Endogenous hydrogen sulfide insufficiency as a predictor of sexual dysfunction in aging rats

Abstract

Objective: Our earlier studies showed that endogenous hydrogen sulfide (H₂S) pathway contributed significantly to erectile function. In this study, we tested the hypothesis that age-dependent changes in the bioavailability of H₂S increased the risk of erectile dysfunction (ED). Methods: Young, adult (3-month) and older (18-month) male Sprague-Dawley rats (n = 6−8/group) were treated daily with sodium hydrosulfide hydrate (NaHS), DL-propargylglycine, sildenafil or l-NAME for 10 weeks. Subsequent to cavernous nerve electrical stimulation, intracavernosal pressure (ICP) responses were determined, and the samples were collected and processed for hormonal (plasma) and gaseous parameters (plasma and erectile corpus cavernosum [CC]) using standard assay protocols. Results: Aging significantly reduced the ICP response (35.9 ± 2.0 mmHg vs. 45.2 ± 1.9 mmHg in young controls), which was countered by NaHS (53.5 ± 6.0) or sildenafil (52.8 ± 9.8) treatment. In these rats, marked increments to testosterone (T) or estradiol resulted from NaHS supplementation. Similar to age-dependent decline in NO, the plasma and CC level of H₂S was significantly lower in senescent rats when compared with young animals (p < 0.05). Conclusion: Our results confirm that ED with aging may be linked to a derangement in the H₂S pathway accompanied by low T levels. It is likely that a pharmacologic intervention delivering H₂S will provide additional benefits to sexual function from an improved T milieu.

Keywords::

• Aging
• erectile dysfunction
• gasotransmitter
• hydrogen sulfide
• testosterone

Acknowledgments

Authors wish to acknowledge the award of the research grant R-174-000-104-213 by the National Medical Research Council (NMRC), Ministry of Health, Singapore for the conduct of this work. The technical help provided by Ms. Jameelah SM and Ms. Liaw RL is also gratefully acknowledged.

Declaration of Interest: The authors report no conflicts of interest.