OBJECTIVETo investigate NF-kappaB activity and the expression of phosphorylated p38 MAPK protein in lung tissue of acute paraquat poisoned rats and the effect of MT.

METHODSOne hundred and twenty-eight Sprague-Dawley (SD) rats were randomly divided into three experimental groups: poisoned group, MT group and control group. On the 1st, the 3rd, the 7th and the 14th day after exposure, levels of malondialdehyde (MDA) in serum were detected, NF-kappaB activity in the lung tissues was assessed by electrophoresis mobility shift assay (EMSA), the expression of the phosphorylated p38 MAPK was evaluated by Western blot method, the lung pathological changes of rats were observed.

RESULTSThe level of malondialdehyde (MDA) in serum increased significantly in poisoned group on the 1st day (4.45 +/- 1.23), the 3rd day (3.77 +/- 1.12) and the 7th day (2.84 +/- 0.96) nmol/ml compared with that in control group (1.36 +/- 0.52) nmol/ml (P < 0.01). There was a significant decrease in MT group on the 1st day (2.68 +/- 0.85), the 3rd day (1.97 +/- 0.74) and the 7th day (1.53 +/- 0.62) nmol/ml compared with poisoned group (P < 0.05). The expression of the phosphorylated p38 MAPK and NF-kappaB activity in lung tissue of poisoned group significantly increased compared with control group (P < 0.01). There was a significant decrease in NF-kappaB activity and expression of the phosphorylated p38 MAPK in the lung tissues in MT group compared with poisoned group (P < 0.05).

CONCLUSIONNF-kappaB and p38 MAPK could play an important role in lung injury of poisoned rats. MT may inhibit the expression of NF-kappaB and phosphorylated p38 MAPK, and therefore might have the therapeutical effect on acute paraquat poisoning.