Kontakt 2009, 11(2):453-458 | DOI: 10.32725/kont.2009.068

Radioprotective effects of therapeutic laserBiomedicine

Zuzana Freitinger Skalická^*, Zdeněk Hon, Leoš Navrátil

Jihočeská univerzita v Českých Budějovicích, Zdravotně sociální fakulta, katedra radiologie a toxikologie

Ionizing 60Co gamma-radiation used in radiotherapy belongs to main exogenous sources of free radicals, which can cause damage to healthy biomolecules and tissues. Free radicals are characterized by unpaired electrons. In the presence of oxygen, a molecule of oxygen is immediately bound instead of the unpaired electron, thus producing a peroxylic radical, which tends to get the missing electron from the another compound with forming the other free radical. This chain reaction is discontinued either by a bond of two radicals one to another or by a reaction with an antioxidant. After depletion of the anti-oxidative protection, the ratio between reduced and oxidized glutathione in cells, which is a sensitive parameter of the oxidative stress, decreases. The initial activity of main anti-oxidative enzymes - superoxide dismutase (SOD) and glutathione peroxidase is also of importance. Possibilities of interactions of ionizing and non-ionizing radiation (therapeutic laser) are considered in works of many foreign authors - for example different speed of the action of ionizing radiation itself in the concomitant action of ionizing radiation and therapeutic laser. Therapeutic lasers demonstrably affect cell organelles, membrane channels, nociceptors, mediators and cytokines. In clinical medicine, there are obvious analgesic anti-inflammatory and immunostimulating effects and also effects on healing of wounds. For the verification of the measure of the damage to the organism with ionizing radiation and possible radioprotective effect of laser, superoxide dismutase was studied in CD1 strain mice, which were exposed to 60Co gamma rays, therapeutic laser and their combination. Superoxide dismutase is an enzyme making the superoxide radical non-harmful by its conversion to molecular oxygen and hydrogen peroxide, which can be furthermore decomposed by catalase or peroxidase. The results demonstrated a statistically significant difference in the group exposed to laser in combination with gamma rays 1.5 Gy compared with the other groups. Superoxide dismutase values were statistically significantly reduced, which indicates a lower anti-oxidative protection of the organism investigated.

Keywords: therapeutic laser; superoxide dismutase; ionizing radiation

Received: September 4, 2009; Accepted: November 9, 2009; Published: December 18, 2009  Show citation