The effects of potassium bromate on the apoptosis and survivability of human cell lines

Potassium bromate (KBrO₃) is a food additive used by companies to increase oxidation in bread and fermented drinks, thereby improving texture or increasing carbonation. We hypothesized that KBrO₃ would significantly increase apoptosis and other forms of cell death in human cell lines since it has been shown to induce renal dysfunction and ulceration in mice. We used two major human cell lines, CCD-18 and U937 cells, to model chronic gut diseases. We used an MTT cell viability assay to assess damage after 24 hours and 7 days of KBrO₃ exposure. Within CCD-18 cells, we observed significant effects in the 24-hour incubation, where KBrO₃ reduced cell viability to ~82% at all concentrations. In U937 cells, we recorded a similar reduction in viability. CCD-18 cells after a 7-day treatment displayed similar results to the 24-hour trials, where we recorded reductions in cell viability to 77%–86%. In contrast, 7-day treatments on U937 cells reduced viability to ~50%, which suggested more severe damage. We performed a caspase-3 assay to assess the effects of KBrO₃ on apoptosis. In CCD-18 cells, we observed significant increases in caspase activity of 105% at 0.03 μM, and of 74% at 30 μM. In U937 cells, results fluctuated drastically and there was no clear conclusion. This may be attributed to necrosis taking over as the primary path for cell death. These results suggest that KBrO₃ may cause a range of detrimental effects on immune and epithelial cells and may contribute to chronic gut conditions like IBD.