Kolkata, Jun 20 (IANS): Long-time exposure to pesticides via inhalation may cause moderate to severe blood toxicity and reduction in the total number of bone marrow cells, leading to several degenerative diseases like aplastic anaemia, researchers at the School of Tropical Medicine (STM) here say.

The researches arrived at the conclusion from procedures performed on mice.

"As a whole, exposure to pesticides reduced the total number of bone marrow cells or, in other words, suppressed them," Sujata Law, assistant professor (Stem Cell Biology) at STM's Department of Medical Biotechnology, told IANS.

Bone marrow is the soft, flexible tissue found in long bones such as the thigh bone and the hip bone that contain immature cells called stem cells.

Stem cells, particularly the haematopoeitic stem cells (HSC) or the blood-forming stem cells can develop into the following types - red blood cells that carry oxygen, white blood cells that fight infection and platelets that help to clot blood.

So, in effect, bone marrow is the birthplace of these important cells.

"Bone marrow suppression leads to a number of degenerative diseases like aplastic anaemia, where the deficiency in the number of cells in the circulating blood (peripheral cytopenia) is the main feature," Law said.

The exact underlying mechanism is unknown but it has been concluded from the research published in the Journal of Environmental Toxicology that the microenvironment of the stem cells, in which they develop, is somehow deranged and this prevents their development into the various types of cells.

"In order to prevent degenerative diseases related to pesticide exposure, it is of prime importance that those handling pesticides take precautions like wearing protective clothing, including masks and gloves," she said.

"Also pesticides should be stored in properly labelled containers, away from food, and kept out of reach of children and animals," Law said.