[Lycium barbarum miR2911-loaded exosomes promote spermatogenic function recovery in rats with non-obstructive azoospermia by regulating Wnt/β-catenin signaling pathways].

Objective: To investigate the effect of exosomes loaded with Lycium barbarum miRNA (Lb-miR2911) on spermatogenic function recovery in non-obstructive azoospermia (NOA) rats through cross-regulation of the Wnt/β-catenin signaling pathways.

Methods: We established an NOA model in 30 four-week-old male SD rats by intraperitoneal injection of busulfan. At 5 weeks after modeling, we equally randomized the rats into a model control group (MC，untreated), an Lb-miR2911EXO group (Lb-miR2911EXO ，treated by intratesticular injection of Lb-miR2911-loaded exosomes), and a sham group (Shame，treated by intratesticular injection of exosomes-empty drug), with another 10 male SD rats taken as normal controls（NC）. We observed the uptake and metabolic changes of Lb-miR2911 in the testis tissue of the rats by RNA FISH at 2 and 6 weeks after treatment, detected cell proliferation, spermatogenesis and gene expressions of the Wnt/β-catenin signaling pathways in the testis tissue by Transcriptome sequencing analysis combined with Western blot and RT-PCR at 12 weeks, evaluated the recovery of the spermatogenic function based on the testis tissue morphology and sperm quality, and assessed the organ toxicity of Lb-miR2911 in the tissue and organs of the rats based on histomorphological analysis and the levels of serum TNF-α, IL-1β, Aspartate aminotransferase (AST), Alanine aminotransferase (ALT) and other relevant indicators.

Results: After 12 weeks of treatment, histomorphological analysis showed regular arrangement of spermatogenic cells at all levels in the testis tissue, with a large number of mature sperm in the tubular lumen, and with significantly higher Johnsen scores, testis weight, testicular index, sperm concentration and sperm motility in the Lb-miR2911EXO than in the sham group (all P< 0.05). Compared with the model controls, the Lb-miR2911EXO group exhibited remarkably down-regulated gene expression of DACT3 (P< 0.05), up-regulated expressions of DVL2 and β-catenin (P< 0.05), elevated levels of p-DVL2 and β-catenin (nucleus) proteins (P< 0.05), increased expressions of cell proliferation-related genes CCND1, CCNE1 and CCNE2 (P< 0.05) and spermatogenesis-related genes DMC1, CCR6, JAM2 and KLC3 (P< 0.05). No pathological changes were observed in the lung, liver and kidney tissues of the rats, or in the levels of serum TNF-α, IL-1β, AST, ALT, creatinine and urea nitrogen in the rats treated with Lb-miR2911EXO compared with the normal controls (P > 0.05).

Conclusion: Lb-miR2911-loaded exosomes promote spermatogenic function recovery in NOA rats through cross-regulation of the DACT3, Wnt and β-catenin signaling pathways.