Neuroprotective effects of carvacrol against cadmium-induced neurotoxicity in rats: role of oxidative stress, inflammation and apoptosis

Cadmium (Cd), is a heavy metal reported to be associated with oxidative stress and inflammation. In this paper, we investigated the possible protective effects of carvacrol against Cd-induced neurotoxicity in rats. Adult male Sprague Dawley rats were treated orally with Cd (25 mg/kg body weight) and with carvacrol (25 and 50 mg/kg body weight) for 7 days. Carvacrol decreased the levels of malondialdehyde (MDA), glial fibrillary acidic protein (GFAP) and monoamine oxidase (MAO), and significantly increased the levels of glutathione (GSH) and activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in brain tissue. Additionally, carvacrol alleviated the in levels of inflammation and apoptosis related proteins involving p38 mitogen-activated protein kinase (p38 MAPK), cyclooxygenase-2 (COX-2), nuclear factor kappa B (NF-κB), B-cell lymphoma-3 (Bcl-3), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), myeloperoxidase (MPO), prostaglandin E2 (PGE2), neuronal nitric oxide synthase (nNOS), inducible nitric oxide synthase (iNOS), cysteine aspartate specific protease-3 (caspase-3) and Bcl-2 associated X protein (Bax) in the Cd-induced neurotoxicity. Carvacrol also decreased the mRNA expression of matrix metalloproteinases (MMP9 and MMP13), as well as 8-hydroxy-2'-deoxyguanosine (8 - OHdG) level, a marker of oxidative DNA damage. Collectively, our findings indicated that carvacrol has a beneficial effect in ameliorating the Cd-induced neurotoxicity in the brain of rats.