Figure 3: FeSO4-mediated blocking of cytotoxicity (A) and apoptosis (B) in human dermal fibroblasts treated with Cr(VI). Fibroblasts were treated with Cr(VI) and FeSO4 at the indicated concentrations and cytotoxicity and apoptosis were determined by MTT assay and TUNEL assay, respectively, as described in the text. The experiment was repeated four times and the data is presented as mean ± S.E. For TUNEL assay, four independent microscopic fields, each consisting of 30-50 cells, were counted per experiment and the data is used. Statistical analysis was done by Tukey’s Honest Significant Difference (HSD) procedure .