Levels of Cyclooxygenase 2, Interleukin-6, and Tumour Necrosis Factor-α in Fibroblast Cell Culture Models after Photobiomodulation at 660 nm

Abstract

Chemicals and signaling molecules released by injured cells at the beginning of wound healing prompt inflammation. In diabetes, prolonged inflammation is one of the probable causes for delayed wound healing. Increased levels of cyclooxygenase-2 (cox-2), interleukin–6 (IL-6), and tumour necrosis factor-alpha (TNF-α) are associated with the inflammatory response and in diabetes, and increased levels of these contribute to chronic wounds that do not heal. Rising levels of cox-2, IL-6, and TNF-α have also been associated with increased oxidative stress. Photobiomodulation (PBM) may impact wound healing processes by affecting the signaling pathways and molecules pertinent to tissue repair. In the present study, the effect of PBM (wavelength: 660 nm; energy density: 5 J/cm2) on levels of cox-2, IL-6, and TNF-α was determined in fibroblast cell culture models. Four WS1 models (normal, normal wounded, diabetic, and diabetic wounded) were irradiated at 660 nm, and the culture media was collected at 0, 24, and 48 h postirradiation. Cells that were not irradiated (0 J/cm2) served as the controls. The following parameters were determined postirradiation: cell morphology using light microscopy, cell viability using the Trypan Blue exclusion assay, and levels of the inflammatory markers cox-2, IL-6, and TNF-α were measured using ELISA. Cell migration increased in the wounded groups over the 48 h interval after PBM; viability improved postirradiation in the diabetic wounded groups at 0 and 24 h ( $P\le 0.05$ and $P\le 0.01$ , respectively); levels of cox-2 decreased in normal and diabetic wounded groups at 0 h ( $P\le 0.001$ ) and increased in the diabetic and diabetic wounded groups at 48 h postirradiation ( $P\le 0.05$ and $P\le 0.01$ , respectively), while levels of IL-6 decreased in the normal ( $P\le 0.01$ ), diabetic ( $P\le 0.05$ ), and diabetic wounded ( $P\le 0.001$ ) groups at 24 h and in the diabetic and diabetic wounded groups at 48 h ( $P\le 0.05$ ) postirradiation. TNF-α was decreased in the normal wounded groups ( $P\le 0.05$ ) at 48 h. Through its effect on decreased IL-6 levels in diabetic cell models, PBM at 660 nm may be successful at decreasing oxidative stress; however, the present study also found an increase in cox-2 levels at 48 h postirradiation.