Efeito da fotobiomodulação na pressão arterial de ratos hipertensos

Abstract

Introduction: Hypertension affects a quarter of the Brazilian adult population and is the main risk factor for myocardial infarction, stroke and chronic kidney disease, and has been considered a global health problem. Prospective studies have reported that lowering blood pressure may substantially decrease cardiovascular risks. Although advances in understanding the pathophysiology of hypertension and implementing effective prevention and treatment strategies, hypertension remains one of the major public health problems in the world. It is known that in the blood vessels, light (or photobiomodulation) induces NO release leading to vasodilation. Aims: In renal hypertensive rats (2K-1C), to evaluate the effect of Photobiomodulation (FBM) on blood pressure. Methods: Wistar rats of the Rattus norvegicus, specie were used. In agreed animals, systolic blood pressure (SBP) was determined by the technique of tail plethysmography (NIBP System-ADinstruments) before the surgical procedure and six weeks after this procedure. Hypertensive animals (2K-1C) with SBP greater than or equal to 160 mmHg were used. Subsequently, the hypertensive animals were anesthetized to implant the cannula in the femoral artery in order to evaluate the arterial pressure after acute photobiomodulation in different energies 0.6; 1.8; 3.6; 7.2; 13.8; 28.2; 55.8 and 111.6 Joule. In addition, it was performed vascular reactivity studies and the nitric oxide was quantified. Results: Our results indicate that the acute abdominal application of FBM at 660 nm induced a long-lasting hypotensive effect in hypertensive rats, being this energy effect dependent. The application of FBM in isolated aortic rings induced vasodilation by NO-dependent mechanism. Conclusion: We conclude that photobiomodulation with the red laser (660 nm) at an irradiation in the energy range of 7.2 to 55.8 J presents an effective therapeutic window to reduce SBP, PAD, MAP, HR and induces a hypotensive effect lasting, with loss of effect in higher energy irradiation (111.6 J).