Doxorubicin decreases cell viability and UCP2 mRNA levels in H9C2 cells. H9C2 cells were left untreated or were treated with 0.5 or 1 μM doxorubicin (DOX) for 24 h, then (A) cell viability was measured by the MTT method and (B) UCP2 expression was measured by reverse transcription and quantitative real-time PCR, with GAPDH (glyceraldehyde-3-phosphate dehydrogenase) as the internal control. The results are expressed relative to the control value and are the mean ± S.D. for three independent experiments. *: p <0.05 compared to the untreated control; **: p <0.01 compared to the untreated control.