Infrared photobiomodulation (PBM) therapy improves glucose metabolism and intracellular insulin pathway in adipose tissue of high-fat fed mice

Abstract

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/cm, 10 J/cm, 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.

Insulin resistance is improved in high‐fat fed mice by photobiomodulation therapy at 630 nm

“…Pro‐inflammatory cytokines can activate JNK, and therefore, as PBMT reduces inflammation, this therapy can reduce JNK phosphorylation. In support of that, we recently showed that HFD‐fed mice had increased JNK activation in epididymal adipose tissue that was attenuated by chronic PBMT .…”

“…It can be noted that all these studies used PBMT combined with physical exercise. Therefore, in a previous study we hypothesized whether infrared PBMT alone would affect HFD‐induced obesity, insulin resistance and intracellular insulin signaling pathway. We showed that 4 weeks of infrared PBMT in HFD‐fed mice reduced epididymal and mesenteric adipocyte area, reduced total serum cholesterol concentration, and improved glucose tolerance.…”

Under the spotlight: mechanisms of photobiomodulation concentrating on blue and green light

“…Interestingly, Silva et al explored the effects of 780 nm light at a radiant exposure of 10 J/cm² on JNK phosphorylation of mice with diet-induced obesity. They concluded that PBM induced a significant reduction in JNK phosphorylation and hence could prove useful in treating effects induced by a high fat diet (147). Similarly, in a mouse model for depression, Salehpour et al evaluated the effects of 810 nm light at a radiant exposure of 33.3 J/cm² and found that PBM induced reductions in JNK phosphorylation and other members of the MAPK signalling pathway including p38 (148).…”

Efeito agudo da terapia de fotobiomodulação nas capacidades de força e desempenho funcional em indivíduos diabéticos

“…Há diversos artigos na literatura que trazem o uso da TPBM relacionado com o diabetes mellitus (DM) em ratos, como no efeito da reparação do tecido muscular (Assis et al, 2016;França et al, 2012), nos marcadores de estresse oxidativo após exercício de alta intensidade (Frigero et al, 2018), efeito vasodilatador (Kesler et al, 2017, melhora do diabetes mellitus (DM) com a aplicação de fotobiomodulação em diferentes partes do corpo (Peplow e Baxter, 2013), melhora do metabolismo da glicose (Silva et al, 2018), efeito na reperfusão após isquemia muscular (Takhtfooladi et al, 2016). Além disso, obsevou-se uma diminuição aguda dos níveis de glicose quando em combinação com exercício moderado em homens diabéticos (Francisco et al, 2018).…”