The role of superoxide (O_2~-) in the damage of bone marrow cells induced by cyclophosphamide in mice

Objective To investigate the noxious effect of superoxide (O- 2) and the protective action of superoxide dismutase (SOD) on the depression of the proliferation of bone marrow cells induced by cyclophosphamide (CTX) in mice. Methods 40 rats were divided randomly into 4 groups.They were administered intraperitoneally normal saline (control) and CTX of low (37.5 mg/kg),middle (56.25 mg/kg) and high (75 mg/kg) doses respectively. Another 20 rats, divided into 2 groups (10 for each) were first given intraperitoneally a high dose of CTX and then normal saline and SOD solution respectively. Results The content of O- 2 in bone marrow cells was evidently and proportionally higher in the CTX groups than that in the control group (P0.01). The bone marrow cell count and DPM were significantly decreased in the CTX groups (P0.01). The values of bone marrow cell count, DPM and O- 2 content in the CTX group with SOD added differed markedly from that without (P0.01), but approximated those in the group of normal mice (P0.05). Conclusion High concentration of O- 2 induced by CTX may be one of its mechanisms affecting the proliferation of bone marrow cells, and SOD protects the bone marrow cells from the toxicity of CTX in mice.