OBJECTIVETo 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.

METHODSFifty 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 value- ated by immunohistochemistry staining.

RESULTSCompared 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.

CONCLUSIONThe 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 pathogenesis of diabetic ED and its treatment.