[The effect of ethylmethylhydroxypyridine succinate on the parameters of chronic neuroinflammation and plastic processes in the brain of old rats during course of dexamethasone administration].

Objective: To study was to evaluate the potential modulatory impact of succinate/SUCNR1 signaling on the non-genomic immunosuppressive and gene-mediated inflammatory-degenerative effects of glucocorticoid receptor (GR) activation in the cerebral cortex (CC) of aging rats.

Material and methods: Using Western blot analysis, we assessed the expression level of pro-inflammatory (TNF-α, IL-1β), anti-inflammatory cytokines (IL-10, TGF-β1), mitochondriogenesis markers (PGC-1α, NDUFV2, SDHA, cyt c1, COX2, ATP5A), angiogenesis marker VEGF, neurotrophin BDNF, GR, succinate receptor SUCNR1 in the CC of 18-month-old rats with isolated administration of the highly specific GR ligand dexamethasone (1 mg/kg, i.p., daily, 10 days) and its combined administration with the succinate-containing drug Mexidol (100 mg/kg, i.p., daily, 10 days).

Results: Dexamethasone caused a decrease in the content of all detectable parameters in the CC of 18-month-old rats, including anti-inflammatory IL-10, TGF-β1, PGC-1α, VEGF, BDNF, which progressed by 10 days, amounting to 40-60%, which is consistent with the literature data on transrepression by GR of key pro-inflammatory (NFkB, AP1, STAT1), anti-inflammatory (PPARγ, ERRα), pro-anabolic transcription factors (estrogen, androgen receptors). The administration of Mexidol daily an hour after the injection of dexamethasone did not affect the dexamethasone-induced suppression of pro-inflammatory cytokines, but increased the expression levels of anti-inflammatory cytokines, protein markers of mitochondrio-, angio- and synaptogenesis.

Conclusion: The study demonstrates for the first time the prospect and pathogenetic foundation of the combined use of dexamethasone and Mexidol in an aging body in order to minimize the activity of GC aimed at suppressing pro-anabolic programs and mechanisms for resolving inflammation.