Establishment of Diabetic Rats Model with Erectile Dysfunction and Change of nNOS in Corpus Cavernosum

Objective To investigate the ideal diabetic rats model with erectile dysfunction and the nNOS change in corpus cavernosum.Methods 1.24 male SD rats were randomly divided into four groups(control group,STZ 40 mg/kg group,STZ 60 mg/kg group,Buffer group),6 rats in each group.And all rats were observed four days,one week,two weeks and three weeks after STZ injection.The mass,erectile frequency induced by apomorphine and fasting blood glucose should be recorded.2.40 rats were first divided into two groups randomly:4 week group and 7 week group,diabetes mellitus rats model with erectile dysfunction were made through streptozotocin (STZ) injection according to the model standard,and then 4 week group and 7 week group were divided into four groups,which were control group (5 rats each,without STZ injection),diabetes mellitus rats with erectile dysfunction group (DM ED group),diabetes mellitus rats without erectile dysfunction group (DM group) and rats without diabetes mellitus and erectile dysfunction group after STZ injection(none group).Immunohistochemical staining method and color image analysis and IOD were used to observe expression of nNOS in rats corpus cavernosum of different groups.Results 1.There are significant differences in mass and fasting food glucose among groups of different test time and different dose of STZ injection (P 0.001).Significant difference exists in erectile frequency induced by apomorphine among groups of different dose of STZ injection(F =2.831,P =0.046).2.There is significant difference in nNOS expression (IOD) between DM ED group and other three groups (F=3.864,P =0.020) in the 4 week group and 7 week group.Expression of nNOS(IOD) in corpus cavernosum in DM ED group is the lowest in all four groups (P 0.05).Conclusions 1.Diabetic rats model with erectile dysfunction can be considered if fasting serum glucose exceeds 7.2 mmol/L and penile erection do not appear after APO injection.2.The expression of nNOS has a descent tendency in diabetic rats with erectile dysfunction.The decreasing of nNOS may be one of the mechanisms of diabetic erectile dysfunction.