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Photobiomodulation (PBM) has evolved as a rapidly growing therapeutic biophysical non-invasive approach for the acceleration of tissue repair, mitigation of pain, inflammation and restoration of cellular functions. This study compares the PBM effect of pulsed-mode (10 Hz) of NIR laser (810 nm) and LED (808 ± 3 nm) with identical treatment regimen (average power 70 mW; average irradiance 40 mW/cm2; total fluence 24 J/cm2, duty cycle 50%; pulse duration 50 msec; peak irradiance 80 mW/cm2; 10 min exposure once daily for 7 days) on full-thickness, third-degree burn wound in rat using comprehensive analysis of quantitative label-free global proteomics, followed by validation of the proteomics data by various biophysical, biochemical, molecular, histological and immunohistochemical (IHC) assays. The proteomic analysis clearly revealed the common biological processes indicated by modulation of similar biological pathways (known for tissue repair process) associated with neuronal (4), metabolic (10), vascular (3), inflammation (4) and cell signaling (12) in both laser and LED treated groups. Validation of proteomic analysis using various healing markers demonstrated attenuated inflammatory response like decreased TNF-α, IL-1β, IL-6, COX-2 levels (ELISA), enhanced cellular proliferation (PCNA, TGF-β2), collagen, ECM accumulation (biochemical, H&E, Masson's trichrome staining, IHC assays), wound contraction and cytoprotection (TUNEL assay) in both laser and LED-treated groups as compared to the control. Collectively, the proteomics data revealed previously know molecules along with novel identified molecules post-PBM treatment, which broaden the understanding of tissue repair mechanisms. This study profoundly signifies that both laser and LED in 810 nm wavelength range at pulsed-mode (10 Hz) are equally effective for PBM-mediated potential treatment to accelerate burn wound healing.

Visible lasers emitting in the green spectral region are being routinely employed in various medical and defense fields namely treatment of pigmented lesions, tattoo inks, port wine stains, dazzling the target or mob dispersal. Despite their increasing applications, lasers also tend to pose occupational hazards to operators, ancillary personnel, individuals undergoing laser therapies. This study was aimed at investigating the effects of different doses of 532-nm continuous wave laser on rat skin. The present study demonstrated that higher fluences of 532-nm continuous wave (CW) laser induces significant tissue damage through induction of tumor necrosis factor-α, cyclooxygenase-2, tumor protein (p53), PARP 1, caspase3 which in turn leads to tissue damage and cell death. Furthermore, level of heat shock proteins, pAkt were found up-regulated as a cope up response to laser-induced stress. On the basis of the findings, irradiation with 532-nm CW laser up to 2.5 J/cm2 was found within the safe exposure limits. Thus, it is probably the first attempt to demonstrate the tissue damage induced by 532-nm CW laser on skin, which may help in choosing safe laser dose for certain skin-based applications and evolving methods to ameliorate laser-inflicted injuries.