ObjectiveTo investigate the effects of Ditantang on metabolic dysfunction-associated fatty liver disease （MAFLD） in rats by focusing on the regulation of glycogen synthesis mediated by the uridine diphosphate glucose （UDPG）-site-1-protease （S1P）-sterol regulatory element-binding protein （SREBP） axis. MethodsMAFLD was modeled in SD rats by feeding a high-fat diet for 12 weeks. Rats were randomized into a control group， a model group， low-， medium-， and high-dose （2.68， 5.36， and 10.72 g·kg^-1·d^-1， respectively） Ditantang groups， and a positive control （Yishanfu， 0.18 g·kg^-1·d^-1） group. Starting from week 9 of modeling， each treatment group received corresponding drug interventions via gavage. After the experiment， the serum levels of total cholesterol （TC）， triglyceride （TG）， low-density lipoprotein cholesterol （LDL-C）， and high-density lipoprotein cholesterol （HDL-C） were measured. The levels of TG， non-esterified fatty acids （NEFA）， glycogen， glucose-6-phosphate （G6P）， glucose-1-phosphate （G1P）， and UDPG in the liver tissue samples were measured by biochemical assay kits. Liver pathological morphology and lipid/glycogen deposition were observed via hematoxylin-eosin （HE） staining， oil red O staining， and Periodic acid-Schiff （PAS） staining. Immunofluorescence assay was conducted to detect the expression and localization of phosphoglucomutase-1 （Pgm1） and UDP-glucose pyrophosphorylase 2 （Ugp2） in the rat liver. Real-time PCR and Western blot were employed to quantify mRNA and protein levels， respectively， of key glycogen synthesis enzymes （Pgm1 and Ugp2）， key lipogenesis-related transcription factor SREBP and its target genes ［acetyl-CoA carboxylase （ACC）， fatty acid synthetase （FASN）， and stearoyl-CoA desaturase （SCD1）］， as well as S1P. ResultsCompared with the control group， the model group exhibited elevated levels of TC， TG， LDL-C in the serum and TG and NEFA in the liver， decreased serum HDL-C level （P<0.01）， reduced hepatic levels of G1P， G6P， UDPG， and glycogen （P<0.01）， appearance of fat vacuoles of varying sizes and abundant red lipid droplets， with prominent lipid deposition and reduced areas of deep glycogen staining in the liver tissue， upregulated mRNA and protein levels of SREBP1， S1P， ACC， FASN， and SCD1 （P<0.01）， and downregulated mRNA and protein levels of Pgm1 and Ugp2 （P<0.01）. Compared with the model group， all doses of Ditantang reduced the levels of TC and TG in the serum and TG and NEFA in the liver， while elevating the serum HDL-C level. Additionally， medium- and high-dose Ditantang reducted the LDL-C level （P<0.05）. Ditantang at all doses increased the hepatic levels of G1P， G6P， UDPG， and glycogen， alleviated hepatic steatosis and lipid deposition， enhanced glycogen storage， downregulated the mRNA and protein levels of SREBP1， S1P， ACC， FASN， and SCD1 （P<0.05）， while upregulating the expression of Pgm1 and Ugp2 （P<0.01）. Immunofluorescence analysis revealed decreased fluorescence intensity of S1P and enhanced fluorescence intensity of Ugp2 （P<0.01）. ConclusionDitantang can regulate glycogen synthesis through the UDPG-S1P-SREBP axis to prevent and treat MAFLD.