Development and validation of a GC-MS/MS method for the determination of iodoacetic acid in biological samples

Iodoacetic acid (IAA) is a halogenated disinfection by-product of growing concern due to its high cytotoxicity, genotoxicity, endocrine disruptor effects, and potential carcinogenicity. However, the data on distribution and excretion of IAA after ingestion by mammals are still scarce. Here, we developed a reliable and validated method for detecting IAA in biological specimens (plasma, urine, feces, liver, kidney, and tissues) based on modified QuEChERS sample preparation combined with gas chromatography-tandem triple quadrupole mass spectrometry (GC-MS/MS). The detection method for IAA exhibited satisfactory recovery rates (62.6-108.0%) with low relative standard deviations (RSD < 12.3%) and a low detection limit for all biological matrices ranging from 0.007 to 0.032 ng/g. The study showed that the proposed method was reliable and reproducible for analyzing IAA in biological specimens. It was successfully used to detect IAA levels in biological samples from rats given gavage administration. The results indicated that IAA was found in various tissues and organs, including plasma, thyroid, the liver, the kidney, the spleen, gastrointestinal tract, and others, 6 h after exposure. This study provides the first data on the in vivo distribution in and excretion of IAA by mammals following oral exposure.

Enhanced detection of monoiodoacetic acid at ng/L level by ion chromatography with novel derivatization-free pretreatment

Concerns have recently arisen regarding the formation of carcinogenic and genotoxic iodinated haloacetic acids (HAAs), such as monoiodoacetic acid (MIAA), during the disinfection of iodine-containing water with chloramine. Existing detection methods for MIAA rely on either labor-intensive derivatization operations or expensive instruments, making analysis challenging. To bypass these issues, this study proposed a novel two-step liquid-liquid extraction strategy to enrich MIAA and then pioneered the integration of common ion chromatography (IC) with an ultraviolet detector to measure trace MIAA precisely. This novel approach achieved a remarkable 155.6-fold enrichment of MIAA and significantly reduced the need for water and chemicals, hence enhancing its efficiency and environmental friendliness. Besides, this method effectively removed coexisting anions and separated MIAA from other interferents by adjusting IC column and eluent conditions. The method detection limit of MIAA is an impressive 21.44 ng/L, and the recoveries in synthetic and real water samples ranged from 85 to 113%, with maximum deviations of 7.59%. We validated the reliability of our approach by comparing it with the USEPA 552.3 method. In conclusion, this IC-based method proves to be a robust and environment-benign solution for detecting trace MIAA in complex water components.

Stimulation of nuclear receptor REV-ERBs alleviates monosodium iodoacetate-induced osteoarthritis pathology of mice and the induction of inflammatory molecules expression in primary cultured chondrocytes

Because inflammation in chondrocytes contributes to the induction of osteoarthritis (OA), regulation of their activity is essential. A previous study showed that stimulation of the reverse erythroblastosis virus (REV-ERB) nuclear receptors in spinal glial cells elicits anti-inflammatory and antinociception effects in animal models of chronic pain. However, the involvement of REV-ERBs in chondrocyte functions and OA pathologies remains to be elucidated. In the current study, we found that pretreatment with the REV-ERB agonist SR9009 significantly blocked the increases in inflammatory molecules [(matrix metalloproteinase (MMP) 3, MMP9, and MMP13] and cytokines (interleukin-1β and tumor necrosis factor) in primary cultured chondrocytes following treatment with lipopolysaccharide. Furthermore, repeated intra-articular treatment with SR9009 significantly prevented monosodium iodoacetate-induced mechanical hypersensitivity and tended to partially reduce knee joint damage in mice. In conclusion, our findings suggest that REV-ERBs have a critical role in alleviating nociceptive hypersensitivity in OA pathologies by negatively regulating inflammation in chondrocytes.

Integrated Analysis of DNA Methylation and Gene Expression Profiles in a Rat Model of Osteoarthritis

Osteoarthritis (OA) is common and affected by several factors, such as age, weight, sex, and genetics. The pathogenesis of OA remains unclear. Therefore, using a rat model of monosodium iodoacetate (MIA)-induced OA, we examined genomic-wide DNA methylation using methyl-seq and characterized the transcriptome using RNA-seq in the articular cartilage tissue from a negative control (NC) and MIA-induced rats. We identified 170 genes (100 hypomethylated and upregulated genes and 70 hypermethylated and downregulated genes) regulated by DNA methylation in OA. DNA methylation-regulated genes were enriched in functions related to focal adhesion, extracellular matrix (ECM)-receptor interaction and the PI3K-Akt and Hippo signaling pathways. Functions related to extracellular matrix organization, extracellular matrix proteoglycans, and collagen formation were involved in OA. A molecular and protein-protein network was constructed using methylated expression-correlated genes. Erk1/2 was a downstream target of OA-induced changes in DNA methylation and RNA expression. We found that the integrin subunit alpha 2 (ITGA2) gene is important in focal adhesion, alpha6-beta4 integrin signaling, and the inflammatory response pathway in OA. Overall, gene expression changes because DNA methylation influences OA pathogenesis. ITGA2, whose gene expression changes are regulated by DNA methylation during OA onset, is a candidate gene. Our findings provide insights into the epigenetic targets of OA processes in rats.

The Combined Intraosseous Administration of Orthobiologics Outperformed Isolated Intra-articular Injections in Alleviating Pain and Cartilage Degeneration in a Rat Model of MIA-Induced Knee Osteoarthritis

BACKGROUND

Intra-articular (IA) platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) injections have shown efficacy and safety in treating osteoarthritis (OA). However, the effectiveness and mechanisms of combined intraosseous (IO) administration of these orthobiologics have yet to be explored.

PURPOSE/HYPOTHESIS

The purpose of this study was to evaluate the effect on pain, cartilage, synovium/infrapatellar fat pad (IFP), and subchondral bone in rat knee OA, comparing isolated IA with combined IA and IO (IA+IO) injections of PRP or BMAC. It was hypothesized that combined injections would be superior to sole IA injections.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 48 rats were divided into 6 groups: sham (only joint puncture during OA induction with IA+IO saline injection treatment) and 5 groups with OA induction, control (IA+IO saline injection), PRP (IA PRP+IO saline injection), BMAC IA (IA BMAC+IO saline injection), PRP IA+IO (IA+IO PRP injection), and BMAC IA+IO (IA+IO BMAC injection). OA was induced by IA injection of monosodium iodoacetate (MIA). Rats were administered different orthobiologics according to their grouping 3 weeks after the MIA injection. Pain changes were evaluated using the weightbearing ratio assay at weeks 3, 4, 5, 7, and 9 after OA induction. Rats were euthanized at week 9 for gross, radiological, histological, immunohistochemical, and immunofluorescence assessments of cartilage, synovium, and subchondral bone.

RESULTS

Compared with the control group, all orthobiologics injection groups had reduced joint pain. Compared with IA injection, IA+IO injections provided superior pain relief by suppressing calcitonin gene-related peptide and substance P in both the synovium/IFP and subchondral bone. IA+IO injections slowed the progression of subchondral bone lesions by inhibiting CD31hiEmcnhi vessel formation and excessive osteoclast and osteoblast turnover while preserving subchondral bone microarchitecture, slowing cartilage degeneration. However, IA+IO injections did not outperform isolated IA injections in reducing synovitis and synovium/IFP fibrosis. Compared with PRP, BMAC exhibited superior inhibition of pain-related mediators, but no significant differences were observed in synovitis suppression, infrapatellar fat pad fibrosis, and subchondral bone protection.

CONCLUSION

IA+IO injections of orthobiologics were more effective in relieving pain, slowing cartilage degeneration, and inhibiting abnormal vascularization and remodeling compared with isolated IA injections. BMAC showed superior pain relief in the synovium/IFP and subchondral bone compared with PRP. Further research is needed to optimize PRP and BMAC components for enhanced efficacy in OA management.

CLINICAL RELEVANCE

Our findings contribute to advancing the understanding of pain relief mechanisms and support the endorsement of IO injection of orthobiologics for the treatment of OA and joint pain.

Inhibition of Brd4 alleviates osteoarthritis pain via suppression of neuroinflammation and activation of Nrf2-mediated antioxidant signalling

BACKGROUND AND PURPOSE

Osteoarthritis (OA) pain remains a major clinical problem. It is urgent to identify novel therapeutic approaches for OA pain states. Bromodomain and extra-terminal (BET) protein inhibitors have robust anti-inflammatory effects in several pain models. However, the underlying mechanisms of these inhibitors in OA pain have not been determined. We, therefore, investigated the effects and the underlying mechanism(s) of BET inhibition on pain-related behaviours in a rat model of OA.

EXPERIMENTAL APPROACH

The OA model was established by intra-articular injection of monosodium iodoacetate (MIA) in rat knees. Pain behaviours were assessed in rats by hindlimb weight-bearing asymmetry, mechanical allodynia and thermal hyperalgesia. Possible mechanisms underlying BET inhibition were explored in the MIA-induced OA pain model in the spinal cord and dorsal root ganglia (DRG).

KEY RESULTS

Inhibiting bromodomain-containing protein 4 (Brd4) with either JQ1 or MS417, or using AAV2/9-shRNA-Brd4-EGFP-mediated knockdown of Brd4 genes, significantly attenuated MIA-induced pain behaviours. Brd4 inhibition suppressed NF-κB and NF-κB-mediated inflammatory cytokines in both the spinal cord and DRG in rats with MIA-induced OA pain. Brd4 inhibition also attenuated the oxidative stress and promoted nuclear factor erythroid-2-related factor 2 (Nrf2)-dependent antioxidant genes in both the spinal cord and DRG in our odel of MIA-induced OA pain.

CONCLUSIONS AND IMPLICATIONS

In conclusion, Brd4 inhibition alleviated MIA-induced OA pain in rats, via suppression of neuroinflammation and activation of Nrf2-mediated antioxidant signalling. Although our model does not perfectly represent how OA develops in humans, inhibition of Brd4 may provide novel insights into possible treatments for OA pain.

Low Glycolysis Is Neuroprotective during Anoxic Spreading Depolarization (SD) and Reoxygenation in Locusts

Migratory locusts enter a reversible hypometabolic coma to survive environmental anoxia, wherein the cessation of CNS activity is driven by spreading depolarization (SD). While glycolysis is recognized as a crucial anaerobic energy source contributing to animal anoxia tolerance, its influence on the anoxic SD trajectory and recovery outcomes remains poorly understood. We investigated the effects of varying glycolytic capacity on adult female locust anoxic SD parameters, using glucose or the glycolytic inhibitors 2-deoxy-d-glucose (2DG) or monosodium iodoacetate (MIA). Surprisingly, 2DG treatment shared similarities with glucose yet had opposite effects compared with MIA. Specifically, although SD onset was not affected, both glucose and 2DG expedited the recovery of CNS electrical activity during reoxygenation, whereas MIA delayed it. Additionally, glucose and MIA, but not 2DG, increased tissue damage and neural cell death following anoxia-reoxygenation. Notably, glucose-induced injuries were associated with heightened CO2 output during the early phase of reoxygenation. Conversely, 2DG resulted in a bimodal response, initially dampening CO2 output and gradually increasing it throughout the recovery period. Given the discrepancies between effects of 2DG and MIA, the current results require cautious interpretations. Nonetheless, our findings present evidence that glycolysis is not a critical metabolic component in either anoxic SD onset or recovery and that heightened glycolysis during reoxygenation may exacerbate CNS injuries. Furthermore, we suggest that locust anoxic recovery is not solely dependent on energy availability, and the regulation of metabolic flux during early reoxygenation may constitute a strategy to mitigate damage.

Effective Technical Protocol for Producing a Mono-Iodoacetate-Induced Temporomandibular Joint Osteoarthritis in a Rat Model

An animal model of osteoarthritis (OA) induced by monosodium iodoacetate (MIA) can be effectively adjusted based on the concentration of MIA to control the onset, progression, and severity of OA as required. The rat temporomandibular joint osteoarthritis (TMJOA) model using MIA is a useful tool for studying the effectiveness of disease-modifying OA drugs in TMJOA research. However, the intricate and complex anatomy of the rat TMJ often poses challenges in achieving consistent TMJOA induction during experiments. In the previous article, a reference point was established by drawing parallel lines based on the line connecting the external ear and the zygomatic arch. However, this is not suitable for the anatomical characteristics of the rat. We used the zygomatic arch as a reference, which is a technical protocol that considers it. In our protocol, we designated a point ∼1 mm away from the point where the zygomatic arch bends toward the ear as the injection site. To ensure precise injection of MIA and increase the likelihood of inducing OA, it is recommended to insert the needle at a 45° angle so that the needle tip contacts the joint projection. To confirm TMJOA induction, we identified changes in the condyle using in vivo microcomputed tomography (CT) in a rat model of MIA-induced OA and measured the degree of pain-related inflammation using head withdrawal threshold (HWT) measurements. Micro-CT scanning revealed typical OA-like lesions, including degenerative changes and subchondral bone remodeling induced by MIA in the TMJ. Pain, a major clinical feature of OA, showed an appropriate response corresponding to the structural changes shown in micro-CT scanning. In addition, the MIA concentration suitable for long-term observation of lesions was determined through ex vivo micro-CT imaging and HWT measurements. The 8 mg concentration exhibited a significant difference compared with others, confirming the sustained presence of lesions, particularly through changes in subchondral bone over an extended period. Consequently, we have successfully established a reliable rat TMJOA induction model and identified the MIA concentration suitable for long-term observation of subchondral bone research, which will greatly contribute to the study of TMJOA-an incurable disease lacking specific treatment options. The Clinical Trial Registration number is 2021-12-208.

Ameliorative Effects of Prolotherapy on Histomorphology of Tibial Articular Cartilage of Chemically Induced Osteoarthritic Knee Joint in a Rat Model

OBJECTIVE

To determine the ameliorative effects of prolotherapy on monosodium iodoacetate (MIA) induced and histomorphological changes in the articular cartilage of tibial condyles at rat knee joint.

STUDY DESIGN

An experimental study. Place and Duration of the Study: Department of Anatomy, Army Medical College Rawalpindi, NUMS, Rawalpindi, from August to November 2021.

METHODOLOGY

Thirty adult male Sprague Dawley rats were divided into three groups, each having 10 rats. Group A was control. Group B was injected with single dose of 1mg MIA intraarticularly in the right knee to induce osteoarthritic changes. Group C was injected with single dose of 1mg MIA intraarticularly, in right knee was followed by 0.1ml Prolotherapy (3ml of 25% dextrose, 2ml of 2% xylocaine, 1ml of injection neurobion, and 1ml of injection methecobal) as intra articular injection at week 2, 6 and 10 in right knee. Rats were sacrificed after one month of the last dose of Prolotherapy. Articular cartilage was collected for gross and histological examination and compared among the groups.

RESULTS

Articular cartilage belonging to control group A was normal. While group B showed statistically significant deterioration in gross appearance (p = 0.001**), reduction in number of chondrocytes (p = 0.005*) and thickness of articular cartilage (p = 0.001**) in comparison to group A. In group C due to prolotherapy statistically significant improvement in gross appearance (p = 0.034*), increase in number of chondrocytes (p = 0.003*), and thickness of articular cartilage (p = 0.001**) was observed as compared to group B.

CONCLUSION

Prolotherapy significantly ameliorates histomorphology of tibial articular cartilage against MIA induced osteoarthritic changes in rat knee joint.

KEY WORDS

Articular cartilage, Knee joint, Monosodium iodoacetate, Osteoarthritis, Prolotherapy.

Remarkably efficient Pt/CeO2-Al2O3 catalyst for catalytic hydrodeiodination of monoiodoacetic acid: Synergistic effect of Al2O3 and CeO2

Monoiodoacetic acid (MIAA) is one of the highly toxic halogenated disinfection by-products, which is formed during water disinfection processes. Catalytic hydrogenation with supported noble metal catalyst is a green and effective technique for the transformation of halogenated pollutant, but its activity still needs to be identified. In this study, Pt nanoparticles were supported on CeO₂ modified γ-Al₂O₃ (Pt/CeO₂-Al₂O₃) by chemical deposition method and the synergistic effect of Al₂O₃ and CeO₂ on catalytic hydrodeiodination (HDI) of MIAA was systematically studied. Characterizations revealed that Pt dispersion could be improved by the introduced CeO₂ through the formation of Ce-O-Pt bond and MIAA adsorption could be facilitated by high Zeta potential of Al₂O₃ component. Furthermore, optimal Ptⁿ⁺/Pt⁰ could be obtained by adjusting CeO₂ deposition amount on Al₂O₃, which could effectively facilitate the activation of C-I bond. Therefore, Pt/CeO₂-Al₂O₃ exhibited remarkable catalytic activities and TOF values compared with those of Pt/CeO₂ and Pt/Al₂O_3. Through detailed kinetic experiments and characterization, the extraordinary catalytic performance of Pt/CeO₂-Al₂O₃ can be attributed to the abundant Pt sites as well as the synergistic effect between CeO₂ and Al₂O₃.

A Combination of Surgical and Chemical Induction in a Rabbit Model for Osteoarthritis of the Knee

BACKGROUND

Appropriate animal models of osteoarthritis (OA) are essential to develop new treatment modalities for OA. A combination of surgical and chemical induction could be appropriate for OA models.

METHODS

Rabbit knee OA models developed by surgical induction (anterior cruciate ligament transection [ACLT]), chemical induction (monosodium iodoacetate [MIA] injection), and a combination of both were compared to assess compositional and structural destruction of the knee joint. Twenty-one New Zealand white rabbits were randomly divided into 3 groups to induce OA (group 1: ACLT, n = 3; group 2: MIA [3, 6, 9 mg] injection, n = 9; group 3: ACLT + MIA [3, 6, 9 mg] injection, n = 9).

RESULTS

In all groups, the Modified Mankin score was significantly higher in the osteoarthritis-induced knee than in the control. Modified Mankin scores were compared by category. The ACLT group was observed to score high in cartilage structure. In the MIA group, chondrocytes and matrix staining showed higher scores, and the ACLT+MIA group scored higher in all categories for cartilage structure, chondrocytes, matrix staining, and tidemark integrity. The ACLT + 3 mg MIA showed definite OA characteristics such as cartilage surface destruction and degeneration of cartilage layers, and the ACLT + 6 mg MIA and ACLT + 9 mg MIA showed more prominent OA characteristics such as cartilage surface destruction, matrix disorganization, and osteophyte formation.

CONCLUSION

The combination of MIA injection and ACLT could be an appropriate method for OA induction in rabbit models.

[Construction and pathological characterization of 3 animal models of temporomandibular joint degenerative joint disease in mice]

Objective: To explore the pathological characteristics of three mice models of temporomandibular joint degenerative joint disease (TMJDJD), including osteoarthritis and osteoarthrosis, and to provide references for animal experimental study regarding the pathological mechanism of osteoarthritis and osteoarthrosis. Methods: A total of 54 8-week-old male C57BL/6 mice were selected to construct three TMJDJD animal models, including bilateral temporomandibular joint (TMJ) Freund's complete adjuvant (FCA) injection model, bilateral TMJ monosodium iodoacetate (MIA) injection model, and right TMJ discectomy model. FCA injection model (15 mice) was divided into saline injection group, FCA injection group-1 week, FCA injection group-2 week, FCA injection group-4 week and FCA injection group-6 week, 3 mice were used at each time point, with a total of 6 TMJs on both sides. MIA injection model (15 mice) was separated into saline injection group, MIA injection group-1 week, MIA injection group-2 week, MIA injection group-4 week and MIA injection group-6 week, 3 mice were used at each time point, with a total of 6 TMJs on both sides. TMJ discectomy model (24 mice) was split into control group, discectomy group-2 week group, discectomy group-4 week and discectomy group-6 week, six mice were used at each time point, with a total of six right TMJs. General pictures of the bilateral joints area of mice were collected 1 day after drug injection, and stereoscopic images of condylar tissues were collected 4 weeks after microsurgery for discectomy. Mouse TMJ tissue sections from each time point were stained with HE and toluidine blue, respectively, synovial tissues were scored for synovial inflammation, and the percentage of proteoglycan in condylar cartilage was quantitatively analyzed. Results: One day after intra-articular FCA or MIA injection, the width of bilateral TMJ were significantly increased in FCA injection groups [(24.60±0.46) mm] compared with the saline injection group [(21.63±0.52) mm] (t=4.25, P<0.013), the width of bilateral TMJ in MIA injection groups [(24.50±0.62) mm] were also significantly higher than that in saline injection group [(21.40±0.52) mm] (t=3.82, P=0.019). The synovitis scores in FCA injection groups 1, 2, 4, 6 weeks after FCA injection were significantly higher than that of the saline injection group (F=18.09, P<0.001), with the proteoglycan of condylar cartilage increased firstly and then decreased compared with the saline injection group (F=21.59, P<0.001). Condylar cartilage proteoglycan loss in different degrees were observed 1, 2, 4 and 6 weeks after MIA injection (F=13.59, P<0.001), and synovitis scores were increased at different degrees compared with saline injection group (F=14.79, P<0.001). The morphology of condylar cartilage in discectomy groups mice were severely damaged, synovial tissues showed dense connective tissue lesions at 2, 4 and 6 weeks postoperatively, condylar cartilage tissues showed a time-dependent loss of proteoglycan compared with the control group (F=40.62, P<0.001). Conclusions: Intra-articular FCA injection establishes a mouse model of TMJ osteoarthritis with severe synovial inflammation. Intra-articular MIA injection constructs a mouse model of typical TMJ osteoarthritis. Discectomy establishes a mouse TMJ osteoarthrosis model with severe condylar cartilage destruction.

Coenzyme Q10 encapsulated in micelles ameliorates osteoarthritis by inhibiting inflammatory cell death

Background

Osteoarthritis (OA) is the most common degenerative joint disease and is characterized by breakdown of joint cartilage. Coenzyme Q10 (CoQ10) exerts diverse biological effects on bone and cartilage; observational studies have suggested that CoQ10 may slow OA progression and inflammation. However, any effect of CoQ10 on OA remains unclear. Here, we investigated the therapeutic utility of CoQ10-micelles.

Methods

Seven-week-old male Wistar rats were injected with monosodium iodoacetate (MIA) to induce OA. CoQ10-micelles were administered orally to MIA-induced OA rats; celecoxib served as the positive control. Pain, tissue destruction, and inflammation were measured. The expression levels of catabolic and inflammatory cell death markers were assayed in CoQ10-micelle-treated chondrocytes.

Results

Oral supplementation with CoQ10-micelles attenuated OA symptoms remarkably, including pain, tissue destruction, and inflammation. The expression levels of the inflammatory cytokines IL-1β, IL-6, and MMP-13, and of the inflammatory cell death markers RIP1, RIP3, and pMLKL in synovial tissues were significantly reduced by CoQ10-micelle supplementation, suggesting that CoQ10-micelles might attenuate the synovitis of OA. CoQ10-micelle addition to cultured OA chondrocytes reduced the expression levels of catabolic and inflammatory cell death markers.

Conclusions

CoQ10-micelles might usefully treat OA.

Imperatorin alleviated NLR family pyrin domain-containing 3 inflammasome cascade-induced synovial fibrosis and synovitis in rats with knee osteoarthritis

We aimed to clarify the therapeutic effects of imperatorin (IMP) on knee osteoarthritis (KOA). Thirty 3-month-old SD male rats were randomly divided into Normal, monosodium iodoacetate (MIA) and MIA+IMP groups. Their synovial tissues were subjected to histopathological analysis. Primary synovial fibroblasts obtained from additional normal rats were treated by lipopolysaccharide (LPS) and then IMP. The mRNA and protein expressions of factors related to synovitis and synovial fibrosis were detected by qRT-PCR and Western blotting, respectively. The concentrations of inflammatory factors IL-1β and IL-18 were measured by ELISA. IMP reduced HIF-1α, NLR family pyrin domain-containing 3 inflammasome expression and IL-1β, IL-18 production in synovial fibroblasts induced by LPS. IMP also downregulated synovial fibrosis markers. In vitro study revealed that MIA-induced synovitis and synovial fibrosis were relieved by IMP. IMP relieves the inflammation associated with synovitis and synovial fibrosis. It reduces the production of pro-inflammatory mediators and cytokines and inhibits TGF-β1, TIMP-1 and VEGF expressions that promote synovial fibrosis.

Synthesis and Biological Evaluation of C-17-Amino-Substituted Pyrazole-Fused Betulinic Acid Derivatives as Novel Agents for Osteoarthritis Treatment

A series of pyrazole-fused betulinic acid (BA) derivatives were designed and synthesized by replacing the carboxyl group at C-17 with aliphatic amine, amide, and urea groups. The suppressive effects of the compounds on osteoclast (OC) formation and inflammatory cytokine production were evaluated on murine macrophages, RAW264.7 cells, conditioned with receptor activator for nuclear factor-κB ligand (RANKL)/macrophage colony stimulating factor (M-CSF) or lipopolysaccharide (LPS), respectively. Results showed that, compared with betulinic acid, most of these compounds exhibited significant improvements in inhibitory potency. Compound 25 exhibited distinguished activities on inhibiting OC differentiation with an IC50 value of 1.86 μM. Meanwhile, compound 25, displaying the most promising suppression on IL-1β secretion from RAW264.7 cells, was further found to possess therapeutic effects in the sodium monoiodoacetate (MIA)-induced osteoarthritis rat model. Dose-dependent benefits were observed in MIA-elicited rats with ameliorated joint pain as well as decreased cartilage damage and bone changes after compound 25 treatment.

CB2 agonism controls pain and subchondral bone degeneration induced by mono-iodoacetate: Implications GPCR functional bias and tolerance development

BACKGROUND AND PURPOSE

The endocannabinoid system became a promising target for osteoarthritis (OA) treatment. Functional selectivity of cannabinoids may increase their beneficial properties while reducing side effects. The aim of the present study was to evaluate the analgesic potential of two functionally biased CB2 agonists in different treatment regimens to propose the best pharmacological approach for OA management.

EXPERIMENTAL APPROACH

Two functionally selective CB2 agonists were administered i.p. - JWH133 (cAMP biased) and GW833972A (β-arrestin biased), in a chemically induced model of OA in rats. The drugs were tested in acute and chronic treatment regimens. Analgesic effects were assessed by pressure application measurement and kinetic weight bearing. X-ray microtomography was used for the morphometric analysis of the femur's subchondral bone tissue. Underlying biochemical changes were analysed via RT-qPCR.

KEY RESULTS

Dose-response studies established the effective dose for both JWH133 and GW833972A. In chronic treatment paradigms, JWH133 was able to elicit analgesia throughout the course of the experiment, whereas GW833972A lost its efficacy after 2 days of treatment. Later studies revealed improvement in subchondral bone architecture and decrement of matrix metalloproteinases and proinflammatory factors expression following JWH133 chronic treatment.

CONCLUSION AND IMPLICATIONS

Data presents analgesic and disease-modifying potential of CB2 agonists in OA treatment. Moreover, the study revealed more pronounced tolerance development for analgesic effects of the β-arrestin biased CB2 agonist GW833972A. These results provide a better understanding of the molecular underpinnings of the anti-nociceptive potential of CB2 agonists and may improve drug development processes for any cannabinoid-based chronic pain therapy.

Androgenic and Teratogenic Effects of Iodoacetic Acid Drinking Water Disinfection Byproduct in Vitro and in Vivo

Iodoacetic acid (IAA) is the most genotoxic iodinated disinfection byproduct known in drinking water. Previous studies have shown that IAA may be an endocrine disruptor. However, whether IAA has reproductive and developmental toxicity remains unclear. In this study, the reproductive and developmental toxicity of IAA was evaluated using a battery of in vitro and in vivo reproductive/developmental toxicity screening tests. The results of E-Screen, uterotrophic, and H295R steroidogenesis assays were negative. The Hershberger bioassay revealed that IAA could induce significant increases in absolute and relative weights of paired Cowper's glands. Moreover, there was an increasing trend in the relative weights of the ventral prostate. The micromass test showed that IAA could inhibit the differentiation of midbrain and limb bud cells. A reproductive/developmental toxicity screening test showed that IAA resulted in significantly increased relative weights of testis and seminal vesicles plus coagulating glands in parental male rats, with a dose-response relationship. IAA could not only induce head congestion in offspring but also decrease litter weight, viability index, and anogenital distance index of male pups on postnatal day 4. All these results indicated that IAA had reproductive and developmental toxicity.

d-Mannose suppresses osteoarthritis development in vivo and delays IL-1β-induced degeneration in vitro by enhancing autophagy activated via the AMPK pathway

Osteoarthritis (OA) is a heterogeneous disease that is consistently difficult to treat due to the complexity of the regulatory network involved in OA pathogenesis, especially in terms of cartilage degeneration. As a C-2 epimer of glucose, d-mannose can alleviate bone loss and repress immunopathology by upregulating regulatory T cells; however, the role of d-mannose in OA-related cartilage degeneration remains unknown. In this study, we investigated the chondroprotective effect of d-mannose in vitro and in vivo on OA. We found that incubating interleukin (IL)-1β-treated rat chondrocytes with d-mannose restrained OA degeneration by elevating cell proliferation, strongly activating autophagy, reducing apoptosis, and downregulating catabolism. Additionally, oral gavage administration of d-mannose to monosodium iodoacetate (MIA)-treated rats revealed that a median (1.25 g/kg/day) rather than high or low dose of d-mannose suppressed OA progression and attenuated OA development based on lower macroscopic scores for cartilage, decreased histological scores for cartilage and synovium, strongly activated autophagy, and downregulated catabolism. In terms of a downstream mechanism, we showed that d-mannose might attenuate OA degeneration by activating autophagy in IL-1β-treated rat chondrocytes by promoting the phosphorylation of 5' AMP-activated protein kinase (AMPK). Our in vitro findings revealed that d-mannose delayed IL-1β-induced OA degeneration in rat chondrocytes by enhancing autophagy activation through the AMPK pathway. Furthermore, the in vivo results indicated that a median dose of d-mannose suppressed MIA-induced OA development. These results suggested that d-mannose exhibits chondroprotective effects and represents a potential disease-modifying drug and novel therapeutic agent for OA.

Galactomannan of Delonix regia seeds reduces nociception and morphological damage in the rat model of osteoarthritis induced by sodium monoiodoacetate

This study investigated the effects of the protein-free galactomannan obtained from Delonix regia seeds (GM-DR) in an experimental osteoarthritis (OA) model. GM-DR was obtained from water-homogenized endosperms by collection of the supernatant and precipitation with ethanol. The remaining proteins in the galactomannan were removed by alkaline hydrolysis. Weight average molar mass (Mw) of the galactomannan was estimated in 5.8 × 105 g mol-1, presenting mannose:galactose ratio of 2.39:1. Rats received sodium monoiodoacetate (OA groups, 1 mg/25 μL) or saline (sham group) in the right tibio-tarsal joint. GM-DR (30-300 μg) was administered by intra-articular route at days 14 and 21 after OA induction. Hypernociception was evaluated daily by the measurement of the mechanical threshold required to cause joint flexion and paw withdrawal reflex. The 56-day animal groups were euthanized for joint histopahological analysis using the OARSI score system. Lower doses of GM-DR (30 and 100 μg) promoted antinociception from day 15 until the endpoint at day 56. Joint damage was reduced by GM-DR administration (100 μg) in OA-subjected animals, compared to the vehicle-treated OA group (5.9 ± 1.8 vs 19.0 ± 1.8, respectively, p < 0.05). Conclusion: Both antinociception and damage reduction suggest that Delonix regia galactomannan is a promising approach for osteoarthritis therapy.

Evans Blue Might Produce Pathologically Activated Neuroprotective Effects via the Inhibition of the P2X4R/p38 Signaling Pathway

The main pathological features of ischemic stroke include neuronal damage and blood-brain barrier (BBB) dysfunction. Previous studies have shown that Evans Blue, a dye used to probe BBB integrity, could enter the brain only during the pathological status of ischemic stroke, indicating the potential pathologically activated therapeutic use of this chemical to treat ischemic stroke. In this study, we have reported that Evans Blue could produce in vitro neuroprotective effects against iodoacetic acid (IAA)-induced hypoxia neuronal death in HT22 cells. We further found that P2X purinoreceptor 4 (P2X4R), a subtype of ATP-gated cation channel, was expressed in HT22 cells. Evans Blue could prevent IAA-induced increase of P2X4R mRNA and protein expression. Interestingly, shRNA of P2X4R could protect against IAA-induced activation of p38, and SB203580, a specific inhibitor of p38, could reverse IAA-induced neurotoxicity, indicating that p38 is a downstream signaling molecule of P2X4R. Molecular docking analysis further demonstrated the possible interaction between Evans Blue and the ATP binding site of P2X4R. Most importantly, pre-treatment of Evans Blue could largely reduce neurological and behavioral abnormity, and decrease brain infarct volume in middle cerebral artery occlusion/reperfusion (MCAO) rats. All these results strongly suggested that Evans Blue could exert neuroprotective effects via inhibiting the P2X4R/p38 pathway, possibly by acting on the ATP binding site of P2X4R, indicating that Evans Blue might be further developed as a pathologically activated therapeutic drug against ischemic stroke.

Monohaloacetic Acids and Monohaloacetamides Attack Distinct Cellular Proteome Thiols

Disinfection byproduct (DBP) exposure has been linked to multiple adverse health outcomes. However, the molecular initiating events by which DBPs induce their toxicities remain unclear. Herein, we combined reporter cell lines and activity-based protein profiling (ABPP) chemical proteomics to identify the protein targets of three monohaloacetic acids (mHAAs) and three monohaloacetamides (mHAMs), at the proteome-wide level. While mHAAs and mHAMs have similar potencies in reducing MTT activity, mHAMs induced greater Nrf2-mediated oxidative stress responses, demonstrating their distinct toxicity pathways. ABPP on crude cell lysates suggested that general proteome thiol reactivity correlates with cytotoxicity. Interestingly, live cell ABPP results revealed class-specific proteins attacked by mHAMs or mHAAs. Subsequent proteomic analysis identified >100 unique targets per DBP. mHAMs preferentially react with redox proteins including disulfide oxidoreductase enzymes, accounting for their stronger Nrf2 responses. To further probe alkylation mechanisms, we directly monitored protein adducts and identified 120 and 37 unique peptides with iodoacetamide and iodoacetic acid adducts, respectively. Of the latter, we confirmed glyceraldehyde-3-phosphate dehydrogenase as a key target of IAA, specifically attacking the catalytic Cys 152. This is the first study reporting the distinct cellular protein targets of mHAAs and mHAMs at the proteome-wide level, which highlights their different toxicity pathways despite their similar structures.

Gumiganghwal-tang ameliorates cartilage destruction via inhibition of matrix metalloproteinase

ETHNOPHARMACOLOGICAL RELEVANCE

Kyung-Bang Gumiganghwal-tang tablet (GMGHT) is a standardized Korean Medicine that could treat a cold, headache, arthralgia and fever. Although GMGHT has been used for arthritis-related diseases including a sprain, arthralgia, unspecified arthritis and knee arthritis, there is no pre-clinical evidence to treat osteoarthritis (OA). This study determined the drug dosage and the mechanisms of GMGHT for OA.

METHODS

OA was induced by intra-articular monoiodoacetic acid (MIA) injection in Sprague-Dawley rats. As calculated from the human equivalent dose formula, GMGHT was orally administered at the doses of 9.86, 98.6 and 986 mg/kg for 4 weeks. The arthritis score was performed by a blind test, and histological changes in articular cartilage were indicated by hematoxylin and eosin, Safranin O and toluidine blue staining. SW1353 chondrocytes were stimulated by interleukin (IL)-1β recombinant to analyze the expressions of Type II collagen, matrix metalloproteinases (MMPs) and nuclear factor (NF)-κB.

RESULTS

Rough and punctate surfaces of the femoral condyle induced by MIA, were recovered by the GMGHT treatment. The arthritis score was significantly improved in the 968 mg/kg of GMGHT-treated cartilage. Loss of chondrocytes and proteoglycan were ameliorated at the deep zone of the subchondral bone plate by the GMGHT administration in OA rats. The expression of Type II collagen was increased, while MMP-1, -3 and -13 levels were decreased in the GMGHT-treated SW1353 chondrocytes. In addition, the GMGHT treatment regulated NF-κB activation along with IL-6, transforming growth factor-β and IL-12 production.

CONCLUSIONS

GMGHT promoted the recovery of articular cartilage damage by inhibiting MMPs, accompanied with its anti-inflammatory effects in OA. GMGHT might be an alternative therapeutic treatment for OA.

Contribution of salidroside to the relieve of symptom and sign in the early acute stage of osteoarthritis in rat model

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Rhodiola has been used to treat cough, hemoptysis, fever, pain, bruise and other symptoms which are related to injury and inflammation over a thousand years in traditional Tibetan medicine. Salidroside (p-hydroxyphenethyl-β-D-glucoside) is one of the most potent bioactive ingredients of the genus Rhodiola.

AIM OF STUDY

The present study aimed to explore whether salidroside could alleviate the clinical symptom and sign in the early acute stage of osteoarthritis (OA) in monosodium iodoacetate (MIA) rat model, and its underlying mechanisms.

MATERIALS AND METHODS

Osteoarthritis (OA) was induced in rat knees by intra-articular injection of MIA; simultaneously salidroside was administered by intravenous injection. Pain behaviors were evaluated by knee-bend test, hind limb weight-bearing asymmetry and hind paw mechanical withdrawal threshold. The joint swelling was determined by the difference of knee joint diameter. Inflammatory exudates in synovial fluid were evaluated by leukocyte counting and protein content. Cytokines, chemokines, reactive oxygen species (ROS) and reactive nitrogen species (RNS) markers were determined by Enzyme-linked immunosorbent assay (ELISA) and colorimetric assay in synovial fluid. Pro-inflammatory gene expressions in synovial tissue were detected by quantitative real time RT-PCR (qRT-PCR). Nuclear factor kappa-B (NF-κB) DNA binding assay and western blot were used to determine NF-κB activation and ROS marker protein expression in synovial tissue. Glycosaminoglycan (GAG) content in the cartilage was measured by dimethylmethylene blue method. Hematoxylin and eosin (H&E), Safranin O-fast green and a modified Mankin grading system were used to evaluate the histology of articular cartilage.

RESULTS

Salidroside could alleviate pain and joint swelling in the early acute stage of OA in rat model, reduced the number of leukocytes, total protein content, proinflammatory mediators and ROS/RNS markers in synovial fluid, down regulated the expression of proinflammatory genes in synovium, inhibited the activation of NF- κ B and oxidative stress response in synovium, promoted the synthesis of cartilage GAG, prevented the loss of proteoglycan and chondrocyte degeneration.

CONCLUSIONS

Salidroside effectively alleviates acute symptom and sign of OA in rat model by its anti-inflammatory and antioxidant affects to inhibit synovial inflammation, which provides a new strategy to prevent the onset and progression of OA.

Effect and mechanism of the CACNA2D1-CGRP pathway in osteoarthritis-induced ongoing pain

This study built an OA model in rats by monosodium iodoacetate (MIA) injection to determine the effects and mechanism of the voltage-dependent calcium channel subunit alpha-2/delta-1 (CACNA2D1)-calcitonin gene-related protein (CGRP) pathway in osteoarthritis (OA)-induced ongoing pain. CACNA2D1 expression was measured by qPCR assay, western blotting assay, and immunofluorescence. Pain behaviors in rats were assessed with the measurement of thermal paw withdrawal latency (PWL) and mechanical paw withdrawal threshold (PWT). The expression of CACNA2D1, neuropeptide Y (NPY), activating transcription factor 3 (ATF3), CGRP, protein kinase A (PKA), phosphorylated (p)-PKA, adenylyl cyclase (AC), protein kinase C (PKC), p-PKC, phospholipase C (PLC), and mitogen-activated protein kinase (MAPK) signaling pathway proteins were measured, OA rats had higher CACNA2D1 expression than normal rats. Knockdown of CACNA2D1 led to the elevation of the pain threshold of OA rats, and CACNA2D1 over-expression decreased the pain threshold of normal rats. Moreover, CACNA2D1 over-expression inhibited the expression of CGRP, up-regulated the expressions of NPY, ATF3, p-PKA, AC, p-PKC, PLC, p-Jun N-terminal kinase (JNK), and p-p38, and had no significant effect on phosphorylated extracellular signal-regulated kinase (p-ERK) expression in vivo and in vitro. Using this model of MIA-induced OA, we demonstrated that CACNA2D1 might be involved in the process of pain by modulating the CGRP and AC-PKA/PKC/MAPK signaling pathways in the dorsal root ganglion.

MSC encapsulation in alginate microcapsules prolongs survival after intra-articular injection, a longitudinal in vivo cell and bead integrity tracking study

Mesenchymal stem cells (MSC) are promising candidates for use as a biological therapeutic. Since locally injected MSC disappear within a few weeks, we hypothesize that efficacy of MSC can be enhanced by prolonging their presence. Previously, encapsulation in alginate was suggested as a suitable approach for this purpose. We found no differences between the two alginate types, alginate high in mannuronic acid (High M) and alginate high in guluronic acid (High G), regarding MSC viability, MSC immunomodulatory capability, or retention of capsule integrity after subcutaneous implantation in immune competent rats. High G proved to be more suitable for production of injectable beads. Firefly luciferase-expressing rat MSC were used to track MSC viability. Encapsulation in high G alginate prolonged the presence of metabolically active allogenic MSC in immune competent rats with monoiodoacetate-induced osteoarthritis for at least 8 weeks. Encapsulation of human MSC for local treatment by intra-articular injection did not significantly influence the effect on pain, synovial inflammation, or cartilage damage in this disease model. MSC encapsulation in alginate allows for an injectable approach which prolongs the presence of viable cells subcutaneously or in an osteoarthritic joint. Further fine tuning of alginate formulation and effective dosage for might be required in order to improve therapeutic efficacy depending on the target disease.

Commiphora Extract Mixture Ameliorates Monosodium Iodoacetate-Induced Osteoarthritis

Osteoarthritis (OA) is a chronic inflammatory joint disease that affects millions of elderly people around the world. The conventional treatments for OA consisting of nonsteroidal anti-inflammatory drugs and steroid have negative health consequences, such as gastrointestinal, renal, and cardiac diseases. This study has evaluated the Commiphora extract mixture (HT083) on OA progression as an alternative treatment in animal models. The root of P. lactiflora and the gum resin of C. myrrha have been in use as traditional medicines against many health problems including bone disorders since ancient time. The extracts of P. lactiflora root and C. myrrha gum resin were mixed as 3:1 for their optimal effects. Male Sprague-Dawley rats were injected with monosodium iodoacetate (MIA) into the knee joints to induce the symptoms identical to human OA. HT083 substantially prevented the loss of weight-bearing inflicted with MIA in rats. The MIA-induced cartilage erosion as well as the subchondral bone damage in the rats was also reversed. In addition, the increase of serum IL-1β concentration, a crucial pro-inflammatory cytokine involved in OA progression was countered by HT083. Furthermore, HT083 significantly reduced the acetic acid-induced writhing response in mice. In vitro, HT083 has shown potent anti-inflammatory activities by inhibiting the production of NO and suppressing the interleukin -1β, interleukin -6, cyclooxygenase-2, and inducible nitric oxide synthase expression in lipopolysaccharide -stimulated RAW 264.7 cells. Given its potent analgesic and anti-inflammatory activities in MIA rats and acetic acid-induced writhing in mice, HT083 should be further studied in order to explain its mechanism of actions in alleviating OA pain and inflammation.

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.

Comparison of the therapeutic effect of amniotic fluid stem cells and their exosomes on monoiodoacetate-induced animal model of osteoarthritis

The cartilage tissue engineering associated with stem cell-related therapies is becoming very interesting since adult articular cartilage has limited intrinsic capacity for regeneration upon injury. Amniotic fluid stem cells (AFSC) have been shown to produce exosomes with growth factors and immunomodulating molecules that could stop tissue degradation and induce cartilage repair. Based on this state of the art, the main aim of this study was to explore the efficacy of the secreted exosomes, compared to their AFSC source, in MIA-induced animal model of osteoarthritis mimicking a chronic and degenerative process, where inflammation is also involved and lead to irreversible joint damage. Exosomes, obtained by the use of a commercial kit, prior to the injection in animal knee joints, were characterized for the presence of typical markers and HGF, TGFβ, and IDO. Then, analyses were performed by histology, immunohistochemistry, and behavioral scoring up to 3 weeks after the treatment. Exosome-treated defects showed enhanced pain tolerance level and improved histological scores than the AFSC-treated defects. Indeed by 3 weeks, TGFβ-rich exosome samples induced an almost complete restoration of cartilage with good surface regularity and with the characteristic of hyaline cartilage. Moreover, cells positive for resolving macrophage marker were more easily detectable into exosome-treated joints. Therefore, a modulating role for exosomes on macrophage polarization is conceivable, as demonstrated also by experiments performed on THP1 macrophages. In conclusion, this study demonstrates for the first time the efficacy of human AFSC exosomes in counteract cartilage damage, showing a positive correlation with their TGFβ content.

Development of an ultrathin sheet plastination technique in rat humeral joints with osteoarthritis induced by monosodium iodoacetate for neovascularization study

Injection with monosodium iodoacetate (MIA) is widely used to produce osteoarthritis (OA). Ultrathin sheet plastination has been used to study the morphology of structures, with strong application in anatomical education and research. Our aim was to carry out, for the first time, ultrathin sheet plastination of rat humeral joints to observe the neovascularization provoked by OA. We injected 0.1 mL of MIA into the left humeral joints of ten Sprague-Dawley rats. The right shoulders of the same rats were used as control. Sixteen weeks after the injection, the animals were euthanized and were given an immediate red epoxy resin injection through the thoracic aorta. The samples were fixed in 10% formalin, prior to the plastination process, without decalcification. Samples were dehydrated with acetone (100%) at - 25 °C, for 10 days. Later, for degreasing, samples were immersed in methylene chloride at room temperature during 1 week. Forced impregnation was performed inside a stove within a vacuum chamber. The plastinated blocks obtained were cut with a slow velocity diamond blade saw. Slices were placed in curing chambers to achieve curing and final tissue transparentation. 230 μm thickness slices were obtained. The slices were analyzed under magnifying glass and microscope, achieving visualization of OA neovascularization. The cartilage affected by OA loses its ability to remain avascular, and blood vessels invade it from the subchondral bone to the calcified and uncalcified cartilage. Ultra-thin sheet plastination is useful to observe articular cartilage neovascularization, caused by OA induced with MIA in humeral rat joint.

Agkistrodon ameliorates pain response and prevents cartilage degradation in monosodium iodoacetate-induced osteoarthritic rats by inhibiting chondrocyte hypertrophy and apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Osteoarthritis (OA), characterized by joint pain and cartilage degradation, is the most common form of joint disease worldwide but with no satisfactory therapy available. The ethanol extract of Agkistrodon acutus (EAA) has been widely used as a traditional Chinese medicine (TCM) for the treatment of arthralgia and inflammatory diseases, but there is no report regarding its efficacy on OA to date. Here, we determined the effects of EAA on the pain behavior and cartilage degradation in vivo and clarified its target genes and proteins associated with chondrocyte hypertrophy and apoptosis in vitro.

MATERIALS AND METHODS

In vivo OA model was established by intra-articular injection (1.5 mg) of monosodium iodoacetate (MIA) into rats and weekly treated by intra-articular administration of EAA at a dose range from 0.3 to 0.9 g/kg for four weeks. The pain behavior parameters, thermal withdrawal latency (TWL) and mechanical withdrawal threshold (MWT) were tested before and after the treatment. Then histopathologic, immunohistochemical and TUNEL analyses of the articular cartilage were conducted, followed by Mankin's scoring. In vitro, the effects of EAA on chondrocytes were evaluated via assays of cell viability, immunofluorescence, real time PCR, and Western blot. UPLC-MS was applied to determine the chemical composition of EAA.

RESULTS

The animal data showed that EEA not only attenuated the pain hypersensitivity but also blocked the cartilage degeneration by improving chondrocyte survival and suppressing chondrocyte apoptosis at a dose-dependent manner in OA rats. Furthermore, EAA remarkably restored the abnormal expression of collagen type II (Col2) and matrix metalloproteinase-13 (MMP13) in cartilage of OA rats. The cellular data showed that EAA significantly increased the cell viability of chondrocytes against OA-like damage and restored the abnormal expressions of Col2 and MMP13 in damaged chondrocytes. The molecular data showed that EAA significantly restored the abnormal mRNA expressions of Col2, Col10, MMP2 and MMP13 as well as the abnormal protein expressions of MMP13, PARP (total and cleaved) in chondrocytes under pathological condition. UPLC-MS analysis showed the known main components of EAA, including amino acides (glycine, L-aspartic acid, L-glutamic acid, and L-hydroxyproline), nucleoside (uridine), purines (xanthine and hypoxanthine), and pyrimidine (uracil).

CONCLUSIONS

Our data demonstrate that EAA exerts antinociceptive and chondroprotective effects on OA through suppressing chondrocyte hypertrophy and apoptosis with restoration of the molecular expressions of anabolism and catabolism in chondrocytes. It provides a promising TCM candidate of novel agent for OA therapy.

Iodoacetic Acid Disrupting the Thyroid Endocrine System in Vitro and in Vivo

Exposure to drinking water disinfection byproducts (DBPs) is potentially associated with adverse developmental effects. Iodoacetic acid (IAA), an unregulated DBP, has been shown to be cytotoxic, mutagenic, genotoxic, and tumorigenic. However, its endocrine-disrupting effects remain unknown. This study evaluated the IAA-induced disruption of the thyroid endocrine system using in vitro and in vivo assays. Rat pituitary tumor GH3 cells were treated with IAA in the presence and absence of triiodothyronine (T3). IAA exposure significantly reduced T3-activated GH3 cell proliferation, indicating the antagonistic activity of IAA in vitro. Sprague-Dawley rats were also subjected to IAA treatment through oral gavage for 28 consecutive days. IAA exposure significantly down-regulated the mRNA expression levels of the thyrotropin receptor (TSHR), the sodium/iodide symporter (NIS), and type I deiodinase and simultaneously reduced the protein expression levels of TSHR and NIS. IAA exposure decreased T3 levels but increased the weights of hypothalamus and the levels of thyrotropin releasing hormone and thyrotropin. In addition, IAA induced the formation of smaller and more depleted follicles or even vacuolization in the thyroid. These results suggested that IAA potentially disrupts the thyroid endocrine system both in vitro and in vivo.

Protective Effects of Peucedanum japonicum Extract against Osteoarthritis in an Animal Model Using a Combined Systems Approach for Compound-Target Prediction

Peucedanum japonicum Thunberg is an herbal medicine used to treat neuralgia, rheumatoid arthritis, and inflammatory-related diseases. However, its effects on osteoarthritis (OA) and its regulatory mechanisms have not been investigated by network analysis. Here, we investigated the pharmacological effects of Peucedanum japonicum extract (PJE) on OA, by combining in vivo effective verification and network pharmacology prediction. Rats in which OA was induced by monosodium iodoacetate (MIA) were treated with PJE (200 mg/kg), and histopathological parameters, weight bearing distribution and inflammatory factors in serum and joint tissue were measured after 28 days of treatment. Additionally, in silico network analysis was used to predict holistic OA regulatory mechanisms of PJE. The results showed that PJE exerted potential protective effects by recovering hind paw weight bearing distribution, alleviating histopathological features of cartilage and inhibiting inflammatory mediator levels in the OA rat model. Furthermore, network analysis identified caspase-3 (CASP3), caspase-7 (CASP7), and cytochrome P450 2D6 (CYP2D6) as potential target genes; in addition, the TNF (Tumor necrosis factor) signaling pathway was linked to OA therapeutic action. Our combined animal OA model and network analysis confirmed the therapeutic effects of PJE against OA and identified intracellular signaling pathways, active compounds and target genes linked to its therapeutic action.

In Vitro and In Vivo Anti-Osteoarthritis Effects of 2,3,5,4'-Tetrahydroxystilbene-2-O-β-d-Glucoside from Polygonum Multiflorum

Polygonum multiflorum Thunb. is a traditional herbal medicine that is rich in polyphenols. The major compound, 2,3,5,4'-tetrahydroxystilbene-2-O-β-d-glucoside (THSG) has many pharmacological activities, such as antioxidative and free radical-scavenging properties, and the abilities to reduce hyperlipidemia, prevent lipid peroxidation, and protect the cardiovascular system. In this study, the anti-osteoarthritis (OA) effects of THSG were explored using in vitro and in vivo models. THSG inhibited nitric oxide (NO) and prostaglandin E₂ (PGE₂) production and inducible NO synthase (iNOS) and cyclooxygenase-2 expressions by lipopolysaccharide-stimulated RAW 264.7 cells. On the other hand, THSG inhibited PGE₂ production and iNOS and matrix metalloproteinase-13 expressions by interleukin-1β-stimulated primary rat chondrocytes. Through a mono-iodoacetate-induced rat OA model assay, THSG reduced paw edema and improved the weight-bearing distribution. Therefore, THSG has anti-inflammatory activity and could be applied as a lead compound for the development as an OA drug.

Cell-type-specific gene expression patterns in the knee cartilage in an osteoarthritis rat model

Osteoarthritis (OA) is a chronic degenerative disease that leads to joint failure, pain, and disability. Gene regulation is implicated as a driver of the imbalance between the expression of catabolic and anabolic factors that eventually leads to the degeneration of osteoarthritic cartilage. In our model, knee-joint OA was induced in male Wistar rats by intra-articular sodium monoiodoacetate (MIA) injections. Whole-genome microarrays were used to analyse the alterations in gene expression during the time-course of OA development (at 2, 14, and 28 days post-injection) in rat knee joints. The identified co-expressed groups of genes were analysed for enriched regulatory mechanisms, functional classes, and cell-type-specific expression. This analysis revealed 272 regulated transcripts (ANOVA FDR < 0.1% and fold > 2). Functionally, the five major gene expression patterns (A–E) were connected to PPAR signalling and adipogenesis (in cluster A), WNT signalling (in cluster B), endochondral ossification (in cluster C), matrix metalloproteinases and the ACE/RAGE pathway (in cluster D), and the Toll-like receptor, and IL-1 signalling pathways (in cluster E). Moreover, the dynamic profiles of these transcriptional changes were assigned to cellular compartments of the knee joint. Classifying the molecular processes associated with the development of cartilage degeneration provides novel insight into the OA disease process. Our study identified groups of co-regulated genes that share functional relationships and that may play an important role in the early and intermediate stages of OA.

Novel role of CCN3 that maintains the differentiated phenotype of articular cartilage

Knowledge of the microenvironment of articular cartilage in health and disease is the key to accomplishing fundamental disease-modifying treatments for osteoarthritis. The proteins comprising the CCN Family are matricellular proteins with a remarkable relevance within the context of cartilage metabolism. CCN2 displays a great capability for regenerating articular cartilage, and CCN3 has been shown to activate the expression of genes related to articular chondrocytes and to repress genes related to endochondral ossification in epiphyseal chondrocytes. Moreover, mice lacking CCN3 protein have been shown to display ostearthritic changes in their knee articular cartilage. In this study, we employed a monoiodoacetic acid (MIA)-induced osteoarthritic model to investigate whether osteoarthritic changes in the cartilage are reciprocally accompanied by CCN3 down-regulation and an inducible overexpression system to evaluate the effects of CCN3 on articular chondrocytes in vitro. Finally, we also investigated the effects of exogenous CCN3 in vivo during the early stages of MIA-induced osteoarthritis. We discovered that CCN3 is expressed by articular chondrocytes in normal rat knees, whereas it is rapidly down-regulated in osteoarthritic knees. In vitro, we also discovered that CCN3 increases the proteoglycan accumulation, the gene expression of type II collagen, tenascin-C and lubricin, as well as the protein production of tenascin-C and lubricin in articular chondrocytes. In vivo, it was discovered that exogenous CCN3 increased tidemark integrity and produced an increased production of lubricin protein. The potential utility of CCN3 as a future therapeutic agent and possible strategies to improve its therapeutic functions are also discussed.

Acute effect of Capparis spinosa root extracts on rat articular pain

ETHNOPHARMACOLOGICAL RELEVANCE

Capparis spinosa L. originates from dry regions of Asia and Mediterranean basin. In traditional medicine of these areas, infusions from caper root are considered to be beneficial for the treatment of rheumatism, gout and against abdominal pains.

AIM OF THE STUDY

To evaluate the pain relieving properties of a Syrian cultivar of Capparis spinosa roots in rat models of osteoarthritis and rheumatoid arthritis.

MATERIALS AND METHODS

Decoction (DEC) and hydroalcoholic extract (EtH₂O) were obtained from powdered roots; the latter was further separated in CH₂Cl₂ and aqueous (H₂O-Res) fractions. The extracts were characterized in terms of spermidine alkaloids by HPLC/DAD/MS and stachydrine by NMR. Different amount of free and glycosilated forms of capparispine and analogues (from 0.5% w/w for DEC up to 7.6% w/w for CH₂Cl₂ fraction) were detected. Rat models of rheumatoid arthritis and osteoarthritis were induced by the intra-articular administration of Complete Freund's Adjuvant (CFA) or monosodium iodoacetate (MIA), respectively.

RESULTS

Fourteenth days after CFA or MIA injection, the different preparations of Capparis spinosa (3, 30, 100 and 300mgkg^-1) were acutely administered p.o.. Powdered roots (300mgkg^-1), DEC (100mgkg^-1), and EtH₂O (300mgkg^-1) significantly reduced hypersensitivity to mechanical noxious stimuli as well as spontaneous pain evaluated as hind limb bearing alterations in both models. The CH₂Cl₂ and the H₂O-Res (30mgkg^-1) were the most potent in reverting pain threshold alterations despite the different content of free alkaloids.

CONCLUSIONS

Capparis spinosa extracts relieved pain related to rheumatoid arthritis and osteoarthritis after single administration. A synergistic effect due to a specific "phytochemical mixture" is suggested.

Anti-Osteoarthritic Effects of the Litsea japonica Fruit in a Rat Model of Osteoarthritis Induced by Monosodium Iodoacetate

Osteoarthritis (OA) is a degenerative chronic disease that affects various tissues surrounding the joints, such as the subchondral bone and articular cartilage. The onset of OA is associated with uncontrolled catabolic and anabolic remodeling processes of the joints, including the cartilage and subchondral bone, to adapt to local biological and biochemical signals. In this study, we determined whether 70% ethanolic (EtOH) extract of Litsea japonica fruit (LJFE) had beneficial effects on the articular cartilage, including structural changes in the tibial subchondral bone, matrix degradation, and inflammatory responses, in OA by using a rat model of monosodium iodoacetate-induced OA. Our results showed that administration of LJFE increased the bone volume and cross-section thickness, but the mean number of objects per slice in this group was lower than that in the OA control (OAC) group. In addition, the LJFE decreased the expression of inflammatory cytokines. Compared to the OAC group, the group treated with high doses of LJFE (100 and 200 mg/kg) showed a more than 80% inhibition of the expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases. Our results suggest that LJFE can be used as a potential anti-osteoarthritic agent.

Development of monosodium acetate-induced osteoarthritis and inflammatory pain in ageing mice

Most conditions associated with ageing result from an age-related loss in the function of cells and tissues that maintain body homeostasis. In osteoarthritis (OA) patients, an inadequate response to stress or joint injury can lead to tissue destruction which can result in chronic pain. Here, we evaluated the development of monoiodoacetate (MIA)-induced OA in 3-, 15- and 22-month-old mice and assessed the pain-like behaviours and the spinal microglial changes associated with MIA administration. We observed that in aged mice, nocifensive behaviour was significantly attenuated in comparison to young adults despite similar knee joint pathology. Specifically referred mechanical allodynia associated with the MIA initial inflammatory phase (0-10 days) was significantly attenuated in 22-month-old mice. In contrast, the late phase of MIA-induced mechanical allodynia was comparable between age groups. Significant increase of microglia cell numbers was detected in 3, but not 15- and 22-month-old spinal cords. Furthermore, in the zymosan model of acute inflammation, mechanical allodynia was attenuated, and microglial response was less robust in 22 compared to 3-month-old mice. This study suggests that nocifensive responses to damaging stimuli are altered with advancing age and microglial response to peripheral damage is less robust.

Dissecting the contribution of knee joint NGF to spinal nociceptive sensitization in a model of OA pain in the rat

OBJECTIVE

Although analgesic approaches targeting nerve growth factor (NGF) for the treatment of osteoarthritis (OA) pain remain of clinical interest, neurophysiological mechanisms by which NGF contribute to OA pain remain unclear. We investigated the impact of local elevation of knee joint NGF on knee joint, vs remote (hindpaw), evoked responses of spinal neurones in a rodent model of OA pain.

DESIGN

In vivo spinal electrophysiology was carried out in anaesthetised rats with established pain behaviour and joint pathology following intra-articular injection of monosodium iodoacetate (MIA), vs injection of saline. Neuronal responses to knee joint extension and flexion, mechanical punctate stimulation of the peripheral receptive fields over the knee and at a remote site (ipsilateral hind paw) were studied before, and following, intra-articular injection of NGF (10 μg/50 μl) or saline.

RESULTS

MIA-injected rats exhibited significant local (knee joint) and remote (lowered hindpaw withdrawal thresholds) changes in pain behaviour, and joint pathology. Intra-articular injection of NGF significantly (P < 0.05) increased knee extension-evoked firing of spinal neurones and the size of the peripheral receptive fields of spinal neurones (100% increase) over the knee joint in MIA rats, compared to controls. Intra-articular NGF injection did not significantly alter responses of spinal neurones following noxious stimulation of the ipsilateral hind paw in MIA-injected rats.

CONCLUSION

The facilitatory effects of intra-articular injection of NGF on spinal neurones receiving input from the knee joint provide a mechanistic basis for NGF mediated augmentation of OA knee pain, however additional mechanisms may contribute to the spread of pain to remote sites.

Silymarin potentiates the anti-inflammatory effects of Celecoxib on chemically induced osteoarthritis in rats

Silymarin (SMN) is used as an antioxidant complex to attenuate the pro-oxidant effects of toxic agents. This study was carried out to investigate the effect of SMN, Celecoxib (CLX) individually and in combination on monoiodoacetate (MIA)-induced osteoarthritis (OA) in rat. Forty adult Wistar rats were assigned to control and test groups. Animals in the test group following OA induction were subdivided into 4 subgroups according to the treatment profile: OA(+); received saline normal (5ml/kg, b.w.), OA(+)CLX(+); received CLX (100mg/kg, orally), OA(+)SMN(+), received SMN (50mg/kg, orally), and OA(+)CLX(+)SMN(+), received both CLX and SMN. The animals received test compounds by gastric gavage for 14 consecutive days. Animals in the OA(+) group showed a significant (p<0.01) increase in serum and synovial levels of IL-1β, while both test compounds reduced the IL-1β level. Both CLX and SMN lowered the OA-increased level of malondialdehyde by 77% and 79% and nitric oxide by 73% and 76%, respectively, in the synovial tissue. Special safranin O (SO) histopathological staining revealed that CLX and SMN improved the MIA-induced destruction and fibrillation in cartilage surface. CLX and SMN regulated the MIA-up regulated IL-1β at mRNA level. The combination therapy resulted in an additive effect between CLX and SMN in biochemical, histopathological and molecular assays. These findings suggest that SMN exerts anti-inflammatory effect and also potentiates the anti-inflammatory effect of CLX on MIA-induced OA. The anti-inflammatory property of SMN may attribute to its antioxidant capacity, which affects the proinflammatory mediators at translational and transcriptional level.

Sequential alterations in catabolic and anabolic gene expression parallel pathological changes during progression of monoiodoacetate-induced arthritis

Chronic inflammation is one of the major causes of cartilage destruction in osteoarthritis. Here, we systematically analyzed the changes in gene expression associated with the progression of cartilage destruction in monoiodoacetate-induced arthritis (MIA) of the rat knee. Sprague Dawley female rats were given intra-articular injection of monoiodoacetate in the knee. The progression of MIA was monitored macroscopically, microscopically and by micro-computed tomography. Grade 1 damage was observed by day 5 post-monoiodoacetate injection, progressively increasing to Grade 2 by day 9, and to Grade 3-3.5 by day 21. Affymetrix GeneChip was utilized to analyze the transcriptome-wide changes in gene expression, and the expression of salient genes was confirmed by real-time-PCR. Functional networks generated by Ingenuity Pathways Analysis (IPA) from the microarray data correlated the macroscopic/histologic findings with molecular interactions of genes/gene products. Temporal changes in gene expression during the progression of MIA were categorized into five major gene clusters. IPA revealed that Grade 1 damage was associated with upregulation of acute/innate inflammatory responsive genes (Cluster I) and suppression of genes associated with musculoskeletal development and function (Cluster IV). Grade 2 damage was associated with upregulation of chronic inflammatory and immune trafficking genes (Cluster II) and downregulation of genes associated with musculoskeletal disorders (Cluster IV). The Grade 3 to 3.5 cartilage damage was associated with chronic inflammatory and immune adaptation genes (Cluster III). These findings suggest that temporal regulation of discrete gene clusters involving inflammatory mediators, receptors, and proteases may control the progression of cartilage destruction. In this process, IL-1β, TNF-α, IL-15, IL-12, chemokines, and NF-κB act as central nodes of the inflammatory networks, regulating catabolic processes. Simultaneously, upregulation of asporin, and downregulation of TGF-β complex, SOX-9, IGF and CTGF may be central to suppress matrix synthesis and chondrocytic anabolic activities, collectively contributing to the progression of cartilage destruction in MIA.

Purification and properties of cysteine protease from rhizomes of Curcuma longa (Linn.)

BACKGROUND

Turmeric rhizome (Curcuma domestica Linn.) contains proteases and has proteolytic activity. Curcumin from turmeric rhizomes has been used for healing many ailments, including cancer. The purpose of this study was to purify turmeric protease and to research their biochemical characteristics [corrected].

RESULTS

Cysteine protease from C. domestica has been purified to homogeneity using acetone precipitation followed by preparatory native polyacrylamide gel electrophoresis (PAGE). This protocol resulted in six fold purification with 28% final recovery. The purified turmeric protease showed a prominent single peak and band on high-performance liquid chromatography and sodium dodecyl sulfate-PAGE, respectively, and an estimated molecular weight of 43 KDa, and exhibited optimal activity between 37 and 60 degrees C. The protease activity of the turmeric protease was significantly inhibited by iodoacetic acid. The turmeric protease had higher alanine and glutamate content and cleaved synthetic peptides N-Cbz-Ile-Pro and N-Cbz-Phe-Leu in a time-dependent manner. Peptide mass fingerprint using matrix-assisted laser desorption/ionization-time of flight mass spectroscopy revealed peptide matches to proteasome subunit alpha type 3 of Oryza sativa ssp. japonica (Rice). The turmeric protease showed antifungal activity at 10 microg mL(-1) towards pathogens Pythium aphanidermatum, Trichoderma viride and Fusarium sp.

CONCLUSION

Cysteine addition significantly activated turmeric protease. The protease inhibition test suggested that turmeric protease belonged to the cysteine type. The biochemical characteristics of turmeric protease described in this paper can provide useful information for potential end uses of turmeric protease for pharmaceutical industry applications such as therapeutics.

Evidence for a conformational change in subunit III of bovine heart mitochondrial cytochrome c oxidase

The role of subunit III in the function of mitochondrial cytochrome c oxidase is not clearly understood. Previous work has shown that chemical modification of subunit III with N,N'-dicyclohexylcarbodiimide (DCCD) reduced the proton-pumping efficiency of the enzyme by an unknown mechanism. In the current work, we have employed biochemical approaches to determine if a conformational change is occurring within subunit III after DCCD modification. Control and DCCD modified beef heart enzyme were subjected to limited proteolysis in nondenaturing detergent solution. Subunit III in DCCD treated enzyme was more susceptible to chymotrypsin digestion than subunit III in the control enzyme. We also labeled control and DCCD-modified enzyme with iodoacetyl-biotin, a sulfhydryl reagent, and found that subunit III of the DCCD-modified enzyme was more reactive when compared to subunit III of the control enzyme, indicating an increase in reactivity of subunit III upon DCCD binding. The cross linking of subunit III of the enzyme induced by the heterobifunctional reagent, N-succinimidyl(4-azidophenyl -1,3'-dithio)-propionate (SADP), was inhibited by DCCD modification, suggesting that DCCD binding prevents the intersubunit cross linking of subunit III. Our results suggest that DCCD modification of subunit III causes a conformational change, which most likely disrupts critical hydrogen bonds within the subunit and also those at the interface between subunits III and I in the enzyme. The conformational change induced in subunit III by covalent DCCD binding is the most likely mechanism for the previously observed inhibition of proton-pumping activity.

Bacteriophage formation without bacterial growth; the effect of iodoacetate, fluoride, gramicidin, and azide on the formation of bacteriophage

1. Iodoacetate, fluoride, and azide have been found to prevent the formation of phage and to inhibit the synthesis of ATP by Staphylococcus muscae. It is suggested that energy-rich phosphate is needed for the synthesis of phage. 2. Gramicidin prevented the formation of phage. 3. No differences were found between normal bacteria and phage-infected bacteria in the inorganic phosphate, adenosinetriphosphate, ribonucleic acid, and desoxyribonucleic acid content of the cells. 4. The mechanism of phage formation is discussed.

Structural pathology in a rodent model of osteoarthritis is associated with neuropathic pain: increased expression of ATF-3 and pharmacological characterisation

Intra-articular injection of mono-iodoacetate (MIA) in the rat knee joint induces a histopathology with similarities to osteoarthritis (OA). Typically, a synovitis (days 1-3) is observed followed by thinning of articular cartilage and subsequent lesion of subchondral bone at days 8-14 onwards. Behaviourally, weight-bearing asymmetry is observed, which is sensitive to anti-inflammatory pharmacology at early but not later (days 14+) time points. As subchondral bone is densely innervated, an intriguing possibility is that focal bone pathology may cause neuropathy in this model. In male Wistar rats, activating transcription factor (ATF)-3-immunofluorescence was used as a marker of nerve injury in lumber (L)4 and L5 dorsal root ganglia of the ipsilateral knee. Significantly increased ATF-3-immunoreactivity following MIA treatment was measured in L5 on days 8 and 14 (P<0.05, Kruskal-Wallis and Mann-Whitney U-test), compared to saline controls. Furthermore, in an additional study animals were orally dosed vehicle (5 ml/kg), naproxen (0.3-10 mg/kg), celecoxib (1-10 mg/kg), amitriptyline (3-30 mg/kg) and gabapentin (10-100mg/kg) and evaluated for weight-bearing asymmetry on days 14, 21 and 28 post-MIA. Significant resolution of weight-bearing was observed at high and intermediate doses of amitriptyline and gabapentin at all time points (P<0.05, ANOVA, post-hoc Bonferroni's, vs pre-dose measurements). Transient and weak effects were observed with naproxen (10mg/kg) on days 14 and 28, whereas celecoxib showed no significant effects. Collectively, these data suggest that this putative model of OA is associated with an early phase neuropathy in the L5 innervation territory of the knee.