Neuromodulatory effects of green coffee bean extract against brain damage in male albino rats with experimentally induced diabetes.

Diabetes mellitus is an increasing metabolic disease worldwide associated with central nervous system disorders. Coffee is a widely consumed beverage that enriched with antioxidants with numerous medicinal applications. Accordingly, the present study aimed to investigate the therapeutic potential of orally administered green coffee bean water extract (GCBWE) against cortical damage induced by high fat diet (HFD) followed by a single injection of streptozotocin (STZ) in rats. Metformin (Met) was used as standard antidiabetic drug. Animals were allocated into six groups: control, GCBWE (100 mg/kg), HFD/STZ (40 mg/kg), HFD/STZ + GCBWE (50 mg/kg), HFD/STZ + GCBWE (100 mg/kg) and HFD/STZ + Met (200 mg/kg) which were treated daily for 28 days. Compared to control rats, HFD/STZ-treated rats showed decreased levels of cortical dopamine, norepinephrine and serotonin with marked increases in their metabolites. Further, HFD/STZ treatment resulted in notable elevations in malondialdehyde, protein carbonyl and total nitrite levels paralleled with declines in antioxidant markers (SOD, CAT, GPx, GR and GSH) and down-regulations of Sod2, Cat, GPx1 and Gsr gene expression. Neuroinflammation was evident in diabetic animals by marked elevations in TNF-α, IL-1β and up-regulation of inducible nitric oxide synthase. Significant rises incaspase-3 and Bax with decline in Bcl-2 level were noticed in diabetic rats together with similar results in their gene expressions. Cortical histopathological examination supported the biochemical and molecular findings. GCBWE administration achieved noteworthy neuroprotection in diabetic animals in most assessed parameters. The overall results suggested that antioxidant, anti-inflammatory; anti-apoptotic activities of GCBWE restored the cortical neurochemistry in diabetic rats.