左旋精氨酸对糖尿病大鼠阴茎海绵体氧化应激损伤的保护作用

Protective effect of L-Arginine on oxidative stress in cavernous tissue of diabetic rats

目的探讨左旋精氨酸(L-Arg)对糖尿病大鼠阴茎海绵体氧化应激损伤的保护作用。方法大剂量STZ腹腔注射建立糖尿病大鼠模型,随机分为糖尿病组、L-Arg治疗组,并设正常对照组。治疗8周后用电刺激各组大鼠勃起神经测定海绵体内压评价勃起功能采用黄嘌呤氧化酶法检测阴茎海绵体组织中超氧化物歧化酶(SOD)活性,硫代芭比妥酸法测丙二醛(MDA)含量;光镜下观察Masson染色切片。结果糖尿病组较正常对照组,阴茎海绵体MDA含量显著增高(P<0.01),SOD活性显著下降(P<0.05),最大海绵体内压(ICP)显著降低(P<0.05);与糖尿病组比较,L-Arg可使海绵体MDA含量明显降低(P<0.05),显著提高其SOD活性及ICP(P<0.05)。糖尿组大鼠阴茎组织中胶原纤维含量明显减少,排列紊乱、稀疏,平滑肌减少变薄,出现断裂;L-Arg组大鼠阴茎组织结构可见明显改善。结论糖尿病大鼠阴茎海绵体存在氧化应激损伤,导致海绵体结构的改变是其勃起水平下降的重要因素,通过补充L-Arg,可以减轻勃起组织的氧化应激损伤,改善组织结构,从而提高勃起能力。

Objective To explore the effects of L-Arginine （L-Arg） on oxidative stress in cavernous tissue of diabetic rats. Methods The diabetic rat models induced by streptozotocin were randomly divided into the diabetes group and the treated group with L-Arg. The normal rats were raised as normal control group. Eight weeks later, erectile function of rats was assessed by measurement of intracavernous pressure （ICP） of the rats following cavernous nerve eletrostimulation. The levels of Malondialdehyde （MDA） and the activities of superoxide dismutase（SOD） in cavernous tissue were detected. The Masson staining was used to show the structure of rat penis. Results Compared with that of the normal control group, the levels of MDA increased remarkably in cavernous tissue of rats in the diabetes group and the activities of SOD decreased significantly, meawhile a significant decrease in ICP was found in the diabetic rats. Compared with that of diabetes group, the levels of MDA decreased significantly in cavernous tissue of rats in the treated group with L-Arg and the activities of SOD increased remarkably. The Masson staining showed remarkable reduction of smooth muscle fibers and collagen fibers in cavernous tissue of the diabetic rats. Disrupted continuity and integrity of smooth muscles were also obersved. However, cavernous tissue structure of the diabetic rats were improved in the treated group with L-Argo Conclusion Hyperglycemia could cause oxidative stress in the cavernous tissue of diabetic rats which contributed to diabetic erectile dysfunction. Supplements of L-Arg might attenuate oxidative stress and improve erectile function.