Neutrophil production in drug-depleted rat bone marrow

Abstract

The present study was designed to determine the capacity of neutrophil precursors to regenerate in drug-depleted rat bone marrow.

Myleran (15 mg/Kg body weight) was introduced by stomach tube into 200g male albino rats (day zero). Five daily intraperitoneal injections of Hydrocortone Acetate (5 mg/Kg body weight) was administered to five day post-Myleran treated rats. Replicate serial qualitative and quantitative sampling procedures were carried out on the left femoral bone marrow of experimental and control animals at 13, 15, 17, and 18 days post-Myleran injection. Tritiated thymidine (.5 μc/g) was injected intraperitoneally 30 minutes before sampling time. Autoradiography which was used is described. The labeling index and absolute numbers of myeloblasts, promyelocytes, myelocytes, metamyelocytes, lymphocytes, and transitional cells were determined.

The labeling index of myeloblasts-promyelocytes and myelocytesmetamyelocytes increase significantly at days 17 and 15 respectively in the experimental animals. Absolute numbers of non-segmented and segmented neutrophils in the experimental were significantly lower than control animals. There are no significant differences within experimental animals for both cell types.

The labeling index of lymphocytes are significantly higher in experimental than control animals at days 17 and 18. Absolute numbers of these cells in experimental animals are significantly lower than control animals for all days sampled. There are no significant differences within each group. No significant increase in either labeling index or absolute numbers of transitional cells occurred.

These results indicate that for neutrophil precursors there is a significant increase in the labeling index reflects an actual increase in the absolute numbers of dividing cells. The data also indicates that bone marrow lymphocytes do not function as stem cells for neutrophil production.