Endocrine Abstracts

Fludioxonil, a phenylpyrrole fungicide, is extensively used to protect particularly fruits and vegetables from fungi. On the contrary, it has been reported that fludioxonil caused low weight birth in rats at parentally toxic doses. However, its developmental toxicity on cardiac differentiation has not yet been understood. In the present study, the early developmental toxicity of fludioxonil on the cardiac differentiation of mouse embryonic stem cells (mESCs) was evaluated. Firstly, the effect of fludioxonil (10⁻⁵–10⁻⁹ M) on mESCs viability was determined by the water soluble tetrazolium (WST) assay conducted for 5 days. The cell viability significantly decreased under 50% at 10⁻⁵ M fludioxonil, but there was no change in cell morphology by fludioxonil (10⁻⁵–10⁻⁹ M). Then, the colony formation assay was performed to confirm the effect of fludioxonil on cell proliferation. Cell proliferation was suppressed by 10⁻⁵ M fludioxonil, compared to the control (0.1% DMSO) at 5 days, but it was re-increased at 10 and 15 days. In hanging drop assay to test embryoid body (EB) formation capacity of mESCs, fludioxonil reduced the EB size at 10⁻⁵ M. In the process of differentiation to cardiomyocytes derived from mESCs, 10⁻⁵ M fludioxonil completely inhibited the beating ratio (the ratio of the number of contracting cells to the number of attached EBs) of cardiomyocytes at early stage of differentiation (day 5), but the beating ratio gradually increased after 5 days at 10⁻⁵ M fludioxonil. It seemed that fludioxonil delayed the differentiation of mESCs to cardiomyocytes at 10⁻⁵ M compared to control. These results imply that fludioxonil may have a potential toxicity on the developmental process of mESCs, especially into cardiac lineage. For more information for developmental toxicity of fludioxonil, further studies on the mechanisms of fludioxonil to induce altered cell proliferation and cardiac differentiation of mESCs are needed.

Keywords: Pesticides, fludioxonil, mouse embryonic stem cells, cardiomyocytes