Intraperitoneal Single Injection of Dexamethasone Leads to Region‐Specific Changes in the Profile of Neuron‐Specific Proteins in the Rat Brain

This study aims to investigate the effect of dexamethasone (DEX) injection on the production of growth-associated protein 43 (GAP-43), the protein that promotes calpain-2 activation. Increased levels of GAP-43 in the central nervous system can stimulate plastic and regenerative processes in the brain, which can be used to treat neurodegenerative diseases. However, GAP-43 is a target for the specific apoptotic protease calpain-2, whose hyperactivation may have negative consequences for the CNS. We found that DEX stimulates GAP-43 mRNA and protein production in the rat hippocampus. DEX administration at a dose of 8 mg/kg (once intraperitoneally) leads to an increase in GAP-43 protein levels and calpain-2 activation in the striatum and prefrontal cortex of rats; however, calpain-2 protein production is increased in the striatum and decreased in the prefrontal cortex. Our data support the hypothesis that DEX can be used to enhance the production of GAP-43 and other proteins crucial for brain function, such as tyrosine hydroxylase and calpains. This approach could potentially be employed to stimulate regenerative processes in the brain following acute injury or as a pulse therapy for chronic neurodegenerative conditions.