褪黑素抗氧化治疗糖尿病大鼠阴茎勃起功能障碍的研究

目的 观察褪黑素对糖尿病大鼠阴茎勃起功能的影响,探讨氧化应激在糖尿病性勃起功能障碍发病机制中的作用.方法 一次性腹腔注射STZ建立糖尿病大鼠模型,随机分为糖尿病组、褪黑素(MT)治疗组以及对照组.8周后通过电刺激各组大鼠勃起神经来检测海绵体内压,评价勃起功能；采用硫代芭比妥酸法检测阴茎海绵体组织中丙二醛(MDA)含量,黄嘌呤氧化酶法测超氧化物氧化酶(SOD)活性；免疫组化染色半定量分析各组大鼠阴茎海绵体中平滑肌及内皮的含量.结果 与正常对照组相比,阴茎海绵体组织中MDA含量显著增加(P＜0.01),SOD活性降低(P＜0.05),最大海绵体内压(ICP)亦显著降低(P＜0.05)；与糖尿病组相比,MT组大鼠海绵体MDA含量明显降低(P＜0.05),其SOD活性和ICP显著升高(P＜0.05)；且其海绵体平滑肌及海绵窦内皮细胞含量明显提高.结论 MT可通过改善组织中氧化应激水平,促进阴茎海绵体平滑肌和内皮组织修复,提高勃起功能；抗氧化治疗可能为糖尿病性勃起功能障碍的防治提供新的策略.

Effect of melatonin on oxidative stress in cavernous tissue of diabetic rats

ObjectiveTo explore the effects of melatonin on oxidative stress in cavernous tissues of diabetic rats and to investigate the mechanism of oxidative stress during the development of diabetic erection dysfunction. MethodsThe diabetic model rats induced by streptozotocin were randomly divided into the diabetic group and melatonin treatment group. The normal rats were raised as normal control group. Eight weeks later, the erectile function was assessed by measuring the rise in intracavernous pressure （ICP） of the rats following cavernous nerve electrostimulation before the rats were sacrificed. The levels of malondialdehyde （MDA） and the activities of superoxide dismutase （SOD） in cavernous tissues were detected. The content of endothelium and smooth muscle in penis were analyzed with immunohistochemical assay. ResultsA significant decrease in ICP was recorded in the diabetic rats （P＜0.01）. The levels of MDA increased remarkably （P＜0.01） and the activities of SOD decreased significantly （P＜0.05） in cavernous tissues of the diabetic group. Compared with the diabetic group, the levels of MDA decreased significantly （P＜0.05） and the activities of SOD increased remarkably （P＜0.05） in cavernous tissues of the melatonin treatment group. Meanwhile, melatonin increased the concentration of endothelium and smooth muscle in penis of diabetic rats. Conclusions Supplements of melatonin could attenuate oxidative stress and improve erectile function. Oxidative stress plays an important role in diabetic erectile dysfunction and our study might provide a new insight for the prevention and treatment for it.