Expressions of toll-like receptor 4 mRNA and nuclear factor-κB mRNA in lung tissue of rats with acute paraquat poisoning

Objective To investigate the expressions of toll-like receptor 4 mRNA and nuclear factor-κB (TLR4-NF-κB) mRNA in lung tissue of rats with acute paraquat poisoning.Methods Thirty male SD rats were randomly divided into two groups,namely normal saline group (NS group,n =6) and the PQ groups (n =24).The rats of PQ group were administered with 20 mg/kg PQ by intraperitoneal injection to establish the models of PQ induced lung injury.The saline was administered once instead in normal saline group.The rats of PQ group were sacrificed separately at 6 h,12 h,24 h,48 h and 72 hours after modeling,while at 6 hours the rats of normal saline group was sacrificed.The expressions of TLR4 mRNA,NF-κB mRNA,and the levels of tumor necrosis factor-α and interleukin-6 in lung (serum) of rats were detected.Meanwhile,pathological changes of the lung tissue were examined under optical microscope.Results There were no histopathological changes such as alveolar edema,hemorrhage and inflammatory cell infiltration found in NS group other than in PQ group.At the 72 h,the expressions of TLR4 mRNA (9.61 ±0.21),NF-κB mRNA (5.62 ± 0.24),and the levels of TNF-α (153.08 ± 5.02) pg/ml,and interleukin-6 (230.08 ± 10.64) pg/mL in lung tissue of rats were significantly higher in PQ group than those in control group (P ＜ 0.01).Conclusions In rats after PQ poisoning,the expressions of TLR4 mRNA,NF-κB mRNA,and the levels of TNF-αand IL-6 were higher than those in normal rats,and the TLR4-NF-κB pathway could play an important role in lung injury of rats with PQ poisoning. Key words: Paraquat;  Acute lung injury ;  Rat ;  Lung tissue ;  Toll-like receptor 4 ;  Nuclear factor-κB ;  Tumor necrosis factor-α;  Interleukin-6