Department of Urology, College of Medicine, Seoul National University, Seoul, Korea.
J Sex Med. 2011 Feb;8(2):400-10. doi: 10.1111/j.1743-6109.2010.01724.x.
It has been suggested that the up-regulation of the contractile RhoA/Rho-kinase (ROCK) signaling pathway is one of the important mechanisms for diabetes-associated erectile dysfunction (ED). However, the exact role of RhoA/ROCK signaling in the pathogenesis of diabetes-related ED has not been fully delineated.
To determine whether the RhoA/ROCK pathway is involved in the regulation of corporal apoptosis and whether administration of insulin or fasudil, a specific ROCK inhibitor, could ameliorate ED in streptozotocin-induced diabetic rats.
At 16 weeks after diabetes induction, erectile function was assessed by cavernous nerve stimulation. Penile tissue was assessed for apoptosis with terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate (dUTP) nick end labeling assay. Expression of myosin phosphatase target subunit 1 (MYPT1), protein kinase B (Akt), and phospho-endothelial nitric oxide synthase (eNOS) were evaluated by Western blot. Immunohistochemical study was carried out for smooth muscle alpha-actin, B-cell leukemia/lymphoma 2 (Bcl-2), and Bcl-2-associated X Protein (Bax). Activity of caspase-3 and phosphatase and tensin homolog deleted on chromosome ten (PTEN) was also determined.
Male Sprague-Dawley rats (8 weeks old) were randomly divided into four groups: age-matched controls, diabetic controls, and diabetic rats treated with insulin (10 U/day, subcutaneous injection) or fasudil (30 mg/kg/day, oral) for the last 4 weeks of the 16 weeks after diabetes induction.
Diabetic rats showed impairment of erectile function, increased MYPT1 phosphorylation, and corporal apoptosis. Expression of phospho-Akt, phospho-eNOS, and Bcl-2 were decreased, whereas activity of PTEN and caspase-3 and expression of Bax were increased. Treatment with fasudil normalized these molecular and histologic alterations, and restored erectile function. Insulin treatment showed similar effects to those of fasudil, however, the effects were smaller than fasudil.
This study indicates that up-regulation of the penile RhoA/ROCK pathway in diabetic rats enhances corporal apoptosis via the PTEN/Akt pathway resulting in ED, which could be prevented by chronic treatment with fasudil.
有人提出，收缩型 RhoA/ Rho-激酶（ROCK）信号通路的上调是糖尿病相关勃起功能障碍（ED）的重要机制之一。然而，RhoA/ROCK 信号通路在糖尿病相关 ED 发病机制中的确切作用尚未完全阐明。
确定 RhoA/ROCK 通路是否参与调节海绵体细胞凋亡，以及胰岛素或 ROCK 特异性抑制剂法舒地尔是否可以改善链脲佐菌素诱导的糖尿病大鼠的 ED。
糖尿病诱导 16 周后，通过海绵体神经刺激评估勃起功能。末端脱氧核苷酸转移酶介导的 2'-脱氧尿苷 5'-三磷酸（dUTP）缺口末端标记法评估阴茎组织凋亡。通过 Western blot 评估肌球蛋白磷酸酶靶亚单位 1（MYPT1）、蛋白激酶 B（Akt）和磷酸化内皮型一氧化氮合酶（eNOS）的表达。进行平滑肌α-肌动蛋白、B 细胞淋巴瘤/白血病 2（Bcl-2）和 Bcl-2 相关 X 蛋白（Bax）的免疫组织化学研究。还测定了半胱天冬酶-3 和磷酸酶和张力蛋白同源物缺失的第十染色体（PTEN）的活性。
将 8 周龄雄性 Sprague-Dawley 大鼠随机分为 4 组：年龄匹配的对照组、糖尿病对照组和糖尿病大鼠，糖尿病大鼠在糖尿病诱导后 16 周的最后 4 周内分别接受胰岛素（10 U/天，皮下注射）或法舒地尔（30 mg/kg/天，口服）治疗。
糖尿病大鼠勃起功能受损，MYPT1 磷酸化增加，海绵体凋亡增加。磷酸化 Akt、磷酸化 eNOS 和 Bcl-2 的表达减少，而 PTEN 和半胱天冬酶-3 的活性以及 Bax 的表达增加。法舒地尔治疗可使这些分子和组织学改变正常化，并恢复勃起功能。胰岛素治疗显示出与法舒地尔相似的作用，但效果小于法舒地尔。
本研究表明，糖尿病大鼠阴茎 RhoA/ROCK 通路的上调通过 PTEN/Akt 通路增强海绵体细胞凋亡，导致 ED，慢性法舒地尔治疗可预防 ED。
