Role of hydrogen sulfide in erectile dysfunction in diabetic rats

AIM:To study the effects of hydrogen sulfide(H 2 S) on erectile dysfunction(ED) in a diabetic rat model.METHODS:Diabetes mellitus(DM) was induced in 60 male adult Sprague-Dawley rats by intraperitoneal injection of streptozocin(STZ) and 49 DM rats were established,in which 36 DM rats were accompanied with ED by detecting apomorphine-induced erections.The DM + ED rats were further randomly divided into 3 groups:DM group,DM + NaHS group and DM + sildenafil group.Meanwhile,another 10 normal SD rats were used as control group.The rats in DM + NaHS group were treated with NaHS at dose of 50 μmol / kg by intraperitoneal injection everyday for 12 weeks.The rats in DM + sildenafil group were gavaged with sildenafil at dose of 5 mg / kg every day for 12 weeks.Equal volume of sterile saline was injected in the rats in normal control group and DM group.The erectile function of all rats was evaluated after injection of apomorphine.The blood concentration of H 2 S was detected.Furthermore,the activity and expression level of cystathionine γ-lyase(CSE) in the penile tissue were investigated.RESULTS:STZ-induced DM had a successful rate of 81.7%(49 /60),and the proportion of DM rats with ED was 73.5%(36 /49).Compared with DM group,the rats in DM + NaHS group and DM + sildenafil group had a better erectile function,with erection frequencies of(33.3 ± 5.5) %,(54.5 ±5.3) % and(63.6 ±9.1) %,respectively.Compared with the normal rats,the activity and expression level of CSE in all DM groups were decreased,which were also significantly lower in DM + NaHS group than those in both DM group(P 0.05) and DM + sildenafil group(P 0.05).CONCLUSION:STZ-induced diabetic rats have a high incidence of ED.H2S plays a certain role in promoting erectile function in diabetic rats with ED.Exogenous administration of H2S may establish a negative feedback inhibition on the activity and expression of CSE in rat penile tissue.