CXCL5 Cytokine Is a Major Factor in Platelet-Rich Plasma's Preservation of Erectile Function in Rats After Bilateral Cavernous Nerve Injury.

BACKGROUND: The neuro-protective and tissue-protective properties of platelet-rich plasma (PRP) have been demonstrated through treating bilateral cavernous nerve (CN) injury in rats, although the underlying mechanisms have not been fully clarified. AIM: To determine factors released from PRP and explore their role in mediating preservation of erectile function (EF) in a rat model of CN injury. METHODS: Male Sprague-Dawley rats (aged 10 weeks) were used in this study. 6 rats were used to obtain blood for PRP and whole plasma preparation. We probed samples using a cytokine antibody array and performed enzyme-linked immunosorbent assay (ELISA). We determined the expression patterns of C-X-C motif chemokine ligand 5 (CXCL5) and receptors in the major pelvic ganglion (MPG) and corpus cavernosum via immunostaining. 32 rats were divided into 4 groups based on the type of injection received: (i) sham, (ii) vehicle, (iii) 400 µL of PRP, and (iv) 30 ng/kg of CXCL5. Groups 2-4 were subjected to bilateral CN crush (BCNC) injury. 4 weeks later, EF was assessed by CN electrostimulation, and CNs and penile tissue were collected for histological analysis. OUTCOME: Cytokine antibody array, ELISA, erectile response, and immunofluorescence staining readings. RESULTS: The PRP contained high levels of CXCL5. MPG neurons expressed CXCL5 and CXCR2. PRP intracavernous injection stabilized CXCR2 and increased CXCL5 expression in the MPG after BCNC, thus enhancing neuroprotection. CXCL5 injection improved BCNC-induced erectile dysfunction by preventing smooth muscle atrophy. CLINICAL IMPLICATIONS: The therapeutic efficacy of PRP in CN injury-induced erectile dysfunction may arise from the synergy among multiple biomolecules. Our study serves as a basis for future studies on PRP formulation to provide safe and effective medications for the maintenance of EF after radical prostatectomy in patients with prostate cancer. STRENGTHS & LIMITATIONS: A strength of our study is that our model was able to isolate the role of cytokines, specifically CXCL5, as part of the mechanism responsible for PRP's protective properties. However, the rat cytokine array provided limited experimental targets. The rats used were not at the age corresponding to prostate cancer patients in clinical settings. Our study did not explore CXCL5 blocking in the PRP group. Finally, the main protein quantification results by western blotting were hampered because of small tissue samples. CONCLUSIONS: This study provides evidence for the role of CXCL5 and CXCR2 as mediators of PRP effects in the preservation of EF after CN injury. Wu YN, Liao CH, Chen KC, et al. CXCL5 Cytokine Is a Major Factor in Platelet-Rich Plasma's Preservation of Erectile Function in Rats After Bilateral Cavernous Nerve Injury. J Sex Med 2021;18:698-710.

Optimization of platelet-rich plasma and its effects on the recovery of erectile function after bilateral cavernous nerve injury in a rat model.

Platelet-rich plasma (PRP) containing autologous growth factors is applied in regenerative medicine, but the lack of an optimized PRP preparation protocol causes unstable therapeutic effects. The aim of this study was to optimize the PRP preparation method and compare the effects of PRP from different preparation methods in restoration of erectile function in a rat model. The in vivo experiments used Sprague-Dawley male rats (n = 24), which were randomly divided into four groups of equal numbers: group I underwent sham operation, while the remaining three groups underwent bilateral CN crush. Crush injury groups were treated at the time of injury with an application of general PRP, optimized PRP [with the largest amount of platelet-derived growth factor (PDGF)-AB] or normal saline-only injection in the corpus cavernosum, respectively. Four weeks later, erectile function was assessed by CN electrosimulation, and penile tissue was collected for histology. Results demonstrated that in the PRP group prepared with the ACD-A anticoagulant, chitosan and incubated at -20°C for 15 days had the largest amount of PDGF-AB and showed a synergistic effect on release (p < 0.05). Functional outcome measurement and immunofluorescence staining for the dorsal nerve revealed that improvement after bilateral CN injury occurred in the optimized PRP group (p < 0.05). It was concluded that optimized PRP with a high level of growth factors was more stable, and its injection into the corpus cavernosum facilitated recovery of erectile function. Copyright © 2013 John Wiley & Sons, Ltd.

Effect of Ginkgo biloba Extract (EGb-761) on Recovery of Erectile Dysfunction in Bilateral Cavernous Nerve Injury Rat Model.

OBJECTIVE: To investigate whether the therapeutic effect of Ginkgo biloba extract (GBE) in a rat model can improve erectile dysfunction after bilateral cavernous nerve injury. METHODS: Forty-three male Sprague-Dawley rats underwent cavernous nerve crush injury and were randomized into 4 groups, including: vehicle only, high-dose GBE, medium-dose GBE, and low-dose GBE. Eight animals underwent sham operation. Four weeks later, erectile function was assessed by cavernous nerve electrostimulation, and penile tissue was collected for histologic analysis. RESULTS: Significant recovery of erectile function was observed in the high-dose GBE group in a dose-dependent manner as compared with the vehicle-only group (P <.001). The high-dose GBE group had a significant increase in neurofilament-1 expression (P <.001), preservation of neural nitric oxide synthase nerve fibers of the dorsal penile nerve (P <.05), and increased smooth muscle cell content (P <.001) compared with the vehicle-only group. In addition, high-dose GBE markedly augments the smooth muscle-to-collagen ratio (P <.05) and reduces the apoptotic index. CONCLUSION: Administration of GBE increases neuron survival and preserves the neural nitric oxide synthase nerve fiber and contents of the corpus cavernosum after bilateral cavernous nerve injury. These implications indicate the beneficial effects of GBE use in the repair of the cavernous nerve and recovery of erectile function after radical prostatectomy.