Induction of HepG2 cell apoptosis by Irgarol 1051 through mitochondrial dysfunction and oxidative stresses

In this study, HepG2 cells were exposed to 0.04–40 mg/L Irgarol 1051. Results show that Irgarol 1051 can damage cell morphology and cause a significant decrease in cell viability. Positive staining by Annexin V, caspase-3 activity enhancement, and the damage in cell ultrastructure indicated an apoptotic mode of cell death for 4.0 mg/L Irgarol 1051 treatment. At the same time, caspase-9 was also significantly induced by 0.4 and 4.0 mg/L Irgarol 1051 at 72 h, which suggests that the intrinsic mitochondria pathway was involved in the apoptosis. The mitochondrial membrane potential decreased significantly after the HepG2 cells were exposed to Irgarol 1051 for 6 and 72 h. Especially, the translocation of cytochrome c from mitochondria to cytosol was recorded, supporting the idea that the mitochondrial pathway was involved in the apoptosis signal pathways induced by Irgarol 1051. The significantly increased levels of intracellular reactive oxygen species (ROS) and an immediate ROS burst were also recorded. The results here may imply that Irgarol 1051 induces HepG2 cell apoptosis through mitochondrial dysfunction and oxidative stresses. Although it is possible that this chemical has no detrimental effects on human health at the environmentally relevant concentration, it may cause problems to top coastal predators due to bio-accumulation through the food chain.