抑制SLC31A1表达调节铜稳态对小鼠酒精性脂肪肝病变的影响及其机制OA

Objective To investigate the effect of inhibiting the expression of solute carrier family 31 member 1(SLC31A1)on alcoholic fatty liver disease(AFLD)in mice by regulating copper homeostasis and its underlying mechanisms.Methods Thirty healthy male C57BL/6N mice aged 6-8 weeks were randomly divided into control group,ethanol group,and plasmid group(n=10).Control group was fed a control liquid diet daily,while ethanol and plasmid groups were fed an ethanol-containing liquid diet daily.Plasmid group was injected with 0.2 ml of SLC31A1-sgRNA plasmid(2 mg/kg)via the tail vein by hydrodynamic injection,and ethanol and control groups were injected with an equal volume of normal saline via the tail vein.At the end of the 8th week,the mice were euthanized after ocular blood collection,and liver tissue were harvested.qPCR and Western blotting were used to detect the mRNA and protein expression levels of SLC31A1 in liver tissue.Immunohistochemistry(IHC)was employed to detect the expression of SLC31A1 in liver tissue.Colorimetric assay was adopted to determine the copper content in liver tissue and serum.Microplate assay was used to detect the activity of superoxide dismutase(SOD),and the contents of glutathione(GSH),malondialdehyde(MDA),total cholesterol(TC),and triglycerides(TG)in liver tissue,as well as the activity of alanine aminotransferase(ALT)and aspartate aminotransferase(AST),and the contents of TC and TG in serum.HE staining,Oil Red O staining,and periodic acid-Schiff(PAS)staining were conducted to assess liver injury,lipid accumulation,and glycogen changes,respectively.Western blotting was used to detect the protein expression levels of nuclear factor E2-related factor 2(Nrf2),cytochrome P450 family 2 subfamily E member 1(CYP2E1),adenosine monophosphate-activated protein kinase alpha 1(AMPKα1),peroxisome proliferator-activated receptor alpha(PPAR-α),nuclear factor κB p65 subunit(NF-κB p65),inhibitor of nuclear factor κB alpha(IκB-α),c-Jun N-terminal kinase(JNK),and p38 mitogen-activated protein kinase(p38 MAPK).Results The results of qPCR,Western blotting,and IHC showed that SLC31A1-sgRNA plasmid could effectively inhibit the expression of SLC31A1(P<0.001).Compared with control group,ethanol group had increased liver injury scores and lipid droplet area ratio,and decreased collagen area ratio;the SLC31A1-positive area ratio,mRNA and protein expression levels of SLC31A1,and copper content in liver tissue and serum were increased;the activities of ALT and AST,and the contents of MDA,TC,and TG were increased,while the SOD activity and GSH content were decreased;the protein expression level of CYP2E1,and the ratios of p-JNK/JNK,p-p38 MAPK/p38 MAPK,p-NF-κB p65/NF-κB p65,and p-IκB-α/IκB-α were up-regulated,whereas the protein expression levels of Nrf2 and PPAR-α,and the ratio of p-AMPKα1/AMPKα1 were down-regulated(P<0.05).Compared with ethanol group,plasmid group had decreased liver injury score and lipid droplet area ratio,and increased collagen area ratio;the SLC31A1-positive area ratio,mRNA and protein expression levels of SLC31A1,and copper content in liver tissue and serum were decreased(P<0.001);the activities of ALT and AST,and the contents of MDA,TC,and TG were reduced,while the SOD activity and GSH content were elevated;the protein expression levels of CYP2E1,and the ratios of p-JNK/JNK,p-p38 MAPK/p38 MAPK,p-NF-κB p65/NF-κB p65,and p-IκB-α/IκB-α were down-regulated;and the protein expression levels of Nrf2 and PPAR-α,and the ratio of p-AMPKα1/AMPKα1 were up-regulated(P<0.05).Conclusion Inhibition of SLC31A1 may alleviate ethanol-induced fatty liver lesions in AFLD mice by reducing copper content,thereby attenuating oxidative stress injury,lipid metabolism disorder,and inflammatory injury.