| Lung injury caused by endotoxin shock,the treatment is intractable and the pathogenesis is complex and not clear. Triggered by the ALI/ARDS current research is still hot and difficult field of critically ill patients. Analysis of this complex mechanism, to improve the prognosis and has important clinical significance to reduce the mortality rate.Our previous studies have shown that heme oxygenase-1(HO-1) is considered to be against oxidative stress, inflammatory cell reaction and adaptability, HO-1metabolites of bilirubin is a powerful antioxidant, anti-inflammatory.In the endotoxic shock induced acute lung injury models, but the specific mechanisms are still unclear.Transcription factor NF-E2 related factor 2(Nrf2) has the effects of anti-inflammatory, antioxidant, inhibition of apoptosis in multiple biological activities,an important transcription factor Nrf2, plays an important role in maintaining cell survival, can protect cells, a subset of which belongs to the basic leucine zipper,which widely exists in the body tissue. And the antioxidant response element(ARE)sequence is composed of the Keapl-Nrf2/ARE pathway.Protein kinase C(PKC) is a serine / threonine protein kinase, is a phospholipid dependent protein kinase, Ca2+, is involved in cell differentiation, proliferation, apoptosis, migration, cell scaffold structure, and plays an important role in transmembrane signal transduction, the mechanism is to induce the phosphorylation of Ser/Thr proteins. PKC signal transduction pathway is a highly conserved three kinase cascade signaling pathway.Septic shock occurs, the start of the pathway, can reduce hemodynamic fluctuations, to maintain relatively stable vital signs.PKC alpha is a traditional or is the typical PKC(classicalor conventional PKC, CPKC), belong to A group in a subclass, the activation of the signs are usually think there is a translocation of PKC.It can promote the activation of Nrf2, into the nucleus, which play a role in the up regulation of HO-1 expression.This study through the establishment of endotoxic shock model of acute lung injury and application related pathway inhibitor and inducer to evaluate the role of PKC alpha-Nrf2-HO-1 Pathway in rabbit endotoxic shock in acute lung injury, andprovide a theoretical basis for the future related research.Ojective To investigate the effect of PKCα-Nrf2-HO-1 pathway on endotoxic shock-induced acute lung injury in rabbits.Methods Seventy healthy New Zealand white rabbits,aged 2 months,weighing2.0 ~ 2.5 kg,were randomly divided into 7 groups(n =10 each) using a random number table: normal control group(group C); endotoxic shock-induced ALI model group(group M); model + CHE group(group CHE+M); model + PMA group(group PMA+M); PKCα inhibitor CHE group(group CHE);PKCα inducer PMA(group PMA); solvent DMSO(group Dimethyl Sulphoxide).Ear vein injection of LPS 5mg/kg(dissolved in 2 ml saline) in groups M, CHE+M, PMA+M, Other groups were injected with normal saline 2ml in group PMA, group DMSO, group CHE and group C. Two hours after the injection of LPS after ear vein, carotid artery were the average arterial pressure monitoring changes to the original value of 75% and below, can be regarded as successful model. In LPS injection to 6 hours of experimental rabbits of each group were sacrificed, Intraperitoneal injection of chelerythrine(Chelerythrine,CHE) 8mg/kg(soluble in 0.5ml Dimethyl Sulphoxide) 30 min before LPS or nomal saline administration in groups CHE and CHE+M, and 0.02 mg/kg Phorbol-12-myristate-13-acetate(soluble in 0.5ml DMSO) was also injected intraperitonealy 30 min before LPS or nomal saline administration in groups PMA and PMA+M, C group received intraperitoneal injection of normal saline 0.5ml, other groups were injected with DMSO 0.5ml in the same way. Blood samples were collected 3.5 ml of common carotid artery and the pulmonary tissue. Take pathological observation of lung tissue and pathological score of lung tissue,determination of W/D ratio, SOD activity and MDA content in serum, TNF- alpha and IL-10 concentration and Nrf2 in lung tissue of mRNA, HO-1 mRNA,total and nuclear protein of Nrf2,PKCalpha protein were also determined.Result Compared with group C, the pathological score, TNF-α and IL-10 concentration, W/D, MDA content were increased, Nrf2 mRNA, HO-1 mRNA expression, Nrf2 total protein, Nrf2 nuclear protein, HO-1 protein expression was up-regulated and SOD activity was reduced in group M,group CHE+M and group PMA+M(P<0.05), PKC α protein was up-regulated in group M and groupPMA+M(P<0.05), but no significant changes were found in group CHE+M(P>0.05).,And there were no significant changes in groups CHE, PMA and DMSO(P>0.05).Compared with group M, the pathological score, TNF-αconcentration, W/D, MDA content were increased, Nrf2 mRNA, HO-1 mRNA expression, Nrf2 total protein,Nrf2 nuclear protein, PKCα protein,HO-1 protein expression, was down-regulated,IL-10 concentration and SOD activity reduced in group CHE+M(P<0.05); The pathological score, TNF-α concentration, W/D, MDA content were decreased, Nrf2 mRNA, HO-1 mRNA expression, Nrf2 total protein, Nrf2 nuclear protein, PKCαprotein,HO-1 protein expression were up-regulated,IL-10 concentration and SOD activity were increased in group PMA+M(P<0.05); Compared with group CHE+M,the pathological score, TNF-α concentration, W/D, MDA content were decreased,Nrf2 mRNA, HO-1 mRNA expression, Nrf2 total protein, Nrf2 nuclear protein,PKCα protein,HO-1 protein expression, was up-regulated, IL-10 concentration and SOD activity were increased in group PMA+M(P<0.05).Conclusions The PKCα-Nrf2-HO-1 pathway maybe involved in HO-1 gene transcription and up regulating, reduces acute lung injury induced by endotoxic shock in rabbits,... |
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