NITOROGEN & He-Ne LASER EXPOSURE INCREASES APOPTOTIC DEATH RATE FOR MONOCYTES FROM HUMAN BLOOD

Apoptosis is a physiological process of cell death. Activation of macrophages by lipopolysaccharides delays macrophage apoptosis. However, the extended life of macrophages further stimulates inflammation and results in local tissue damage. Exposure to low level lasers is also known to activate mononuclear phagocytes. Therefore, we determined if monocytes exposed to low level lasers (He-Ne & Nitrogen lasers) exhibit delayed apoptosis. Monocytes from 5 healthy volunteers were isolated from peripheral blood and cultured in microwells in-vitro. Replicate wells containing macrophages were exposed to He-Ne and Nitrogen lasers thrice on alternate days and the percentage of apoptotic cells were counted after staining with acridine orange stain. Apoptosis was observed in 0.52 to 12 % of the non-irradiated control cells, compared with 22 to 99 % of cells exposed to Nitrogen laser. He-Ne laser exposed cells showed a greater percentage of apoptotic cells than controls, but less so than Nitrogen laser exposed cells. The present observations revealed increased apoptotic death rates for monocytes exposed to He-Ne and Nitrogen lasers, suggesting that both lasers may reduce inflammation in diseases such as tuberculosis.