罗汉果皂苷Ⅵ对小鼠脓毒症致急性肝损伤的作用及其机制探讨

Effect of mogroside Ⅵ on acute liver injury induced by sepsis in mice and related mechanisms

目的探讨罗汉果皂苷Ⅵ(MⅥ)对小鼠脓毒症致急性肝损伤的作用及其可能作用机制。方法将60只雄性C57BL/6小鼠随机分成假手术组、模型组、MⅥ低剂量组(低剂量组,25 mg/kg)、MⅥ高剂量组(高剂量组,100 mg/kg)和过氧化物酶增殖激活受体γ辅助激活物1α(PGC-1α)抑制剂组(抑制剂组,100 mg/kg MⅥ+30 mg/kg PGC-1α抑制剂SR-18292),每组12只。采用盲肠结扎穿孔术制备脓毒症小鼠模型,造模成功后开始腹腔注射给药,每天1次,连续3 d。ELISA法检测血清中丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)浓度;比色法检测肝组织中丙二醛(MDA)、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)水平;苏木精-伊红染色观察肝组织病理学变化;检测肝脏线粒体呼吸功能,计算线粒体呼吸控制率;RT-PCR检测肝组织线粒体DNA(mtDNA)的拷贝数及肝组织中PGC-1α、核呼吸因子1(NRF-1)、线粒体转录因子A(TFAM)的mRNA水平;Western blot检测肝组织中PGC-1α、NRF-1和TFAM的蛋白表达水平。结果与假手术组比较,模型组小鼠血清中ALT、AST水平及肝组织中MDA含量显著增加(P<0.05),肝组织中GSH-Px和SOD活性显著降低(P<0.05);肝组织病理学损伤严重;肝组织线粒体呼吸控制率和mtDNA拷贝数,以及肝组织中PGC-1α、NRF-1、TFAM的mRNA及其蛋白表达水平均显著降低(P<0.05)。与模型组比较,高剂量组小鼠血清中ALT、AST水平及肝组织中MDA含量显著减少(P<0.05),肝组织中GSH-Px和SOD活性显著增加(P<0.05);肝组织病理学损伤得到改善;肝组织线粒体呼吸控制率和mtDNA拷贝数,以及肝组织中PGC-1α、NRF-1、TFAM的m RNA及其蛋白表达水平均显著上升(P<0.05);低剂量组上述指标差异均无统计学意义(P>0.05)。PGC-1α抑制剂SR-18292可显著抑制高剂量MⅥ的干预效果(P<0.05)。结论MⅥ能有效减轻小鼠脓毒症致急性肝损伤,其机制可能与增强PGC-1α介导的线粒体生物合成有关。[中国当代儿科杂志,2020,22(11):1233-1239]

Objective To study the effect of mogroside VI(MVI)on acute liver injury induced by sepsis in mice and its possible mechanisms.Methods A total of 60 male C57BL/6 mice were randomly divided into five groups:sham-operation,model,low-dose MVI(25 mg/kg),high-dose MVI(100 mg/kg),peroxisome proliferator-activated receptor gamma coactivator-1 alpha(PGC-1α)inhibitor(100 mg/kg MVI+30 mg/kg PGC-1αinhibitor SR-18292),with 12 mice in each group.Cecal ligation and puncture were performed to establish a mouse model of sepsis.The drugs were given by intraperitoneal injection after the model was established,once a day for 3 consecutive days.ELISA was used to measure the serum levels of alanine aminotransferase(ALT)and aspartate aminotransferase(AST).Colorimetry was used to measure the levels of malondialdehyde(MDA),superoxide dismutase(SOD),and glutathione peroxidase(GSH-Px)in liver tissue.Hematoxylin-eosin staining was used to observe liver histopathological changes.Liver mitochondrial respiratory function was measured,and mitochondrial respiratory control rate was calculated.RT-PCR was used to measure the copy number of mitochondrial DNA(mtDNA)in liver tissue and the mRNA expression levels of PGC-1α,nuclear respiratory factor-1(NRF-1),and mitochondrial transcription factor A(TFAM)in liver tissue.Western blot was used to measure the protein expression levels of PGC-1α,NRF-1,and TFAM in liver tissue.Results Compared with the sham-operation group,the model group had significant increases in the serum levels of ALT and AST and the content of MDA in liver tissue(P<0.05)and significant reductions in the activities of GSH-Px and SOD in liver tissue(P<0.05).The model group had also severe liver histopathological injury and significant reductions in the mitochondrial respiratory control rate,the copy number of mtDNA,and the mRNA and protein expression levels of PGC-1α,NRF-1,and TFAM in liver tissue(P<0.05).Compared with the model group,the high-dose group had significant reductions in the serum levels of ALT and AST and the content of MDA in liver tissue(P<0.05),significant increases in the activities of GSH-Px and SOD in liver tissue(P<0.05),significant improvement in liver histopathological injury,and significant increases in the mitochondrial respiratory control rate,the copy number of mtDNA,and the mRNA and protein expression levels of PGC-1α,NRF-1,and TFAM in liver tissue(P<0.05).There were no significant differences in the above indicators between the low-dose and model groups(P>0.05).The PGC-1αinhibitor SR-18292 significantly inhibited the intervention effect of high-dose MVI(P<0.05).Conclusions MVI can effectively alleviate acute liver injury caused by sepsis in mice,possibly by enhancing mitochondrial biosynthesis mediated by PGC-1α.[Chin J Contemp Pediatr,2020,22(11):1233-1239]