Adipose-derived stem cells-conditioned medium (ADMSCs-CM) improves testicular function and sperm DNA damage via Nrf2 antioxidant signaling pathways in rat unilateral varicocele

Varicocele is an excessive dilation of the pampiniform plexus. Although the accurate mechanism of varicocele-induced infertility is still unknown, oxidative stress plays a major function. A great attention has recently been attracted towards the MSCs' secreted factors for the treatment of diseases. So, we investigated the effect of adipose derived stem cells-conditioned medium (ADMSCs- CM) on Nrf2 signaling pathway, downstream antioxidant enzymes, sperm DNA and acrosome damage following varicocele surgery. Rats were divided into sham, varicocele, Varicocele + DMEM/F-12, and ADMSCs-CM groups. ADMSCs were isolated, confirmed, and ADMSCs-CM was prepared. Spermatogenesis quantification was done by H& E-stained testicular sections. The percentage of sperm DNA fragmentation and acrosome integrity was assessed through acridine orange and coomassie blue stainings. The testicular levels of MDA, TAC, SOD, and CAT were assessed. Relative expression of Nrf2/ Ho-1 genes evaluated through Real-time PCR. Mean percentage of sperm acrosome integrity, TDI, SPI, and Johnsen's criteria decreased (p < 0.0001), mean percentage of sperm DNA fragmentation (p < 0.0001), and testicular MDA (p < 0.001) significantly increased in the varicocele group. Unilateral varicocele reduced notably testicular levels of TAC (p < 0.0001), SOD (p < 0.01), and CAT (p < 0.05). ADMSCs-CM improved significantly sperm acrosome integrity (p < 0.01) and sperm DNA fragmentation (p < 0.05). Also, results demonstrated a remarkable recovery in spermatogenic parameters. There is a significant improvement in MDA, SOD (p < 0.05), and TAC (p < 0.01) levels in the ADMSCs-CM group. Treatment with AMSCs resulted in a non-significant increase in the mRNA expression of both Nrf2 and Ho-1 genes compared with the varicocele group, whereas a significant increase was observed compared with the sham group. Intratesticular administration of ADMSCs-CM could be a promising approach for the partial restoration of spermatogenesis and sperm damage potentially through Nrf2 antioxidant signaling pathway and reducing oxidative injury induced by varicocele.