Functional Restoration of Erectile Function Using End-to-side Autonomic-to-somatic Neurorrhaphy in Rats

To investigate the feasibility of erectile function rehabilitation using end-to-side autonomic-to-somatic neurorrhaphy in rats.

Thirty-six adult male Sprague-Dawley rats were divided into 3 groups (n = 12 per group): in the end-to-side coaptation group, the left L6 and S1 spinal nerves were transected, and the distal stump of L6 ventral root was sutured to L4 ventral root through end-to-side neurorrhaphy; in the no-coaptation group, the rats did not undergo coaptation; and in the control group, the left L6 and S1 spinal nerves were transected, but L6 ventral root was preserved. After 4 months, retrograde tracing, histomorphological technique, mating test, and evaluation of functional properties of the regenerated nerve were performed.

Mating test showed a significantly higher intromission behavior rate in the end-to-side coaptation group (41.7%) and control group (58.3%) than in the no-coaptation group (0%) (P < .001). Intracavernous pressure in end-to-side coaptation group was 31.6 ± 12.0 mmHg, significantly higher than in the no-coaptation group (3.1 ± 1.4 mmHg), but lower than in the control group (67.9 ± 18.0 mmHg) (P < .0001). Retrograde tracing indicated the establishment of the new neural pathway. Axon counting and ultrastructure observation confirmed axonal regeneration in the end-to-side coaptation group. The bilateral tibialis anterior muscles wet weight in the end-to-side coaptation group were 0.6686 ± 0.0427 g and 0.6707 ± 0.0515 g (P = .93). The wet weight and morphology of the tibialis anterior muscles revealed no detrimental effect on the donor nerve.

Nerve regeneration can be achieved using end-to-side autonomic-to-somatic neurorrhaphy, and erectile function can be restored without the functional impairment of the donor somatic nerve.