Avaliação dos mecanismos de reparo do DNA e efeitos de laser infravermelho de baixa potência em modelo experimental de lesão pulmonar aguda

Abstract

An infectious condition (sepsis) may culminate in the induction of acute lung injury (ALI). ALI is characterized by a hyperinflammatory and hypoxemic response, with increased alveolar barrier permeability. Due to the lesion profile, there is no specific treatment. Low power infrared lasers (LPIL) have been used in the resolution of the inflammatory process, however photobiostimulatory effects are not fully understood. Few studies correlate lung diseases with laser therapy and current therapeutic strategies are considered palliative. Therefore, a new therapy is needed. Thus, the objective of this work was to evaluate the effects of LPIL in a Wistar rats ALI model regarding morphological alterations, infiltrate cell analysis, induction of DNA fragmentation and apoptotic pathway gene mRNA levels and DNA repair. Male Wistar rats were divided into six groups: Control, ALI, L10, L20, ALI-L10 and ALI-L20 and exposed to LPIL (AsGaAl, 808nm, 100mW, 4 points per lung in 1 session). ALI was induced intraperitoneal administration of E. coli lipopolysaccharide. Samples of lung tissue were collected for histological processing and staining for stereological analysis and evaluation of mRNA levels by RT-qPCR. Experimental data obtained in this study showed alterations in the morphological profile of septa and alveoli in animals affected by ALI after exposure to LPIL, as well as modulation of apoptosis and DNA repair gene mRNA levels, and increased DNA fragmentation in cells of the ALI. inflammatory infiltrate and reduction in alveolar epithelium. The results obtained in this study suggest that LPIL exposure improves lung parenchyma, suggests that DNA repair is part of the cellular response to sepsis and that LPIL exposure alters mRNA levels of apoptotic genes and induces DNA fragmentation. in inflammatory and alveolar cells, with selective action, which may be part of the anti-inflammatory effect induced by low power infrared lasers.