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AIM:To investigate the efficacy and molecularmechanisms of induced heme oxygenase(HO)-1 in protecting liver from warm ischemia/reperfusion(I/R)injury.METHODS:Partial warm ischemia was produced in the left and middle hepatic lobes of SD rats for 75min,followed by 6 h of reperfusion.Rats were treated with saline,cobalt protoporphyrin(Co PP)or zinc protoporphyrin(Zn PP)at 24 h prior to the ischemia insult.Blood and samples of ischemic lobes subjected to ischemia were collected at 6 h after reperfusion.Serum transaminases level,plasma lactate dehydrogenase and myeloperoxidase activity in liver were measured.Liver histological injury and inflammatory cell infiltration were evaluated by tissue section and liver immunohistochemical analysis.We used quantitative reverse transcription polymerase chain reaction to analyze liver expression of inflammatory cytokines and chemokines.The cell lysates were subjected to immunoprecipitation with anti-Toll-IL-1R-containing adaptor inducing interferon-β(TRIF)and anti-myeloid differentiation factor 88(My D88),and then the immunoprecipitates were analyzed by SDS-PAGE and immunoblotted with the indicated antibodies.RESULTS:HO-1 protected livers from I/R injury,as evidenced by diminished liver enzymes and wellpreserved tissue architecture.In comparison with Zn PP livers 6 h after surgery,Co PP treatment livers showed a significant increase inflammatory cell infiltration of lymphocytes,plasma cells,neutrophils and macrophages.The Toll-like receptor(TLR)-4 and TANK binding kinase1 protein levels of rats treated with Co PP significantly reduced in TRIF-immunoprecipitated complex,as compared with Zn PP treatment.In addition,pretreatment with Co PP reduced the expression levels of TLR2,TLR4,IL-1R-associated kinase(IRAK)-1 and tumor necrosis factor receptor-associated factor 6 in My D88-immunoprecipitated complex.The inflammatory cytokines and chemokines m RNA expression rapidly decreased inCo PP-pretreated liver,compared with the Zn PP-treated group.However,the expression of negative regulators Tollinteracting protein,suppressor of cytokine signaling-1,IRAK-M and Src homology 2 domain-containing inositol-5-phosphatase-1 in Co PP treatment rats were markedly up-regulated as compared with Zn PP-treated rats.CONCLUSION:HO-1 protects liver against I/R injury by inhibiting TLR2/TLR4-triggered My D88-and TRIFdependent signaling pathways and increasing expression of negative regulators of TLR signaling in rats.
AIM: To investigate the efficacy and molecular mechanisms of induced heme oxygenase (HO) -1 in protecting liver from warm ischemia / reperfusion (I / R) injury. METHODS: Partial warm ischemia was produced in the left and middle hepatic lobes of SD rats for 75 min followed by 6 h of reperfusion. Rats were treated with saline, cobalt protoporphyrin (Co PP) or zinc protoporphyrin (Zn PP) at 24 h prior to the ischemia insult. Blood and samples of ischemic lobes subjected to ischemia were collected at 6 h after reperfusion. Serum transaminases level, plasma lactate dehydrogenase and myeloperoxidase activity in liver were measured. Liver histological injury and inflammatory cell infiltration were evaluated by tissue section and liver immunohistochemical analysis. We used quantitative reverse transcription polymerase chain reaction to analyze liver expression of inflammatory cytokines and chemokines. The cell lysates were subjected to immunoprecipitation with anti-Toll-IL-1 R-containing adapter inducing interferon-beta ( TRIF) and anti-myeloid differentiation factor 88 (My D88), and then the immunoprecipitates were analyzed by SDS-PAGE and immunoblotted with the indicated antibodies. RESULTS: HO- 1 protected livers from I / R injury, as evidenced by diminished liver enzymes and wellpreserved tissue architecture.In contrast with Zn PP livers 6 h after surgery, Co PP treatment livers showed a significant increase of inflammatory cell infiltration of lymphocytes, plasma cells, neutrophils and macrophages. The Toll-like receptor (TLR) -4 and TANK binding kinase1 protein levels of rats treated with CoPP significantly reduced in TRIF-immunoprecipitated complex, as compared with Zn PP treatment.In addition, pretreatment with Co PP reduced the expression levels of TLR2, TLR4, IL-IR-associated kinase (IRAK) - 1 and tumor necrosis factor receptor-associated factor 6 in My D88-immunoprecipitated complex. The inflammatory cytokines and chemokines m RNA expression rapidly decreased in CoPP-pretreated liver, compared with the Zn PP-treatedThe expression of negative regulators Tollinteracting protein, suppressor of cytokine signaling-1, IRAK-M and Src homology 2 domain-containing inositol-5-phosphatase-1 in Co PP treatment rats were markedly up-regulated as compared with Zn PP-treated rats. CONCLUSION: HO-1 protects liver against I / R injury by inhibiting TLR2 / TLR4-triggered My D88-and TRIFdependent signaling pathways and increasing expression of negative regulators of TLR signaling in rats.