基于抗炎、抗氧化反应探讨石斛多糖改善对乙酰氨基酚致肝损伤的作用机制

Mechanisms of dendrobium polysaccharides in alleviating acetaminophen-induced hepatic injury through anti-inflammatory and antioxidant reaction

目的探讨石斛多糖(dendrobium polysaccharide,DOP)拮抗对乙酰氨基酚(acetaminophen,APAP)致小鼠肝损伤的作用及其机制。方法将健康雄性昆明种小鼠随机分为对照组,APAP模型组,DOP低、中、高剂量干预组(225、450、900 mg·kg^(-1))、DOP对照组,其中APAP组每天灌胃300 mg·kg^(-1),DOP干预组灌胃DOP 2 h后再灌胃APAP,其余组灌胃等体积生理盐水,各组连续灌胃7 d,末次给药后20 h处死小鼠收集血清、肝脏。检测小鼠肝脏大体形态及肝脏系数;TUNEL和HE染色观察肝脏细胞凋亡和病理组织学;试剂盒检测相关指标;Western blot分析肝脏中氧化应激、炎症和凋亡相关蛋白水平。结果APAP组小鼠肝脏系数明显增加,肝脏空泡性坏死、凋亡细胞数增多,血清ALT、AST水平明显增加;与APAP组相比,DOP干预后尤其以900 mg·kg^(-1)组小鼠肝脏系数、血清ALT、AST水平明显降低,肝脏病理变化得到改善;且APAP组氧化应激、炎症水平升高,肝脏中凋亡、炎症和氧化应激相关蛋白表达失衡;DOP干预后尤其以900 mg·kg^(-1)组能够明显逆转APAP诱导的肝脏氧化应激、凋亡增加及炎症反应,并升高Nrf2、HO-1表达但降低NLRP3、HMGB1表达水平。结论DOP的保肝作用机制主要在于其抗氧化与抗炎反应,可能与DOP激活Nrf2/HO-1通路及抑制HMGB1/NLRP3通路相关。

Aim To investigate the protective effects of dendrobium polysaccharide(DOP)against paracetamol(APAP)-induced liver injury in mice and elucidate its underlying mechanism.Methods Healthy male Kunming mice were randomly assigned to the following groups:control group,APAP model group,low,medium,high-dose DOP intervention group(225,450,900 mg·kg^(-1)),and DOP control group.The APAP model group was given 300 mg·kg^(-1)per day,the DOP intervention group was given DOP for 2 h and then APAP was given,and the remaining groups received an equal volume of normal saline daily for seven consecutive days.After the final administration,serum and liver samples from the mice were collected and tested after 20 hours.Liver morphology and liver coefficient were examined.Liver histopathological alterations and apoptosis were examined using HE staining and TUNEL staining.Additionally,medium biochemical indexes were assessed in serum and liver tissue using kits.The levels of oxidative stress,inflammation,and apoptosis-related proteins in liver tissue were determined using Western blotting.Results In the APAP model group,liver coefficient increased significantly,the number of liver vacuolar necrosis and apoptosis cells increased,and the serum ALT and AST levels significantly increased.Compared with the APAP group,the liver coefficient,serum ALT and AST levels were significantly reduced,and the liver pathology was improved after DOP intervention,especially in the 900 mg·kg^(-1)group.The levels of oxidative stress and inflammation in the APAP group increased,and the expression of apoptosis,inflammation and oxidative stress related proteins in liver was unbalanced.DOP intervention,especially in the 900 mg·kg^(-1)group,could significantly reverse the oxidative stress,apoptosis and inflammatory response induced by APAP in liver,and increase the expression levels of Nrf2 and HO-1,but reduce the expression levels of NLRP3 and HMGB1.Conclusions The hepatoprotective mechanism of DOP is mainly due to its antioxidant and anti-inflammatory response,which may be related to the activation of Nrf2/HO-1 pathway and the inhibition of HMGB1/NLRP3 pathway by DOP.