Chronic benzene exposure impairs the self-renewal capacity of HSPCs in C57BL/6 mice

Abstract In this study, we aimed to investigate the effects of chronic benzene exposure on the self-renewal capacity of C57BL/6 bone marrow HSPCs. Twenty-four male C57BL/6 mice were randomly divided into two groups: the control group and the benzene-exposed group. Mice in the benzene-exposed group inhaled 1,000 mg/m3 (308 ppm; conversion factor: 20 °C, 101 kPa, 1 ppm = 3.25 mg/m3) benzene for 32 weeks and the control group mice inhaled clean air. The peripheral blood hematological alterations were monitored every two weeks. Competitive bone marrow transplantation was performed to assess the self-renewal capacity of bone marrow HSPCs and the donor cell chimerism was quantified through flow cytometry. By the fourth week of benzene exposure, significant reductions in leukocytes, erythrocytes, and hemoglobin levels (P < 0.05) were observed, suggesting the development of benzene poisoning in mice. In the B6.SJL recipient mice, the chimerism ratio of bone marrow cells from C57BL/6 donors exposed to benzene for 20 weeks significantly decreased after transplantation (16 weeks post-transplant: 52.58% ± 17.38% in controls vs. 3.89% ± 1.96% in the benzene group, P < 0.05). Furthermore, the chimerism ratio in recipients of 32-week benzene-exposed donors approached zero by week 84 post-transplant, suggesting a loss of self-renewal capacity in bone marrow HSPCs due to benzene exposure. The study concludes that bone marrow suppression and the diminished self-renewal ability of C57BL/6 bone marrow HSPCs may lead to bone marrow failure in mice, contributing to the potential occurrence of MDS.