<title>Role of biological rhythms in the formation of cell and tissue response on laser irradiation</title>

Abstract

Abstract To understand the effects of laser radiation on live cells and tissues it is important to take intoaccount not only the laser parameters but also the temporal and spatial peculiarities of the live objects.The temporal dynamics of the parameters of a live cell or tissue should be taken into considerationwhen making the prognosis of the effects of any laser. The chronobiological approach allows toautomatically take into account the individual peculiarities and the current functional state of the liveobjects, which makes it possible to exclude nonstandart effects of laser action and to diminish theirpoor determinability and high variability. Modulation of the intensity of laser irradiation by the signalsof registered biorhythms of the irradiated cell or organism enables to guarantee stable amplification of plastic processes, restoration of the levels of function and biosynthesis. 1. Theoretical backgroundIt is generally known that laser radiation wavelength, power density, average power, and thedoze of irradiation are the major determinants of laser action on a biological object, and the responseof the latter [1]. Nonetheless even for these parameters it is very difficult to make the prognosis of thephysiological limit of the response reactions of live cells and tissues as well as to distinguish thermaland nonthermal laser action. The border between thermal and nonthermal effects depends on the heatcapacity and conductivity of the tissue in the irradiated site and, consequently, on the phases of theoscillations of local bloodflow velocity, lymphflow velocity and on the structure of capillary network.The magnitude and the sign of the response reactions of a cell and tissue, in their turn, depend on theoscillation phases of the sensivity and the exitability as well as on the limits of development of the