Expression Of SK3 In Cavernous Tissue Of Diabetes Mellitus Rat

Background: Diabetes mellitus (DM) is a systemic metabolic disorders,can cause many organs lesions, such as blood vessels,peripheral nerve ect al. Erectile dysfunction (ED) is a common complication of diabetes. The incidence of diabetic mellitus erectile dysfunction (DMED) is 35%-90% or so. Currently, phosphodieste- rase type 5 inhibitor (PDE5i) is a very important drug for the clinical treatment of ED. But the clinical practice have confirmed that PDE5i are not effective to all the ED patients. Researches have found that the treatment efficiention of PDE5i in DMED has a significant reduction, only about 50%, and in the presence of clinical contraindications, and still has some side effects. Therefore,etiology, pathogenesis and treatment of DMED need to be further explored. Endothelium derived hyperpolarizing factor (EDHF) is the important vasodilator. Type of small conductance Cacium dependent potassium channels of SK3 is a key material in the EDHF pathway. In vitro study found that hypertension, diabetes and other diseases can affect the role of EDHF vasodilator pathway, but DM damage EDHF pathway is not clear. Objective:To investigate the expression of SK3 in cavernous tissue of rat with diabetes mellitus and discussed the possible mechanism of damage to EDHF pathway and SK3 expression in DMED. Methods: All of 60 male Sprague-Dawley rats were divided into 2 groups: control group(n=10) and diabetic group(n=50). The diabetes mellitus model was established by the injection of streptozocin(STZ, 60mg/kg). The rat of failing diabetes model in diabetic group set up to STZ group(n=15). After 8 weeks erection function was examined by apomorphine(APO) injection. The expressions of SK3mRNA and protein were measured by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, respectively. Results: There were 9 rats deaths in the DM group, no death in the NDM group and STZ group. DM group (26) of 14 rats penile erection, erection rate was 54%, STZ group (15) and NDM (10) group rats full erection, erectile erection rate were 100%. SK3 mRNA expressions in DM group (0.50±0.09) was significantly lower than STZ group (1.15±0.03) and the NDM group (1.21±0.04) (P <0.05). SK3 protein expressions in DM group (0.65±0.06) and the STZ group (1.28±0.039) and NDM groups (1.34±0.047) compared with significant difference (P <0.05). STZ group and between the NDM group of rat penile erection and SK3mRNA and protein expression was no difference (P> 0.05).Conclusion: Diabetes can be significantly reduced erectile function in rats, and this may be related to decreased SK3 expressions in rat corpus cavernosum .