PCB congeners induced mitochondrial dysfunction in Vero cells

Two PCB congeners were assessed for their cytotoxicity on Vero cells, in the attempt to compare their structure-activity relationship and to investigate the role of mitochondria involved in toxicity. Flow cytometry was used to monitor the changes of mitochondrial membrane potential (Δψm), cell size and apoptosis rate. Treatments of Vero cell cultures with both PCB 126 and PCB 153 resulted in loss of cell viability in our experimental conditions. In ortho-substituted PCB 153 treated cells, loss of cell viability was accompanied by decreased Δψm and cell shrinkage. The coplanar congener, PCB 126, had no significant effects on Δψm or cell size in this time period of exposure. These studies showed that PCB 153 is more toxic than coplanar PCB 126 to Vero cells within 24 h exposure. The cytotoxicity mechanism caused by coplanar or non-coplanar PCB congener was different, and apoptosis might be the main cell death pathway in PCB 153 treated cells.