Lipopolysaccharide-Elicited Systemic Inflammation Induces Selective Vulnerability of Cerebral Cortex and Striatum of Developing Glutaryl-CoA Dehydrogenase Deficient ( Gcdh −/− ) Mice to Oxidative Stress

We investigated redox homeostasis in cerebral and peripheral tissues of wild type (WT) and glutaryl-CoA dehydrogenase knockout mice ( Gcdh −/− ) submitted to inflammation induced by lipopolysaccharide (LPS) since patients with glutaric aciduria type I (GA I) manifest acute encephalopathy during catabolic events triggered by inflammation. WT and Gcdh −/− mice fed a low (0.9%) or high (4.7%) Lys chow were euthanized 4 h after LPS intraperitoneal injection. Cerebral cortex of Lys - restricted Gcdh −/− animals presented no alterations of redox homeostasis, whereas those fed a high Lys chow showed increased malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity, compared to WT mice. Furthermore, Gcdh −/− mice receiving low Lys and injected with LPS presented elevated MDA levels and decreased reduced glutathione (GSH) concentrations, glutathione peroxidase (GPx), and glutathione reductase (GR) activities in cerebral cortex. LPS administration also decreased GSH values, as well as GPx and GR activities in cerebral cortex of Gcdh −/− mice receiving Lys overload. Further experiments performed in WT and Gcdh −/− mice injected with LPS and receiving either a low or high Lys chow revealed increased MDA levels and decreased GSH concentrations in cerebral cortex and striatum, but not in hippocampus, liver and heart of Gcdh −/− mice, suggesting a selective vulnerability of these cerebral structures to oxidative stress during an inflammatory process. LPS administration also increased S100B and NF-κF protein levels in brain of Gcdh −/− mice receiving high Lys. These data support the hypothesis that low Lys diet is beneficial in GA I by preventing redox imbalance, whereas a high Lys diet or systemic inflammation per se or combined induce oxidative stress in striatum and cerebral cortex that are mainly damaged in this disorder.