The effect of UV-radiation dose on biological tissues laser-induced fluorescence spectra

摘要

The method of laser-induced fluorescence (LIF), excited by UV laser radiation, is widely used in investigating biological tissues. But the radiation itself may cause some changes in the tissues irradiated. The results of our experiments have shown that exposure to the UV-radiation leads to some changes of LIF spectrum of a cross-striated muscle, myocardium, aorta. In particular, a noticeable attenuation of intensity of tryptophan fluorescence band (330 nm) takes place. The intensity is shown to depend on the number of pulses. At lower energy of the exciting radiation the intensity falls off more slowly. Quantitative information is obtained on the tryptophan inactivation cross section. The conclusion on commensuration of the inactivation cross sections of tryptophan and cystine within 248 nm wavelength is proved. The influence of radiation on lymphocytes viability was investigated. Nonetheless, although some changes take place in the tissues exposed to laser radiation, they have not time to exceed the magnitude of random scatter for the period needed in our experiments for the LIF spectra recording (around 30 pulses), so these changes do not influence the final result.