miR-145-enriched BMSCs-derived exosomes ameliorate neurogenic erectile dysfunction in aged rats via TGFBR2 inhibition

Neurogenic erectile dysfunction (ED) is a prevalent complication following radical prostatectomy in elderly patients, primarily resulting from the apoptosis of corpus cavernosum smooth muscle cells (CCSMCs) and the subsequent excessive fibrosis of the corpus cavernosum.

This study aimed to compare the therapeutic effects of exosomes derived from lentivirus-transfected miR-145 bone marrow mesenchymal stem cells (Exo-145) and unmodified BMSCs-derived exosomes (Exo) in aged rats with bilateral cavernous nerve injury (BCNI) and investigate the underlying mechanisms.

Twenty-four-month-old male rats were assigned to four groups, namely Sham, BCNI, Exo, and Exo-145. Three weeks after treatment, erectile function was assessed by measuring the maximal intracavernosal pressure to mean arterial pressure (ICP/MAP) ratio. Apoptosis and fibrosis were semi-quantitatively analyzed using TUNEL and Masson's trichrome staining, respectively. In vitro, CCSMCs were subjected to H₂O₂-induced oxidative stress, and the protective effects of Exo-145 were evaluated through flow cytometry and Western blot. Lastly, the targets and mechanisms of miR-145 were further validated using dual-luciferase reporter assays and rescue experiments.

Exo-145 significantly outperformed Exo in restoring erectile function in aged BCNI rats, as evidenced by the significantly higher maximal ICP/MAP ratio, a marked reduction in TUNEL-positive cell count, and marked suppression of fibrosis in cavernous tissue. Moreover, Masson's trichrome staining displayed a substantial decrease in collagen deposition. In vitro, Exo-145 alleviated H₂O₂-induced apoptosis in CCSMCs by downregulating Cleaved Caspase-3 expression and Bax while concurrently upregulating Bcl-2 expression. TGFBR2 was identified as a direct target of miR-145 through dual-luciferase reporter assays, with its overexpression partially reversing the protective effects of Exo-145.

Exo-145 demonstrates superior efficacy compared to Exo in treating aged neurogenic ED by targeting TGFBR2 to alleviate apoptosis and fibrosis. It may represent a promising cell-free therapeutic option for neurogenic erectile dysfunction in elderly patients and could offer new perspectives for improving their prognosis.