Vitamin C protects oligodendrocyte lineage cells and modulates microglial inflammation during OGD/R in vitro

To investigate the protective effects of vitamin C (VitC) against oxygen-glucose deprivation/reoxygenation (OGD/R) injury and its underlying mechanisms involving oxidative stress and inflammation in oligodendrocyte lineage cells and microglia. Primary rat oligodendrocyte precursor cells (OPCs), mature oligodendrocytes (OLs), and BV2 microglia were subjected to OGD/R with or without VitC. Apoptosis (TUNEL), differentiation (MBP⁺/PDGFRα⁺), oxidative stress (ROS, MDA), and microglial cytokine profiles (qRT-PCR/ELISA) were assessed. Co-culture experiments were conducted in transwell systems using primary rat OPCs or mature OLs seeded in the upper inserts and BV2 microglia seeded in the lower chambers, allowing paracrine communication without direct cell-cell contact. Biological replicates: n = 3-5 litters for primary cells; ≥3 passages for BV2. OGD/R increased apoptosis in OPCs(P < 0.01) and OLs(P < 0.01) and impaired OPC differentiation(P < 0.001); VitC attenuated apoptosis (OPCs: P < 0.01; OLs: P < 0.05) and restored differentiation(P < 0.01). VitC reduced OGD/R‑induced elevations in intracellular ROS and MDA (all P < 0.05). In BV2 microglia, VitC suppressed pro-inflammatory (COX-2, IL-1β, IL-6, TNF-α, iNOS) and enhanced anti-inflammatory (IL-10, CD206) markers at both mRNA and protein levels (all P < 0.05). In co-culture, OGD/R increased OPCs apoptosis (P < 0.001) and reduced differentiation (both vs. CON, P < 0.001), with VitC normalizing these parameters (P < 0.01). Cytokine changes mirrored those in monocultures. Notably, OGD/R did not alter OLs apoptosis in OL-BV2 co-cultures (P > 0.05). VitC (5 µg/mL) protects oligodendrocyte lineage cells via direct antioxidant effects and bidirectional modulation of microglial inflammation, supporting its potential as a multi‑target agent for white‑matter disorders.