LOW LEVEL LONG WAVELENGTH LASER IRRADIATION EFFECTS ON CELL CYCLE PROGRESSION AND APOPTOSIS OF ENERGY RESTRICTED JURKAT T-CELLS

MIHAELA PISLEA*, TEOFILA SEREMET*, GYÖNGYVÉR KATONA**, MAGDALENA MOCANU*, I.O. DOAGĂ***, E. RADU****, JUDIT HORVÁTH*****, E. TANOS*****, EVA KATONA*

*Department of Biophysics, **Department of Medical Biochemistry, ****Department of Molecular and Cellular Medicine, Medical Faculty, ***Department of Biophysics, Dentistry Faculty, “Carol Davila” University of Medicine and Pharmaceutics, Bucharest, Romania
*****LASEUROPA CO., Budapest, Hungary

Abstract. We investigated the effects of low power 680 nm far-red (FR) and 830 nm near-infrared (NIR) laser light on viability, survival/proliferation, apoptosis rate, and cell cycle progression of noninjured and energy restricted human acute T leukemic Jurkat cells. Data obtained both by microscopy and by flow cytometry demonstrated significant changes in the explored parameters. Energy restriction induced by blockade of oxidative phosphorylation with low concentrations of cyanide (1 mM NaCN) caused intoxication duration dependent viability and survival rate decrease, and apoptosis induction. NIR laser irradiation increased the percentage of live subpopulation in both non-injured and in cyanide intoxicated cell samples. FR laser light did not offer protection to non-injured Jurkat cells, but increased the percentage of live subpopulation in cyanide intoxicated samples. Cyanide intoxication caused G2/M stage blockade and apoptosis induction in an intoxication duration dependent manner. NIR and FR laser irradiation effects on human T leukemia lymphoblasts distribution in various cell cycle stages, as well as modulation of cyanide induced changes were dependent on cells state, duration of intoxication, and on irradiation dose. Low dose NIR irradiation promoted cell cycle progression, while at higher doses, an increase in percentage of cell subpopulations in G1 and G2 phases, and S-phase blockade with apoptosis promotion were observed in the NIR and FR irradiated non-injured samples, respectively. In same conditions, with first irradiation applied early in the intoxication period, enhancement of the cyanide-induced G2 phase blockade and apoptosis induction occurred in FR irradiated samples, while NIR laser light appeared to cause S-phase cell accumulation in cyanide intoxicated samples.
Key words: AlGaInP/GaAs laser, cyanide-intoxication, human T leukemia lymphoblasts, photobiomodulation, cell viability.

Corresponding author’s e-mail: eva_katona@yahoo.com

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