Role Of Melatonin In NF-?B Signalling Pathway-mediated Inflammation After Hepatic Ischaemia-reperfusion Injury In Rats

Objective:To investigate the contributions and potential mechanisms of melatonin(M)on the inflammatory response after hepatic ischaemia-reperfusion(I/R)injury.Methods:60 adult male SD rats were randomly divided into a sham group(n=20),ischaemia-reperfusion(I/R)injury group(n=20),and melatonin treatment(M+I/R)group(n=20).rats in the sham group only performed the operation of cutting open and suturing abdomen as well as separation of the peripheral ligaments of the within liver.rats in the I/R group were used to vascular clamp to occluded the first porta hepatis to induce 45 min of liver ischaemia,followed by 5 h or 24 h of reperfusion(I/R-5 h and I/R-24 h,respectively).rats in the M+I/R group were injected by melatonin(10 mg/kg,i.v.)prior to 15 min of ischaemia and immediately after the beginning of reperfusion.At 5 h and 24 h after hepatic I/R surgery,respectively.said above 6 rats in each group(n=6)were sacrificed,and serum and liver lobes subjected to the I/R injury were collected for future analysis.Serum levels of alanine aminotransferase(ALT)and lactate dehydrogenase(LDH)were measured.HE staining was used to observe the pathological changes of liver tissue.Immunohistochemical(IHC)method was used to detect the expression levels of inflammatory factors(IL-6 and TNF-?)in liver tissue.TUNEL assay to examine the degree of hepatocellular apoptosis,immunofluorescence(IF)and western blotting(WB)to evaluate the activity of NF-?B signalling pathway.after hepatic I/R surgery,7-days survival rate were calculated.Results:Compared with rats in the Sham group,the survival rate of rats in the I/R group was significantly reduced,and liver function and liver tissue pathological changes were seriously damaged,indicating that the 70%hepatic I/R model of SD rats in I/R group was successfully established.Compared with rats from the I/R group,rats in the M+I/R group,the postoperative survival rate were climbed,liver function and pathological changes of liver tissue injury were significantly improved,and the level of inflammatory factors and the number of hepatocellular apoptosis were significantly reduced.The results of immunoblotting showed that the levels of IL-6,p-NF-?B-p65/t-NF-?B-p65 and p-I?B-?/t-I?B-? in rats from the M+I/R group were significantly lower than that in rats from the I/R group.The results of immunofluorescence detection further showed that the expression level of p-NF-?B-p65 in rats from the M+I/R group was lower than that in rats from the I/R group,and the difference was statistically significant(P<0.05).Compared with ones in the I/R group,the activity of NF-?B signalling pathway in rats from the M+I/R group was significantly downregulatedConclusions:1.Melatonin can alleviate hepatic ischaemia-reperfusion injury by inhibiting hepatocellular apoptosis and inflammation;2.Melatonin can reduce levels of IL-6 and TNF-? within liver tissue;3.Melatonin maybe by suppressing the activity of NF-?B signalling pathway in early and late stages of hepatic I/R injury,alleviating the inflammatory response in hepatic I/R injury,clipping the survival of reperfusion in rats from M+I/R group.