[Leukocyte stimulation by DNA fragments shored up protamine in cyclophosphamide-induced leukopoiesis in mice]

Our study showed that protamine (80% w/w to DNA) effectively protected its molecules from degradation by native nucleases of the mammalian blood serum. Exogenous DNA bound to protamine effectively stimulated restoration of cyclophosphamide-induced leukopoiesis in mice. It is suggested that the phenomenon was due to repair processes taking place in hemopoietic stem cells damaged by a cross-linking cytostatic drug such as cyclophosphamide. DNA dosage may be reduced and the original DNA fragment size maintained by DNA binding to protamine. As a result, it might involve longer DNA fragments into repair processes of homologous recombination and eventually increase the cell's chances of getting rid of extensive damage.