外源性硫化氢通过抑制阴茎海绵体平滑肌细胞凋亡改善海绵体神经损伤大鼠勃起功能障碍

目的 观察外源性硫化氢对双侧海绵体神经损伤（BCNI）大鼠阴茎海绵体平滑肌细胞（CCSMC）凋亡及勃起功能障碍的影响。方法 将24只SD雄性大鼠随机分为3组（n=8只/组）：假手术组、双侧海绵体神经损伤组（BCNI组）、硫化氢干预组（BCNI+NaHS组）。通过钳夹损伤双侧海绵体神经构建BCNI模型。BCNI+NaHS组每天腹腔注射100 μmol/kg的NaHS溶液；BCNI组每日腹腔注射等量生理盐水。治疗4周后检测海绵体内压（ICP）和平均动脉压（MAP），并通过Western blot检测胱硫醚-β-合成酶（CBS）和胱硫醚-γ-裂解酶（CSE），α-SMA，Collagen-Ⅰ，Caspase-3、Bax、Bcl-2表达水平，通过免疫组化检测CBS、CSE表达情况，Masson’s Trichrome染色检测海绵体平滑肌/胶原比值，以及 TUNEL+α-SMA组织免疫荧光双染检测CCSMC凋亡水平。结果 治疗4周后，BCNI+NaHS组ICP/MAP比值高于BCNI组（P<0.05）；Masson’s Trichrome染色结果显示，BCNI+NaHS组海绵体平滑肌/胶原比值较 BCNI 组显著升高（P<0.05）；Western blot 结果显示 BCNI+NaHS 组α-SMA 蛋白表达高于 BCNI 组（P<0.05），同时 Collagen-Ⅰ蛋白表达低于 BCNI组（P<0.05）；TUNEL+α-SMA组织免疫荧光双染结果显示，BCNI+NaHS组CCSMC凋亡数较BCNI组降低（P<0.05）。与BCNI组相比，BCNI+NaHS组Caspase-3、Bax蛋白表达降低（P<0.05），Bcl-2蛋白表达、Bcl-2/Bax比值升高（P<0.05）。BCNI组CBS、CSE表达较其余两组显著降低（P<0.05）。结论 外源性硫化氢可提高经典的抗凋亡蛋白Bcl-2及抑制CCSMC凋亡，进而改善BCNI大鼠勃起功能。

Exogenous hydrogen sulfide improves erectile dysfunction by inhibiting apoptosis of corpus cavernosum smooth muscle cells in rats with cavernous nerve injury

Objective To explore the effects of exogenous hydrogen sulfide (H2S) on apoptosis of corpus cavernosum smooth muscle cells (CCSMCs) and erectile dysfunction (ED) in rats with bilateral cavernous nerve injury (BCNI). Methods Twentyfour male SD rats were randomly divided into 3 groups (n=8): sham operation group, bilateral cavernous nerve injury group (BCNI group) and H2S intervention group (BCNI+NaHS group). In BCNI and BCNI+NaHS groups, BCNI was induced by clamp injury of the bilateral cavernous nerves, and the rats were subjected to daily intraperitoneal injection of normal saline and 100 μmol/kg NaHS solution for 4 weeks, respectively. After the treatment, the intracavernous pressure (ICP) and mean arterial pressure (MAP),) of the rats were measured. Western blotting was used to detect the expressions of cystathionine β synthetase (CBS), cystathionine γ lyase (CSE), α-SMA, collagen-I, caspase-3, Bax and Bcl-2 in the penile cavernous tissue, and the expressions of CBS and CSE were also detected immunohistochemically. The ratio of cavernous smooth muscle to collagen was detected using Masson’s Trichrome staining. The apoptosis level of CCSMC was detected by TUNEL + α-SMA immunofluorescence double staining. Results After 4 weeks of treatment, the rats in BCNI+NaHS group showed a significantly higher ICP/MAP ratio than those in BCNI group (P<0.05). The results of Masson’s Trichrome staining showed that the ratio of cavernous smooth muscle/collagen was significantly higher in BCNI + NaHS group than in BCNI group (P<0.05). Western blotting showed a significantly higher expression of α- SMA protein but a lower expression of collagen-I protein in BCNI+NaHS group than in BCNI group (P<0.05). TUNEL+α-SMA immunofluorescence double staining revealed a significantly lower number of apoptotic CCSMCs in BCNI+NaHS group than in BCNI group (P<0.05). Compared with those in BCNI group, the rats in BCNI+NaHS group had significantly decreased expressions of caspase-3 and Bax proteins (P<0.05) with significantly enhanced Bcl-2 protein expression and an increased Bcl-2/Bax ratio (P<0.05). The expressions of CBS and CSE were significantly lower in BCNI group than in the other two groups (P<0.05). Conclusion Exogenous H2S enhance the expression of the classic apoptotic protein Bcl-2 and reduces apoptosis of CCSMC to improve the erectile function in rats with BCNI.