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Objective To investigate the role of TLR4/NF-κB signal pathway in pathogenesis of brain inju-ry during deep hypothermia circulatory arrest(DHCA). Methods BV2 microglia cells were subjected to oxygen-glucose deprivation/reoxygenation(OGD/R),in vitro model for DHCA. The BV2 were randomly divided into the control group(C group)and the experimental group(O group). BV2 viability was determined by CCK-8 assay. TLR4 and its downstream signaling molecules ,MyD88 and phosphorylated NF-κB (p-p65) expressions were detected by Western blotting. TLR4 mRNA expression in BV2 microglial cells were determined by RT-PCR. Level of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) in culture medium was detected by ELASA. Results Compared with the group C,BV2 microglia cell viability in experiment group was obviously weaker(P<0.05). Expressions of TLR4,MyD88 and phosphorylated NF-κB(p-p65)from the experiment group increased remarkedly than those from the group C (P < 0.05). TLR4 mRNA level was higher significantly in the group O than in the group C (P < 0.01). Production of IL-6 and TNF-α in the group O were up-regulated apparently compared to the group C(P<0.01). Conclusion TLR4/NF-κB signaling pathway contributed to activation of BV2 microglia cells treated by OGD/Reoxygenation ,which was probably the exactly way that involved in pathogenesis of brain injury during deep hypothermia circulatory arrest.
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Objective To investigate the role of TLR4/NF-κB signal pathway in pathogenesis of brain inju-ry during deep hypothermia circulatory arrest(DHCA). Methods BV2 microglia cells were subjected to oxygen-glucose deprivation/reoxygenation(OGD/R),in vitro model for DHCA. The BV2 were randomly divided into the control group(C group)and the experimental group(O group). BV2 viability was determined by CCK-8 assay. TLR4 and its downstream signaling molecules ,MyD88 and phosphorylated NF-κB (p-p65) expressions were detected by Western blotting. TLR4 mRNA expression in BV2 microglial cells were determined by RT-PCR. Level of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) in culture medium was detected by ELASA. Results Compared with the group C,BV2 microglia cell viability in experiment group was obviously weaker(P<0.05). Expressions of TLR4,MyD88 and phosphorylated NF-κB(p-p65)from the experiment group increased remarkedly than those from the group C (P < 0.05). TLR4 mRNA level was higher significantly in the group O than in the group C (P < 0.01). Production of IL-6 and TNF-α in the group O were up-regulated apparently compared to the group C(P<0.01). Conclusion TLR4/NF-κB signaling pathway contributed to activation of BV2 microglia cells treated by OGD/Reoxygenation ,which was probably the exactly way that involved in pathogenesis of brain injury during deep hypothermia circulatory arrest.
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AIM:To observe the expression of hypoxia-inducible factor 1 (HIF-1) and neuroglobin (NGB) in piglet cortex during deep hypothermic circulatory arrest.METHODS:Wuzhishan piglets were randomly assigned to car-diopulmonary bypass group ( CPB group) , 40 min of circulatory arrest ( CA) at 18 ℃ without cerebral perfusion ( DHCA group) or with selective antegrade cerebral perfusion ( SACP group) .After 180 min of reperfusion, cortical tissue was har-vested for determining HIF-1αand NGB expression by HE staining, Western blot and real-time PCR.RESULTS:Severer cerebral injury was observed in DHCA group than that in SACP group.After 180 min of reperfusion, HIF-1αprotein and mRNA levels were significantly higher in DHCA group than those in CPB group (P<0.05).Accordingly, SACP animal had higher levels of HIF-1αprotein and mRNA than those in DHCA group (P<0.05).Simultaneously, higher NGB pro-tein and mRNA levels were found in DHCA group than those in CPB group after 180 min of reperfusion ( P<0.05) .The SACP animal had higher levels of NGB protein and mRNA than those in DHCA group (P<0.05).CONCLUSION:Up-regulation of HIF-1 and NGB are involved in the mechanism against cerebral injury resulting from DHCA in the cortex and possibly a part of cerebral protective effect of SACP.
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Objective To explore the expression of TLR4/NF-κB pathway in cerebral injury resulting from DHCA ( deep hypothermia circulatory arrest ) as well as the effect of SACP ( selective antegrade cerebral perfusion). Methods Twelve pigs were randomly assigned to DHCA group (n = 6) or SACP group (n = 6) at 18 ℃ for 80 min. IL-6 was assayed by ELISA. Apoptosis and NF-κB proteins were detected by fluorescence TUNEL and Western blot, respectively. The level of TLR4 was determined through qRT-PCR and Western blot. Results Serum IL-6 level of SACP group was significantly lower at the end of circulation arrest and experiment and apoptotic index and NF-κB protein were apparently lower in SACP group (P < 0.05). The level of TLR4 protein and mRNA from SACP group decreased significantly (P < 0.05). Conclusions TLR4/NF-κB pathway plays a critical role in pathogenesis of DHCA cerebral injury and attenuating TLR4/NF-κB cytokines probably contributes to neuroprotection of SACP. TLR4/NF-κB pathway may be a novel target for DHCA.