Expressions of CSE and CBS in the penile corpus cavernosum of hyperglycemia rats and their implications

Objective: To investigate the impact of hyperglycemia on the hydrogen sulfide( H2S) signaling pathway in rat penile tissue and its relationship with erectile function. Methods: Twenty healthy male Sprague Dawley( SD) rats aged 8 weeks were randomly divided into groups A( 4-week healthy control),B( 4-week diabetes mellitus model),C( 6-week healthy control) and D( 6-week diabetes mellitus model). The rats in groups B and D were injected intraperitoneally with streptozotocin at 50 mg/kg to induce diabetes mellitus,while those in groups A and C with the same volume of normal saline. The animals were killed at 4( groups A and B) and 6 weeks( groups C and D) after treatment for measurement of the maximal intracavernous pressure / mean arterial blood pressure( ICPmax/ MAP) by electrostimulation,determination of the H2S concentration in the plasma and penile tissue,and detection of the expressions of cystathionine-β-synthetase( CBS) and cystathionine-γ-lyase( CSE) in the penile corpus cavernosum by immunohisto-chemistry and Western blot. Results: With electrostimulation of the pelvic ganglia at 5V and 7 V,ICPmax/ MAP was significantly reduced in groups B( 0. 19 ± 0. 03 and 0. 29 ± 0. 04) and D( 0. 14 ± 0. 04 and 0. 25 ± 0. 04) as compared with A( 0. 46 ± 0. 07 and 0. 68 ± 0. 09) and C( 0. 43 ± 0. 07 and 0. 65 ± 0. 16)( P 0. 05). No statistically significant differences were found in the level of serum testosterone either between groups A and B( [469. 19 ± 126. 46]ng / dl vs [359. 08 ± 60. 06]ng / dl,P 0. 05) or between C and D( [470. 44 ± 209. 28]ng / dl vs [297. 01 ± 96. 58]ng / dl,P 0. 05). Groups B and D showed remarkable reduction in the H2S concentration( P 0. 05) and the expressions of CBS and CSE( P 0. 05) in comparison with A and C,and the CBS and CSE expressions were even more significantly decreased in D than in B( P 0. 05). Conclusion: The reduced concentration of H2S and decreased expressions of CBS and CSE in the penile corpus cavernosum of the diabetic rats suggested that the H2S signaling pathway might be involved in hyperglycemia-induced erectile dysfunction.