Effect of taurine on brain 8-hydroxydeoxyguanosine and 3-nitrotyrosine levels in endotoxemia.

Taurine is a sulfur-containing β-amino acid that is found in milimolar concentrations in most mammalian tissues and plasma. It was shown to have cytoprotective effects in many in vitro and in vivo studies and these actions are often attributed to an antioxidant mechanism. In this study, we aimed to investigate the effect of acute taurine administration on endotoxin-induced oxidative and nitrosative stress in brain. Fourty adult male guinea pigs were divided into four groups: control, taurine, endotoxemia, and endotoxemia + taurine. Taurine (300 mg/kg), lipopolysaccharide (LPS, 4 mg/kg), or taurine plus LPS was administered intraperitoneally. After 6 h of incubation, when highest blood levels of taurine and endotoxin were attained, the animals were killed and brain tissue samples were collected. 3-Nitrotyrosine (3-NT), 8-hydroxydeoxyguanosine (8-OHdG) and taurine levels were measured using high-performance liquid chromatography methods. LPS administration significantly increased 3-NT, 8-OHdG levels, and dramatically reduced taurine concentrations in brain tissue compared to control group. The groups in which taurine was administered alone or with LPS, contradiction to well-known antioxidant effect, taurine caused elevated concentrations of 3-NT and 8-OHdG compared to both control and endotoxemia groups. In conclusion, endotoxemia leads to tyrosine nitration and DNA base modification that can be assessed by 3-NT and 8-OHdG, respectively. Taurine did not exhibit any antioxidant effect; moreover, it may contribute to neuronal damage at this dose. Thus, we can suggest that lower dose of taurine administration may be benefial for neuronal protection or adversely taurine administration may have toxic effect at all doses.