The protective role of zinc and N-acetylcysteine in modulating zidovudine induced hematopoietic toxicity

The role of zinc and N-acetylcysteine (NAC) has been investigated in protecting the hematopoietic progenitor cells from zidovudine (AZT)-induced toxicity. Murine bone marrow progenitor cells (BMPC, 1 x 10(6)) were exposed to various concentrations (0.1-50 mu M) of AZT in the presence and absence of zinc acetate (100 mu M) or NAC (100 mu M). The cell survival was determined by the colony forming assays of erythroid (CFU-E) and granulocytic (CEU-GM) lineage. The IC50 values of AZT in the presence of zinc were increased approximately 3-fold (from 3.0 to 9.5 mu M) in the CFU-E assay and 7-fold (from 4.3 to 28.8 mu M) in the CFU-GM assay whereas in the presence of NAC, the IC50 values were increased by 2- and 4-fold, respectively. To delineate the mechanism of significant protection of BMPC by zinc, the mRNA levels of metallothionein (MT) were monitored by using a 31-mer cDNA probe. Zinc produced a concentration-dependent increase in the MT mRNA levels in BMPC. These results suggest that zinc and NAC dietary supplementation can be conveniently used to reduce AZT-induced bone marrow toxicity.