Effect Of Free Radical Quenchers On Dye-Mediated Laser Light Induced Photosensitization Of Leukemic Cells

The effect of free radical quenchers (ascorbate, catalase, and mannitol) on merocyanine 540 (MC540) mediated, laser light induced photolysis of human acute promyelocytic leukemia cell line (HL-60) was investigated. Results show that in the presence of human albumin (0.25%), dye-mediated (2014/m1), laser light induced photolysis of leukemic cells resulted in a 99.9999% cell kill. Seventy percent of the normal bone marrow cells survived the treatment. The addition of free radical quenchers prior to laser irradiation procedure increases the HL-60 cell survival. Increases of 5.5% and 4.4%, respectively, were observed in the presence of catalase and ascorbate or mannitol. In the presence of a mixture of catalase and mannitol or catalase and ascorbate, this increase in viability was not observed. However, the viability of normal bone marrow cells under these conditions also decreased from 70% to 63%. These findings may be useful in ex-vivo bone marrow purging.