CELLULAR STRESS BY LIGHT AND ROSE-BENGAL IN HUMAN-LYMPHOCYTES

Human lymphocyte cultures were supplemented with 10(-8)-10(-4) M Rose Bengal and irradiated with fluorescent light (Philips 40-W daylight-fluorescent lamp, 380-550 nm) and chromosomal aberrations and catalase and superoxide dismutase activities in the cells were determined. Chromosomal lesions and both enzymatic activities increased additively or synergistically in human lymphocytes after Rose Bengal sypplementation and fluorescent light irradiation. Chromosomal lesions (expressed as chromosomal aberrations/cells) were (a) 0.12 +/- 0.03, (b) 0.18 +/- 0.12, (c) 1.58 +/- 0.11 and (d) 3.20 +/- 0.17 in the following conditions: (a) control; (b) after 3 h light irradiation, (c) supplemented with 10(-5) M Rose Bengal and (d) with dye treatment and light irradiation. Superoxide dismutase activity was: (a) 16.5 +/- 1.5; (b) 19.5 +/- 1.2; (c) 29.2 +/- 1.5 and (d) 35.4 +/- 2.1 U/mg protein and catalase activity was: (a) 10.3 +/- 0.5, (b) 12.8 +/- 0.7, (c) 22.4 +/- 0.5 and (d) 27.6 +/- 1.1 U/mg protein in the same experimental conditions. These findings suggest that Rose Bengal supplementation plus fluorescent light irradiation of human lymphocytes lead to the synthesis of superoxide dismutase and catalase in a manner similar to the heat-shock response. A threshold of chromosomal damage (about 2 chromosomal aberrations/cell) is apparently required to activate oxidative stress genes.