Lead-Induced Cytotoxicity and Oxidative Stress in Human Leukemia (HL-60) Cells

Lead poisoning has been extensively studied over the years. Many adverse physiological and behavioral impacts on the human body have been reported due to the entry of this heavy metal. It especially causes the hematological effects to people of all ages. However, its molecular mechanisms of action remain largely unknown. Hence, the aim of the present study was to evaluate the cytotoxicity and oxidative stress induced by lead nitrate in a human leukemia cell line using the MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide], and lipid hydroperoxide assays, respectively. HL-60 cells were treated with different doses of lead nitrate for 24 h prior to cytotoxicity oxidative stress assessment. The results obtained from the MTT assay indicated that lead nitrate significantly decreases the viability of HL-60 cells in a dose-dependent manner. Similar result was obtained with the trypan blue exclusion test. Data generated from lipid hydroperoxide assay resulted in a significant increase (p < 0.05) in the production of hydroperoxides (degradation products of lipid peroxidation) with increasing doses of lead nitrate. Upon 24 h of exposure, the hydroperoxide concentrations in the sample [μM] (mean ±SE, n = 3) compared to untreated control were 6.7 ± 2, 7.1 ± 1, 14.7 ± 2, 15.7 ± 1, 16.2 ± 1, and 15.2 ± 1 in 0, 10, 20, 30, 40, and 50. μg/mL of lead nitrate, respectively. In summary, findings from this study demonstrated that lead nitrate is cytotoxic to HL-60 cells. This cytotoxicity is found to be associated with oxidative stress.