Low-Intensity Pulsed Ultrasound Promotes Autophagy-Mediated Migration of Mesenchymal Stem Cells and Cartilage Repair.

Mesenchymal stem cell (MSC) migration is promoted by low-intensity pulsed ultrasound (LIPUS), but its mechanism is unclear. Since autophagy is known to regulate cell migration, our study aimed to investigate if LIPUS promotes the migration of MSCs via autophagy regulation. We also aimed to investigate the effects of intra-articular injection of MSCs following LIPUS stimulation on osteoarthritis (OA) cartilage. For the in vitro study, rat bone marrow-derived MSCs were treated with an autophagy inhibitor or agonist, and then they were stimulated by LIPUS. Migration of MSCs was detected by transwell migration assays, and stromal cell-derived factor-1 (SDF-1) and C-X-C chemokine receptor type 4 (CXCR4) protein levels were quantified. For the in vivo study, a rat knee OA model was generated and treated with LIPUS after an intra-articular injection of MSCs with autophagy inhibitor added. The cartilage repair was assessed by histopathological analysis and extracellular matrix protein expression. The in vitro results suggest that LIPUS increased the expression of SDF-1 and CXCR4, and it promoted MSC migration. These effects were inhibited and enhanced by autophagy inhibitor and agonist, respectively. The in vivo results demonstrate that LIPUS significantly enhanced the cartilage repair effects of MSCs on OA, but these effects were blocked by autophagy inhibitor. Our results suggest that the migration of MSCs was enhanced by LIPUS through the activation autophagy, and LIPUS improved the protective effect of MSCs on OA cartilage via autophagy regulation.

A comparative study of low-level laser efficacy on autologous activity of PRP injected in knee arthritis, in vivo study.

There were many studies that attempt to measure the effect of growth factors of platelets through platelet-rich plasma (PRP) techniques on repairing of different human tissues and their efficiency either by platelets account or measuring the concentrations of growth factors secreted from platelets at various experimental conditions, to get the optimal parameters for platelets functions in healing processes. There were little trails dealing with laser and PRP for accelerating healing process that generally takes two methods, either by studding the stimulation effect of LLLT (low-level laser therapy), by subjecting laser irradiation on injured part and left for a period of time that is necessary for photobiostimulation of cell proliferations, then PRP treatment followed, or by studding the direct effects of laser on PRP factors activity. The objectives of this study are to investigate the indirect and prolonged influence of laser irradiation (650 nm with 100 mW output power) on healing processes of knee joints with induced osteoarthritis (OA), by comparison of radiated and non-radiated PRP on repairing of joint cartilage. In material and methods, we used 9 rats divided in to four groups: C1, control without any treatment, for positive comparisons of healing; C2 and C3, controls with induced OA, left for 14 days, then sacrificed for histological analysis of negative comparisons; and P and L groups that had induced with OA for 14 days and then treated with non-irradiated and radiated PRP, respectively. Preparation of PRP (condensed platelets account with high concentration of growth factors) in order to accelerate repairing processes on induced- osteoarthritis cartilage in rats groups. To estimate the efficacy of photobiostimulation or photobioinhibition on platelets' granules, we determine the absorbance of PRP by spectrophotometer. The technique was based on PRP, as a feature of platelets quantity, that compares the quality of PRP on healing of induced osteoarthritis with and without irradiation of laser, using Wistar rats as a model. The quality of platelets was measured by time required for healing according to histopathological observations and grades of OA. Finally, the results were analyzed statistically using ANOVA test (P = 0.05). Our conclusion was emphasizing the idea of inhibiting the effect of LLLT on growth factors of PRP that is responsible of speed up healing of OA.

A Combinational Therapy of Articular Cartilage Defects: Rapid and Effective Regeneration by Using Low-Intensity Focused Ultrasound After Adipose Tissue-Derived Stem Cell Transplantation.

BACKGROUND: Although low-intensity pulsed ultrasound has been reported to be potential cartilage regeneration, there still unresolved treatment due to cartilage fibrosis and degeneration by a lack of rapid and high-efficiency treatment. The purpose of this study was to investigate the effect of a combination therapy of focused acoustic force and stem cells at site for fast and efficient healing on cartilage regeneration. METHODS: Using a rat articular cartilage defects model, one million adipose tissue-derived stem cells (ASCs) were injected into the defect site, and low-intensity focused ultrasound (LOFUS) in the range of 100-600 mV was used for 20 min/day for 2 weeks. All experimental groups were sacrificed after 4 weeks in total. The gross appearance score and hematoxylin and eosin (H&E), Alcian blue, and Safranin O staining were used for measuring the chondrogenic potential. The cartilage characteristics were observed, and type II collagen, Sox 9, aggrecan, and type X collagen were stained with immunofluorescence. The results of the comprehensive analysis were calculated using the Mankin scoring method. RESULTS: The gross appearance scores of regenerated cartilage and chondrocyte-like cells in H&E images were higher in LOFUS-treated groups compared to those in negative control or ASC-treated groups. Safranin O and Alcian blue staining demonstrated that the 100 and 300 mV LOFUS groups showed greater synthesis of glycosaminoglycan and proteoglycan. The ASC + LOFUS 300 mV group showed positive regulation of type II collagen, Sox 9 and aggrecan and negative regulation of type X collagen, which indicated the occurrence of cartilage regeneration based on the Mankin score result. CONCLUSION: The combination therapy, which involved treatment with ASC and 300 mV LOFUS, quickly and effectively reduced articular cartilage defects.

Histomorphometric evaluation of the effects of mandibular advancement appliance and low level laser therapy (LLLT) with different doses on condylar cartilage and subchondral bone in rats / Evaluación histomorfométrica de los efectos del aparato de avance mandibular y la terapia con láser de bajo nivel (TLBN) con diferentes dosis en cartílago condilar y hueso subcondral en ratas

The aim of this study was to evaluate the effects of mandibular advancement appliance and low level laser therapy (LLLT) with different doses on cellular hypertrophic changes in the mandibular condyle of rats. Forty-eight 8-week-old male Wistar albino rats weighing between 260 and 280 g were randomly divided into four experimental and control groups. Group I was the control group; group II was the mandibular advancement appliance group; group III was the 8 J/cm2 (0.25 W, 20 s) laser irradiation with mandibular advancement appliance group; and group IV was the 10 J/cm2 (0.25 W, 25 s) laser irradiation with mandibular advancement appliance group. Mandibular condyle cartilage and subchondral bone changes with different LLLT dose and mandibular advancement appliance were evaluated by histomorphometrical analysis. Subchondral bone fraction results showed that there were no significant differences between groups (p<0.05). The statistically significant differences found between control group and experimental groups in anterior and posterior cartilage layers thickness (p<0.05) and (p<0.01). Posterior and anterior condylar cartilage layers of rats react differentially to LLLT and mandibular advancement application. Maximum changes in condylar cartilage layers were found in 8 J/cm2 laser irradiation with mandibular appliance group.

El objetivo de este estudio fue evaluar los efectos del aparato de avance mandibular y la terapia con láser de bajo nivel (TLBN) con diferentes dosis sobre los cambios hipertróficos celulares, en el cóndilo mandibular de ratas. Cuarenta y ocho ratas albinas macho Wistar de 8 semanas de edad con un peso de 260 y 280 g se dividieron aleatoriamente en cuatro grupos experimentales y control. El grupo I control; grupo II, dispositivos de avance mandibular; grupo III de irradiación con láser de 8 J / cm2 (0.25 W, 20 s) con el grupo dispositivos de avance mandibular; y grupo IV con irradiación láser de 10 J / cm2 (0,25 W, 25 s) con el grupo de dispositivos de avance mandibular. El cartílago del cóndilo mandibular y los cambios en el hueso subcondral con diferentes dosis de TLBN y dispositivo de avance mandibular, se evaluaron mediante análisis histomorfométrico. Los resultados de la fracción ósea subcondral indicaron que no hubo diferencias significativas entre los grupos (p <0,05). Las diferencias estadísticamente significativas encontradas entre el grupo control y los grupos experimentales, en el grosor del cartílago anterior y posterior (p<0,05) y (p<0,01). Las capas de cartílago condilar posterior y anterior de las ratas reaccionan de manera diferencial a la aplicación de TLBN y avance mandibular. Se encontraron cambios significativos en las capas de cartílago condilar con irradiación láser de 8 J /cm2 con el grupo de dispositivos mandibulares.

Pulsed electromagnetic fields promote repair of focal articular cartilage defects with engineered osteochondral constructs.

Articular cartilage injuries are a common source of joint pain and dysfunction. We hypothesized that pulsed electromagnetic fields (PEMFs) would improve growth and healing of tissue-engineered cartilage grafts in a direction-dependent manner. PEMF stimulation of engineered cartilage constructs was first evaluated in vitro using passaged adult canine chondrocytes embedded in an agarose hydrogel scaffold. PEMF coils oriented parallel to the articular surface induced superior repair stiffness compared to both perpendicular PEMF (p = .026) and control (p = .012). This was correlated with increased glycosaminoglycan deposition in both parallel and perpendicular PEMF orientations compared to control (p = .010 and .028, respectively). Following in vitro optimization, the potential clinical translation of PEMF was evaluated in a preliminary in vivo preclinical adult canine model. Engineered osteochondral constructs (∅ 6 mm × 6 mm thick, devitalized bone base) were cultured to maturity and implanted into focal defects created in the stifle (knee) joint. To assess expedited early repair, animals were assessed after a 3-month recovery period, with microfracture repairs serving as an additional clinical control. In vivo, PEMF led to a greater likelihood of normal chondrocyte (odds ratio [OR]: 2.5, p = .051) and proteoglycan (OR: 5.0, p = .013) histological scores in engineered constructs. Interestingly, engineered constructs outperformed microfracture in clinical scoring, regardless of PEMF treatment (p < .05). Overall, the studies provided evidence that PEMF stimulation enhanced engineered cartilage growth and repair, demonstrating a potential low-cost, low-risk, noninvasive treatment modality for expediting early cartilage repair.

Laser photobiomodulation for cartilage defect in animal models of knee osteoarthritis: a systematic review and meta-analysis.

To review and assess the efficacy of laser photobiomodulation for cartilage defect in animal models of knee osteoarthritis (KOA). Medline, Web of Science, and EMBASE were searched. Studies were considered if the global quality score of cartilage were parallelly reported between laser and untreated control groups. The methodological quality of each study was assessed using a modified 10-item checklist. The effect size was estimated by standardized mean difference (SMD) and pooled based on the random-effects model. Stratified analysis and regression analysis were conducted to partition potential heterogeneity. An adjusted significant level of 0.01 was acceptable. Five hundred eight initial search recordings were identified, of which 14 studies (including 274 animals) were included for quantitative analysis. The global quality scores mostly weighted by the structural integrity and chondrocyte distribution were measured by different four scales including Histologic Histochemical Grading System (HHGS), Osteoarthritis Research Society International (OARSI), Pineda, and Huang. There were considerable variances on laser parameters and irradiation time among those included studies. Overall, a moderate level of methodological qualities was determined. The synthesis results indicated that the SMD effect size was significantly larger in HHGS (z = 2.61, P = 0.01) and Huang (z = 4.90, P < 0.01) groups. Stratified by irradiance, SMD of low (< 1 W/cm2) but not high (≥ 1 W/cm2) level estimated significant difference (z = 5.62, P < 0.01). Meta-regression identified a significant association for SMDs and irradiation time (P < 0.01). Yet, Egger's test detected small study effect (P < 0.01). No individual study with significant variance was found in homogeneity tests. The results demonstrated the positive effect of laser photobiomodulation for cartilage defect in animal models of KOA under proper irradiance and adequate irradiation time.

Photobiomodulation and Mandibular Advancement Modulates Cartilage Thickness and Matrix Deposition in the Mandibular Condyle.

Objective: We evaluated the effects of photobiomodulation (PBM), mandibular advancement (MA), and the combination of both treatments (PBM+MA) on condylar growth, by the analysis of cartilage and bone formation, fibrillar collagen deposition, proteoglycan content, cell proliferation, and clastic cell index (CCI). Methods: Forty male Wistar rats were randomly assigned to CONTROL, PBM, positive control-MA, and PBM+MA groups. The appliance was worn 10 h/day. Laser was irradiated bilaterally on mandibular condyles in 8 alternate days (1 irradiation point per condyle) using the following parameters: 780 nm, 10 J/cm2, 40 mW, 1 W/cm2, 10 sec/point, 0.4 J/point, and cumulative dose per point: 3.2 J. PBM+MA received both treatments simultaneously. After 15 days, the animals were euthanized and the condyles dissected and embedded in paraffin. Histological sections from the intermediate portion of the condyle were used for morphometric analysis. The relative frequency (%) of fibrillar collagens was determined in sections stained with picrosirius red-hematoxylin under polarized light or Gömöri's method for reticular fibers. Proteoglycan content was evaluated by computerized photocolorimetric analysis. CCI was determined by tartrate-resistant acid phosphatase (TRAP), and proliferating cell nuclear antigen (PCNA) was detected by immunohistochemistry. Results: PBM and MA influenced condylar cartilage thickeness and matrix deposition, but none of the treatments affected significantly the area of the condyle. CCI were not influenced by the treatments, but clastic cells distribution was influenced by MA and PBM+MA treatments. There was no significant difference in proliferating cells among the groups. Conclusions: This study demonstrated that PBM and MA stimulates matrix deposition and cartilage thickening in the mandibular condyle, but was not able to demonstrate a synergistic effect between the treatments. Additional studies should be conducted to evaluate the possible synergistic effect between PBM and MA.

Photobiostimulation activity of different low-level laser dosage on masticatory muscles and temporomandibular joint in an induced arthritis rat model.

This study aimed to investigate the anti-inflammatory effects of different dosage of low-level laser therapy (LLLT) in an experimental model of temporomandibular joint (TMJ) arthritis. One hundred male Wistar rats were used and divided into the following groups: CG, control group; AG, animals group with left TMJ arthritis induced by intra-articular injection of Complete Freund's adjuvant - CFA; LG5, LG10 and LG20 - animals with arthritis and treated with LLLT at doses 5, 10, and 20 J/cm2, respectively. Morphological analysis was performed by TMJ histological sections stained with hematoxylin-eosin (HE), picrosirius (PSR), and toluidine blue (TB), as well as histomorphometric evaluation of cartilage, articular disc, and masticatory muscles. The amount of feed consumed within 3 weeks was evaluated, and biochemical analysis of TMJ tissues included measurement of sulfated glycosaminoglycans (GAGs), matrix metalloproteinases (MMPs) 2 and 9 zymography, and ELISA for cytokines IL-6, TNF-α, and IL-1ß. Only the 20 J/cm2 dose promoted higher feed intake compared to AG. On the other hand, all LLLT doses promoted better organization of articular disc collagen fibers, greater number of proteoglycans in articular cartilage, increased area and diameter of left lateral pterygoid fibers, reduced latent and active MMP 9 and 2 activity, and lower IL-1ß concentration compared to AG. Considering the study limitations, it was observed that LLLT treatments were effective in protecting and tissue cleansing joint structures, accelerating tissue repair, especially at lower doses.

Ultraviolet light (365 nm) transmission properties of articular cartilage as a function of depth, extracellular matrix, and swelling.

Current tissue engineering approaches for treatment of injured or diseased articular cartilage use ultraviolet light (UV) for in situ photopolymerization of biomaterials to fill chondral and osteochondral defects as well as resurfacing, stiffening and bonding the extracellular matrix and tissue interfaces. The most commonly used UV light wavelength is UVA 365 nm, the least cytotoxic and deepest penetrating. However, little information is available on the transmission of UVA 365 nm light through the cartilage matrix. In the present study, 365 nm UV light transmission was measured as a function of depth through 100 µm thick slices of healthy articular cartilage removed from mature bovine knees. Transmission properties were measured in normal (Native) cartilage and after swelling equilibration in phosphate-buffered saline (Swollen). Single-factor and multiple linear regression analyses were performed to determine depth-dependencies between the effective attenuation coefficients and proteoglycan, collagen and water contents. For both cartilages, a significant depth-dependency was found for the effective attenuation coefficients, being highest at the articular surface (superficial zone) and decreasing with depth. The effective attenuation coefficients for full-thickness cartilages were approximately a third lower than the total attenuation coefficients calculated from the individual slices. Analysis of absorption and scattering effects due to the ECM and chondrocytes found that UV light scatter coefficients were ∼10 times greater than absorption coefficients. The greater transmittance of UV light through the thicker cartilage was attributed to the collagen within the ECM causing significant backscatter forward reflectance.

Continuous low-intensity ultrasound attenuates IL-6 and TNFα-induced catabolic effects and repairs chondral fissures in bovine osteochondral explants.

BACKGROUND: Cartilage repair outcomes are compromised in a pro-inflammatory environment; therefore, the mitigation of pro-inflammatory responses is beneficial. Treatment with continuous low-intensity ultrasound (cLIUS) at the resonant frequency of 5 MHz is proposed for the repair of chondral fissures under pro-inflammatory conditions. METHODS: Bovine osteochondral explants, concentrically incised to create chondral fissures, were maintained under cLIUS (14 kPa (5 MHz, 2.5 Vpp), 20 min, 4 times/day) for a period of 28 days in the presence or absence of cytokines, interleukin-6 (IL-6) or tumor necrosis factor (TNF)α. Outcome assessments included histological and immunohistochemical staining of the explants; and the expression of catabolic and anabolic genes by qRT-PCR in bovine chondrocytes. Cell migration was assessed by scratch assays, and by visualizing migrating cells into the hydrogel core of cartilage-hydrogel constructs. RESULTS: Both in the presence and absence of cytokines, higher percent apposition along with closure of fissures were noted in cLIUS-stimulated explants as compared to non-cLIUS-stimulated explants on day 14. On day 28, the percent apposition was not significantly different between unstimulated and cLIUS-stimulated explants exposed to cytokines. As compared to non-cLIUS-stimulated controls, on day 28, cLIUS preserved the distribution of proteoglycans and collagen II in explants despite exposure to cytokines. cLIUS enhanced the cell migration irrespective of cytokine treatment. IL-6 or TNFα-induced increases in MMP13 and ADAMTS4 gene expression was rescued by cLIUS stimulation in chondrocytes. Under cLIUS, TNFα-induced increase in NF-κB expression was suppressed, and the expression of collagen II and TIMP1 genes were upregulated. CONCLUSION: cLIUS repaired chondral fissures, and elicited pro-anabolic and anti-catabolic effects, thus demonstrating the potential of cLIUS in improving cartilage repair outcomes.

Knee and Hip Joint Cartilage Damage from Combined Spaceflight Hazards of Low-Dose Radiation Less than 1 Gy and Prolonged Hindlimb Unloading.

Reduced weight bearing, and to a lesser extent radiation, during spaceflight have been shown as potential hazards to astronaut joint health. These hazards combined effect to the knee and hip joints are not well defined, particularly with low-dose exposure to radiation. In this study, we examined the individual and combined effects of varying low-dose radiation (≤1 Gy) and reduced weight bearing on the cartilage of the knee and hip joints. C57BL/6J mice (n = 80) were either tail suspended via hindlimb unloading (HLU) or remained full-weight bearing (ground). On day 6, each group was divided and irradiated with 0 Gy (sham), 0.1 Gy, 0.5 Gy or 1.0 Gy (n = 10/group), yielding eight groups: ground-sham; ground-0.1 Gy; ground-0.5 Gy; ground-1.0 Gy; HLU-sham; HLU-0.1 Gy; HLU-0.5 Gy; and HLU-1.0 Gy. On day 30, the hindlimbs, hip cartilage and serum were collected from the mice. Significant differences were identified statistically between treatment groups and the ground-sham control group, but no significant differences were observed between HLU and/or radiation groups. Contrast-enhanced micro-computed tomography (microCECT) demonstrated decrease in volume and thickness at the weight-bearing femoral-tibial cartilage-cartilage contact point in all treatment groups compared to ground-sham. Lower collagen was observed in all groups compared to ground-sham. Circulating serum cartilage oligomeric matrix protein (sCOMP), a biomarker for ongoing cartilage degradation, was increased in all of the irradiated groups compared to ground-sham, regardless of unloading. Mass spectrometry of the cartilage lining the femoral head and subsequent Ingenuity Pathway Analysis (IPA) identified a decrease in cartilage compositional proteins indicative of osteoarthritis. Our findings demonstrate that both individually and combined, HLU and exposure to spaceflight relevant radiation doses lead to cartilage degradation of the knee and hip with expression of an arthritic phenotype. Moreover, early administration of low-dose irradiation (0.1, 0.5 or 1.0 Gy) causes an active catabolic response in cartilage 24 days postirradiation. Further research is warranted with a focus on the prevention of cartilage degradation from long-term periods of reduced weight bearing and spaceflight-relevant low doses and qualities of radiation.

The Effect of Platelet-Rich Plasma on the Temporomandibular Joint After Radiotherapy in Rabbits.

OBJECTIVES: Platelet-rich plasma (PRP) was administered into the temporomandibular joint (TMJ) space, which had been exposed to radiotherapy (RT), in an attempt to prevent and/or treat the late-term complications associated with RT when used for the treatment of head and neck cancers (nasopharyngeal cancer in particular) on the musculoskeletal system. METHODS: A total of 13 adult male New Zealand ( Oryctolagus cuniculus) rabbits were used in the study. The animals were classified into 3 groups: 6 in the RT group, 6 in the RT+PRP group, and 1 in the control group (exposed to neither). The TMJ space of each rabbit was exposed to 2240 cGy external RT in total, and PRP was administered into the TMJ space 1 month later. The joints were surgically removed 1 month later and examined histopathologically. RESULTS: In the group given RT+PRP, the level of inflammation, amount of muscle fibrosis, vascular wall fibrosis, synovial membrane and condyle cartilage thickness, temporal extrabone fibrous cell layer count, and intramuscular changes were similar to those recorded in the control group, although the positive effects of PRP were not found to be statistically significant. CONCLUSIONS: The findings of the present study demonstrate that injections of PRP may increase joint inflammation and therefore enhance blood supply, resulting in the onset of regeneration. These favorable effects of PRP may be helpful in the fight against late-term musculoskeletal complications of RT and may minimize such side effects as sore jaw, malnutrition, and weight loss.

Effects of low-level laser therapy on the organization of articular cartilage in an experimental microcrystalline arthritis model.

The aim of this study was to evaluate the effects of low-level laser therapy using the gallium arsenide laser (λ = 830 nm) on the articular cartilage (AC) organization from knee joint in an experimental model of microcrystalline arthritis in adult male Wistar rats. Seventy-two animals were divided into three groups: A (control), B (induced arthritis), and C (induced arthritis + laser therapy). The arthritis was induced in the right knee using 2 mg of Na4P2O7 in 0.5 mL of saline solution. The treatments were daily applied in the patellar region of the right knee after 48 h of induction. On the 7th, 14th, and 21st days of treatment, the animals were euthanized and their right knees were removed and processed for structural and biochemical analysis of the AC. The chondrocytes positively labeled for the TUNEL reaction were lower in C than in B on the 14th and 21st days. The content of glycosaminoglycans and hydroxyproline in A and C was higher than B on the 21st day. The amount of tibial TNF-α in B and C was lower than in A. The amount of tibial BMP-7 in B and C was higher than in A. The femoral MMP-13 was lower in B and C than for A. The tibial TGF-ß for C was higher than the others. The femoral ADAMT-S4 content of A and C presented similar and inferior data to B on the 21st day. The AsGa-830 nm therapy preserved the content of glycosaminoglycans, reduced the cellular changes and the inflammatory process compared to the untreated group.

Low-intensity pulsed ultrasound induces cartilage matrix synthesis and reduced MMP13 expression in chondrocytes.

Low-intensity pulsed ultrasound (LIPUS) is used for bone healing in orthopedics. In previous in vivo and in vitro studies, LIPUS has been shown to have promising effects on cellular elements in articular cartilage, particularly chondrocytes in patients with osteoarthritis. However, the effects of LIPUS on the cellular mechanisms through which LIPUS alters extracellular matrix (ECM) synthesis in chondrocytes are unclear. In this study, we investigated the effects of the optimal intensity and cellular mechanisms of LIPUS on the regeneration of cartilage matrix in chondrocytes. LIPUS induced collagen synthesis and the remodeling of aggrecan via the activation of ERK1/2. In contrast, MMP13 expression was decreased in chondrocytes. Additionally, chondrocytes responded optimally to LIPUS at an intensity higher than the clinical setting for bone fracture healing. These results suggested that LIPUS induced ECM regeneration via increases in hypertrophic chondrocytes and delayed endochondral ossification in chondrocytes.

Low-Dose Radiotherapy Has No Harmful Effects on Key Cells of Healthy Non-Inflamed Joints.

Low-dose radiotherapy (LD-RT) for benign inflammatory and/or bone destructive diseases has been used long. Therefore, mechanistic investigations on cells being present in joints are mostly made in an inflammatory setting. This raises the question whether similar effects of LD-RT are also seen in healthy tissue and thus might cause possible harmful effects. We performed examinations on the functionality and phenotype of key cells within the joint, namely on fibroblast-like synoviocytes (FLS), osteoclasts and osteoblasts, as well as on immune cells. Low doses of ionizing radiation showed only a minor impact on cytokine release by healthy FLS as well as on molecules involved in cartilage and bone destruction and had no significant impact on cell death and migration properties. The bone resorbing abilities of healthy osteoclasts was slightly reduced following LD-RT and a positive impact on bone formation of healthy osteoblasts was observed after in particular exposure to 0.5 Gray (Gy). Cell death rates of bone-marrow cells were only marginally increased and immune cell composition of the bone marrow showed a slight shift from CD8⁺ to CD4⁺ T cell subsets. Taken together, our results indicate that LD-RT with particularly a single dose of 0.5 Gy has no harmful effects on cells of healthy joints.

Interleukin-10 and collagen type II immunoexpression are modulated by photobiomodulation associated to aerobic and aquatic exercises in an experimental model of osteoarthritis.

The aim of this study was to compare the effects of photobiomodulation (PBM) associated with an aerobic and an aquatic exercise training on the degenerative process related to osteoarthritis (OA) in the articular cartilage in rats. Fifty male Wistar rats were randomly divided into 5 groups: OA control group (CG), OA plus aerobic training group (AET), OA plus aquatic training group (AQT), OA plus aerobic training associated with PBM group (AETL), OA plus aquatic training associated with PBM group (AQTL). The aerobic training (treadmill; 16 m/min; 50 min/day) and the aquatic training (water jumping; 50-80% of their body mass) started 4 weeks after the surgery and they were performed 3 days/week for 8 weeks. Moreover, PBM was performed after the physical exercise trainings on the left joint. Morphological characteristics and immunoexpression of IL-10, TGF-ß, and collagen type I (Col I) and II (Col II) of the articular cartilage were evaluated. The results showed that all the treated groups (exercise and PBM) presented less intense signs of degradation (measured by histopathological analysis and OARSI grade system). Additionally, aerobic and aquatic exercise training rats (associated or not with PBM) showed increased IL-10 (AET p = 0.0452; AETL p = 0.03; AQTL p = 0.0193) and Col II (AET p = 0.012; AQT p = 0.0437; AETL p = 0.0001; AQTL p = 0.0001) protein expression compared to CG. Furthermore, a statistically higher TGF-ß expression was observed in AET (p = 0.0084) and AETL (p = 0.0076) compared to CG. These results suggest that PBM associated with aerobic and aquatic exercise training were effective in mediating chondroprotective effects and maintaining the integrity of the articular tissue in the knees of OA rats.

Laser-ultrasonic delivery of agents into articular cartilage.

Research is ongoing to develop drug therapies to manage osteoarthritis (OA) and articular cartilage (AC) injuries. However, means to deliver drug to localized AC lesions are highly limited and not clinically available. This study investigates the capability of laser ultrasound (laser-induced plasma sound source) to deliver agents (methylene blue, MB, in PBS) into bovine AC. Treatment samples (n = 10) were immersed in MB solution simultaneously with LU exposure, while adjacent control 1 tissue (n = 10) was pre-treated with LU followed by immersion in MB and adjacent control 2 tissue (n = 10) was only immersed in MB. AC exposed (n = 22) or not exposed (n = 27) to LU were characterized for anomalies in structure, composition, viability or RNA expression. Optically detected MB content was significantly (p < 0.01) higher in treatment samples up to a depth of 500 µm from AC surface as compared to controls. No major unwanted short-term effects on AC structure, proteoglycan or collagen contents, chondrocyte viability or RNA expression levels were detected. In conclusion, LU can deliver agents into AC without major short-term concerns on safety. LU could reveal new strategies for the development of localized drug therapies in AC.

Low-intensity laser therapy efficacy evaluation in FVB mice subjected to acute and chronic arthritis.

Rheumatoid arthritis, an autoimmune inflammation, has a high prevalence in the population, and while therapy is available, it required often injection of drugs causing discomfort to patients. This study evaluates the clinical and histological effect of low-intensity laser therapy (LILT) as an alternative treatment, in a murine model of acute and chronic inflammation. FVB mice received either a Zymosan A injection into one knee joint inducing acute inflammation, followed after 15 min or 24 h by LILT or a collagen bovine type II injection emulsified in "Freund's Complete Adjuvant" to induce chronic arthritis, followed at 4 weeks with multiple LILT sessions. LILT mediated by either 660, 808, or 905 nm and tissue response was evaluated based on clinical symptoms and histological analysis of inflammatory infiltrate and damage to the articular surfaces. LILT can be effective in elevating clinical symptoms, so Kruskal-Wallis testing indicated no significant differences between knees affected by acute arthritis and treated once with LILT and an injured knee without treatment (p > 0.05) for 660 and 808 nm with some improvements for the 905-nm LILT. Mice receiving two treatments for acute arthritis showed exacerbation of inflammation and articular resorption following therapy with a 660-nm continuous laser (p < 0.05). For chronic inflammation, differences were not noted between LILT treated and untreated injured knee joints (p > 0.05). Among the lasers, the 905 nm tends to show better results for anti-inflammatory effect in acute arthritis, and the 660 nm showed better results in chronic arthritis. In conclusion, LILT wavelength selection depends on the arthritis condition and can demonstrate anti-inflammatory effects for chronic arthritis and reduced resorption area in this murine model.

The Role of Low-Intensity Pulsed Ultrasound on Cartilage Healing in Knee Osteoarthritis: A Review.

Ultrasound (US) is a therapeutic modality that has been used in the treatment of musculoskeletal conditions for decades. In recent years, there have been technological advancements using low-intensity pulsed ultrasound (LIPUS) as a clinical modality. The purpose of this review was to critically examine the medical literature to determine the effects of LIPUS on the chondrogenic properties of knee osteoarthritis. A literature search of 3 major databases (PubMed, Scopus, and EMBASE) was performed. Two independent physician reviewers screened titles and abstracts, yielding a total of 18 relevant articles after the inclusion and exclusion criteria were applied. Results favored that LIPUS has a promising effect on the cellular elements in articular cartilage, specifically on chondrocytes in knee osteoarthritis. Although the use of LIPUS is encouraging based on basic science and preclinical data, there is a paucity of evidence with respect to humans. Consequently, there is insufficient evidence to recommend for or against LIPUS in clinical OA populations. We suggest future directions for research centered on LIPUS in both human and animal models to delineate the effect on the biologic properties of cartilage in knee osteoarthritis. LEVEL OF EVIDENCE: III.

Magneto-therapy of human joint cartilage.

PURPOSE: The topic of the present paper concerns the human joint cartilage therapy performed by the magnetic induction field. There is proved the thesis that the applied magnetic field for concrete cartilage illness should depend on the proper relative and concrete values of applied magnetic induction, intensity as well the time of treatment duration. Additionally, very important are frequencies and amplitudes of magnetic field as well as magnetic permeability of the synovial fluid. MATERIAL AND METHODS: The research methods used in this paper include: magnetic induction field produced by a new Polish and German magneto electronic devices for the therapy of human joint cartilage diseases, stationary and movable magnetic applicators, magnetic bandage, ferrofluid injections, author's experience gained in Germany research institutes and practical results after measurements and information from patients. RESULTS: The results of this paper concern concrete parameters of time dependent electro-magnetic field administration during the joint cartilage therapy duration and additionally concern the corollaries which are implied from reading values gained on the magnetic induction devices. CONCLUSIONS: The main conclusions obtained in this paper are as follows: Time dependent magnetic induction field increases the dynamic viscosity of movable synovial fluid and decreases symptoms of cartilage illness for concrete intensity of magnetic field and concrete field line architecture. The ferrofluid therapy and phospholipids bilayer simultaneously with the administrated external electromagnetic field, increases the dynamic viscosity of movable synovial fluid.