Effects of inorganic arsenic on bone marrow hematopoietic cells: an emphasis on apoptosis and Sca-1/c-Kit positive population.

Apoptosis, proliferation and differentiation are balanced molecular processes which may alter their pattern during environmental insults. Arsenic is an environmental pollutant, ranks 20(th) in abundance in the earth crust, 14(th) in sea water and 12(th) in the human body. Millions of people worldwide are chronically exposed to arsenic often due to naturally occurring arsenic in ground water. Hematopoietic stem cells within the bone marrow are the source of all haematopoietic cell lineages and are essential for tissue development throughout the life. In this experimental study, we have evaluated the impact of arsenic, on blood and blood forming cells by the changes in their cellular morphology, immune functional capacity, alteration of bone marrow CD34 positive stem/progenitors and changes in the phenotype of Sca-1, c-Kit dual positive primitive stem cell population. The study revealed that arsenic has a significant effect on bone marrow and hematopoietic stem cells, their immune capacity and upregulation of death process, all indicative of impairment in differentiation suggesting presence of deregulation in their precursors by arsenic toxicity.