Efecto bioestimulante del láser de diodo y su aplicabilidad en la regeneración de tejidos blandosúlceras por presión

Resum

ABSTRACT Damaged tissue has the tendency to repair by itself naturally. Sometimes, this process is slow and torpid, which leads to the chronification of the wound. The most common chronic wounds are pressure ulcers (PU). These injuries are caused by various mechanical factors (pressure, force and shear) along with other factors related to the patient (health status, lifestyle, nutrition and medication, among others). Suffering these injuries has serious consequences for the patient, their families and the health system. Thus, it is necessary to treat PU in order to reduce these important adverse events and improve the quality of life of the individuals and their families, as well as improving health care. Photobiomodulatory therapy or photobiomodulation (PBM) is one of the most widely used regenerative treatments in different areas such as dentistry, cosmetic therapies or dermatology. It consists of the application of energy in the form of light in order to promote biochemical, bioenergetic and structural changes in the receptor tissue. Nowadays, there are a wide variety of devices that promote PBM, being the diode lasers belonging to the red or infrared region of the electromagnetic spectrum, which are generally used for this purpose. The 940nm diode laser (infrared laser) particularly has been studied on another cell population, such as osteoblast, where it promotes the proliferation and differentiation of these cells. However, the effects of this device on the soft tissue have not been demonstrated yet, as well as the most suitable dosimetry parameters for its the repair. The objective of this doctoral thesis was to study the effect of the 940nm diode laser on cultured human fibroblasts, through the study of growth, antigenic profile and gene expression because fibroblasts are the main cellular component of soft tissues and are essential in the tissue repair process. The CCD-1064Sk line of human epithelial fibroblasts was treated with a 940nm diode laser at different energy doses (power of 0.2, 0.5 or 1W, and energy densities between 1 and 7J/cm2), and emission modes (continuous and pulsed) to determine the effect on cell growth, antigenic profile and gene expression. Cell growth was evaluated analyzing the cell proliferation (using MTT technique, which is a spectrophotometric technique that measures cellular respiration) and cell cycle (using a flow cytometry technique). Antigenic profile was assessed by confocal microscopy. Gene expression of different tissue repair markers was determined through the quantitative technique of the polymerase chain reaction in real time. The laser treatment increased the proliferative capacity at 24 and 72h of the cultured fibroblasts. Nevertheless, this effect was modulated according to the dose of energy applied. The most effective energy parameters were the power of 0.2 and 0.5 W and the energy density between 1 and 4 J / cm2, regardless of the energy mode used. No effect was found when the laser was applied at 1W power. No significant changes were detected, as a consequence of the treatment, with respect to the control group in the cell cycle test. The study of the antigenic expression showed an increase of the expression of α-actin of the treated cells observed, which suggests a possible cellular differentiation. In addition, the results obtained showed a significant increase in the expression of FGF, TGF-β1, TGFβR1, TGFβR2, α-actin, fibronectin, decorin and MMP2 was observed after the application of two treatment guidelines. The analysis of the expression of DDR2 only showed an increase in expression when the cells were subjected to two doses of energy. Likewise, when applying this treatment regimen, a decrease in the expression of the CTGF and elastin markers was observed. These results explain the PBM effect of the diode laser on the fibroblast, which demonstrate an increase in short-term proliferation and long-term myofibroblast differentiation. Besides, it would also justify the therapeutic potential of the diode laser in wound repair, although more studies are needed in animal models that allow us to extrapolate its use in clinical practice in the treatment of chronic wounds such as PU. These results reveal the 940nm diode laser has photobiomodulatory properties on the fibroblast; stimulating the proliferative capacity and cell differentiation, without altering the cell cycle, besides modulating the gene expression. These findings justify its possible clinical usefulness in the regeneration of wounds.