Abstract: Objective The aim of this experiment was to investigate molecular mechanism of diethyldithiocarbamate (DDC) in improving metabolic dysfunction associated steatohepatitis (MASH) by regulating Insr/Akt signaling pathway. Methods 18 male C57BL/6 mice were randomly divided into control, MASH and DDC-intervened group (n=6 in each) and MASH model was established by feeding a choline-deficient, L-amino acid-defined (CDAA) diet, and the intervention was carried out by DDC gavage simultaneously. The expression of insulin receptor (Insr) and pro-apoptotic molecule, e.g., Bax in mouse liver tissue were detected by real-time PCR and Western blot. Model of lipotoxicity was established by induction of palmitic acid (PA) on AML12 cells, and was treated with DDC simultaneously. The expression of Insr, Akt, pAkt, Bax and Bcl2 were detected by Western blot. Results Insr mRNA level in liver tissue in MASH group was (0.38±0.13), significantly lower than [(1.03±0.27), P<0.05] in the control; the expression of Insr protein in liver tissues in MASH group was (0.61±0.11), significantly lower than [(1.68±0.58),P<0.05] in the control, while the expression of Insr protein in liver tissues in DDC-intervened group was (1.03±0.11), significantly higher than that in MASH group (P<0.05); the expression of Bax protein in liver tissue in MASH group was (1.14±0.39), significantly higher than [(0.47±0.26), P<0.05] in the control; the expression of Bax protein in liver tissues in DDC-intervened group was (0.66±0.19), significantly lower than that in MASH group (P<0.05); the expression of Insr protein in AML12 cells in PA group was (0.38±0.13), significantly lower than [(0.74±0.21), P<0.05] in the control, while the expression of Insr protein in AML12 cells in DDC-intervened group was (0.71±0.20), significantly higher than that in PA group (P<0.05); the ratio of pAkt/Akt protein in AML12 cells in PA group was (0.28±0.07), significantly lower than [(0.69±0.06), P<0.05] in the control, while the ratio of pAkt/Akt protein in AML12 cells in 25 μM or in 50 μM DDC-intervened groups were (0.85±0.02) and (0.97±0.04), both significantly increased than in PA group (P<0.05); the ratio of Bcl2/Bax in AML12 cells in PA group was (1.28±0.29), much lower than [(1.74±0.10),P<0.05] in the control, while the ratio of Bcl2/Bax in AML12 cells in DDC-intervened group was (2.30±0.78), much higher than that in PA group (P<0.05). Conclusion The Insr/Akt pathway is inhibited and apoptosis is increased in liver tissues in mice with CDAA diet-induced MASH, and DDC might inhibit hepatocyte apoptosis by stimulating Insr/Akt signaling pathway, thereby improving MASH progression.

Key words: Metabolic dysfunction associated steatohepatitis, Diethyldithiocarbamate, Insulin receptor, AML12 cells, Mices