TLR4/Myd88/NF-κB通路介导表没食子儿茶素没食子酸酯对脓毒血症大鼠急性肾损伤的保护作用
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摘要
目的观察表没食子儿茶素没食子酸酯(EGCG)对脂多糖(LPS)诱导大鼠急性肾损伤(AKI)的保护作用及TLR4/Myd88/核因子kappa B (NF-κB)的作用机制。方法将SD大鼠随机分为假手术组(Sham组)、LPS诱导急性肾损伤组(AKI组)、EGCG治疗组(EGCG组)和EGCG+LPS+TLR4抑制剂组(TLR4组),每组10只。建立内毒素血症大鼠模型,检测血清肌酐(Cr)和尿素氮(BUN)的变化;ELISA检测血清中白细胞介素-6 (IL-6)、白细胞介素-1β(IL-1β)、白细胞介素-10 (IL-10)和肿瘤坏死因子-α(TNF-α)水平;HE检测肾脏病理组织学变化,Western blotting和实时PCR检测大鼠肾脏中TLR4、Myd88和NF-κB蛋白及m RNA表达。结果与Sham组相比,AKI组大鼠肾脏损伤明显,血清中Cr、BUN及促炎性细胞因子水平显著升高,IL-10水平显著降低,TLR4、Myd88和NF-κB蛋白及mRNA表达显著升高;而在建模前给予EGCG可以改善AKI,明显降低炎性细胞因子表达,降低TLR4、Myd88和NF-κB表达;给予TLR4抑制剂后,EGCG对AKI的保护作用受到抑制。结论 EGCG对LPS导致的AKI具有保护作用,其机制可能与抑制TLR4/Myd88/NF-κB通路的激活有关。
Objective To evaluate the protective effect of epigallocatechin gallate(EGCG) on lipopolysaccharide(LPS)-induced acute kidney injury(AKI) in rats and its underlying mechanisms. Methods Sprague-Dawley rats were randomly divided into the Sham group,AKI group,EGCG group and TLR4 group(n = 10 each). To establish the rat model of endotoxemia,serum creatinine(Cr) and urea nitrogen(BUN) levels were detected by biochemical assays; serum interlukin(IL)-6,IL-1β,IL-10,and TNF-α levels were detected by ELISA; kidney histopathology was examined by hematoxylin and eosin(HE) staining method; and expression of TLR4,Myd88 and nuclear factor-kappa B(NF-κB) in rat kidneys at both protein and mRNA levels was detected by Western blotting and qRT-PCR,respectively.Results Kidney injury increased significantly in AKI group compared to the sham group. Serum Cr,BUN,IL-6,IL-1β,and TNF-α levels significantly increased whereas IL-10 levels significantly decreased in AKI group compared to the sham group. Expression levels of TLR4,Myd88,and NF-κB also significantly increased at both protein and mRNA levels in AKI group compared to the sham group. Treatment with EGCG prior to induction of LPS-mediated AKI conferred protection against AKI by significantly reducing the expression of inflammatory markers such as,TLR4,Myd88,and NF-κB. Given TLR4 inhibitor based on this,the protective effect of EGCG on AKI was via inhibition of the TLR4/Myd88/NF-κB pathway. Conclusion EGCG exhibited a protective effect against LPS-induced AKI by inhibiting the activation of TLR4/Myd88/NF-κB pathway.
Objective To evaluate the protective effect of epigallocatechin gallate(EGCG) on lipopolysaccharide(LPS)-induced acute kidney injury(AKI) in rats and its underlying mechanisms. Methods Sprague-Dawley rats were randomly divided into the Sham group,AKI group,EGCG group and TLR4 group(n = 10 each). To establish the rat model of endotoxemia,serum creatinine(Cr) and urea nitrogen(BUN) levels were detected by biochemical assays; serum interlukin(IL)-6,IL-1β,IL-10,and TNF-α levels were detected by ELISA; kidney histopathology was examined by hematoxylin and eosin(HE) staining method; and expression of TLR4,Myd88 and nuclear factor-kappa B(NF-κB) in rat kidneys at both protein and mRNA levels was detected by Western blotting and qRT-PCR,respectively.Results Kidney injury increased significantly in AKI group compared to the sham group. Serum Cr,BUN,IL-6,IL-1β,and TNF-α levels significantly increased whereas IL-10 levels significantly decreased in AKI group compared to the sham group. Expression levels of TLR4,Myd88,and NF-κB also significantly increased at both protein and mRNA levels in AKI group compared to the sham group. Treatment with EGCG prior to induction of LPS-mediated AKI conferred protection against AKI by significantly reducing the expression of inflammatory markers such as,TLR4,Myd88,and NF-κB. Given TLR4 inhibitor based on this,the protective effect of EGCG on AKI was via inhibition of the TLR4/Myd88/NF-κB pathway. Conclusion EGCG exhibited a protective effect against LPS-induced AKI by inhibiting the activation of TLR4/Myd88/NF-κB pathway.
引文
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[15]JIN S,WANG J,CHEN S,et al.A novel limonin derivate modulates inflammatory response by suppressing the TLR4/NF-kappaB signalling pathway[J].Biomed Pharmacother,2018,100:501-508.DOI:10.1016/j.biopha.2018.02.046.
[16]NAIR AR,MASSON GS,EBENEZER PJ,et al.Role of TLR4 in lipopolysaccharide-induced acute kidney injury:protection by blueberry[J].Free Radic Biol Med,2014,71:16-25.DOI:10.1016/j.freeradbiomed.2014.03.012.
[2]CHEN X,TONG H,CHEN Y,et al.Klotho ameliorates sepsis-induced acute kidney injury but is irrelevant to autophagy[J].Onco Targets Ther,2018,11:867-881.DOI:10.2147/OTT.S156891.
[3]FANI F,REGOLISTI G,DELSANTE M,et al.Recent advances in the pathogenetic mechanisms of sepsis-associated acute kidney injury[J].J Nephrol,2017,2017(8):1-9.DOI:10.1007/s40620-017-0452-4.
[4]HULTSTROM M,BECIROVIC-AGIC M,JONSSON S.Comparison of acute kidney injury of different etiology reveals in-common mechanisms of tissue damage[J].Physiol Genomics,2018,50(3):127-141.DOI:10.1152/physiolgenomics.00037.2017.
[5]HERING D,WINKLEWSKI PJ.R1 autonomic nervous system in acute kidney injury[J].Clin Exp Pharmacol Physiol,2017,44(2):162-171.DOI:10.1111/1440-1681.12694.
[6]SHUM HP,YAN WW,CHAN TM.Recent knowledge on the pathophysiology of septic acute kidney injury:a narrative review[J].J Crit Care,2016,31(1):82-89.DOI:10.1016/j.jcrc.2015.09.017.
[7]ZHANG Z,ZHANG H,CHEN R,et al.Oral supplementation with ursolic acid ameliorates sepsis-induced acute kidney injury in a mouse model by inhibiting oxidative stress and inflammatory responses[J].Mol Med Rep,2018,17(5):7142-7148.DOI:10.3892/mmr.2018.8767.
[8]MOHAMED AF,SAFAR MM,ZAKI HF,et al.Telluric acid ameliorates endotoxemic kidney injury in mice:involvement of TLR4,Nrf2,and PI3K/Akt signaling pathways[J].Inflammation,2017,40(5):1742-1752.DOI:10.1007/s10753-017-0617-2.
[9]ENG QY,THANIKACHALAM PV,RAMAMURTHY S.Molecular understanding of epigallocatechin gallate(EGCG)in cardiovascular and metabolic diseases[J].J Ethnopharmacol,2018,210:296-310.DOI:10.1016/j.jep.2017.08.035.
[10]FUNAMOTO M,MASUMOTO H,TAKAORI K,et al.Green tea polyphenol prevents diabetic rats from acute kidney injury after cardiopulmonary bypass[J].Ann Thorac Surg,2016,101(4):1507-1513.DOI:10.1016/j.athoracsur.2015.09.080.
[11]TAN F,CHEN Y,YUAN D,et al.Dexmedetomidine protects against acute kidney injury through downregulating inflammatory reactions in endotoxemia rats[J].Biomed Rep,2015,3(3):365-370.DOI:10.3892/br.2015.427
[12]GUO R,ZHOU FM,SU CJ,et al.Epigallocatechin-3-gallate attenuates acute and chronic psoriatic itch in mice:involvement of antioxidant,anti-inflammatory effects and suppression of ERK and Akt signaling pathways[J].Biochem Biophys Res Commun,2018,496(4):1062-1068.DOI:10.1016/j.bbrc.2018.01.122.
[13]CHANG EJ,MUN KC.Effect of epigallocatechin gallate on renal function in cyclosporine-induced nephrotoxicity[J].Transplant Proc,2004,36(7):2133-2134.DOI:10.1016/j.transproceed.2004.08.020.
[14]EL-MOWAFY AM,AL-GAYYAR MM,SALEM HA,et al.Novel chemotherapeutic and renal protective effects for the green tea(EGCG):role of oxidative stress and inflammatory-cytokine signaling[J].Phytomedicine,2010,17(14):1067-1075.DOI:10.1016/j.phymed.2010.08.004.
[15]JIN S,WANG J,CHEN S,et al.A novel limonin derivate modulates inflammatory response by suppressing the TLR4/NF-kappaB signalling pathway[J].Biomed Pharmacother,2018,100:501-508.DOI:10.1016/j.biopha.2018.02.046.
[16]NAIR AR,MASSON GS,EBENEZER PJ,et al.Role of TLR4 in lipopolysaccharide-induced acute kidney injury:protection by blueberry[J].Free Radic Biol Med,2014,71:16-25.DOI:10.1016/j.freeradbiomed.2014.03.012.