Therapy of empagliflozin plus metformin on T2DM mice shows no higher amelioration for glucose and lipid metabolism than empagliflozin monotherapy

Aims: This study was designed to compare the effects of empagliflozin monotherapy and its combination with metformin on glucose and lipid modulations in T2DM mice. Main methods: Nine-week-old male C57BLKS/J db/db mice (n = 32) were used as T2DM model, and their age-matched C57BLKS/J db/m mice (n = 8) were used as normal control. A total of 32 db/db mice were randomly divided into four groups (n = 8/group): the DMT1 group, treated with metformin (250 mg/kg/day); the DMT2 group, treated with metformin (250 mg/kg/day) plus empagliflozin (10 mg/kg/day); the DMT3 group, treated with empagliflozin (10 mg/kg/day); the T2DM control group (DM), received 0.5% Natrosol. The db/m mice received same administration as DM group. Key findings: After four-week treatments, compared with T2DM control (DM), the empagliflozin or its combination with metformin dramatically increased the levels of plasma HDL-C (139.6% and 154.9%, respectively), with significant decrease in plasma TC (22.9% and 13.7%, respectively) and plasma TG (26% and 19.7%, respectively) and in hepatic TG (30.3% and 28.6%, respectively). The protein expressions of SREBP1c (75.3% and 54.0%, respectively) and APOC-III (51.2% and 50.2%, respectively) were reduced, while CPT1A (304.0% and 221.4%, respectively) and ApoA1 levels (90.0% and 85.3%, respectively) were enhanced. Although both interventions improve above-mentioned lipid homeostasis, there were no statistic differences between two groups (p > 0.05). Significance: Our study demonstrated that current dose of combination therapy may have no higher amelioration than empagliflozin monotherapy for glucose and lipid metabolism in male T2DM mice when it followed a treatment shorter than that expected during clinical treatment.