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Selective myelotoxicity of propanil
G Blyler1, K S Landreth, T Lillis
1Department of Microbiology and Immunology, West Virginia University School of Medicine, Morgantown 26506-9177.
Abstract:
Propanil, a commonly used herbicide, has been previously shown to be immunotoxic for selected immune functions as well as specific cell types, such as the macrophage. Propanil has also been shown to cause a methemoglobulinemia and anemia through direct action on the erythrocyte. Demonstrated toxicity to both macrophages and erythrocytes raised concern for the possible myelotoxicity of propanil which could contribute to the observed effects of exposure. Therefore, the effect of propanil on several stem and progenitor cell types was assessed 7 days after acute propanil exposure. The results described herein show that propanil, at doses of 50-200 mg/kg body wt, resulted in reduction in the number of myeloid stem cells and early myeloid and erythroid progenitor cells. No reduction in the numbers of more differentiated myeloid and erythroid progenitor cells was noted at even the highest dose used (200 mg/kg). In addition, no statistically significant difference in number of leukocytes per femur was noted. These data suggest that propanil is myelotoxic to early hemapoietic stem cells, but that this reduction is apparently compensated by proliferation of more differentiated progenitor cells for the myeloid and erythroid lineages. It remains unknown whether chronic exposure leads to progressive depletion of additional myeloid and erythroid cells.
Insights
Propanil herbicide exposure reduces early hematopoietic stem cells and progenitor cells in mice. While early cell populations decrease, later-stage cells compensate, suggesting potential resilience to acute propanil toxicity.
Area of Science:
- Toxicology
- Hematology
- Immunology
Background:
- Propanil is a widely used herbicide with known immunotoxicity affecting macrophages.
- Propanil also causes methemoglobinemia and anemia via direct erythrocyte damage.
- Concerns exist regarding propanil's potential myelotoxicity due to its effects on macrophages and erythrocytes.
Purpose of the Study:
- To investigate the myelotoxic effects of acute propanil exposure on hematopoietic stem and progenitor cells.
- To assess the impact of propanil on early and late-stage myeloid and erythroid progenitor populations.
Main Methods:
- Mice were exposed to varying doses of propanil (50-200 mg/kg body weight).
- Hematopoietic stem and progenitor cell populations were analyzed 7 days post-exposure.
- Cell counts included myeloid stem cells, early and late myeloid progenitors, and early and late erythroid progenitors.
Main Results:
- Propanil exposure (50-200 mg/kg) significantly reduced myeloid stem cells and early myeloid/erythroid progenitor cells.
- No significant reduction was observed in more differentiated myeloid and erythroid progenitor cells, even at the highest dose.
- Leukocyte counts per femur remained statistically unchanged after acute propanil exposure.
Conclusions:
- Propanil exhibits myelotoxicity towards early hematopoietic stem cells.
- The reduction in early hematopoietic cells appears to be compensated by the proliferation of more differentiated progenitor cells.
- The long-term effects of chronic propanil exposure on hematopoietic cell populations remain undetermined.