BIOLOGICAL EFFECTS OF PULSED NEAR-ULTRAVIOLET LASER IRRADIATION IN MOUSE LYMPHOMA-CELLS (EL-4)

Murine lymphoma EL-4 cells were exposed to different pulsed near-ultra violet laser doses (337.1 nm), generated by light, to investigate some effects of this radiation on tumor cells using biophysical, biochemic al, and cytogenetic methods. Our results reveal a good correlation bet ween the growth rate of EL-4 cells and the interrogation irradiation, from 89.7% at 1.5 kJ/m(2) to 17.8% at 4.5 kJ/m(2). Nucleic acid synthe sis was found to be inhibited at any laser irradiation dose. The morph ological changes induced by laser irradiation of EL-4 cells and reveal ed by phase contrast and scanning electron microscopy (SEM) indicate a partial or total (depending on dose) loss of cellular microviliositie s, the appearance of different kinds of buds and bleaching all over th e cellular membrane, and also numerous necrotic lesions. By reversion of irradiated EL-4 cells, the presence of cells having morphological c haracteristics of lymphoid dendritic cells was observed by phase contr ast and SEM. The cytogenetic analysis showed the presence of different chromosomal abnormalities: chromatidin and chromosomal fractures, rin gs, chromosomal markers, polyploids, and premature chromatid condensat ion. Our experimental results suggest the existence of morphological l esions as well as biochemical and genetic lesions induced by pulsed ne ar-ultraviolet laser doses in mouse lymphoma EL-4 cells. (C) 1996 Soci ety of Photo-Optical Instrumentation Engineers.