糖尿病性勃起功能障碍大鼠阴茎海绵体组织中神经生长因子的表达及其治疗作用的研究

目的:本研究通过检测糖尿病性勃起功能障碍(ED)大鼠阴茎组织中神经生长因子(NGF)表达,并使用hNGF进行治疗,以探讨糖尿病性ED发病机制及NGF治疗作用的机制。方法:成年雄性SD大鼠60只,随机取50只大鼠用于制作糖尿病模型,饲养8周后,取正常组和糖尿病组大鼠阴茎海绵体组织,采用RT-PCR和W estern印迹法检测NGF的mRNA及蛋白水平。从造模成功的糖尿病大鼠中筛选出有ED大鼠,把所有大鼠分为5组:正常组、糖尿病性ED组、糖尿病性ED单用NGF组(NGF组)、糖尿病性ED单用胰岛素组(R I组)、糖尿病性ED联合应用NGF和胰岛素组(NGF+R I组,胰岛素通过颈部皮下注射给药,NGF通过腹腔内注射给药),8周后测海绵体内压(ICP),并取所有大鼠阴茎海绵体组织用免疫组化法观察nNOS神经纤维的变化。结果:与正常组相比,糖尿病性ED组大鼠阴茎海绵体组织中NGF的mRNA表达增加,蛋白含量增加。与糖尿病性ED组相比,NGF组、R I组、NGF+R I组ICP水平显著升高(P<0.05);NGF组、R I组、NGF+R I组阴茎组织中nNOS神经纤维水平显著升高(P<0.05)。结论:糖尿病晚期勃起神经出现损伤并发生ED,推测可能与NGF分泌增加的幅度小于高血糖状态对勃起神经的损伤程度有关,也可能与NGF与其相应受体结合转运能力损害有关,给予外源性NGF可能有助于糖尿病性ED局部神经病变减轻和勃起功能改善。提示NGF的异常在糖尿病性ED的发病及治疗中可能具有重要作用。

Expression of Nerve Growth Factor in Cavernous Tissue and Its Effects on the Treatment of Rats with Diabetic Erectile Dysfunction

Objective: To investigate the content of nerve growth factor(NGF) in penis of rats with diabetic erectile dysfunction(DED) and apply rhNGF to treat the DED rat model to study the pathogenesis mechanism of DED and treatment effects by NGF for DED rat model.Methods: Fifty adult male SD rats were randomly selected to make up diabetic models.After 8 weeks,the mRNA and protein levels of NGF in rat penis were detected.Then the rest of rats were divided into 5 groups: normal control group,non-treated diabetes group,NGF treatment group,insulin treatment group,NGF plus insulin treatment group.After 8 weeks of treatment,intracavernous pressure(ICP) was measured.The content of neuronal nitric oxide synthase(nNOS) in the erectile tissue was also evaluated by immunohistochemistry staining.Results: Compared with those of normal control group,the mRNA content of NGF and protein in the penis of non-treated diabetic rats is increased significantly.Compared with non-treated diabetic group,ICP was much higher in the treated groups which received NGF or/and insulin therapy,and the changes in nNOS staining of those groups were the same.Conclusion: The injury of pelvic splanchnic nerves in advanced stage of diabetes may lead to DED,which may be relevant to the abnormal of NGF level or the NGF receptors.The increased extent of NGF in penis of rat with DED suggests that erectile nerves be severely damaged by diabete and the increase of producing NGF couldn't compensate the needs for reproduction of the nerve fibers.The ability of combination of NGF with its receptor may also be damaged.It is helpful to use exogenous NGF to lessen the partly neuropathy and improve the erectile dysfunction of diabetic rats.The abnormal of NGF may play an important role in the pathosenesis of diabetic ED and its treatment.Natl J Androl,2005,11(10):748-751,754