Efeitos do laser de baixa intensidade (830 nm) na inflamação pulmonar aguda em um modelo de Síndrome do Desconforto Respiratório Agudo (SDRA) intra e extrapulmonar induzida por LPS

Abstract

Acute respiratory distress syndrome (ARDS) is a syndrome that presents high mortality rates, and the results of both insults pulmonary or extra-pulmonary (pneumonia or septic shock) are high, and is a disease characterized by respiratory insufficiency from the inflammatory response that leads to alteration of alveolar-capillary permeability, pulmonary edema and hypoxemia refractory to high flow oxygen. One of the most important mechanisms that determined the severity of this injury is the magnitude of the injury of alveolar epithelial barrier. The possibility of repairing epithelial at an early stage is the major determinant of recovery. Many of therapeutic modalities based on the attempt to decrease lung inflammation to minimize the initial injury and much of the inflammatory process occurs through activation of local and systemic cytokines such as TNF-α and IL-1β. A growing number of studies report that Low Level Laser Therapy (LLLT) have anti-inflammatory effects in models of LPS-induced pulmonary ARDS, however, so far, only the red spectrum lasers were studied. Therefore, this study aimed to investigate the role of infra red laser (830nm), 3J/cm2, 35mw, 80 seconds per point (03 points per application), in pulmonary inflammation, lung using LPS model (intratracheal) and also extrapulmonary (intraperitoneal) inducing ARDS. The laser application was performed directly in contact with the skin in the chest three points (corresponding to the end of the trachea - Section 01 right lung - point 02 and left lung - point 03), three times, beginning 01 hour after LPS administration. BALB / c mice (n = 40) were divided into control (n = 08; not administered LPS), IT (n = 07; intratracheal administered LPS (10 µg / mouse), IT + LLLT (n = 09; intratracheal LPS administered (10 µg / mouse) + LLLT), IP (n = 07; LPS administered intraperitoneal (100 µg / mouse), IP + LLLT (n = 09; administered intraperitoneal LPS (100 µg / mouse) + LLLT). Twenty-four hours after administration of LPS and Laser, animals were euthanized and the lungs removed for studies of pulmonary inflammation: Total cell count and differential, bronchoalveolar lavage (BAL), cytokines (IL-1beta, IL-6, IL-10, KC and TNF-α), BAL levels were also analyzed quantitatively the number of neutrophils in the lung parenchyma in lung tissue using histomorphometry techniques. Results showed that LLLT significantly reduced pulmonary and extra-pulmonary LPS induced in both configurations Experimental of ARDS, as evidenced by a reduction in the number of total cells and neutrophils in BAL, reduced levels of IL-1β, IL-6, KC, and TNF-α in BAL fluid as well as the number of neutrophils in the lung parenchyma. Therefore, we conclude that the 830nm infrared laser is effective in reducing pulmonary inflammation in both models pulmonary or extrapulmonary LPS-induced experimental ARDS.