| Objective: To preliminarily explore the changing trend of Th17/Treg ratio of inflammatory cells and short-chain fatty acids(SCFAs)of intestinal microbial metabolites in the early progression of acute pancreatitis(AP)and the possible relationship between them,and to evaluate the role of SCFAs changes in the early progression of AP.Methods: Experiment selected45 SFP SD rats,weighting 300±20g.After adaptive feeding for 1 week,the rats were randomly divided into sham-operation(Sham)group(n = 15),acute edematous pancreatitis(AEP)group(n = 15),acute necrohemorrhagic pancreatitis(ANP)group(n = 15).In a sterile environment,Sham group only turned the pancreas gently and then closed the abdomen.In a sterile environment,the AEP and ANP models of rats were replicated by retrograde bile duct injection of 0.5% and 4% sodium taurocholate solution respectively.Five rats were randomly selected to collect peripheral blood and pancreatic tissue at the time point of 24 h,48h and 72 h after the successful modeling.After the pancreatic tissue was collected,it was fixed with 10% neutral formaldehyde and sent to the department of pathology of the affiliated hospital of southwest medical university for HE staining sections.Histopathological score was performed according to the pathological score standard of Kuddke pancreatic tissue to evaluate the degree of pancreatic injury in rats.Meanwhile,the serum Amylase(AMY)level in peripheral blood serum was determined by turbidimetric method to help evaluate the success of the model building.Peripheral blood mononuclear cell(PBMC)was isolated by density gradient centrifugation,and the ratio of Th17 and Treg cells in peripheral blood was detected by flow analysis,and the Th17/Treg ratio was calculated.Enzymelnked immunosorbent assay(ELISA)was used to detect SCFAs in peripheral serum.Comprehensive analysis: 1.Inflammatory indicators: changes of pro-inflammatory T lymphocyte Th17,anti-inflammatory T lymphocyte Treg,and Th17/Treg balance in early AP in AEP and ANP groups.2.Intestinal microbial metabolism indexes: the change trend of SCFAs content in peripheral blood of AEP and ANP groups.3.Spearman correlation analysis was conducted on the change of Th17/Treg ratio and the pathological score of pancreatic tissue with SCFAs,respectively,to further understand the relationship between the change of Th17/Treg ratio and the level of pancreatic injury and the content of intestinal microbial metabolite SCFAs in the AP model.Results: 1.The contents of AMY in peripheral blood of AEP group and ANP group at the time point of 24 h,48h and 72 h were higher than those of Sham group(P < 0.05),and higher than that of Sham group by 3 times.2.At the time point of 24 h,48h and 72 h,the degree of pancreatic injury in AEP group and ANP group was more serious than Sham group,and the pathological score was significantly higher than Sham group(P < 0.05).Meanwhile,the degree of pancreatic injury in the ANP group was significantly worse than that in the AEP group,and the pathological score was significantly higher than that in the AEP group(P <0.05).The degree of pancreatic injury in the AEP group and the ANP group increased gradually at the time point of 24 h,48h and 72 h,respectively,and the pathological score of the tissue increased(P < 0.05).3.Comparison of Th17 and Treg cell ratios and Th17/Treg ratio changes: AEP group and ANP group were higher than Sham group at the time point of 24 h,48h and 72h(P < 0.05),and ANP group was significantly higher than AEP group(P < 0.05).In the AEP and ANP groups,the proportion of Th17 cells and Th17/Treg ratio were gradually increased(P < 0.05).However,the proportion of Treg cells presented a gradually decreasing trend(P < 0.05).4.Changes in SCFAs of intestinal microbial metabolites in peripheral blood: AEP group and ANP group were higher than Sham group at the time point of 24 h,48h and 72h(P < 0.05),andANP group was significantly higher than AEP group(P < 0.05).Serum SCFAs increased gradually in AEP and ANP groups(P < 0.05).Spearman correlation analysis res μ Lt: the change in Th17/Treg ratio was significantly correlated with the SCFAs content in peripheral blood(Spearman correlation coefficient was 0.877,P < 0.05).Conclusion: 1.Retrograde bile duct injection of sodium taurocholate with different concentrations could effectively replicate acute pancreatitis in rats with different degrees of severity.2.The proportion of Th17 and Treg cells,the blood indicators reflecting the pro-inflammatory and anti-inflammatory imbalance in the rat model of acute pancreatitis,increased significantly,and the increase of Th17 was more obvious,that is,the balance of Th17/Treg drifted towards Th17,promoting the development of SIRS and aggravating the disease.3.In rat models of acute pancreatitis,SCFAs,a metabolite of intestinal microorganisms in peripheral blood,is positively correlated with Th17/Treg cell imbalance,which may play an important role in regulating the differentiation and imbalance of Th17 and Treg cells. |
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