The effects of low-level laser irradiation on cellular viability and proliferation of human skin fibroblasts cultured in high glucose mediums

Abstract

Delayed wound healing is one of the most challenging complications of diabetes mellitus (DM) in clinical medicine. This study has aimed to evaluate the effects of low-level laser therapy (LLLT) on human skin fibroblasts (HSFs) cultured in a high glucose concentration. HSFs were cultured either in a concentration of physiologic glucose (5.5 mM/l) or high glucose media (11.1 and 15 mM/l) for either 1 or 2 weeks after which they were subsequently cultured in either the physiologic glucose or high concentration glucose media during laser irradiation. LLLT was carried out with a helium-neon (He-Ne) laser unit at energy densities of 0.5, 1, and 2 J/cm(2), and power density of 0.66 mW/cm(2) on 3 consecutive days. HSFs' viability and proliferation rate were evaluated with the dimethylthiazol-diphenyltetrazolium bromide (MTT) assay. The LLLT at densities of 0.5 and 1 J/cm(2) had stimulatory effects on the viability and proliferation rate of HSFs cultured in physiologic glucose (5.5 mM/l) medium compared to their control cultures (p = 0.002 and p = 0.046, respectively). All three doses of 0.5, 1, and 2 J/cm(2) had stimulatory effects on the proliferation rate of HSFs cultured in high glucose concentrations when compared to their control cultures (p = 0.042, p = 0.000, and p = 0.000, respectively). This study showed that HSFs originally cultured for 2 weeks in high glucose concentration followed by culture in physiologic glucose during laser irradiation showed enhanced cell viability and proliferation. Thus, LLLT had a stimulatory effect on these HSFs.

Photobiomodulation of a flowable matrix in a human skin ex vivo model demonstrates energy‐based enhancement of engraftment integration and remodeling

“…In tissue repair, more specifically in granulation tissue, these cells are activated and acquire α‐SMA, changing their phenotype to myofibroblasts involving synthesis and deposition of extracellular matrix components that replace the provisional matrix . Of note, fibroblasts irradiated with 632.8 nm light show an increase in their proliferation and viability, demonstrating the stimulatory effect of PBM and the potential use of this therapy in the wound repair process . Remarkably, our findings demonstrated an increase in α‐SMA (a reliable marker of the myofibroblast‐like phenotype) expression in PMB + IFWM group, when compared to wounded skin alone.…”

Proposed Mechanisms of Photobiomodulation or Low-Level Light Therapy

“…This is useful for the improvement of epithelial healing [104]. Furthermore, fibroblasts irradiated with 632.8 nm light had their proliferation stimulated and their cell viability increased, demonstrating the stimulatory effect of PBM and the usefulness of this therapy in the wound healing process [105]. …”

Influence of 660 and 830 nm Laser Irradiation on Genetic Profile of Extracellular Matrix Proteins in Diabetic Wounded Human Skin Fibroblast Cells

“…A diabetic wounded in vitro model was achieved as previously described [13]. Briefly, WS1 cells were continuously grown in supplemented Minimum Essential Medium (MEM) containing and additional 17mM/L D-glucose [13,14]. For experiments, 6 X 10 5 cells were seeded into 3.4 cm diameter tissue culture plates and incubated at 37C in 5% CO 2 to allow for attachment.…”