OBJECTIVETo investigate the expression of inflammatory factors in lung tissue of acute paraquat (PQ) poisoned rats.

METHODSFifty male SD rats were randomized divided into two groups: the normal control group (NC group, n = 10) and the PQ group (n = 40). The 1 ml saline was administered once in normal control group. The PQ group was administered with 20 mg/kg 1% PQ by intraperitoneal injection to establish the model of PQ induced lung injury. At six hours, at the first, the third and the seventh day the PQ group were sacrificed, while at the first day the normal control group was sacrificed. The level of tumor necrosis factor alpha (TNF-alpha) mRNA, interleukin 10 (IL-10) mRNA, high mobility group box 1 (HMGB-1) mRNA in lung of rats were detected. Meanwhile, pathological changes of the lung were examined under optical microscope.

RESULTSCompared with that in normal control group, TNF-alpha mRNA expression in lung tissue of PQ group reached the peak at the six hour and decreased slowly at the first day [(0.740 +/- 0.100) and (0.584 +/- 0.049) respectively]. At the six hour and the first day in PQ group it was significantly higher than that in normal control group (P < 0.05 or P < 0.01). IL-10 mRNA expression in lung tissue of PQ group was elevated at the six hour, reached the peak at the first day, at the third day [(0.551 +/- 0.016) and (0.524 +/- 0.010) respectively] and the seventh day also higher than that in normal control group. At the first and the seventh day in the PQ group it was significantly higher than that in normal control group (P < 0.01). Meanwhile, HMGB-1 mRNA expression in lung tissue of PQ group was also elevated at the six hour, reached the peak at the first day, at the third [(0.695 +/- 0.060), (0.871 +/- 0.154) and (0.819 +/- 0.188) respectively] and the seventh day also higher than that in normal control group. At six hour, the first and the third day in the PQ group it was significantly higher than that in normal control group (P < 0.01). The histological changes such as alveolar edema, hemorrhage and inflammatory cell infiltration in the PQ group were more than those in the normal control group.

CONCLUSIONIn rats after PQ intoxication the levels of the inflammatory factors TNF-alpha, IL-10 and HMGB-1 are higher than normal rats, and inflammatory could play an important role in lung injury of poisoned rats.