Bladder cell survival in response to frankincense oil exposure. Cell viability was determined using (A) a colometric XTT assay at 24 hours and (B) trypan blue exclusion at 3 hours after frankincense oil stimulation. All experiments were prepared in triplicate for XTT assay and duplicate for trypan blue exclusion. Data were presented as mean ± standard error of mean (SEM) from at least 3 independent experiments. * indicates statistical difference between frankincense oil-treated J82 cells and UROtsa cells (P < 0.05).