) under the stimulation of the cavernous nerve. The protein expression levels of ROCK1 and phospho (P)-myosin light chain (MLC) in the corpus cavernosum were evaluated using the western blotting method as contractile factors of the corpus cavernosum. The protein expression levels of P-endothelial NO synthase (eNOS) and eNOS in the corpus cavernosum were also evaluated as relaxing factors. The NOx serum concentration was also measured.

Results: The ICP/MAP in the stress group was significantly lower than that in the control group, while that in the stress+fasudil group was significantly higher than that in the stress group. The protein expression levels of ROCK1 and P-MLC in the stress group were significantly higher than those in the control group, while those in the stress+fasudil group were significantly higher than those in the stress group. The P-eNOS/eNOS ratio and NOx serum concentration in the stress group were lower than those in the control group, while those in the stress+fasudil group were higher than those in the stress group.

Conclusions: This study suggests that stress caused ED via enhancement of contraction and decline of relaxation in the corpus cavernosum. Furthermore, this condition is considered to occur due to ROCK1. Therapy targeting both contraction and relaxation in the corpus cavernosum may be effective for stress-induced ED.

Disclosure:

Work supported by industry: no.

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