Résumé
Bone is the main source of lead concentration and is presumed as one of the main targets of the toxic effects of this heavy metal. This study have evaluated the toxic effects of lead on the primary culture of the vertebrate of the human fetus and the expression of the Bax protein in the cell. The present investigation is a laboratory study which initially a primary culture of the vertebrate of the human fetus was prepared by the enzymatic digestion and quantity of the osteoblast cells were then determined by Alkaline phosphatase assay. The effects of lead exposure at serially made concentrations of l0 micro mol to 1.5 micro mol on the cell proliferation, was evaluated in a culture containing 5 and 10 percentages of fetal bovine serum [FBS] by MTT assay [Methyl Thiazolyl Blue Tetrazolium Bromide]. In addition the effects of 0.1 micro mol of lead on Bax gene expression in osteoblast cells was analyzed by immunocytochemistry method. Quantitative analysis of osteoblast cells in the primary culture by the Alkaline phosphatase assay was determined as 80 to 85%. The lead concentrations of 100 to 1500 micromole caused 40 to 81% increase in the cell proliferation in culture containing 10% of FBS. The most growth stimulation was observed at the concentration of micro mol [p<0.001]. By decreasing the FBS, the inhibitory proliferative activities of lead increased as such that the cell growth showed an increase of 15 to 103% with concentration of 10 to l000 jumol, and a decrease was observed in cell growth about 72% in a lead concentration of 1.5 micro mol [p<0.001]. The most cell proliferation stimulation was seen in a concentration of 500 micro mol [p<0.001]. Osteoblast cells exposure to 0.1 micro mol of lead caused an increase in the amount of Bax protein in the cytoplasm in compare with the control culture. The result of this study shows that lead may disturb the natural physiologic function of the bone cells and this heavy metal may act as a mitogenic element