Protective Effects And Mechanisms Of Astragalus Mongolicus Polysaccharide On Acetaminophen Induced Liver Injury In Mice

As a global public health problem,drug-induced liver injury has always been a research hotspot.Acetaminophen(APAP)is one of the most widely used over-the-counter analgesic and antipyretic drugs.Its overuse has always been the main cause of drug-induced liver injury in clinical practice.Oxidative stress and aseptic inflammation are important factors of APAP-induced liver injury,so anti-inflammation and anti-oxidation are important strategies to prevent and treat APAP-induced liver injury.Astragalus membranaceus Bge.var.mongolicus(Bge.Hsiao),a dicotyledonous leguminous plant,is widely cultivated in northeast and northwest region of China.It’s root is used in traditional medicine.Astragalus Mongholicus Polysaccharide(APS)is an effective component of traditional Chinese medicine extracted from Astragalus membranaceus Bge.var.mongolicus(Bge.Hsiao),which has the function of immune activation.Whether APS can protect the drug-induced liver injury induced by APAP and its related mechanisms are poorly studied.The aim of this study is to investigate the protective effect of APS on drug-induced liver injury in mice by intraperitoneal injection of APAP.Male BALB/c mice about 8 weeks old were randomly divided into five groups(n=8): Control group(Ctrl),Astragalus Mongholicus polysaccharide control group(APS100),APAP-induced liver injury model group(APAP)and APS treatment group(APAP/APS100).APS was intragastrically administered to mice with 100 mg/kg for 14 days.The Ctrl group and the APAP group were given the same volume of distilled water.After 14 days,intraperitoneal injection of APAP(300 mg/kg)to construct a mouse model of drug-induced liver injury.After 4h,liver and blood samples were collected.Serum ALT and AST levels were measured by using an automatic biochemical analyzer;the histopathological changes of liver by was observed by HE staining;the changes in the contents of GSH,GSH-PX,MDA,and SOD-2 in the liver were detected by the corresponding kits;Western Blotting technology was used to detect the expression of p-ERK,p-JNK,Bcl-2,Bax,LC3Ⅱ,LC3Ⅰ,Keap-1,P62,Nrf-2 and its downstream target genes HO-1,NQO-1,GCLC,SOD-2 in the liver tissue;Real-time PCR was used to detect the m RNA expression of hepatic TNF-α,IL-6,IL-10,IL-1β,Nrf-2 and downstream target genes HO-1,NQO1,GCLC and SOD-2.Results: APS can significantly reduce APAP-induced increase in serum ALT,AST and hepatic MDA.APS supplementation restored the activity of hepatic GSH,GSH-PX,SOD in APAP-poisioned mice.HE-staining results showed that APS can effectively alleviate APAP-induced liver injury.Western Blot results show that APS can inhibit APAP-induced expression of p-ERK and p-JNK.APS treatment promoted the ratio of Bcl-2/Bax as well as LC3Ⅱ/LC3Ⅰ in APAP-poisoned mice.At the same time,the expression of P62 was increased after APS treatment.Real-time PCR results showed that APS can inhibit APAP-induced hepatic expression of TNF-α,IL-6 and IL-1β.Western Blotting and Real-time PCR technologies jointly proved that APS can activate the expression of Nrf-2,Keap-1 and its downstream target genes.Therefore,APS can exert anti-inflammatory,antioxidant and autophagy promoting function by inhibiting MAPK,activating Nrf-2 and LC3 signaling pathways to protect APAP-induced drug-induced liver injury.