Hydroxyfasudil ameliorates penile dysfunction in the male spontaneously hypertensive rat.

Hypertension represents a major risk factor for erectile dysfunction. Although the etiology of hypertension-induced erectile dysfunction is multifactorial and still unknown, Rho-Rho kinase pathway is one of the key factors. To investigate whether administration of hydroxyfasudil, a Rho kinase inhibitor could prevent dysfunction of NO-induced relaxation in corpus cavernosum smooth muscle in the SHR (spontaneously hypertensive rat), twelve-week-old male SHRs were treated with hydroxyfasudil (3 or 10 mg/kg, i.p.) once a day for 6 weeks. Wistar rats and SHRs treatment with vehicle were used as age-matched controls. Penile cGMP concentrations and Rho kinase activities were determined, and penile function was estimated by organ bath studies with norepinephrine-induced contractions and acetylcholine-induced relaxations. The participation mRNA levels of eNOS and participation protein levels of eNOS and phosphorylated eNOS were investigated by quantitative real-time PCR methods and immunoblot analysis, respectively. The SHR showed significantly decreased cGMP concentrations, increased Rho kinase activities, norepinephrine-induced hyper-contractions, and acetylcholine-induced hypo-relaxations in the penile tissue. Treatment with hydroxyfasudil significantly improved the decreased penile cGMP concentrations, the increased Rho kinase activities, the increased norepinephrine-induced contractions, and the decreased acetylcholine-induced relaxation in a dose-dependent manner. Although there were no significant differences in expression protein levels of eNOS among any of the groups, down-regulation of eNOS mRNAs as well as phosphorylated eNOS were significantly ameliorated after treatment with hydroxyfasudil. Our data suggest that hydroxyfasudil ameliorates hypertension-associated dysfunction of NO-induced relaxation in corpus cavernosum smooth muscle possibly via inhibition of the Rho-Rho kinase pathway and activation of NO-eNOS pathway in the SHR.

Saito M ，Ohmasa F ，Dimitriadis F ，Tsounapi P ，Sejima T ，Shimizu S ，Kinoshita Y ，Satoh K ... -  《-》

Edaravone ameliorates diabetes-induced dysfunction of NO-induced relaxation in corpus cavernosum smooth muscle in the rat.

Diabetes mellitus (DM) represents a major risk factor for erectile dysfunction (ED). Although the etiology of diabetes-induced ED is multifactorial and still unknown, reactive oxygen species are thought to be one of the key factors. The aim of this article is to investigate whether administration of edaravone, a free radical scavenger, could prevent type 1 diabetes-induced dysfunction of nitric oxide (NO)-induced relaxation in corpus cavernosum smooth muscle in the rat. Six-week-old male Wistar rats were randomly divided into three groups. One group was treated with citrate-phosphate buffer plus normal saline (group Cont), whereas in the other two groups, diabetes was induced by streptozotocin (50 mg/kg intraperitoneally [i.p.]). Subsequently, the diabetic rats were treated for 4 weeks either with edaravone (10 mg/kg/day, i.p.; group DM + E) or with normal saline (group DM). Serum glucose and malondialdehyde levels as well as penile cyclic guanosine monophosphate (cGMP) concentrations were determined, and penile function was estimated by organ bath studies with norepinephrine-mediated contractions and acetylcholine-mediated relaxations. The participation mRNA levels of muscarinic M(3) receptors, neuronal nitrous oxide synthase (nNOS), endothelial NOS (eNOS) and inducible NOS (iNOS), and participation protein levels of nNOS, eNOS, phosphorylated nNOS, and phosphorylated eNOS were investigated by quantitative real-time polymerase chain reaction (PCR) and immunoblot analysis, respectively. Treatment with edaravone prevented partially but significantly the decreased body and penile weight induced by diabetes. Treatment with edaravone significantly improved the increased diabetes-induced malondialdehyde levels, the decreased penile cGMP concentrations, the increased diabetes-induced norepinephrine-mediated contractions, and the decreased acetylcholine-mediated relaxation. Although there were no significant differences in expression levels of mRNAs in nNOS, diabetes-induced upregulation of muscarinic M(3) receptor and iNOS mRNAs as well as diabetes-induced downregulations of eNOS, phosphorylated nNOS, and phosphorylated eNOS were significantly prevented by edaravone. Edaravone decreases the oxidative insult in the penile corpus cavernosum by ameliorating the NO-NOS system and thus preventing partially the developing ED in DM in the rat.

Ohmasa F ，Saito M ，Tsounapi P ，Dimitriadis F ，Inoue S ，Shomori K ，Shimizu S ，Kinoshita Y ，Satoh K ... -  《-》

Fasudil improves the endothelial dysfunction in the aorta of spontaneously hypertensive rats.

We investigated the effects of fasudil, a Rho kinase inhibitor, in the endothelial dysfunction of aortas from spontaneously hypertensive rats (SHRs). SHRs were divided in three groups; intraperitoneally (i.p.) vehicle-treated SHRs (SHR), SHRs treated with fasudil 3 mg/kg i.p. (Fas3), and SHRs treated with fasudil 10 mg/kg i.p. (Fas10). Vehicle-treated Wistar rats were used as normo-tensive control group. After a six-week-treatment, blood pressure and heart rate were measured by the tail cuff method. Afterwards animals were sacrificed and aortas were examined in vitro by organ bath studies to evaluate the contraction and relaxation ability. Rho kinase activity, myosin light chain (MLC), phosphorylated MLC (phospho-MLC), eNOS, phospho-eNOS protein expression and eNOS mRNA levels were evaluated. SHR demonstrated a significant hypercontractility and impaired relaxation compared to the control. Fasudil 10mg/kg significantly corrected the hypercontractility, restored the relaxation, and significantly decreased the mean arterial blood pressure, while no change observed in the systolic blood pressure. Rho kinase activity was significantly higher in the SHR, and was significantly inhibited by the high dose of fasudil. There was a slight up-regulation in the MLC, and phospho-MLC protein levels in the SHR. eNOS and phospho-eNOS protein levels were significantly lower in the SHR, and this abnormality was significantly normalized by fasudil treatment. No significant difference was observed in the eNOS gene expression. This study suggests that fasudil by inhibiting the Rho kinase activity normalizes the eNOS expression and phosphorylation and ameliorates the endothelial dysfunction induced by hypertension in the SHR model.

Tsounapi P ，Saito M ，Kitatani K ，Dimitriadis F ，Ohmasa F ，Shimizu S ，Kinoshita Y ，Takenaka A ，Satoh K ... -  《-》

Effect of an angiotensin II receptor blocker and a calcium channel blocker on hypertension associated penile dysfunction in a rat model.

Shimizu S ，Tsounapi P ，Honda M ，Dimitriadis F ，Taniuchi K ，Shimizu T ，Inoue K ，Saito M ... -  《-》

Hydroxyfasudil ameliorates bladder dysfunction in male spontaneously hypertensive rats.

To investigate the effect of hydroxyfasudil, a nonselective Rho-kinase inhibitor, on hypertension-related bladder dysfunction in spontaneously hypertensive rats (SHRs), as there is an increasing evidence that the Rho-associated protein kinase (ROCK) system plays an important role in bladder contraction. Twelve-week-old male SHRs were treated with hydroxyfasudil (1 mg/kg i.p.) once a day for 6 weeks. Wistar rats and SHRs without treatment with hydroxyfasudil were used as controls. Six weeks after the hydroxyfasudil treatment, voiding functions were evaluated by metabolic cages and cystometric studies under urethane anesthesia (1.0 g/kg i.p.). Bladder blood flow (BBF) was estimated by the hydrogen clearance method. The bladder tissue levels of nerve growth factor (NGF) and ROCK activity were evaluated by the ELISA method. The SHR showed significant increases in micturition frequency and decreases in single-voided volume in metabolic cages, and significantly increases in micturition frequency and intercontractile interval in cystometric studies. Furthermore, the SHR showed significant increases in the BBF and bladder NGF concentration compared with the Wistar rats. These alterations in the SHR were significantly ameliorated after treatment with hydroxyfasudil, with small changes in blood pressure. However, the maximum detrusor pressures during voiding and the ROCK activities in the experimental bladders were similar in all rats examined. Our data indicate that this dose of hydroxyfasudil was effective on the BBF, whereas it had no significant effect on micturition pressure. These findings suggest that hydroxyfasudil could ameliorate hypertension-related bladder dysfunction in the SHR via improvement of the BBF (248 words).

Inoue S ，Saito M ，Takenaka A 《-》