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Abstract
Purpose
Since Rho-Rho kinase calcium sensitizing pathway is being regarded as a potential target not only for the treatment of erectile dysfunction but also atherosclerosis, we designed a study to prevent vasculogenic erectile dysfunction in an atherosclerotic rat model by chronic administration of fasudil, oral Rho kinase inhibitor.
Materials and Methods
Rats (3 months old) were divided into 3 groups (n=10 in each group): control (group 1), atherosclerosis (group 2), and fasudil-treated (group 3). The group 2, 3 received atherosclerosis-prone treatment but group 3 was concurrently treated by fasudil (30mg/kg/day) for 6 weeks. Following the treatment, the erectile function and the amount of pelvic atherosclerosis amount were determined. Cavernosal tissues were prepared for Western blot and malondialdehyde (MDA) assay.
Results
Compared to group 2, the progression of atherosclerosis in iliac and pudendal arteries was significantly suppressed by the chronic administration of fasudil. Also the treatment lowered the level of malondialdehyde in the cavernosal tissue. The results of Western blot revealed that systemically administered fasudil could ameliorate cavernosal molecular environment characterized by the decreased expression of Rho A, transforming growth factor-beta 1 and overexpression of endothelial nitric oxide synthase. As a result, erectile function was maintained by the treatment.
Conclusions
These results indicate that Rho/Rho kinase pathway is substantially involved in the development of penile erection and pelvic atherosclerosis, both of which could be prevented by chronic treatment of fasudil. Thus, Rho-kinase might be considered as a novel target for prevention of vasculogenic erectile dysfunction.
Figures and Tables
Fig. 1
Photomicrographs of representative cross sections of the arteries of the rats in the pilot study. (A) No intimal lesion in the control group. The internal iliac artery (H&E, ×200). (B) Well preserved elastic lamella in the control group. The internal iliac artery (EVG, ×1,000). (C) Normal cellularity and a well preserved internal elastic lamella are observed in the control group. The internal pudendal artery (H&E, ×400). (D) Asymmetrical intimal irregularity and focal thickening of the intima are observed in the 2 week treated rats. The internal iliac artery (H&E, ×200). (E) Widening of the interlamellar spaces and the gradual loss of elastic fiber are observed after a 2 week treatment. The internal iliac artery EVG, ×1,000). (F) No significant intimal change is observed after a 2 week treatment (H&E, ×400). H&E: hematoxylin and eosin, EVG: Elastic van Gieson staining, I: intima; M: media.
Fig. 2
Results of cavernous nerve electrostimulation. Treatment with fasudil effectively ameliorates the deterioration of erectile function. *denotes statistical difference versus atherosclerosis (AS). †denotes statistical difference versus fasudil.
Fig. 3
Photomicrographs of representative cross sections of rat internal iliac (left sided panel) and internal pudendal (right side panel) arteries. The progression of atherosclerosis is substantially attenuated by the fasudil treatment (H&E, ×200 (internal iliac artery) and ×400 (internal pudendal artery)).
Fig. 4
The results of malondialdehyde assay show that fasudil significantly reduces oxidative stress compared to the atherosclerosis (AS) group. *statistically significant differences from control, †statistically significant differences from AS.
Fig. 5
The protein expression of our experimental groups is analysed by Western blotting. TGF-β1: transforming growth factor β1, HIF-1α: hypoxia induced factor 1α, eNOS: endothelial nitric oxide synthase, AS: atherosclerosis. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) served as a control for the loading.
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