Protective effect of annexin-A1 against irreversible damage to cavernous tissue after cavernous nerve injury in the rat

Study Type - Aetiology (case control) Level of Evidence 3b What's known on the subject? and What does the study add? Penile rehabilitation is still controversial regarding good results. Our study shows a non-invasive treatment option to recovery after cavernous nervous damage. The assessment of changes in the intracavernous pressure and karyometry demonstrates the protective effect of annexin-A1 in an animal model of cavernous nerve injury. We found that annexin-A1 effectively preserved erectile function, evidently through significantly protecting the corpus cavernosum tissue against fibrosis. Objective: To evaluate the protective effect of annexin-A1 against irreversible damage to cavernous tissue after cavernous nerve injury. Patients and Methods: Thirty Sprague-Dawley male rats were divided into 3 groups; sham-operated rats (n= 10), bilateral cavernous nerve injury treated intravenously with 100 Âμg/kg annexin-A1 (n= 10), and a crush group of rats submitted to bilateral cavernous nerve injury and vehicle (n= 10). Groups were compared in respect to intracavernous pressure and karyometric parameters. Results: After annexin-A1 treatment, the maximum changes in intracavernous pressure responses were significantly higher in the annexin-A1 group compared to the vehicle-only group on the 7^th postoperative day (p-value <0.05). Hematoxylin-eosin staining showed that the percentage of cavernosal smooth muscle was higher in the annexin-A1 group. Karyometry showed that the nuclear volume was greater in the annexin-A1 group, as was the major/minor smooth muscle cell diameter ratio compared to the vehicle-only group on the 7^th postoperative day (p-value <0.05). Conclusion: This is the first report that, by assessing changes in the intracavernous pressure and karyometry, demonstrates the protective effect of annexin-A1 in an animal model of cavernous nerve injury. We found that annexin-A1 effectively preserved erectile function, evidently through significantly protecting the corpus cavernosum tissue against fibrosis.