Blockade of quinolinic acid-induced neurotoxicity by pyruvate is associated with inhibition of glial activation in a model of Huntington's disease.

Abstract

In this study, we have examined the mechanisms involved in pyruvate-mediated neuroprotection against quinolinic acid (QA)-induced striatal damage. QA injection into the striatum caused widespread neuronal damage and extensive areas of lesions in core and penumbra. The involvement of oxidative-mediated striatal damage was suggested by increased expressions of peroxynitrite, marked lipid peroxidation, and formation of DNA oxidative damage products. Administration of pyruvate, a glycolysis end product with antioxidant activity, significantly reduced QA-mediated striatal lesions, neuronal degeneration, and oxidative damage, whereas another energy substrate, lactate, was ineffective against oxidative damage and only partially effective in reducing lesions and neuronal degeneration. Treatment with the iNOS inhibitor aminoguanidine attenuated QA-mediated striatal lesions and reduced oxidative damage, indicating that iNOS activation may be involved in the striatal oxidative damage induced by QA. A role for glial cells in mediating oxidative damage was suggested because pyruvate blocked the expression of iNOS and nitrotyrosine in activated microglia and astrocytes in QA-injected striatum. These data suggest that pyruvate reduces oxidative free radical damage in QA-injected striatum and could have clinical utility in the treatment of Huntington's disease (HD).