Effect of Laser Phototherapy on the Release of TNF-α and MMP-1 by Endodontic Sealer–Stimulated Macrophages

Modulation of Inflammatory Responses by a Non-Invasive Physical Plasma Jet during Gingival Wound Healing

Gingival wound healing plays an important role in the treatment of a variety of inflammatory diseases. In some cases, however, wound healing is delayed by various endogenous or exogenous factors. In recent years, non-invasive physical plasma (NIPP), a highly reactive gas, has become the focus of research, because of its anti-inflammatory and wound healing-promoting efficacy. So far, since NIPP application has been poorly elucidated in dentistry, the aim of this study was to further investigate the effect of NIPP on various molecules associated with inflammation and wound healing in gingival cells. Human gingival fibroblasts (HGF) and human gingival keratinocytes (HGK) were treated with NIPP at different application times. Cell viability and cell morphology were assessed using DAPI/phalloidin staining. Cyclooxygenase (COX)2; tumour necrosis factor (TNF); CC Motif Chemokine Ligand (CCL)2; and interleukin (IL)1B, IL6 and IL8 were analysed at the mRNA and protein level by a real-time PCR and ELISA. NIPP did not cause any damage to the cells. Furthermore, NIPP led to a downregulation of proinflammatory molecules. Our study shows that NIPP application does not damage the gingival tissue and that the promotion of wound healing is also due to an anti-inflammatory component.

Macrophages Modulated by Red/NIR Light: Phagocytosis, Cytokines, Mitochondrial Activity, Ca2+ Influx, Membrane Depolarization and Viability

Low-level light therapy (LLLT) is emerging as a promising therapeutic approach to modulate the biochemical and molecular processes within living cells. LLLT is known to produce local and systemic effects; therefore, immune cells in local tissues or in the circulation are affected by light. However, this specific effect remains weakly explored. In this study, the effect of red (650 nm) and NIR (808 nm) light on phagocytosis (respiratory burst), cytokine expression, mitochondrial activity, ROS generation, Ca²⁺ influx and membrane depolarization in macrophages in vitro is investigated. Both the phagocytic capacity and adhesion of macrophages strongly (˜2.5 times) increased in the first hours after exposure to light in a dose-dependent manner. The light-evoked upregulation of phagocytosis is found to be less efficient than the maximal pharmacologically induced enhancement of ˜3.2 times. Also, red/NIR light reduces the production of pro-inflammatory cytokines and activates the secretion of anti-inflammatory cytokines by several times in activated macrophages. At the same time, the viability shows a biphasic dose response: it increases after irradiation with lower doses (0.3-1 J cm^-2 ) and decreases after treatment with higher doses (18-30 J cm^-2 ), which is apparently associated with the upregulation of ROS generation, followed by an increase in the mitochondrial activity.

Biomaterial-assisted photoimmunotherapy for cancer

The biomaterials have been well designed as photoabsorbing/sensitizing agents or effective carriers to enhance the photoimmunotherapeutic efficacy and evade their side effects.

Anti-inflammatory and cell proliferative effect of the 1270 nm laser irradiation on the BALB/c nude mouse model involves activation of the cell antioxidant system

Recently, many interdisciplinary community researchers have focused their efforts on study of the low-level light irradiation effects (photobiomodulation, PBM) as a promising therapeutic technology. Among the priorities, a search of new wavelength ranges of laser radiation to enhance the laser prospects in treatment of autoimmune and cancer diseases commonly accompanied by disorders in the antioxidant system of the body. The laser wavelengths within 1265-1270 nm corresponds to the maximum oxygen absorption band. Therefore, PBM effects on a model organism within this spectrum range are of particular interest for preclinical research. Here, we report comprehensive biomolecular studies of the changes in the BALB/c nude mice skin after an exposure to the continuous laser radiation at the 1270 nm wavelength and energy densities of 0.12 and 1.2 J/cm2. Such regime induces both local and systemic PBM effects, presumably due to the short-term increase in ROS levels, which in turn activate the cell antioxidative system.

A brief literature review and own clinical experience in prophylaxis of oral mucositis in children using low level laser therapy

OBJECTIVE

The article describes the experience of clinical application of low level laser therapy in pediatric oncology for the prevention and treatment of chemotherapy complications such as oral mucositis.

BACKGROUND

For this purpose, for the first time in the world non-invasive laser blood illumination is used on the sinocarotid zone (on the projection of the common carotid artery symmetrically) and popliteal fossa in order to stimulate the phagocytic activity of leukocytes.

METHODS

25 children with different oncological diseases were given non-invasive laser blood illumination treatment (904 nm, pulse mode, 100 ns, 50-150 Hz, 5-7 W, 4 cm², 1-2 minutes daily per each procedure) 1-3 days before the beginning of chemotherapy. For the objectification of the results of treatment, the phagocytic activity of leukocytes was evaluated.

RESULTS

None of the children who underwent low level laser therapy course had any complications and no cases of oral mucositis developed.

CONCLUSIONS

Clinical experience has shown high efficacy and safety of low level laser therapy aimed at preventing the development of complications of chemotherapy, primarily oral mucositis, and stimulating the phagocytic activity of leukocytes.

Preoperative low level laser therapy in dogs undergoing tibial plateau levelling osteotomy: A blinded, prospective, randomized clinical trial

Objective: To evaluate the influence of pre-operative low-level laser therapy (LLLT) on therapeutic outcomes of dogs undergoing tibial plateau levelling osteotomy (TPLO).

Methods: Healthy dogs undergoing TPLO were randomly assigned to receive either a single preoperative LLLT treatment (800–900 nm dual wavelength, 6 W, 3.5 J/cm2, 100 cm2 area) or a sham treatment. Lameness assessment and response to manipulation, as well as force plate analysis, were performed pre-operatively, then again at 24 hours, two weeks, and eight weeks postoperatively. Radiographic signs of healing of the osteotomy were assessed at eight weeks postoperatively.

Results: Twenty-seven dogs (27 stifles) were included and no major complications occurred. At eight weeks postoperatively, a significant difference in peak vertical force analysis was noted between the LLLT (39.6% ± 4.7%) and sham groups (28.9% ± 2.6%), (p <0.01 Time, p <0.01 L). There were no significant differences noted between groups for all other parameters. The age of dogs in the LLLT group (6.6 ± 1.6 years) was greater than that for the sham group (4.5 ± 2.0, p <0.01). Although not significant, a greater proportion of LLLT dogs (5/8) had healed at the eight-week time point than in the sham group (3/12) despite the age difference (p = 0.11)

Clinical significance: The results of this study demonstrate that improved peak vertical force could be related to the preoperative use of LLLT for dogs undergoing TPLO at eight weeks postoperatively. The use of LLLT may improve postoperative return to function following ca-nine osteotomies and its use is recommended.

Supplementary Material to this article is available online at https://doi.org/10.3415/VCOT-15-12-0198.

Photobiomodulation with 660-nm and 780-nm laser on activated J774 macrophage-like cells: Effect on M1 inflammatory markers

M1 profile macrophages exert a major influence on initial tissue repair process. Few days after the occurrence of injury, macrophages in the injured region exhibit a M2 profile, attenuate the effects of the M1 population, and stimulate the reconstruction of the damaged tissue. The different effects of macrophages in the healing process suggest that these cells could be the target of therapeutic interventions. Photobiomodulation has been used to accelerate tissue repair, but little is known regarding its effect on macrophages. In the present study, J774 macrophages were activated to simulate the M1 profile and irradiated with two different sets of laser parameters (780 nm, 70 mW, 2.6J/cm(2), 1.5s and 660 nm, 15 mW, 7.5 J/cm(2), 20s). IL-6, TNF-α, iNOS and COX-2 gene and protein expression were analyzed by RT-qPCR and ELISA. Both lasers were able to reduce TNF-α and iNOS expression, and TNF-α and COX-2 production, although the parameters used for 780 nm laser provided an additional decrease. 660 nm laser parameters resulted in an up-regulation of IL-6 expression and production. These findings imply a distinct, time-dependent modulation by the two different sets of laser parameters, suggesting that the best modulation may involve more than one combination of parameters.

Effect of low-level laser therapy on the modulation of the mitochondrial activity of macrophages

BACKGROUND:

Macrophages play a major role among the inflammatory cells that invade muscle tissue following an injury. Low-level laser therapy (LLLT) has long been used in clinical practice to accelerate the muscle repair process. However, little is known regarding its effect on macrophages.

OBJECTIVE:

This study evaluated the effect of LLLT on the mitochondrial activity (MA) of macrophages.

METHOD:

J774 macrophages were treated with lipopolysaccharide (LPS) and interferon - gamma (IFN-γ) (activation) for 24 h to simulate an inflammatory process, then irradiated with LLLT using two sets of parameters (780 nm; 70 mW; 3 J/cm² and 660 nm; 15 mW; 7.5 J/cm²⁾. Non-activated/non-irradiated cells composed the control group. MA was evaluated by the cell mitochondrial activity (MTT) assay (after 1, 3 and 5 days) in three independent experiments. The data were analyzed statistically.

RESULTS:

After 1 day of culture, activated and 780 nm irradiated macrophages showed lower MA than activated macrophages, but activated and 660 nm irradiated macrophages showed MA similar to activated cells. After 3 days, activated and irradiated (660 nm and 780 nm) macrophages showed greater MA than activated macrophages, and after 5 days, the activated and irradiated (660 nm and 780 nm) macrophages showed similar MA to the activated macrophages.

CONCLUSIONS:

These results show that 660 nm and 780 nm LLLT can modulate the cellular activation status of macrophages in inflammation, highlighting the importance of this resource and of the correct determination of its parameters in the repair process of skeletal muscle.

Low-level laser therapy improves the inflammatory profile of rats with heart failure

Following heart failure (HF), immune activation leads to an imbalance between pro-inflammatory and anti-inflammatory cytokines. Low-level laser therapy (LLLT) has been used as an anti-inflammatory treatment in several disease conditions. However, the effect of LLLT on the skeletal muscle of rats with HF remains unclear. The present report aimed to evaluate the influence of LLLT on the inflammatory profile of rats with HF. The left coronary artery was ligated to induce HF and a sham operation was performed in the control groups. Male Wistar rats (n=49) were assigned to one of six groups: placebo sham rats (P-Sham; n=8), LLLT at a dose of 3 J/cm(2) sham rats (3 J/cm(2)-Sham; n=8), LLLT at a dose of 21 J/cm(2) sham rats (21 J/cm(2)-Sham; n=8), placebo HF rats (P-HF; n=9), LLLT at a dose of 3 J/cm(2) HF rats (3 J/cm(2)-HF; n=8), and LLLT at a dose of 21 J/cm(2) HF rats (21 J/cm(2)-HF; n=8). Four weeks after myocardial infarction or sham surgery, rats were subjected to LLLT (InGaAlP 660 nm, spot size 0.035 cm(2), output power 20 mW, power density 0.571 W/cm(2), energy density 3 or 21 J/cm(2), exposure time 5.25 s and 36.75 s) on the right gastrocnemius for 10 consecutive days. LLLT reduced plasma IL-6 levels (61.3 %; P<0.01), TNF-α/IL-10 (61.0 %; P<0.01) and IL-6/IL-10 ratios (77.3 %; P<0.001) and increased IL-10 levels (103 %; P<0.05) in the 21 J/cm(2)-HF group. Moreover, LLLT reduced the TNF-α (20.1 % and 21.3 %; both P<0.05) and IL-6 levels (54.3 % and 37.8 %; P<0.01 and P<0.05, respectively) and the IL-6/IL-10 ratio (59.7 % and 42.2 %; P<0.001 and P<0.05, respectively) and increased IL-10 levels (81.0 % and 85.1 %; both P<0.05) and the IL-10/TNF-α ratio (171.5 % and 119.8 %; P<0.001 and P<0.05, respectively) in the gastrocnemius in the 3 J/cm(2)-HF and 21 J/cm(2)-HF groups. LLLT showed systemic and skeletal muscle anti-inflammatory effects in rats with HF.

Effect of laser phototherapy on wound healing following cerebral ischemia by cryogenic injury

Laser phototherapy emerges as an alternative or auxiliary therapy for acute ischemic stroke, traumatic brain injury, degenerative brain disease, spinal cord injury, and peripheral nerve regeneration, but its effects are still controversial. We have previously found that laser phototherapy immunomodulates the response to focal brain damage. Following direct cortical cryogenic injury the effects of laser phototherapy on inflammation and repair was assessed after cryogenic injury (CI) to the central nervous system (CNS) of rats. The laser phototherapy was carried out with a 780 nm AlGaAs diode laser. The irradiation parameters were: power of 40 mW, beam area of 0.04 cm(2), energy density of 3 J/cm(2) (3s) in two points (0.12 J per point). Two irradiations were performed at 3 h-intervals, in contact mode. Rats (20 non-irradiated - controls and 20 irradiated) were used. The wound healing in the CNS was followed in 6 h, 1, 7 and 14 days after the last irradiation. The size of the lesions, the neuron cell viability percentages and the amount of positive GFAP labeling were statistically compared by ANOVA complemented by Tukey's test (p<0.05). The distribution of lymphocytes, leukocytes and macrophages were also analyzed. CI created focal lesions in the cortex represented by necrosis, edema, hemorrhage and inflammatory infiltrate. The most striking findings were: lased lesions showed smaller tissue loss than control lesions in 6 h. During the first 24 h the amount of viable neurons was significantly higher in the lased group. There was a remarkable increase in the amount of GFAP in the control group by 14 days. Moreover, the lesions of irradiated animals had fewer leukocytes and lymphocytes in the first 24 h than controls. Considering the experimental conditions of this study it was concluded that laser phototherapy exerts its effect in wound healing following CI by controlling the brain damage, preventing neuron death and severe astrogliosis that could indicate the possibility of a better clinical outcome.