Guilu Erxian oral liquid mitigates oxidative damage in spermatogonial cells via miR-6739-5p modulation and PI3K/AKT pathway activation: a functional histocytochemical study

Oxidative stress is a major contributor to male infertility, particularly oligoasthenozoospermia. This study aimed to investigate the cytoprotective mechanism of Guilu Erxian oral liquid (GLEX) against H2O2-induced oxidative damage in spermatogonial cells, focusing on miR-6739-5p regulation and activation of the PI3K/AKT pathway using histocytochemical approaches. An oxidative stress model was established in rat spermatogonial stem cells (SSCs) with 250 µM H2O2. Cell proliferation, apoptosis, reactive oxygen species (ROS) accumulation, and DNA oxidative damage were assessed using EdU incorporation, flow cytometry, immunofluorescence, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) ELISA. Expression of miR-6739-5p and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway components (PIK3CA, p-PI3K, p-AKT) was evaluated by RT-qPCR and Western blotting. The interaction between miR-6739-5p and PIK3CA was confirmed via dual-luciferase reporter assay. The cytoprotective effects of GLEX were examined through pre-treatment and quantified using histochemical and cytological markers. H2O2 treatment significantly impaired cell viability, increased apoptosis and ROS production, and upregulated miR-6739-5p. Overexpression of miR-6739-5p exacerbated damage, while silencing reversed it and restored PI3K/AKT signaling. GLEX pretreatment effectively reduced miR-6739-5p expression, restored cell viability, suppressed oxidative and inflammatory markers (ROS, 8-OHdG, TNF-α, IL-1β), and enhanced PI3K/AKT activation. These effects were comparable to PI3K pathway activation. GLEX confers histocytochemical protection to spermatogonial cells under oxidative stress by downregulating miR-6739-5p and activating the PI3K/AKT pathway. This study highlights a novel regulatory mechanism and supports GLEX as a potential therapeutic agent for oxidative stress-associated male infertility.