Radiation-induced erectile dysfunction using prostate-confined modern radiotherapy in a rat model

Area of Science:

• Urology
• Radiation Oncology
• Reproductive Medicine

Background:

• Mechanisms of radiation-induced erectile dysfunction (ED) remain unclear.
• Previous animal models do not accurately reflect current stereotactic radiotherapy (RT) techniques.
• Clinical studies on radiation-induced ED are limited.

Purpose of the Study:

• To analyze functional and morphological changes in erectile function (EF).
• To utilize image-guided stereotactic prostate-confined RT in a rat model.
• To investigate the impact of RT on erectile function and its underlying mechanisms.

Main Methods:

• Sixty rats were divided into sham and RT groups, receiving a single 20-Gy fraction to the prostate.
• Erectile function was assessed via bioassay and intracavernous pressure (ICP) measurements at 2, 4, and 9 weeks.
• Penile tissues and cavernous nerves were analyzed using immunohistochemistry and perfusion analysis; testosterone levels were measured.

Main Results:

• Statistically significant, time-dependent impairment of EF was observed from 4 weeks post-RT.
• Decreased expression of neuronal nitric oxide synthase (NOS) in the cavernous nerve (CN) and smooth muscle/collagen in penile vessels was noted.
• Reduced perfusion in the corpora cavernosa (CC) was observed, while CD31 expression and testosterone levels remained unaffected.

Conclusions:

• Image-guided stereotactic RT induces time-dependent erectile dysfunction in rats.
• Reduced neuronal NOS expression in the CN may lead to decreased smooth muscle and blood perfusion in the CC, causing veno-occlusive dysfunction.
• This study provides a foundation for understanding radiation-induced ED and developing future research.