Study On The Expression And Significance Of Th17Cell Associated Cytokines In Rat Of Paraquat Poisoning

[Objective]Observe the behavior of paraquat poisoning rats and histopathological changes, study thedynamics changes and the role of Th17cells and related cytokines in rats of paraquatpoisoning,to explore the immune toxicological mechanisms on paraquat poisoning.[Methods]A total of96SPF Wistar rats, which were composed by half male rats and half female rats,were randomly divided into three groups: normal control group, PQ poisoning group, IL-17antibody group. Established the paraquat poisoning rat model by the one-time oral gavageexposure way. The rats of IL-17antibody group were intraperitoneally injected rats IL-17neutralizing antibodies, at the dose of3μg for each one,while the rats of normal control groupand PQ poisoning group were given equal doses of saline. Observe the behavioral changes andcollect the peripheral blood at the following time points: the1st,3rd,7thand21thday aferexposure, Rats were killed and autopsies, then isolated the lung tissue. The level ofinterleukin-17(IL-17)、interleukin-6(IL-6) and transforming growth factor(TGF-β) in serum were detected byELISA and the expressions of RORγt mRNA in lung tissues were detected by Real time PCR.； [Results]Expression of Th17cell-associated cytokines in paraquat poisoning rats1General informationThe rats of PQ poisoning group show a severe toxic reaction, particularly in the first1-3days, and the weight decreased significantly. Compared with the control group, the weightof PQ poisoning group decreased significantly（P<0.05）.2Pathological changes in lung tissue of ratsThe lung tissue structures of rats in the normal control group are basically normal. Theperformance of the PQ poisoning group rats is congestion, edema and a large number ofneutrophils and monocyte-macrophage cell infiltration in acute alveolitis in the early and midstage, Inflammation was the most serious in the first three days; Most of the alveolar structurewas destroyed, alveolar expansion fusion, alveolar septal thickening, and an increase infibroblast proliferation and collagen fibers can be seen in the advanced stage.3The levels of Th17cell associated cytokines in serum(1) Levels of IL-17in serum: Compared with normal control group, the levels of IL-17inserum were increased significantly in PQ poisoning group at all time points, thedifference was statistically significant (P <0.05);(2) Levels of IL-6in serum: Compared with normal control group, the levels of IL-6inserum were increased significantly in PQ poisoning group at all time points, thedifference was statistically significant (P <0.05);(3) Levels of TGF-β in serum: Compared with normal control group, the levels of TGF-βin serum were increased significantly in PQ poisoning group at all time points, thedifference was statistically significant (P <0.05);4The expression levels of RORγt mRNA in lung tissueCompared with normal control group, the levels of RORγt mRNA in lung tissue wereincreased significantly in PQ poisoning group at each time point, the differences werestatistically significant (P <0.05). Intervention Effect of IL-17A antibodies1General informationToxic reactions of IL-17antibody group’rats has been reduced compared with PQpoisoning group, Which is exhibited in weight reduction or without increasing until sevendays after it began to increase.2Pathological changes in lung tissue of ratsPathological changes of lung tissue in IL-17antibody group were less severe than the PQpoisoning group. It mainly manifested as the foam cell infiltration and pulmonary edema inthe early to medium term, several neutrophil infiltration can be observed, but no significantfibrosis was seen in advanced stages.3The levels of Th17related cytokines in serum(1) Levels of IL-17in serum: Compared with the PQ poisoning group, the levels of IL-17inserum were reduced significantly in the IL-17antibody group on the1stand3rdday (P<0.05); it was not statistically significant on the7thand21thdays (P>0.05).(2) Levels of IL-6in serum: Compared with the PQ poisoning group, the levels of IL-6inserum were reduced significantly in the IL-17antibody group on the1stand3rdday (P<0.05); It has a lower expression of the IL-17antibody group on the7thand21thday, butthe difference was not statistically significant (P>0.05)(3) Levels of TGF-β in serum: Compared with PQ poisoning group, there was a significantreduction about the TGF-β levels in serum, especially on the7thand21thdays, thedifference was statistically significant (P<0.05); it was not statistically significant on the1thand3rddays (P>0.05).4The expression levels of RORγt mRNA in lung tissueCompared with the PQ poisoning group, the expression levels of RORγt mRNA in lungtissue were significantly decreased in IL-17antibody group on the1st,3rdand7thday, thedifference were statistically significant (P <0.05), and the difference has no statisticallysignificant on the21stday(P>0.05). [Conclusions]1A significant increase can be seen in Th17cell associated cytokines such as IL-17, IL-6,TGF-β levels in serum and the expression levels of specific transcription factor RORγtmRNA in lung tissue in PQ poisoning group, it means that Th17cell-associatedcytokines involved in the pathogenesis of paraquat poisoning, and confirmed thatparaquat has some immunotoxicity.2After intervened with the rat IL-17antibody, there are mitigate of toxic reactions in rats.Histopathological observation: Compared with the PQ poisoning group, there is somealleviated on the organization of congestion, edema in the IL-17antibody group, someneutrophil and foam cells infiltration can be observed in the alveoli; granulation tissueformation can be seen, but no significant fibrosis can be found in the late stages.3After the intervention of the IL-17antibody in the poisoning rats, there are some reducedin the level of IL-17, IL-6and TGF-β in rat serum and the expression level of RORγtmRNA in lung tissue, the mechanism needs further studies.