Cellular Abnormalities Induced by High Glucose in Mixed Glial Cultures Are Maintained, Although Glucose Returns to Normal Levels

Background: Metabolic memory refers to the long-term adverse effects of short-term disturbances in glucose metabolism. Recent evidence indicates that hyperglycemia-induced metabolic memory contributes to sustained cellular damage even after glycemic control, driven by increased production of reactive oxygen species (ROS), activation of inflammatory pathways, and accumulation of advanced glycation end products (AGEs). Although well characterized in endothelial and smooth muscle cells, this phenomenon may also occur in other cell types, including glial cells. Objective: This study aimed to evaluate the persistence of high-glucose (HG)-induced alterations after returning to normal glucose (NG) conditions in primary mixed glial cell (MGC) cultures. Methods: Primary MGCs were obtained from neonatal Wistar rat pups and cultured under three conditions for 21 days: NG (5.5 mM glucose), HG (25 mM glucose), and HG-NG (14 days in HG followed by 7 days in NG). Cell proliferation, apoptosis, ROS production, lipid peroxidation, mitochondrial activity, TNF-α, IL-6, and AGE formation were assessed. Results: MGCs cultured under HG and HG-NG conditions exhibited reduced proliferation without increased apoptosis. Both HG and HG-NG conditions promoted ROS overproduction accompanied by reduced mitochondrial activity, whereas only HG increased lipid peroxidation. Notably, TNF-α and AGE levels were elevated in both HG and HG-NG conditions, while IL-6 production decreased exclusively in HG-NG. Conclusions: These findings demonstrate the persistence of deleterious effects induced by HG in MGCs, even after restoration to NG conditions.