LOW ENERGY VISIBLE LIGHT INDUCES REACTIVE OXYGEN SPECIES GENERATION AND STIMULATES AN INCREASE OF INTRACELLULAR CALCIUM CONCENTRATION IN CARDIAC CELLS
Irradiation of low energy visible light (LEVL) been shown to exert some beneficial effects on various cell cultures. This article aims to identify the effect photobiostimulation in relation to increased concentration intracellular calcium [Ca2+] and production of reactive oxygen species (ROS) (such as: O2- and H2O2 or free radicals), LEVL after illumination of preserved rat cardiomyocytes for transplantation. Found that visible light causes the production of O2- and H2O2 and externally provided with a concentration of 12mM H2O2 can mimic the effect of LEVL (3.6J/cm 2), which induces a slow and transient increase in [Ca2+]. This lift can be reduced by verapamil, a drug inhibiting calcium channel voltage-dependent. The kinetics of the rise in [Ca2+] and morphological damage after light or adding H2O2 found to be dose dependent. The article suggests that the different kinetics of the elevation of [Ca2+] according to the results represent different levels of adaptation to oxidative stress. What accounts for these adaptive responses of cells to LEVL represented in the transient increase in [Ca2+] and may explain the beneficial effects LEVL. INTRODUCTION
Life on earth depends entirely on the interaction of sunlight with the cells, especially in plant photosynthesis. Sunlight also has medical benefits, which have been exploited for over thousands of years in the treatment of some diseases. Recent observations show that even low-energy visible light (LEVL) can serve as a medical tool. However, the mechanism for LEVL photobiostimulation still not clear and it has been suggested that the reactive oxygen species (ROS) can be produced by photosensitization of cells. It was also discovered that the transient increase in [Ca2+] initiate cell signaling pathways, such as activation and induction of photoreceptor growth factors and contractility. The link between the [Ca2+] and the redox state of the cell is well known in the control of many cellular systems. Other studies have shown to have high growth factors and hormones, by stimulating the production of ROS, which depended on the increase in [Ca2+], in addition to the production of cellular contraction for activating the enzyme responsible. To be most effective in understanding the evidence and the results that were reached in the study has the following table highlights:
| MATERIALS AND METHODS
Measurements of ROS
| Measurements of superoxide anion radicals by electron paramagnetic spin resonance (EPR) using the spin DEPMPO which reacts with ROS as follows:
| illuminated with 3,6 J/cm2 a) Control
| * The first figure indicates the LEVL illumination increases the concentration of H2O2 in the cells. * Resonance results following four figures show the lighting level increases LEVL O2- - in cardiomyocytes. And confirms the presence of O2-
| Effect of visible light irradiation in the [Ca2+]
| To determine whether changes in intracellular calcium are mediated by a specific calcium channel was added to cardiac cells 10μM of verapamil before irradiation LEVL. Fluorescence was measured.We determined whether the light could directly induce increased intracellular [Ca 2 +] even without exogenous photosensitizers.
| a c
a. Blank (no lighting) b. Lighting 1.5 min x 3.6 J/cm2 c. Lighting 5 min x 12 J/cm2 d. Lighting 5 min x 12 J/cm2 + 200 u/mL catalase (degrades H2O2)
a. Lighting 1.5 min x 3.6 J/cm2 b. Lighting 1.5 min x 3.6 J/cm2 + 10μM Verapamil c. 10μM Verapamil
| * The levels of [Ca2+] are dose dependent LEVL lighting. * Catalase but decreases the amount of H2O2 has a similar reaction against the...
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