Objective To explore the effect and mechanism of esculin on hepatocyte steatosis by inhibiting protein kinase RNA-like endoplasmic reticulum kinase(PERK)/eukaryotic translation initiation factor 2A(eIF2A)/activating transcription factor 4(ATF4)signaling pathway.Methods Human normal liver cell line HL-7702 was used to induce a fatty degeneration model of hepatocytes in vitro with 0.5mmol/L free fatty acid(FFA)(oleic acid∶palmitic acid=2∶1)and treated with 50μmol/L,200μmol/L esculin for 24h.After the cell samples were broken by ultrasound,the supernatant was collected and the contents of alanine transaminase(ALT),aspartate transaminase(AST),malondialdehyde(MDA),glutathione(GSH)and triacylglycerol(TG)were detected.Using Nile red fat fluorescence staining to detect intracellular lipid droplets;Quantitative reverse transcriptase-mediated polymerase chain reaction(qRT-PCR)was used to detect the transcription levels of genes related to intracellular lipid metabolism processes.Western blot(WB)was used to detect the protein expression levels of pro apoptotic factors Caspase-3 and Bax,as well as PERK/eIF2A/ATF4 signaling pathway related proteins and phosphorylation levels in cells.Results The results confirmed that treatments of 50μmol/L and 200μmol/L of esculin significantly decreased the levels of FFA induced MDA,ALT and AST in hepatocytes(P＜0.05),and significantly increased the levels of intracellular GSH(P＜0.05).WB results showed that esculin treatment could significantly reduce the protein expression levels of Caspase-3 and Bax(P＜0.01).The results of Nile red staining and TG content detection confirmed that esculin treatment could significantly reduce the accumulation of intracellular lipid droplets and TG content(P＜0.05).The results of qRT-PCR showed that the expression levels of PPARγ,FASN,Srebf1,Dgat2,Mvk and Acaca in hepatocytes were significantly decreased after esculin treatment(P＜0.05).In terms of mechanism,the phosphorylation levels of PERK,eIF2A and ATF4 in hepatocytes were significantly reduced by esculin treatment(P＜0.05).Conclusion Esculin could improve lipid accumulation in hepatocytes by regulating the PERK/eIF2A/ATF4 signalling pathway,which plays a positive role in maintaining the healthy state of hepatocytes.