Photobiomodulation as an antioxidant substitute in post-thawing trauma of human stem cells from the apical papilla

Abstract

Cryopreservation, the most common method of preserving stem cells, requires post-processing because it produces trauma to the cells. Post-thawing trauma typically induces cell death, elevates reactive oxygen species (ROS) concentration, and lowers mitochondrial membrane potential (MMP). Although this trauma has been solved using antioxidants, we attempted to use photobiomodulation (PBM) instead of chemical treatment. We used a 950-nm near-infrared LED to create a PBM device and chose a pulsed-wave mode of 30 Hz and a 30% duty cycle. Near-infrared radiation (NIR) at 950 nm was effective in reducing cell death caused by hydrogen peroxide induced-oxidative stress. Cryodamage also leads to apoptosis of cells, which can be avoided by irradiation at 950 nm NIR. Irradiation as post-processing for cryopreservation had an antioxidant effect that reduced both cellular and mitochondrial ROS. It also increased mitochondrial mass and activated mitochondrial activity, resulting in increased MMP, ATP generation, and increased cytochrome c oxidase activity. In addition, NIR increased alkaline phosphatase (ALP) activity, a biomarker of differentiation. As a result, we identified that 950 nm NIR PBM solves cryodamage in human stem cells from the apical papilla, indicating its potential as an alternative to antioxidants for treatment of post-thawing trauma, and further estimated its mechanism.

Investigating the effects of low intensity visible light on human keratinocytes using a customized LED exposure system

“…However, they are often rigid in design, allowing limited control of the specific wavelength, pulse rate, intensity of light, and are reliant on mains power supply. Illumination often comes from underneath the well plate, making them potentially unsuitable for more complex full-thickness skin models, where top-down illumination may be important to mimic real-world (in vivo) conditions, particularly for blue light as it has a shallow penetration depth 12 , 34 , 35 . Further, inconsistent reporting of key light exposure parameters, including dosimetry and experimental conditions, limit the repeatability of experiments and introduce uncertainties when comparing the literature 28 .…”

“…Non-ionising electromagnetic radiation (EMR) in the visible light spectrum has been used as a therapeutic modality to improve wound and soft tissue healing, reduce the appearance of aging, increase the rate of hair growth, reduce pain and inflammation, and has potential as an alternative cancer therapy [6][7][8][9][10][11] . More recently, light has demonstrated utility during in vitro cell and tissue culture, acting as an antioxidant substitute post-thawing of human stem cells and accelerating the formation of a dermal equivalent for human skin modelling 12,13 . Previously referred to as low-level laser therapy (LLLT), the use of light in biology is now more accurately referred to as photobiomodulation (PBM).…”

Quantitative Assessment of Low-Dose Photodynamic Therapy Effects on Diabetic Wound Healing Using Raman Spectroscopy

“…ROSs are capable of triggering keratinocyte growth factor receptor activation and its internalization, which is an important component in epidermal regeneration [ 81 ]. The current literature indicates that photo-biomodulation can be a potent short-term way to decrease oxidative stress markers and to enhance antioxidant content [ 82 ]. LDPDT could positively affect the diabetic wound healing process, using a low concentration of 5-ALA.…”

Accelerating skin regeneration and wound healing by controlled ROS from photodynamic treatment

“…The current literatures indicate that PBM can be a potent short-term way to decrease oxidative stress markers (e.g., thiobarbituric acid reactive) and to enhance antioxidant contents (e.g., CAT, GPx, and SOD). It seems low-dose PDT can act as PBM in this regard for wound healing [ 151 ].…”