Alpinia Oxyphylla-Shenqi Siwu Decoction protects against high glucose-induced retinal pigment epithelial cell injury involving the PI3K/AKT/mTOR pathway.

Diabetic retinopathy (DR) is a leading cause of vision loss in working-age adults, and current treatments (anti-VEGF drugs, steroids, laser photocoagulation) mainly target late-stage microvascular complications while offering little for the neurodegeneration and neurovascular unit dysfunction that characterize early DR. Multi-component, multi-target traditional Chinese medicine compound decoctions are attractive candidates for early intervention. Here we investigated the protective effect and molecular mechanism of Alpinia Oxyphylla-Shenqi Siwu Decoction (AOSWSD) in a high glucose-induced ARPE-19 injury model of early DR. ARPE-19 cells were exposed to 30 mmol/L glucose and treated with drug-containing rat serum obtained from rats gavaged with AOSWSD at low, middle and high doses (4.6, 9.2 and 18.4 g/kg/day of crude drug), with a matched normal-rat-serum control. Cell viability, migration, apoptosis, intracellular ROS, cytokine secretion, VEGFR2 immunofluorescence, p-AKT/AKT and p-mTOR/mTOR ratios, and mRNA levels of VEGFA, VEGFR2, HIF-1α, PIK3CA, AKT1, mTOR, Caspase-3, Bcl-2 and Bax were quantified by CCK-8 assay, scratch assay, flow cytometry, DCFH-DA staining, ELISA, immunofluorescence and RT-qPCR, respectively. Under high-glucose exposure, AOSWSD-containing serum dose-dependently improved cell viability, restored migration, suppressed apoptosis, reduced intracellular ROS, and lowered the secretion of VEGFA, TNF-α and IL-6. Mechanistically, AOSWSD acted along a coordinated VEGFA/VEGFR2-PI3K/AKT/mTOR axis: it reduced secreted VEGFA and VEGFR2 protein at the upstream end, and lowered PIK3CA, AKT1 and mTOR transcripts together with the p-AKT/AKT and p-mTOR/mTOR ratios at the downstream end. Bcl-2, Bax and Caspase-3 expression and the Bax/Bcl-2 ratio were likewise restored towards control values. AOSWSD protects ARPE-19 cells from high glucose-induced injury through simultaneous, dose-dependent modulation of oxidative stress, inflammation, apoptosis and angiogenic signaling, with the VEGFA/VEGFR2-PI3K/AKT/mTOR cascade acting as a principal molecular substrate. These results support AOSWSD as a candidate multi-target intervention for early-stage DR and provide a basis for further mechanistic, chemical and translational studies.