Effect of light-emitting diode photobiomodulation on rat liver metabolomics after streptozotocin-induced diabetes – an evidence from nuclear magnetic resonance spectroscopy

This study investigated the liver composition in diabetic-induced mice after photobiomodulation (PBM) treatment using nuclear magnetic resonance (NMR) to identify potential molecular alterations. Tissue biopsies were removed from the left lobes of rat livers. Each biopsy was frozen in liquid nitrogen and stored at -80 °C for NMR analysis. For this purpose, a spectrometer was used operating at 600 MHz, with a temperature of 295 K and a rotation rate of 5 kHz on 15 animals. Of these, 10 rats were induced with streptozotocin injection and the remaining 5 were injected with saline solution. Sixty days after diabetes induction, the animals were randomly divided into three groups: the Sham group (n = 5); group A (non-treated diabetic-induced rats, n = 5); and group B (diabetic-induced rats treated with LED at 850 nm, 48 mW, 22 s, 1.0 J, n = 5) in the liver region. The results showed that PBM modulated body weight and water intake in Group B. In diabetic liver samples, glucose and glycogen signals were more intense than in healthy livers, while lipid signals showed the opposite effect. Glucose and glycogen signals were less intense in the diabetic liver treated with PBM, while a strong acetate signal was intensified. In conclusion, glucose and glycogen signals were attenuated by PBM, and acetate signals were intensified in diabetic livers.