PHOTOBIOSTIMULATION EFFECTS CAUSED BY LOW LEVEL ULTRA-HIGH FREQUENCY (v=2.45GHZ) AND LASER RADIATION (λ=650 NM and λ=850 NM) IN THE GROWTH STIMULUS OF BIOLOGICAL SYSTEMS

摘要

This paper has as principal objective to determine the value of some parameters of light that are determinants in the activation or inhibition of the growth stimulus in a biological system. In this case intensity and dose, as important parameters, were considered. Semiconductor and GaAIAs lasers with λ=650 nm were used to irradiate the biological systems. In the first part of this study three different biological systems were defined. In the fist biological system Triticum aestivum L (wheat) seeds were used; for the second biological system Cucumis sativus L (cucumber) seeds were used, and finally for the third biological system human fibroblasts were used. The responses of the three biological systems were analyzed using statistical processes when intensity and dose were varied. The results obtained indicate that when the appropriate light parameters are used activation or inhibition can occur. There are a lot of researchers that have been studying the stimulation of different biological systems like Escherichia coli, DNA replication and division, neurons and lymphocytes, blood and spleen cells. In all the cases they determine optimal values for the parameters of light and analyze the responses at these values using statistical processes. It is important to stay that the variety of biological systems require different parameters of light for each system. In most of the cases He-Ne lasers with λ=633 nm are the grounds of these studies. In some cases they vary the wavelength to obtain a λ=650 nm or for using near infrared radiation [1-6]. In the laser photo-biostimulation there are three levels at which various aspects of stimulation can be considered: molecular, cellular and organism levels. For these three levels exist light parameters that can activate or inhibit natural processes. There are three factors that are determinant to obtain an early photochemical and photobiological response in a biological system; these parameters are the light wavelength (nm). intensity (W/m{sup}1) and dose (J/m{sup}2). If appropriate light parameters are used, activation or inhibition in the grow stimulus will occur. Laser sources are handy tools providing many advantages like efficient fiber optic delivery of light to irradiate interior body parts, high monochromaticity and easy wavelength tunability. With laser light different phenomena of live organisms in different wavelengths at which they are not exposed can be investigated. Up today He-Ne lasers with λ=633 nm, semiconductors lasers, and LED's lasers in the range of λ=600-1000 nm are used. It is important to stay that in some experiments we only irradiate one time and the next reactions occur in the dark. In other clinical conditions we irradiate more than once [5]. We define three biological systems to study their responses when intensity and dose are varied. The first biological system consist of Triticum aestivum L seeds which were irradiated using a semiconductor laser with wavelength of λ=650 nm and intensities of 2.5, 5, 10, 20 and 30 mW/cm{sup}2. The irradiation time for each intensity was 10, 15, 20, 30, 60 and 120 seconds. Seeds were irradiated during the time mentioned and put in germination. It is important to stay that seeds were irradiated once. Groups of 25 seeds were formed and for each dose 4 treatments were used addend 100 seeds. The seeds were put in a special room with temperature (25°C) and humidity (60%) control. The germination time was of one week. The second biological system consists of Cucumis sativus L seeds. These seeds were irradiated with a GaAIAs laser with λ=650 nm wavelength and 30 mW output power. The intensities were of 2.5, 5, 10 and 20 mW/cm{sup}2 and the irradiation time for each intensity was 1, 2, 5 and 10 minutes. Seeds were put in Petri containers with 10 ml of water and no light conditions. The third biological system consists of human fibroblasts that were irradiated with a semiconductor laser with λ=650 nm, continuous wave and power density of