白藜芦醇通过抑制炎症和细胞凋亡预防脂多糖对小鼠肝脏的损伤

Resveratrol Pretreatment Alleviates Lipopolysaccharide-Induced Liver Injury in Mice by Inhibiting Inflammation and Apoptosis

本试验旨在研究白藜芦醇(RES)对脂多糖(LPS)诱导小鼠肝脏损伤的预防作用。首先,将50只小鼠随机分为5组,分别为对照组、LPS组、RES-L+LPS组、RES-M+LPS组、RES-H+LPS组,每组10只。其中,RES-L+LPS组、RES-M+LPS组、RES-H+LPS组小鼠分别连续灌胃300μL含10(低剂量)、20(中剂量)和40 mg/kg BW(高剂量)RES的0.5%羧甲基纤维素钠溶液28 d,随后腹腔注射LPS(5.0 mg/kg BW)作用12 h;LPS组和对照组小鼠连续灌胃等体积的0.5%羧甲基纤维素钠溶液28 d,随后分别注射等体积的LPS和生理盐水作用12 h。处理结束后,称重,收集肝脏组织,计算肝脏指数;用苏木精-伊红(HE)染色后观察肝脏组织病理变化,并用原位缺口末端标记(TUNEL)法分析肝脏组织的凋亡情况;进一步采用实时荧光定量PCR(RT-qPCR)检测肝脏中炎症因子肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)以及凋亡相关基因Bax和Bcl-2 mRNA的表达水平,采用蛋白质免疫印迹(Western Blot)法检测肝脏中Bax及Bcl-2蛋白的表达水平。结果显示:1)LPS诱导后,肝脏组织出现明显的组织病理学变化,可观察到细胞肿胀、部分细胞核深染、中央静脉充血及炎症细胞浸润等,用RES预处理可减少相关病理变化,且呈剂量依赖。通过TUNEL染色发现LPS诱导可引起肝组织中细胞发生凋亡,RES预处理可缓解其细胞凋亡,且以高剂量RES的作用效果较好。2)LPS诱导可极显著促进肝脏中炎症因子IL-6和TNF-α以及促凋亡基因Bax mRNA的表达(P<0.01),并极显著抑制肝脏中抗凋亡基因Bcl-2 mRNA的表达(P<0.01);RES预处理可在一定程度上抑制LPS诱导所致的基因表达的变化;进一步研究发现RES可极显著抑制LPS诱导所致的促凋亡蛋白Bax表达水平的上升(P<0.01),但对抗凋亡蛋白Bcl-2的作用不显著(P>0.05)。由此可见,LPS诱导导致小鼠肝脏发生组织病理损伤,用RES预处理可在一定程度上抑制炎症和细胞凋亡,降低肝脏损伤。

The present study aimed to investigate the preventive effect of resveratrol(RES)on liver injury in mice induced by lipopolysaccharide(LPS).Firstly,fifty mice were randomly divided into 5 groups:control group,LPS group,RES-L+LPS group,RES-M+LPS group and RES-H+LPS group,with 10 mice in each group.The mice in the RES-L+LPS group,RES-M+LPS group and RES-H+LPS group were administered with 300μL 0.5%sodium carboxymethyl cellulose solution containing 10(low dose),20(medium dose)and 40 mg/kg BW(high dose)RES by gavage for 28 d,respectively,followed by intraperitoneal injection of LPS(5.0 mg/kg BW)for 12 h;the mice in the LPS group and control group were given the same volume of RES solvent(0.5%sodium carboxymethyl cellulose)for 28 d,and then injected with equal volume of LPS and normal saline for 12 h,respectively.After treatment,the body weight and liver tissue were weighed,and the liver index was calculated;the pathological changes of liver tissue were observed by hematoxylin eosin(HE)staining,and the apoptosis of liver tissue was detected by terminal-deoxynucleoitidyl transferase mediated nick end labeling(TUNEL)method;the mRNA expression levels of inflammatory factors tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6),apoptosis related genes Bax and Bcl-2 were detected by real-time quantitative PCR(RT-qPCR),and the Western Blot was used to detect the protein expression levels of Bax and Bcl-2 in liver.The results showed as follows:1)after LPS induction,obvious histopathological changes were observed in liver tissue,exhibiting cell swelling,partial nuclear dark staining,central venous congestion and inflammatory cell infiltration.RES pretreatment could reduce the related pathological changes in a dose-dependent manner.TUNEL staining showed that LPS induction could significantly induce apoptosis in liver tissue,and RES pretreatment could alleviate the apoptosis,and the effect of high dose of RES was better.2)LPS induction extremely significantly increased the mRNA expression of inflammatory factors IL-6,TNF-αand pro-apoptotic gene Bax in liver(P<0.01),and significantly inhibited the mRNA expression of anti-apoptotic gene Bcl-2 in liver(P<0.01);RES pretreatment could inhibit the change of gene expression induced by LPS to a certain extent;further studies showed that RES could extremely significantly inhibit the expression of pro-apoptotic protein Bax induced by LPS(P<0.01),but the effect of anti-apoptotic protein Bcl-2 was not significant(P>0.05).In conclusion,LPS induction can cause histopathological changes of liver in mice.RES pretreatment can inhibit inflammation and apoptosis to a certain extent in liver,and reduce liver injury.