Efeito da terapia de fotobiomodulação na expressão de biomarcadores de estresse oxidativo em células HUVEC submetidas à hipóxia

Abstract

Long considered to be an inert cell layer, the endothelium is now recognized as an important regulator of major physiological functions. Endothelial cells respond to chemical stimuli and secrete factors that modulate various physiological processes, especially under hypoxia. This condition can trigger adaptive responses and have harmful effects if it persists for prolonged periods, causing transcriptional changes that result in changes in cellular homeostasis. Photobiomodulation therapy (PBM) can stimulate collagen production, promote DNA and protein synthesis, increase ATP content, modulate cell migration and proliferation, accelerate tissue repair, and induce cell differentiation. In this context, the evaluation of cellular adaptations to hypoxia can provide knowledge to improve treatments and reduce these losses. This in vitro study aimed to evaluate the effects of pre-hypoxic PBM on human umbilical vein endothelial cells (HUVECs), to prevent possible damage caused by hypoxia. The methodology included gene expression and protein activity through in vitro tests. The cells were characterized by the expression of CD31 APC and CD146 APC by flow cytometry. The cells, kept in culture, were released from a 75cm2 matrix bottle and seeded in 25 cm² bottles at a quantity of 1x106. Our results showed that hypoxia only promoted a strong reduction in cell viability and that PBM applied pre-hypoxia increased this parameter. The mRNA expressions of the antioxidant enzymes SOD1 and CAT were reduced by hypoxia, and were increased with the use of PBM. The activities of SOD and GPx were increased by PBM. The expression of Hsp1a/b (HSP70), a cell damage biomarker, was increased by hypoxia, and this effect was blocked by the action of PBM, demonstrating HSP70 levels similar to the control. Increased levels of TBARS and free radicals were found in the hypoxia group compared to the control, interestingly, in the group previously treated with pre-hypoxic PBM therapy we observed a decrease in these oxidative stress markers, bringing values similar to the control. Together, the data suggest that PBM has the potential as a cell protection therapy against oxidative damage under hypoxic conditions, evidenced by the expression of antioxidant enzymes and the reduction of levels of carbonylated proteins and free radicals.