904 nm Low-Level Laser Irradiation Decreases Expression of Catabolism-Related Genes in White Adipose Tissue of Wistar Rats: Possible Roles of Laser on Metabolism.

Background: Adipose tissue is the main energy storage tissue in the body. Its catabolic and anabolic responses depend on several factors, such as nutritional status, metabolic profile, and hormonal signaling. There are few studies addressing the effects of laser photobiomodulation (PBM) on adipose tissue and results are controversial. Objective: Our purpose was to investigate the metabolic effects of PBM on adipose tissue from Wistar rats supplemented or not with caffeine. Materials and methods: Wistar rats were divided into four groups: control (CTL), laser-treated [CTL (L)], caffeine (CAF), and caffeine+PBM [CAF (L)]. Blood was extracted for quantification of triglyceride and cholesterol levels and white adipose tissues were collected for analysis. We evaluated gene expression in the adipose tissue for the leptin receptor, lipase-sensitive hormone, tumor necrosis factor alpha, and beta adrenergic receptor. Results: We demonstrated that the low-level laser irradiation was able to increase the feed intake of the animals and the relative mass of the adipose tissue in the CTL (L) group compared with CTL. Laser treatment also increases serum triglycerides [CTL = 46.99 ± 5.87; CTL (L) = 57.46 ± 14.38; CAF = 43.98 ± 5.17; and CAF (L) = 56.9 ± 6.12; p = 0.007] and total cholesterol (CTL = 70.62 ± 6.80; CTL (L) = 79.41 ± 13.07; CAF = 71.01 ± 5.52; and CAF (L) = 79.23 ± 6.881; p = 0.003). Conclusions: Laser PBM decreased gene expression of the studied genes in the adipose tissue, indicating that PBM is able to block the catabolic responses of this tissue. Interestingly, the CAF (L) and CAF animals presented the same CLT (L) phenotype, however, without increasing the feed intake and the relative weight of the adipose tissue. The description of these phenomena opens a new perspective for the study of the action of low-level laser in adipose tissue.

Photobiomodulation Therapy Modulates Muscle Gene Expression and Improves Performance of Rats Subjected to a Chronic Resistance Exercise Protocol.

Objective: In professional sports activities, the search for increased performance is constant. Electrophysical agents, including photobiomodulation (PBM), have been used in the sports context to accelerate postworkout recovery, prevent injuries, and even to improve performance. This study aims to investigate the effects of infrared laser (904 nm) on skeletal muscle gene expression of performance-related proteins of rats submitted to a chronic resistance training protocol. Materials and methods: Male Wistar rats (n = 40), weighing ±300 g were divided into four groups: sedentary control (CT, n = 10); irradiated control (CTL, n = 10); exercised not irradiated (EX, n = 10); exercised irradiated (EXL, n = 10). To assess the performance, the maximum carrying test was adapted and applied 72 h prior the training and 72 h after the last exercise session. The vertical weight climbing protocol was adapted for resistance training 3 × per week with 48 h interval between each session: first week adaptation, second week 25% of body weight (BW), third week 50% BW, fourth week 75% BW, and fifth week 100% BW. Animals were irradiated before exercise on hind paws 50 sec each, with infrared laser 904 nm 5 days per week, during 4 weeks, 9 J per leg in a total of 18 J energy per day. Results: The EXL performed more climbing (7.1 ± 0.91) compared to EX (4.4 ± 0.63). PBM promoted increased expression of lactate dehydrogenase enzyme, mammalian target of rapamycin protein, and androgen receptor (p < 0.05) but not the myosin heavy chain (p = 0.43). Conclusions: PBM therapy increases the expression of performance-related muscle mass gain genes besides improving the resistance training performance.

Laser Photobiomodulation 904 nm Promotes Inhibition of Hormone-Sensitive Lipase Activity in 3T3-L1 Adipocytes Differentiated Cells.

Background: The lipid metabolism is essential for maintaining the body's energy responses. Laser photobiomodulation triggers many important cellular effects, but these effects on lipid metabolism are not well described. In this study, we analyzed the laser photobiomodulation in the hormone-sensitive lipase (HSL) activity, a key enzyme in the triglycerides (TAG) hydrolysis in adipose tissue 3T3-L1. Methods: Cells were submitted to the differentiation protocol in adipose cells, irradiated with 1, 2, and 3J with laser (904 nm-60 mw-laser diode) and incubated for 4 h after irradiation. Results: The response of laser photobiomodulation was able to trigger an inhibition of HSL activity (control = 0.057 ± 0.0008; 1J = 0.050 ± 0.0003; 2J = 0.0477 ± 0.002; 3J = 0.051 ± 0.002; p = 0.0003 against the control), but no modulation was observed in TAG levels into the medium (control = 26.5856 ± 0.52; 1J = 26.5856 ± 0.52; 2J = 27.2372 ± 1.41; 3J = 25.9991 ± 0.1303; p = 0.18). Conclusions: This is the first study of HSL activity modulation with laser radiation, suggesting that photobiomodulation can influence adipose tissue metabolism and open a new field of study.