Elucidating Mechanisms of Long-Term Gasoline Vehicle Exhaust Exposure-Induced Erectile Dysfunction in a Rat Model

Introduction: Exposure to air pollution poses a risk for morbidity in multiple diseases. However, the role of ambient air pollutant emissions in public sexual health is just beginning to be understood and remains controversial. Aim: We have determined to elucidate the specific role of gasoline vehicle exhaust (VE), a crucial source and toxicant of air pollution, in the penile erectile function via a rat model. Methods: 40 male Sprague Dawley rats, 12 weeks of age, were used in this experiment. Except for the control group (10 rats), rats were equally exposed to VE for total 2 hours, 4 hours, and 6 hours daily for 3 months consecutively. During each VE exposure periods, particulate matter (PM) mass concentrations of PM1, PM2.5, and PM10 were 1.43 +/- 0.036, 1.45 +/- 0.033, and 1.47 +/- 0.037 mg/m(3), respectively. Main Outcome Measure: Erectile function, pulmonary function, serum inflammatory factors, and histologic examinations of the lung and penile tissues were evaluated. Results: Our study indicates that in vivo, 4-hour, and 6-hour daily exposure to VE causes significant reduction of erectile function, as judged by intracavernous pressure measurement. Meanwhile, we have observed that the 4-hour and 6-hour VE exposure rats exhibited remarkable increased levels of serum inflammatory factors, decreased total lung capacity and chord compliance, thickened alveoli septum, destroyed alveoli, pulmonary fibrosis, as well as down-regulation of the messenger RNA and protein expression of endothelial and neuronal nitric oxide synthase in the penile tissue when compared with normal control rats. Clinical Implications: We speculated that the underlying mechanisms of VE inducing erectile dysfunction could be attributed to systemic inflammation, pulmonary dysfunction, and the reduction of nitric oxide synthase activity in the corpus cavernosum. Strength & Limitations: For the first time, our study revealed the deleterious effect of VE on penile erection in vivo. However, the VE exposure model might not entirely mimic the natural condition of ambient air pollution. Conclusion: Our results raise concerns about the potential role played by long-term exposure to gasoline VE in the development of erectile dysfunction. Copyright (C) 2018, International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.