A toxicology study to evaluate the embryotoxicity of metformin compared with the hypoglycemic drugs, the anticancer drug, the anti-epileptic drug, the antibiotic, and the cyclo-oxygenase (COX)-2 inhibitor.

BACKGROUND

The safe use of medications in pregnant females, their embryos and in offspring is important. The aim of the present study was to evaluate embryotoxicity of metformin (MET) compared with other hypoglycemic drugs (rosiglitazone [RSG] and glimepiride [GLIM]), the anticancer drug 5-fluorouracil (5-FU), the anti-epileptic drug diphenylhydantoin (DPH), the antibiotic penicillin G (PenG), and the cyclo-oxygenase (COX)-2 inhibitor nimesulide (NIM) in an embryonic stem cell test (EST).

METHODS

Differences in the expression of developmental marker genes following treatment with the test compounds during the course of differentiation (from embryonic stem cell D3 (D3 cells) to myocardial cells) were determined using real-time quantitative polymerase chain reaction. In these studies, 5-FU was used as a positive control and PenG was used as a negative control. The cytotoxicity of these drugs against D3 cells and 3T3 fibroblasts was determined by the 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Embryotoxicity was classified according to the prediction model of EST.

RESULTS

At concentrations >800 μg/mL MET had a greater cytotoxic effect on D3 cells than 3T3 fibroblasts. At the highest concentration of MET (5 mg/mL), the cell viability of D3 cells and 3T3 fibroblasts was <10% and >30%, respectively. The size of the embryonic body (EB) differentiation area was almost the same over the concentration range 50-200 μg/mL MET, and there was no significant difference in EB differentiation area until a concentration of 400 μg/mL MET. At a concentration of 800 μg/mL MET, the size of EB outgrowth was significantly reduced. The same assays revealed GLIM, RSG, and NIM to be weakly embryotoxic substances.

CONCLUSIONS

Based on the EST, MET can be classified as a weakly embryotoxic substance, which suggests that it should be prescribed with caution to pregnant women with gestational diabetes.