Metformin improves lipid metabolism disorders through reducing the expression of microsomal triglyceride transfer protein in OLETF rats.

OBJECTIVE: This study aimed to investigate the role of MTP on lipid metabolism disorders in insulin-resistant rats and the potential mechanism through which metformin can improve lipid metabolism disorders.

METHODS: 30 OLETF rats served as research subjects and 18 LETO rats of the same strain served as the control group (LETO group). After the first oral glucose tolerance test (at 8-week-old), 6 rats were randomly killed from each group. The remaining 24 OLETF rats were randomly divided into untreated group (OLETF group) and treated group (OLETF/M group, cured with metformin). By the end of the 10th and 20th week of treatment, MTP in the liver was measured for all rats in the study.

RESULTS: All OLETF rats exhibited diabetic phenotypes at 18-week-old, with their triglyceride level higher than in LETO rats at the same age. In OLETF rats, MTP level in the liver was higher than in LETO rats at 18-week-old, and the difference was significant at 28-week-old [(13.79±1.47) vs. (8.20±1.14), p<0.05]. Treatment with metformin for 20weeks decreased triglyceride [(1.06±0.23) vs. (2.20±0.62) mmol/L, p<0.05] and total cholesterol [(1.90±0.19) vs. (2.36±0.14) mmol/L, p<0.05] in OLETF rats. Metformin also decreased MTP level in the liver [(7.65±1.31) vs. (13.79±1.47), p<0.01].

CONCLUSIONS: MTP may be associated with the lipid metabolism disorder in OLETF rats and metformin could improve lipid metabolism through reducing the expression of MTP.