Erectile Functional Restoration With Genital Branch of Genitofemoral Nerve to Cavernous Nerve Transfer After Bilateral Cavernous Nerve Resection in the Rat

Bone marrow mesenchymal stem cells therapy on bilateral pelvic nerve crush-induced voiding dysfunction in rats

INTRODUCTION AND HYPOTHESIS

Neurogenic voiding dysfunction can be induced after radical pelvic surgery and severely affects patients' quality of life. This study aims to investigate the effects of bone marrow mesenchymal stem cells (BMSCs) on neurogenic voiding dysfunction in male rats and explore the underlying mechanisms.

METHODS

Thirty 4-week-old male Sprague-Dawley rats were randomly divided into three groups: (1) sham-operated (sham, n = 10), (2) intrabladder wall injection of phosphate buffer solution (PBS) after bilateral pelvic nerve crush (BPNC+PBS, n = 10), and (3) intrabladder wall injection of BMSCs after bilateral pelvic nerve crush (BPNC+BMSCs, n = 10). Four weeks postoperatively, functional and morphological examinations were performed.

RESULTS

Compared to the sham group, BPNC rats manifested significant augmentation in the frequency of non-voiding contractions and postvoid residual and bladder capacity, and they had decreases in intravesical pressure and voiding efficiency. However, they were markedly improved after BMSC injection. Masson's trichrome staining showed that the ratio of collagen area in bladder wall tissue significantly increased in the BPNC+PBS group but was reduced following BMSC injection. BPNC increased the protein expression of TGF-β1, Smad2/3, and collagen I/III but decreased the expression of α-SMA. BMSC injection stimulated higher expression levels of α-SMA and lower expression levels of the other target proteins. The expression levels of vesicular acetylcholine transporters were reduced at 4 weeks post-BPNC, whereas injection of BMSCs boosted the expression quantity.

CONCLUSIONS

BMSC therapy suppressed detrusor fibrosis, improved intravesical pressure and voiding efficiency, and partially restored voiding function in male rats after BPNC.

Restoration of the penile sensory pathway through end-to-side dorsal root neurorrhaphy in rats

Objective: Spinal cord injury often leads to the loss of penile sensation, and severely affects the individual's sexual function. The present study aimed to restore the penile sensory pathway through end-to-side dorsal root (DR) transfer neurorrhaphy in rats, and preliminarily verified the feasibility of the operation.Design: 40 male adult Sprague-Dawley rats were divided into three groups. In the model (n = 20) and resection (n = 10) groups, the right L6 DR, S1 DR, and the contralateral branch of the dorsal nerve of the penis (DNP) were transected. The distal stump of L6 DR in the model group was then anastomosed to the intact L4 DR. The sham group (n = 10) was not subjected to neural damage. Four months later, retrograde and transganglionic neural labeling, morphological examination, immunofluorescence (IF), and ultrastructural observation were carried out to test the reconstruction of the afferent pathway. Reflective erection (RE) was assessed by detecting the intracavernous pressure elicited by DNP stimulation.Results: The neural labeling tests indicated the integrity of the entire rebuilt penile afferent pathway. The morphological studies, IF, and ultrastructural observation showed that the regeneration of L6 axons in the model group was significantly better than that in the resection group; however, it had not reached the level of the sham group. The sham group rats exhibited typical RE following DNP stimulation, while the model and resection groups produced negative results.Conclusion: Our studies demonstrated the feasibility of end-to-side DR transfer neurorrhaphy for restoring the penile sensory pathway in rats.

Restoration of Penile Sensation Through Neurological Bypass in Rats

OBJECTIVE

To explore the feasibility of the penile afferent pathway by the cutaneous branch of the genitofemoral nerve to the dorsal nerve of penile transfer in rats.

METHODS

A total of 54 male rats were randomly divided into model group (n = 18), resection group (n = 18), and sham group (n = 18). In the model group, the distal stump of bilateral DNP was anastomosed to the proximal stump of the bilateral CGN through end-to-end neurorrhaphy. In the resection group, bilateral DNP was severed and ligated, and no end-to-end anastomosis was performed. Only a surgical incision was made in the sham group, and no nerve injury was caused. After the operation, the feasibility of reconstructing the penile afferent pathway was explored by fluorescent-gold retrograde neural labeling. The intracavernous pressure assessment was then carried out. The morphological examination, histological staining of nerves, and ultrastructural observation were performed accordingly.

RESULTS

Fluorescent-gold labeled L1 and L2 neurons in the model group were positive. The mean ICP in the model group was (12.02 ± 2.03 mmHg), which is higher than the mean value in the resection group (0 mmHg, P < .05) but lower than that in the sham group (36.95 ± 5.33 mmHg; P < .05). The morphological studies, HE, and ultrastructure observation revealed that the regeneration of DNP axons in the model group was significantly better than that in the resection group yet did not reach the level of the sham group.

CONCLUSION

This experiment preliminarily proved the feasibility of restoration of the penile afferent pathway by CGN to DNP transfer in Rats.

Erectile Functional Restoration With Genital Branch of Genitofemoral Nerve to Pelvic Nerve Transfer After Spinal Root Transection in Rats

OBJECTIVE

To investigate the feasibility of erectile function restoration by the genitofemoral nerve to pelvic nerve transfer in rats.

METHODS

Thirty-six male rats were included in this study. Rats in the nerve transfer group (n = 12) were subjected to pelvic nerve, sacral roots, and L6 roots transection and then bilateral genitofemoral nerve to pelvic nerve transfer, rats in the nerve resection group (n = 12) were subjected to pelvic nerve, sacral roots, and L6 roots transection without nerve transfer, and rats in the control group (n = 12) served as controls. After reinnervation, intracavernous pressure (ICP) assessment was performed. Fluoro-Gold was injected into the corpus cavernosum. Immediately before euthanasia, transferred nerves were stimulated to test penile intracavernous pressure. The L6, S1, and L1-2 spinal cord segments were used for retrogradely labeled neurons. Regenerative nerve morphologic examination assessment was performed.

RESULTS

Genitofemoral nerve stimulation induced an increase in ICP in the nerve transfer group. The mean ICP in this group was (33.8 ± 9.4 mm Hg), which is higher than the mean value in the nerve resection group (3.9 ± 1.0 mm Hg) but lower than that in the control group (69.8 ± 12.2 mm Hg; P < .05). The formation of new neural pathways was confirmed by the appearance of Fluoro-Gold labeled neurons in the L-1 and L-2 spinal cord segments in the nerve transfer group. Regenerative nerve morphologic examination showed good axonal regeneration after genitofemoral nerve transfer.

CONCLUSION

Nerve regeneration can be obtained by genitofemoral nerve to pelvic nerve transfer, and erectile function can be restored.

A potential treatment of low intensity pulsed ultrasound on cavernous nerve injury for erectile dysfunction

Erectile dysfunction after nerve injury is a common disease after radical prostatectomy. Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family, which plays an important role in the survival of existing neurons, the differentiation of new neurons, and synaptic plasticity. It has been demonstrated that low-intensity pulsed ultrasound (LIPUS) accelerates bone healing and axonal regeneration after injury. LIPUS may also be able to stimulate neuronal activity and enhance the levels of neurotrophic factors. Evidence suggests that elevated levels of BDNF in the brain have protective effects against neurodegenerative diseases. Previous studies have shown that the treatment on cavernous nerve injury repair, and protective effect plus neuro-regeneration effect by low-intensity pulsed ultrasound. They shared the similar mechanism including several trophic factors stimulation, Pl3K/akt pathway activation, and anti-fibrosis mechanism. We hypothesized that due to its combined neuroregenerative and protective effects, the non-invasive and easy-to-use method of LIPUS stimulation could have a therapeutic effect on erectile dysfunction stemming from cavernous nerve injury.

Reinnervation of the rectum with transfer of the genital branch of the genitofemoral nerve to the pelvic nerve in rats

OBJECTIVE

The purpose of this study was to determine the feasibility of rectum reinnervation with transfer of a primarily genitofemoral nerve to the pelvic nerve in the rat.

METHODS

Thirty-six male rats were randomly divided into 3 groups: rats in the nerve transfer group (n = 12) were subjected to rectal denervation and then bilateral genitofemoral nerve–pelvic nerve transfer; rats in the nerve resection group (n = 12) underwent rectum denervation without nerve transfer; and rats in the control group (n = 12) underwent sham surgery. Rectum denervation was achieved by transection of the L-6 spinal nerves, the spinal nerves below L-6, and the pelvic nerve. Four months postoperatively, retrograde nerve tracing, regenerative nerve morphological examination, and rectal manometry assessment were performed.

RESULTS

Regenerative nerve morphological examination showed good axonal regeneration after genitofemoral nerve transfer. Nerve stimulation induced increased rectal pressures in 10 of 12 rats in the nerve transfer group. The mean rectal pressure in this group was 54.9 ± 7.1 mm Hg, which is higher than the mean value in the nerve resection group (5.5 ± 2.0 mm Hg) but lower than that in the control group (70.6 ± 8.5 mm Hg) (p < 0.05). The appearance of FluoroGold-labeled neurons in the L-1 and L-2 spinal cord segments in the nerve transfer group confirmed the formation of new neural pathways.

CONCLUSIONS

The results have demonstrated that genitofemoral nerve–pelvic nerve transfer can achieve nerve regeneration. In this animal model, the authors were able to reinnervate the rectum by nerve transfer.