Mechanism of signal transduction in distant organ injuries induced by intestinal ischemia/reperfusion / 中华临床营养杂志

ABSTRACT

Objective To investigate the effect of different antibodies on Toll-like Receptor 4-High Mobility Group Box 1 and its downstream signal transductions in distant organ injuries caused by intestinal ischemia/reperfusion in mice.Methods A total of 40 mice (C57BL/6,SPF level) were by random number table method assigned into five groupssham,control,anti-HMGB1,anti-Myeloid differentitation gene,and antiTIR domain containing adaptor inducing IFN-β (n=8).In the control,anti-HMGB1,anti-MyD88,and antiTRIF groups,the IgG,HMGB1,MyD88,and TRIF antibodies were injected,respectively,via the tail vein 30 minutes before ischemia (1 mg/kg body weight,0.025％).After anesthesia and abdomen incision,all mice,except the sham group,underwent intestinal ischemia by clamping the superior mesenteric artery for 60 minutes followed by 60 minutes of reperfusion.Sham group underwent the same surgical procedures except for clamping the artery.Serum nuclear factor-κB p65,Interleukin-6 and Tumor Necrosis Factor-α were measured.Morphological changes in the lung and intestine were evaluated.mRNA and protein expressions of HMGB1 and NF-κB in lung and intestinal tissues were assayed.Results Compared with the control group [(228.53± 24.85),(104.91±31.18),and (70.81±46.97) ng/L],HMGB1 [(145.00±33.63),(62.28±6.73),and (52.76± 5.71) ng/L],MyD88 [(191.12± 13.22),(85.90± 17.37),and (63.19 ± 5.47) ng/L],and TRIF [(183.73±10.81),(78.14±7.38),and (59.70±4.63) ng/L] significantly decreased the serum level of NF-κB (P=0.000,0.005,0.001),IL-6 (P=0.000,0.004,0.000) and TNF-α (P=0.000,0.024,0.002) after ischemia reperfusion.Tissue injuries in the lung and intestine were also alleviated by HMGB1,MyD88,and TRIF.The anti-HMGB1,anti-MyD88,and anti-TRIF groups displayed significant elevations of HMGB1 mRNA [lung (1.89±0.18),(2.35±0.31),and (2.29±0.28),ileum (4.93±0.55),(5.96± 0.73),and (5.76±0.51)],NF-κB mRNA [lung (1.42±0.23),(1.77±0.18) and (1.70±0.13),ileum (2.23±0.55),(3.11±0.38) and (2.99±0.24)] and NF-κB protein expressions in lung and ileum tissues compared to the sham group [lung HMGB1 mRNA (1.04±0.19) (P=0.000,0.000,0.000),NF-κBmRNA (1.03±0.21) (P=0.004,0.000,0.000),ileum HMGB1 mRNA (1.14±0.54) (P=0.000,0.000,0.000),NF-κB mRNA (1.03±0.23) (P=0.000,0.000,0.000)].However,incornparison with the control group [lung HMGB1 mRNA (2.67±0.23) (P=0.000,0.035,0.016),NF-κB mRNA (2.04±0.29) (P=0.000,0.039,0.012),ileum HMGB1 mRNA (6.70±0.66) (P=0.001,0.038,0.015),NF-κBmRNA (3.71±0.53) (P=0.000,0.018,0.006)],the other three groups showed a significant down-regulation,with the most remarkable decrement in the anti-HMGB1 group.Application of anti-HMGB1,anti-MyD88,and anti-TRIF could drastically attenuate the tissue injuries in ischemia reperfusion.anti-HMGB1 exhibited the most significant effect.Conclusions HMGB1 and its downstream signals play an important role in intestinal ischemia reperfusion injuries in mice.Of two downstream signals,the TRIF-dependent pathway exerts a more important effect than that of the MyD88-dependent pathway.