Lysosome Evanescence Mediates Autophagic Flux Impairment in Glucose Imbalanced Environments

Schwann cells (SCs) support axonal function and promote nerve regeneration. This study investigated how various glucose concentrations influence SC viability, oxidative stress, and autophagy, which contribute to diabetic neuropathy. RSC96 SCs were cultured under five glucose conditions (0, 2.5, 5.5, 50, or 100 mM) for 24, 48, and 72 h. Cell viability was assessed by MTT; ROS levels were determined by DCFDA staining, and apoptosis and ER stress markers, as well as autophagy-related proteins were assessed by Western blotting. Autophagic flux was also analyzed using bafilomycin A1 and Cyto-ID. The results revealed time-dependent increases in cell death across all glucose conditions, especially under deprivation and low glucose (LG) conditions. ROS, CHOP, Bax, and cleaved caspase-3 levels increased from 24 to 72 h. The initial increase in the LC3B-II/I ratio indicated that autophagy was overactivated under glucose deprivation or LG conditions but impaired by 72 h, as indicated by reduced Lamp-2 expression. High glucose conditions led to early and persistent autophagy suppression, with minimal autophagic flux and vacuole formation. These findings demonstrate that SCs are sensitive to glucose levels and undergo distinct autophagic impairments through different mechanisms under persistent low or high glucose environments.