© 1994 Oxford University Press
research-article |
Selective Myelotoxicity of Propanil1
,2
*Department of Microbiology and Immunology, West Virginia University School of Medicine P.O. Box 9177, Morgantown, West Virginia 26506-9177
Department of Microbiology and Immunology, University of Arkansas for Medical Sciences Little Rock, Arkansas 72205
Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences Little Rock, Arkansas 72205
Received March 4, 1993; accepted November 5, 1993
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.