Study of low-energy laser radioprotective effects on animal models : Lasers in veterinary medicine

The ability of low-energy laser radiation (LLR) to counteract the detrimental effects of gamma radiation was studied with a murine model. Three control and two experimental groups of mice were used. Control group I consisted of animals unexposed to either gamma or laser irradiation. Group II consisted of mice exposed solely to gamma radiation. Control group III consisted of mice exposed solely to LLR. Experimental group I included mice exposed to gamma radiation initially, followed by LLR for three days. In experimental group II, LLR was applied each of three days prior to gamma irradiation. Gamma radiation was produced by 137 Cs with a total dose of 8.75 Gr (0.02 Gr/min). The source of laser radiation was He-Ne (632.8 nm), and a power density of 0.5 Wt/cm 2 . Irradiation was performed once every three days for 15 see. In an additional set of experiments, the effect of LLR in various doses on survival of gamma-irradiated mice was examined. The effects of laser exposure prior to and after gamma radiation, percent survival, changes in lipid peroxidation in serum and liver, the concentration of S-H groups in serum, and catalase activity in erythrocytes were obtained. LLR reduced average lethality. Successful results were achieved in all sets of experiments and were dependent mostly on the dose of LLR. The biochemical tests exhibited the ability of LLR to modifies the damaging effects of gamma radiation when laser is applied prior to or after gamma radiation. However, the protective effect of LLR was greater in the group with exposure before gamma radiation.