Antioxidative and anti-inflammatory protection from carnosine in the striatum of MPTP-treated mice

Mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were used to examine the neuroprotective effects of carnosine. Carnosine at 0.5, 1, and 2 g/L was directly added to the drinking water for 4 weeks. MPTP treatment significantly depleted striatal glutathione content, reduced the activity of glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase, increased malondialdehyde and reactive oxygen species levels, and elevated interleukin-6, nitrite, and tumor necrosis factor-α production as well as enhanced inducible nitric oxide synthase (iNOS) activity in the striatum (P < 0.05). The preintake of carnosine significantly attenuated MPTP-induced glutathione loss, retained the activity of GPX and SOD, diminished oxidative stress, and lowered inflammatory cytokines and nitrite levels as well as suppressed iNOS activity (P < 0.05). MPTP treatment significantly suppressed GPX mRNA expression and enhanced iNOS mRNA expression (P < 0.05). Carnosine preintake significantly elevated GPX mRNA expression and declined iNOS mRNA expression (P < 0.05). Preintake of carnosine also significantly improved MPTP-induced dopamine depletion and maintained 3,4-dihydroxyphenylacetic acid and homovanillic acid levels (P < 0.05). These results suggest that carnosine could provide antioxidative and anti-inflammatory protection for the striatum against the development of Parkinson's disease.