Figure 8. SeMet attenuated toxic effect of CoNPs on CD34+ HSC/HPCs in rat. Male SD rats were 6-8 weeks old and weighed approximate 800 g at the start of the experiments. CoNPs particles were suspended in a vehicle of 1:1 rat serum: phosphate buffered saline (PBS; Oxoid) by sonication and administered to rats. 50 μL CoNPs (1000 μg/kg BW)-containing vehicle was injected in the right hip joint. The rats were exposed to three injections of the particles at three week intervals. Sham treated rat received 15 ml of vehicle alone. In addition, rats received an oral dose of SeMet (2 mg SeMet/kg BW/day). All rats were sacrificed three weeks after final injection of CoNPs. Bone marrow was collected for analysis of CD34+ HSC/HPCs number by flow cytometry (A), for the measurements of biochemical parameters, including, T-AOC (B), GSH level (C), GPx activity (D) and 8-OHdG level (E), and for comet assay (F). (G) The mechanism diagram shows the mechanism by which SeMet attenuates toxic effect of CoNPs on CD34+ HSC/HPCs. *p < 0.05, **p < 0.01 and ***p < 0.001 vs. control cells that did no subjected to any treatments. ##p < 0.01 and ###p < 0.001 vs. cells treated with CoNPs alone.