Effects of electroacupuncture at "Fenglong"(ST40) and "Zusanli"(ST36) on the SIRT1/FOXO1 signaling pathway in non-alcoholic fatty liver disease model rats.

Objectives: To investigate the effects of electroacupuncture (EA) on liver function, lipid metabolism, hepatic histopathology, and the expression of molecules in the SIRT1/FOXO1 signaling pathway in rats with non-alcoholic fatty liver disease (NAFLD), as well as to explore its potential underlying mechanisms.

Methods: A total of 13 SD rats were assigned to the blank group and fed a standard diet. An NAFLD model was established in 43 SD rats through a 12-week high-fat diet. Three rats from each group were randomly selected to confirm successful model establishment. After confirmation, rats in the modeling group were randomly divided into four groups:model group, EA group, EA+inhibitor group, and agonist group, with 10 rats in each group. The blank and model groups underwent immobilization three times per week for four weeks. The agonist group received intraperitoneal injections of the SIRT1 agonist resveratrol (200 mg/kg) three times per week for four weeks. The EA group received EA at "Fenglong" (ST40) and "Zusanli" (ST36) acupoints for 30 minutes, three times per week for four weeks. The EA+inhibitor group was administered the SIRT1 inhibitor EX527 (5 mg/kg) intraperitoneally, with the remaining treatment identical to that of the EA group. After the interventions, contents of serum high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglycerides (TG), as well as activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured by using colorimetric method. Liver histopathology was assessed using hematoxylin-eosin (HE) and Oil Red O staining. The protein and mRNA expressions of SIRT1, FOXO1, and ABCA1 in liver tissue, as well as the protein expression of acetylated FOXO1 (AC-FOXO1), were detected using Western blot and PCR.

Results: Compared with the blank group, the model group exhibited significantly decreased serum HDL-C contents (P<0.05), along with increased contents of LDL-C, TC, TG, and activities of ALT and AST (P<0.01, P<0.05); histological analysis revealed disorganization of hepatocytes and pronounced fat vacuolization, additionally, the expressions of hepatic SIRT1, FOXO1, and ABCA1 proteins and mRNA were reduced (P<0.05, P<0.01), whereas AC-FOXO1 protein expression was elevated (P<0.05). Compared with the model group, the EA and agonist groups demonstrated increased serum HDL-C contents (P<0.05), along with decreased contents of LDL-C, TC, TG, and ALT and AST activities (P<0.01, P<0.05); histological results showed improved hepatocyte morphology and reduced steatosis, along with elevated expression of SIRT1, FOXO1, and ABCA1 proteins and mRNA (P<0.05, P<0.01) and decreased AC-FOXO1 protein expression (P<0.05). Compared with the EA group, the EA+inhibitor group had significantly lower serum HDL-C contents (P<0.05), and higher contents of LDL-C, TC, TG, and activities of ALT and AST (P<0.01, P<0.05); histological analysis revealed more fat vacuoles and pronounced lipid droplet deposition, alongside decreased hepatic SIRT1, FOXO1, and ABCA1 protein and mRNA expressions (P<0.05, P<0.01), and elevated AC-FOXO1 protein expression (P<0.05).

Conclusions: EA may alleviate liver injury in NAFLD rats by activating the SIRT1/FOXO1 signaling pathway to promote cholesterol efflux.