Introduction. The precise mechanisms underlying erectile dysfunction (ED) occurring after cavernous nerve (CN)-sparing surgery remain to be determined. Aim. To evaluate the expression of interleukin-6 (IL-6) and IL-6 receptor (IL-6R) after CN injury, and the effect of inhibiting IL-6 bioactivity on nerve injury-related ED. Methods. Male Sprague-Dawley rats were divided into three groups: sham operation; bilateral CN dissection without crushing or cutting; and bilateral CN resection. In the interventional experiment, male rats underwent bilateral CN dissection, and anti-rat IL-6 antibody in phosphate-buffered saline (PBS) or vehicle alone was injected intraperitoneally immediately and 24hours after CN dissection. Main Outcome Measures. One, 3, 7, 28, and 56days after surgery, the expression of IL-6 and IL-6R in the major pelvic ganglion (MPG) was examined by real-time polymerase chain reaction. In the interventional experiment, erectile function was assessed by determining intracavernous pressure divided by arterial pressure (ICP/AP) during electrical pelvic nerve stimulation at 4weeks after surgery in the anti-IL-6-injected rats and PBS-injected rats. The degree of nerve injury was also evaluated by retrograde dye tracing with Fluorogold. Results. The expression levels of IL-6 and IL-6R were increased in the early period of CN injury, as compared with the sham group. IL-6 expression on day 1 was particularly enhanced. Four weeks after CN dissection, the anti-IL-6 group had greater ICP/AP and more FG-positive cells than the PBS group. Conclusions. Expression levels of IL-6 in the MPG were increased in the acute phase following CN injury. Inhibition of IL-6 bioactivity attenuated ED following CN dissection. Thus, the suppression of excess inflammatory responses in the acute phase may lead to improvements in ED occurring after nerve-sparing radical prostatectomy.
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