| Background:When cholestasis occurs,a large amount of bile accumulates in the liver and destroys the structure of the biliary tract.The bile enters the blood,causing serious damage to the body.The liver becomes the first damaged organ.Inflammatory cell infiltration,fibroblast proliferation and hepatocyte degeneration and necrosis in liver tissue lead to cholestasis of hepatic fibrosis and cirrhosis.Insulin-like growth factor binding protein-related protein 1(IGFBPrP1)is a secreted protein that can independently participate in a variety of biological functions.IGFBPrP1 is a new liver injury factor discovered by the tutor group in the past ten years.A series of previous studies found that IGFBPrP1 induced liver damage in SD rats and found that kidney and lung tissues had different degrees of damage;IGFBPrPl can also promote the activation of hepatic stellate cells(HSC)in bile duct ligation(BDL)mice,and then produce excessive extracellular matrix(ECM),aggravating liver injury.Activation of the inflammatory response involves many pro-inflammatory cytokines such as tumor necrosis factor(TNF)-α,interleukin(IL)-6,IL-β,IL-10 and other inflammatory mediators.TNF-α,which acts as a first-line cytokine,plays a very important role in it.It is produced by mononuclear macrophages,has functions of immune regulation,participates in fever and inflammation,and IL-6 reflects inflammation and tissue damage.IL-6 is a sensitive index reflecting the severity of inflammation and tissue injury.Its elevation can exacerbate oxidative stress and lead to the release of toxic metabolites,which causes tissue injury.Moreover,IL-6 can be induced by TNF-α.Nuclear factor kappa-B(NF-κB)is a regulatory transcription factor,which isexpressed in almost all mammalian cells and plays a key role in regulating the expression of inflammatory mediators.In the liver,NF-κB is activated due to the stimulation of various injury factors.The continuously activated NF-κB can not only regulate the necrosis and apoptosis of hepatocytes,but also induce Kupffer cells to activate and release various inflammatory factors(such as TNF-α,IL-6,etc.),leading to HSC activation and ECM deposition,promoting liver injury.Our research team has found that IGFBPrPl can enhance the DNA binding activity of NF-κB p65 in HSC in vitro.Cholestasis cirrhosis model can be made by BDL in mice,which is a classic model.Therefore,BDL in mice is proposed to be used as the research model to determine whether the liver injury caused by BDL can also damage the kidney and lung tissue,whether the injury is related to TNF-α,IL-6,NF-κB,and how it is related to IGFBPrPl.At present,there are few literature reports at home and abroad.Objective:To determine if liver injury by bile duct ligation causes modifications in kidney and lung tissue in mice,and to explore the possible mechanism of these changes.Methods:A total of 78 healthy male C57BL/6 wild-type mice were randomly divided into normal control group(Normal group),sham operation group(Sham group)and common bile duct ligation(BDL)group.The BDL group was separated and ligated into the common bile duct.The Sham group only separated the common bile duct and was not ligated,and the other surgical procedures were the same as the BDL group.The Normal group did not do any treatment.Liver,kidney and lung tissue samples were obtained after anesthetized animals at different time points(2,4,6 weekends).Pathological changes of each tissue were observed by hematoxylin-eosin(HE)staining;immunohistochemistry was used to detecteach Distribution and expression of insulin-like growth factor binding protein-related protein 1(IGFBPrP1),nuclear factor(NF)-κB,TNF-α and IL-6 in tissues;detection of IGFBPrP1,NF-κB and TNF in various tissues by Western blot-Expression changes of alpha and IL-6 proteins.The correlation between IGFBPrP1 and NF-κB,TNF-α and IL-6protein expression in liver,kidney and lung tissues of each group was analyzed by Pearson method.Results:The results of HE staining showed that the liver lobules of the Normal group and the Sham group were intact,the hepatic cell lines were arranged neatly,and arranged radially around the central vein.The structure of the renal tubular epithelial cells was regular and intact,and no obvious pathological changes were found in the kidney.The lung cells were arranged regularly,complete structure,no inflammatory cell infiltration.Compared with the Normal group and the Sham group,the BDL group developed with lesions,small bile duct hyperplasia,bile duct dilatation,portal area enlargement,fibrous tissue hyperplasia,pseudolobule formation,inflammatory cell infiltration around the portal area and bile duct;the renal tubules are dilated in a cystic way,and the infiltration of inflammatory cells in glomeruli and renal interstitium is increased;the lung tissue is seen with extensive hyperemia,a large number of inflammatory cells infiltration,capillary hyperplasia and alveolar septa thickening.And the lesions of each tissue were aggravated with the prolongation of BDL.Immunohistochemical results showed that IGFBPrP1,NF-κB,TNF-α and IL-6protein were only expressed in a small amount of liver,kidney and lung cells in Normal group and Sham group at different time points,the difference was not statistically significant(P>0.05).In hepatocytes and portal area,the expression of IGFBPrP1,NF-κB,TNF-α and IL-6 increased at 2 weeks and continued to increase in a time-dependent manner.In renal tissues,the expression of IGFBPrP1,NF-κB and TNF-α increased at 2weeks and increased in a time-dependent manner.IL-6 began to increase at 2 weeks,peaked at 4 weeks,and decreased slightly at 6 weeks.In lung tissue,the expression of NF-κB and IL-6 increased at 2 weeks and increased in a time-dependent manner.IGFBPrP1 and TNF-α increased at 2 weeks,peaked at 4 weeks,and decreased slightly at6 weeks;There were significant differences in the indexes of BDL mice compared with the Normal group and the Sham group(P<0.05).Western blot results were consistent with the trend of immunohistochemistry results.Pearson correlation analysis showed that IGFBPrP1 was positively correlated with transcription factor NF-κB and pro-inflammatory cytokines TNF-α and IL-6 protein in liver,kidney and lung tissues of BDL mice(P<0.05).Conclusion:Kidney and lung tissue were also damaged after liver injury caused by BDL in mice.The mechanism may be related to the high expression of IGFBPrP1,NF-κB,TNF-α and IL-6 in liver,kidney and lung tissues.In the process,increased expression of IGFBPrP1 may be accompanied by activation of the NF-κB pathway and high expression of downstream inflammatory factors TNF-α and IL-6. |
