The influence of He-Ne laser radiation on the formation of new blood vessels in the bone marrow compartment of a regenerating area of the mid-cortical diaphysis of the tibiae of young adult rats was studied. A small hole was surgically made with a dentistry burr in the tibia and the injured area received a daily laser therapy over 7 or 14 days transcutaneously starting 24 h from surgery. Incident energy density dosages of 31.5 and 94.5 Jcm(-2) were applied during the period of the tibia wound healing investigated. Light microscopic examination of histological sections of the injured area and quantification of the newly-formed blood vessels were undertaken. Low-level energy treatment accelerated the deposition of bone matrix and histological characteristics compatible with an active recovery of the injured tissue. He-Ne laser therapy significantly increased the number of blood vessels after 7 days irradiation at an energy density of 94.5 Jcm(-2), but significantly decreased the number of vessels in the 14-day irradiated tibiae, independent of the dosage. These effects were attributed to laser treatment, since no significant increase in blood vessel number was detected between 8 and 15 non-irradiated control tibiae. Molecular mechanisms involved in low-level laser therapy of angiogenesis in post-traumatic bone regeneration needs further investigation.

Effects of low laser irradiation on angiogenesis in injured rat tibiae

Photobiomodulation (PBM) encompasses a light application aimed to increase healing process, tissue regeneration, and reducing inflammation and pain. PBM is specifically aimed to modify the expression of cellular molecules; however, PBM impacts on cellular and molecular pathways especially in bone regenerative medicine have been investigated in scattered different studies. The purpose of the current study is to systematically review evidence on molecular impact of PBM on bone regeneration. A comprehensive electronic search in Medline, Scopus, EMBASE, EBSCO, Cochrane library, web of science, and google scholar was conducted from January 1975 to October 2018 limited to English language publications on administrations of photobiomodulation for bone regeneration which evaluated biological factors. In addition, hand search of selected journals was done to retrieve all articles. This systematic review was performed based on PRISMA guideline. Among these studies, five articles reported in vitro results, twelve articles were in vivo, and three of them were clinical trials. The data tabulated according to the type of markers (osteogenic markers, angiogenic markers, growth factors, and inflammation mediators). PBM's effects depend on many parameters which energy density is more important than the others. PBM can significantly enhance expression of osteocalcin, collagen, RUNX-2, vascular endothelial growth factor, bone morphogenic proteins, and COX-2. Although since the heterogeneity of the studies and their limitations, an evidence-based decision for definite therapeutic application of PBM is still unattainable, the findings of our review can help other researchers to ameliorate their study design and elect more efficient approach for their investigation.

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Molecular impacts of photobiomodulation on bone regeneration: A systematic review.

Background: The aim of this study was to review the evidence regarding the use of low intensity pulsed ultrasound (LIPUS) in the management of acute long bone fractures. Methods: Systematic review of Medline, Embase, and CINAHL databases. Further published studies were retrieved by hand searching bibliographies of relevant articles. Retrieved studies were limited to English-language studies published since 1956. Retrieved studies were excluded from review using the following criteria: case reports, exclusively pathologic fractures, treatment of therapeutic osteotomies and arthrodesis, initiation of ultrasound therapy after the first month following injury, no reporting of assessment of time to fracture healing, cellular studies, and nonclinical articles. Studies were reviewed independently by two reviewers using the CONSORT score. No statistical analysis was performed as the data from the studies were not suitable for pooled analysis. Results: Seven randomized controlled trials and two meta-analyses were retrieved using the search strategy. Conclusion: The literature supports the use of LIPUS in the treatment of acute fractures treated with plaster immobilization.

The Role of Low Intensity Pulsed Ultrasound Therapy in the Management of Acute Fractures : A Systematic Review

The goal of the current experiment is to explore the influence of combined and/or single applications of red and near infrared (NIR) photobiomodulation (PBM) at different wavelengths, energy densities and times on cell viability, population doubling time (PDT), and apoptosis of in vitro cultures of human bone marrow-derived mesenchymal stem cells (hBM-MSCs) and h adipose-derived stem cells (hASCs). Both in vitro hBM-MSCs and hASCs were irradiated with 36 protocols using two different laser types (helium‑neon [He-Ne] and diodes), four different laser wavelengths (He Ne laser, 630 nm, 810 nm, 630 + 810 nm); three different energy densities (0.6 J/cm2, 1.2 J/cm2, 2.4 J/cm2); and three different PBM times (1, 2, and 3). One-way ANOVA analysis showed that PBM with the 630 nm red laser significantly stimulated cellular viability of both hBM-MSCs and hASCs. The 630 nm red laser significantly decreased PDT of hBM-MSCs. One-way ANOVA demonstrated that the 630 + 810 laser significantly stimulated cellular viability, and significantly decreased PDT and apoptosis of hBM-MSCs and hASCs. Two-way ANOVA analysis showed that PBM with the 630 nm red laser and 630 + 810 nm laser significantly stimulated cellular viability of hASCs compared to the control hASCs, and experimental and control hBM-MSCs. Our study demonstrated that PBM with the combined 630 + 810 nm lasers significantly stimulated cell viability, and significantly decreased PDT and apoptosis of hBM-MSCs and hASCs in vitro. We reported new in vitro evidence where PBM administered at 630 nm (one and two times, 0.6 and 1.2 J/cm2) and 630 + 810 nm (three times, 2.4 J/cm2) significantly increased hASC cell viability compared to its control and the PBM-treated hBM-MSC groups.

Photobiomodulation with 630 plus 810 nm wavelengths induce more in vitro cell viability of human adipose stem cells than human bone marrow-derived stem cells.

Fibrin sealants derived from human blood can be used in tissue engineering to assist in the repair of bone defects. The objective of this study was to evaluate the support system formed by a xenograft fibrin sealant associated with photobiomodulation therapy of critical defects in rat calvaria. Thirty-six rats were divided into four groups: BC (n = 8), defect filled with blood clot; FSB (n = 10), filled with fibrin sealant and xenograft; BCPBMT (n = 8), blood clot and photobiomodulation; FSBPBMT (n = 10), fibrin sealant, xenograft, and photobiomodulation. The animals were killed after 14 and 42 days. In the histological and microtomographic analysis, new bone formation was observed in all groups, limited to the defect margins, and without complete wound closure. In the FSB group, bone formation increased between periods (4.3 ± 0.46 to 6.01 ± 0.32), yet with lower volume density when compared to the FSBPBMT (5.6 ± 0.45 to 10.64 ± 0.97) group. It was concluded that the support system formed by the xenograft fibrin sealant associated with the photobiomodulation therapy protocol had a positive effect on the bone repair process.

https://www.mdpi.com/1422-0067/20/7/1761/pdf

Fibrin Sealant Derived from Human Plasma as a Scaffold for Bone Grafts Associated with Photobiomodulation Therapy.

The aim of this paper is to study the in vivo potency of low-level laser therapy (LLLT) and low intensity pulsed ultrasound (LIPUS) alone, accompanied by bone grafts, or accompanied by other factors on fracture healing in animal models and patients. In this paper, we aim to systematically review the published scientific literature regarding the use of LLLT and LIPUS to accelerate fracture healing in animal models and patients. We searched the PubMed database for the terms LLLT or LIPUS and/or bone, and fracture. Our analysis also suggests that both LIPUS and LLLT may be beneficial to fracture healing in patients, and that LIPUS is more effective. These finding are of considerable importance in those treatments with a LIPUS, as a laser device may reduce healing time. The most clinically relevant impact of the LIPUS treatment could be a significant reduction in the proportion of patients who go on to develop a nonunion. If it is confirmed that the therapeutic influence is true and reliable, patients will obtain benefits from LIPUS and LLLT. Further clinical trials of high methodological quality are needed in order to determine the optimal role of LIPUS and LLLT in fracture healing in patients.

Comparison of effects of LLLT and LIPUS on fracture healing in animal models and patients: A systematic review

Postmenopausal osteoporosis (OP) is a major concern for public health. Low-level laser therapy (LLLT) has a positive effect on the health of bone marrow mesenchymal stem cells (BMMSCs). The purpose of this study is to evaluate the influence of LLLT and oxytocin (OT) incubation-individually and in combination-on osteoporotic BMMSCs in ovariectomized rats. Twelve female rats were randomized into two groups to undergo either a sham surgery (sham group) or ovariectomy-induced osteoporosis (OVX group). MSCs harvested from the BM of healthy and OVX rats underwent culture expansion. There were five groups. In Groups one (sham-BMMSC) and two (OVX-BMMSC) the cells were held in osteogenic condition medium without any intervention. In the group three (OT), OT incubation with optimum dose was performed for 48 h (two times, 10-12 molar). In Group four, laser-treated-OVX-BMMSCs were treated with optimum protocol of LLLT (one time, 1.2 J/cm2 ). In Group five (laser + OT group), the OT incubation plus the laser irradiation was performed. The biostimulatory effect of LLLT is demonstrated by a significant increase in the viability of OVX-BMMSCs, cell cycle, and extracellular levels of Transforming growth factor beta (TGF-β), insulin-like growth factor-I (IGF-I), and Alkaline phosphatase (ALP) compared to control OVX-BMMSCs and/or the sham group. OT incubation and laser + OT incubation have a positive effect on OVX-BMMSCs. However, LLLT is more effective statistically. We conclude that LLLT significantly improved cell viability, enhanced the osteogenic potential of the OVX-BMMSCs, and increased the extracellular levels of the TGF-β, IGF-I, and ALP.

Effect of low-level laser therapy and oxytocin on osteoporotic bone marrow-derived mesenchymal stem cells

This study aims to investigate the combined effects of Pulsed wave low-level laser therapy (PW LLLT) and human bone marrow mesenchymal stem cell-conditioned medium (hBM-MSC-CM) on the microbial flora and tensiometrical properties of an infected wound model with methicillin-resistant staphylococcal aureus (MRSA) in an experimental model for Type 1 diabetes mellitus (TIDM). TIDM was induced in rats by streptozotocin (STZ). One full-thickness excision was made on the backs of the rats. Next, the rats were divided into the following groups: Group 1 was the control (placebo) group; Group 2 received hBM-MSCs-CM four times; Group 3 were laser PWLLLT (890 nm, 80 Hz, 0.2 J/cm2 ); and Group 4 received hBM-MSCs-CM +LASER. Wounds were infected with MRSA. Microbiological examinations were performed on days 4, 7, and 15. Tensiometerical examinations were carried out on the 15th day. One-way analysis of variance showed that laser and CM alone and/or in combination significantly increases the tensiomerical properties of the repaired wounds compared with control wounds. A combination of PW laser and CM was statistically more effective than other treated groups. Two-way analysis of variance showed that laser and CM alone and/or in combination significantly decreases the colony-forming units (CFUs) compared with the control group. The application of hBM-MSC-CM and PWlaser alone and/or together significantly accelerates the wound-healing process in MRSA-infected cutaneous wounds in TI DM in rats. Additionally, a combined application of hBM-MSC-CM and PWlaser demonstrates a synergistic effect on the wound-healing process in MRSA-infected cutaneous wounds in Type I DM rats.

The effect of combined pulsed wave low-level laser therapy and mesenchymal stem cell-conditioned medium on the healing of an infected wound with methicillin-resistant Staphylococcal aureus in diabetic rats.

Reza Jalalifirouzkouhi

Papers

Comparison of effects of LLLT and LIPUS on fracture healing in animal models and patients: A systematic review

Effect of low-level laser therapy and oxytocin on osteoporotic bone marrow-derived mesenchymal stem cells

The effect of combined pulsed wave low-level laser therapy and mesenchymal stem cell-conditioned medium on the healing of an infected wound with methicillin-resistant Staphylococcal aureus in diabetic rats.