Sulfite increases lipoperoxidation and decreases the activity of catalase in brain of rats

The main objective of this study was to investigate the in vitro effects of sulfite, a metabolite accumulated in isolated sulfite oxidase deficiency, on Na+, K+-ATPase activity and on some parameters of oxidative stress, namely thiobarbituric acid-reactive substances (TBARS) and catalase activity (antioxidant enzyme) in cerebral cortex, striatum and hippocampus from 10- and 60-day-old rats. Results showed that 500 mu M sulfite significantly increased TBARS and reduced catalase activity in the cerebral structures studied from neonates and adults rats; in contrast, sulfite did not alter Na+, K+-ATPase activity. Our present findings show that sulfite increases lipid peroxidation and decreases antioxidant enzyme defenses in rat brain, suggesting an induction of oxidative stress. We presumed that oxidative stress might be, at least in part, associated with the neuronal dysfunction of patients affected by isolated sulfite oxidase deficiency.