Besides Photothermal Effects, Low-Level CO2 Laser Irradiation Can Potentiate Skin Microcirculation Through Photobiomodulation Mechanisms

Reduced pre-operative skin oxygen saturation predicts revision after open reduction and internal fixation in calcaneal fractures : A reduced pre-operative oxygen saturation as measured by laser-Doppler spectrophotometry in 8 mm depth is associated with revision surgery after open reduction and internal fixation of calcaneal fractures through an extended lateral approach

PURPOSE

To assess which pre-operative parameters correlate with wound revisions after an extended lateral approach to the calcaneus.

METHODS

Pre-operative laser-Doppler spectrophotometry was applied in patients undergoing open reduction and internal fixation. The number of wound revisions was recorded during pos-toperative follow-up. Spearman rho analysis was used to identify factors associated with wound revision and receiver operator characteristics curves were calculated for the identified factors.

RESULTS

Thirty-four patients (29 men, 5 women; 37 calcanei) with a mean patient age of 43 ± 14 years were analyzed. The minimal oxygen saturation value at the five measurement locations as well as the minimal value for flow correlated negatively with wound revisions (p value = 0.025 and 0.038, respectively). The area under the curve for the pre-operative minimal value of oxygen saturation was 0.841 (95%CI 0.64-1.00, p = 0.028), indicating a good accuracy as a test to predict wound revision.

CONCLUSION

A pre-operative oxygen saturation of at least 20.5% across five measurement points along the anticipated incision identified all patients not needing a wound revision (negative predictive value 100%). On the other hand, patients with at least one measurement below 20.5% were at risk for wound revision surgery (sensitivity 100%, specificity 48.5%). ClinicalTrials.gov NCT01264146.

Wound Healing and Cell Dynamics Including Mesenchymal and Dental Pulp Stem Cells Induced by Photobiomodulation Therapy: An Example of Socket-Preserving Effects after Tooth Extraction in Rats and a Literature Review

High-intensity laser therapy (HILT) and photobiomodulation therapy (PBMT) are two types of laser treatment. According to recent clinical reports, PBMT promotes wound healing after trauma or surgery. In addition, basic research has revealed that cell differentiation, proliferation, and activity and subsequent tissue activation and wound healing can be promoted. However, many points remain unclear regarding the mechanisms for wound healing induced by PBMT. Therefore, in this review, we present an example from our study of HILT and PBMT irradiation of tooth extraction wounds using two types of lasers with different characteristics (diode laser and carbon dioxide laser). Then, the effects of PBMT on the wound healing of bone tissues are reviewed from histological, biochemical, and cytological perspectives on the basis of our own study of the extraction socket as well as studies by other researchers. Furthermore, we consider the feasibility of treatment in which PBMT irradiation is applied to stem cells including dental pulp stem cells, the theme of this Special Issue, and we discuss research that has been reported on its effect.

Evaluation of the Efficacy of Ultrapulsed CO2 Laser in Chronic Wounds

BACKGROUND AND OBJECTIVES

Chronic wound repair is a major problem in wound treatment. Recently, several studies have suggested that carbon dioxide (CO₂ ) laser can be used to improve the healing of chronic wounds. The aim of the present study was to preliminarily investigate the efficacy of laser debridement in treating chronic wound through a comparison of traditional instrument/surgical debridement with the ultrapulsed CO₂ laser debridement in terms of wound healing, wound infection control, and wound blood perfusion.

STUDY DESIGN/MATERIALS AND METHODS

Patients with chronic wound admitted to the Wound Repair Clinic at The Affiliated Hospital of Southwest Medical University (Luzhou, China) between February 2019 and May 2019 were enrolled. They were randomly divided into two groups. The patients in one group were treated with traditional sharp instrument/surgical debridement (RT group; number of wounds: 28), while the patients in the other group were treated with ultrapulsed CO₂ laser debridement (LT group; number of wounds: 26). An intergroup comparison was performed based on parameters, such as wound healing, wound infection control, and changes in wound blood perfusion.

RESULTS

The wound healing rate and the total time to achieve healing were significantly better in the LT group versus the RT group at 7, 14, 21, and 28 days after treatment. The wound exudation scores were significantly higher in the LT group versus the RT group at 7, 14, and 28 days after treatment. The positive rate of pre-debridement bacterial culture was significantly lower in the LT group versus the RD group at 14 and 28 days after treatment. The percentage of wound perfusion/normal periwound skin perfusion was significantly higher in the LT group versus the RT group at 1, 7, and 14 days after treatment.

CONCLUSION

For the treatment of chronic refractory wounds, the ultrapulsed CO₂ laser exhibits higher accuracy, more effectively controls wound infection, promotes an increase in wound blood perfusion, and achieves faster wound healing compared with traditional sharp instrument/surgical debridement. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

P2Y13 and P2X7 receptors modulate mechanically induced adenosine triphosphate release from mast cells

Subcutaneous mast cells (MCs) are vulnerable to mechanical stimulation from external environment. Thus, MCs immune function could be modulated by their mechanosensitivity. This property has been identified as the trigger mechanism of needling acupuncture, a traditional oriental therapy. Previously we have demonstrated the release of adenosine triphosphate (ATP), a stress-responsive signalling molecule, from mechanical-perturbed MCs. The current work explores its underlying mechanisms. We noticed that propagation of intracellular free Ca²⁺ occurred among HMC-1 cells in response to 50% hypotonic shock. Additionally, amplifying cascade of ATP-induced ATP release was observed in RBL-2H3 cells stimulated by medium displacement, which could be mimicked by exogenous ATP (exoATP). Secondary ATP liberation induced by low level (50 nmol/L) of exoATP was reduced by inhibiting ecto-ATPase-dependent ADP production with ARL67156, or blocking P2 receptors with suramin or PPADS, or with specific P2Y₁₃ receptor antagonist MRS2211, or siRNA. Secondary ATP release induced by higher dose (200 μmol/L) of exoATP, sufficient to stimulate P2X₇ receptor, was attenuated by suramin, PPADS or specific P2X₇ receptor antagonist BBG, or siRNA. Finally, RT-PCR confirmed mRNA expression of P2Y₁₃ and P2X₇ in RBL-2H3 cells. Additionally, such secondary ATP release was attenuated by DPCPX, specific antagonist of adenosine A1 receptor, but not by MRS2179, specific inhibitor of P2Y₁ receptor. In summary, mechanosensitive ATP release from MCs is facilitated by paracrine/autocrine stimulation of P2Y₁₃ and P2X₇ receptors. This multi-receptor combination could mediate transmission of information from a local site to distal areas, enabling communication with multiple surrounding cells to coordinate and synchronize their function.

Laser Moxibustion Alleviates Knee Osteoarthritis Pain by Inhibiting Spinal Microglial Activation-Mediated Neuroinflammation in Rats

Background: Central sensitization driven by glial activation-mediated neuroinflammation is recognized as a key mechanism in pain processing. Laser moxibustion using low-intensity laser irradiation of corresponding acupoints significantly relieves knee osteoarthritis (KOA) pain. However, the underlying mechanism of its effects on KOA pain is still not completely understood. Objective: In this study, we aimed to investigate whether laser moxibustion could alleviate KOA pain by inhibiting spinal glial activation and proinflammatory cytokines upregulation in monosodium iodoacetate (MIA)-induced KOA pain in rats. Materials and methods: Sprague-Dawley rats were divided randomly into three groups: Saline + Sham Laser, MIA + Laser, and MIA + Sham Laser. A 10.6 μm laser was used to irradiate ST35 (Dubi) for 10 min once every 2 days for a total of seven applications. The paw withdrawal mechanical threshold and weight-bearing distribution were performed to evaluate the nociceptive behaviors. Spinal expressions of microglial marker, ionized calcium binding adaptor molecule-1 (Iba-1); astrocyte marker, glial fibrillary acidic protein (GFAP); pro-inflammatory cytokines, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) were measured 14 days after MIA injection. Results: The results showed that laser moxibustion significantly reversed the MIA-induced mechanical hyperalgesia and weight-bearing difference up to 14 days compared with MIA + Sham Laser group (p < 0.05 or p < 0.01). Moreover, both the protein level and immunofluorescence intensity of Iba-1 in the ipsilateral spinal cord dorsal horn were markedly decreased in the MIA + Laser group than those in the MIA + Sham Laser group (p < 0.01). However, there was no significant difference in the expression of GFAP between groups (p > 0.05). In addition, laser moxibustion decreased the upregulation of TNF-α, IL-1β, and IL-6 compared with the MIA + Sham Laser group (p < 0.01). Conclusions: This study demonstrated that laser moxibustion at ST35 significantly alleviated MIA-induced KOA pain through inhibition of the microglial activation-mediated neuroinflammation, at least partially, by suppressing the production of proinflammatory cytokines, which may provide a potential analgesic target for KOA pain relief.

The Effects of Laser Moxibustion on Knee Osteoarthritis Pain in Rats

Background: Although chronic pain affects the quality of life of patients with osteoarthritis, current medical treatments are either ineffective or have long-term side effects. Recently, low-intensity laser irradiation of corresponding acupoints was demonstrated to alleviate pain. Objective: The aim of the present study was to investigate the effects of 10.6 μm laser moxibustion on a monosodium iodoacetate (MIA)-induced knee osteoarthritis pain model. Methods: Thirty-two rats were randomly assigned to four groups: Saline, MIA, MIA+Laser, and MIA+Sham Laser. The 10.6 μm laser was used to irradiate the ST35 for 10 min once a day for a total of seven applications. The paw withdrawal mechanical threshold and weight-bearing difference were performed to evaluate the analgesic effects of laser moxibustion. At the end of the experiment on days 28, the joint histology, the levels of metalloproteinases-13 (MMP-13) in the cartilage, and TNF-α, IL-1β, and IL-6 in the synovial membrane were measured to determine the chondroprotection and anti-inflammatory effect of laser moxibustion. Results: Early laser moxibustion significantly reversed the MIA-induced mechanical hyperalgesia and weight-bearing difference, especially on the 28th day (p < 0.001). Moreover, laser moxibustion prevented the articular pathological lesions and cartilage destruction on days 28 (p < 0.01). Remarkably, the levels of cartilage MMP-13, and synovial TNF-α, IL-1β, and IL-6 also decreased on day 28 (p < 0.05) after the early treatment of laser moxibustion. Conclusions: 10.6 μm laser moxibustion may have long-lasting analgesic, anti-inflammatory, and chondroprotection effects, suggesting that it may emerge as a potential therapeutic strategy for the chronic pain treatment of osteoarthritis.