Roles of glutathione in antioxidant defense, inflammation, and neuron differentiation in the thalamus of HIV-1 transgenic rats

Inflammation and oxidative stress in the brain are major causes of HIV-associated neurocognitive disorders. Previously we have reported high content of glutathione (GSH) in the thalamus of rats with F344 genetic background. In this study, we investigated the changes of GSH metabolism and GSH-dependent antioxidant enzymes in the rat thalamus in response to HIV-1 transgenesis, and their associations with oxidative stress, inflammation, and neuronal development. Male HIV-1 transgenic (HIV-1Tg) rats and wild type F344 rats at 10 months were used in this study, with 5 rats in each group. Parameters measured in this study included: total and oxidized GSH, glutathione peroxidase (GPx), glutathione-S-transferase (GST), gamma-glutamylcysteine synthetase (GCS), gamma-glutamyl transferase (GGT), cysteine/cystine transporters, 4-hydroxynonenal (HNE), interleukin 12 (IL12), neuronal nuclei (NeuN), microtubule-associated protein (MAP2), and glia fibrillary acidic protein (GFAP). The levels of total GSH, oxidized GSH (GSSG) and MAP2 protein, and enzymatic activities of GCS, GPx and GST were significantly higher in HIV-1Tg rats compared with F344 rats, but the ratio of GSSG/GSH, activity of GGT and levels of HNE, NeuN protein and GFAP protein did not change. HIV-1Tg rats showed a lower level of IL12 protein. GSH positively correlated with GCS, GST and MAP2, GSSG/GSH ratio positively correlated with HNE and IL12, the activities of GPx, GST and GCS positively correlated with each other, and negatively correlated with HNE. These findings suggest an important role of the GSH-centered system in reducing oxidative stress and neuroinflammation, and enhancing neuron differentiation in the thalamus of HIV-1Tg rats.