RESUMO
Obesity represents a continuously growing global epidemic and is associated with the development of type 2 diabetes mellitus. The etiology of type 2 diabetes is related to the resistance of insulin-sensitive tissues to its action leading to impaired blood glucose regulation. Photobiomodulation (PBM) therapy might be a non-pharmacological, non-invasive strategy to improve insulin resistance. It has been reported that PBM therapy in combination with physical exercise reduces insulin resistance. Therefore, the aim of this study was to investigate the effects of PBM therapy on insulin resistance in obese mice. Male Swiss albino mice received low-fat control diet (n = 16, LFC) or high-fat diet (n = 18, HFD) for 12 weeks. From 9th to 12th week, the mice received PBM therapy (LASER) or Sham (light off) treatment and were allocated into four groups: LFC Sham (n = 8), LFC PBM (n = 8), HFD Sham (n = 9), and HFD PBM (n = 9). The PBM therapy was applied in five locations: to the left and right quadriceps muscle, upper limbs and center of the abdomen, during 40 s at each point, once a day, 5 days a week, for 4 weeks (780 nm, 250 mW/cm2, 10 J/cm2, 0.4 J per site; 2 J total dose per day). Insulin signaling pathway was evaluated in the epididymal adipose tissue. PBM therapy improved glucose tolerance and phosphorylation of Akt (Ser473) and reversed the HFD-induced reduction of GLUT4 content and phosphorylation of AS160 (Ser588). Also, PBM therapy reversed the increased area of epididymal and mesenteric adipocytes. The results showed that chronic PBM therapy improved parameters related to obesity and insulin resistance in HFD-induced obesity in mice.
Assuntos
Tecido Adiposo/metabolismo , Dieta Hiperlipídica , Glucose/metabolismo , Raios Infravermelhos , Insulina/metabolismo , Espaço Intracelular/metabolismo , Terapia com Luz de Baixa Intensidade , Transdução de Sinais , Adipócitos/patologia , Tecido Adiposo/efeitos da radiação , Adiposidade/efeitos da radiação , Animais , Peso Corporal/efeitos da radiação , Epididimo/patologia , Epididimo/efeitos da radiação , Hipertrofia , Insulina/sangue , Lipídeos/sangue , Masculino , Camundongos , Tamanho da Amostra , Transdução de Sinais/efeitos dos fármacosRESUMO
BACKGROUND: Advances in treatment of acute lymphocytic leukemia increased the likelihood of developing late treatment-associated effects, such as abdominal adiposity, increasing the risk of cardiovascular disease in this population. Cranial radiotherapy is one of the factors that might be involved in this process. The aim of this study was to determine the effect of cranial radiotherapy on adiposity indexes in survivors of acute lymphocytic leukemia. METHODS: A comparative cross-sectional study of 56 acute lymphocytic leukemia survivors, chronological age between 15 and 24 years, assigned into two groups according to the exposure to cranial radiotherapy (25 irradiated and 31 non-irradiated), assessed according to body fat (dual energy X-ray absorptiometry), computed tomography scan-derived abdominal adipose tissue, lipid profile, and insulin resistance. RESULTS: Cranial radiotherapy increased body fat and abdominal adipose tissue and altered lipid panel. Yet, lipids showed no clinical relevance so far. There were significantly more obese patients among those who received cranial radiotherapy (52% irradiated versus 22.6% non-irradiated), based on dual energy X-ray absorptiometry body fat measurements. Nonetheless, no association was observed between cranial radiotherapy and body mass index, waist circumference, waist-to-height ratio or insulin resistance. CONCLUSIONS: Adolescent and young adult survivors of childhood acute lymphocytic leukemia showed an increase in body fat and an alteration of fat distribution, which were related to cranial radiotherapy. Fat compartment modifications possibly indicate a disease of adipose tissue, and cranial radiotherapy imports in this process.