Time course of MPTP toxicity on translational control protein expression in mice brain.

The present study investigated in mice brain, the time course of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity on the expression of translational control proteins. Mice received intraperitoneal injections of MPTP (30 mg/kg/day) for 5 days and were sacrificed 1, 2, 3, 4 and 7 days after the last injection. The results, obtained by western blot, indicated that MPTP produced an alteration of the expression of proteins involved in the mTOR anti-apoptotic way and the PKR pro-apoptotic pathway of translational control especially in striatum and frontal cortex of mice. These disturbances were associated with a great activation of PKR in hippocampus at D9, the time point corresponding to maximal translational control alterations. Furthermore, whereas no modification of translational control protein expression was observed in mice substantia nigra after western blot procedure, immunofluorescent labeling revealed, in this target region of the toxin MPTP, a decrease of the expression of phospho-mTOR and a great activation of the phosphorylated form of PKR, marker of pathogenesis.