Development of a novel animal model of lumbar vertebral endplate lesion by intervertebral disk injection of monosodium iodoacetate in rats.

PURPOSE: Vertebral endplate lesions (EPLs) caused by severe disk degeneration are associated with low back pain. However, its pathophysiology remains unclear. In this study, we aimed to develop a vertebral EPL rat model mimicking severe intervertebral disk (IVD) degeneration by injecting monosodium iodoacetate (MIA) into the IVDs and evaluating it by assessing pain-related behavior, micro-computed tomography (CT) findings, and histological changes. METHODS: MIA was injected into the L4-5 and L5-6 IVDs of Sprague-Dawley rats. Their behavior was examined by measuring the total distance traveled and the total number of rearing in an open square arena. Bone alterations and volume around the vertebral endplate were assessed using micro-CT. Safranin-O staining, immunohistochemistry, and tartrate-resistant acid phosphatase (TRAP) staining were performed for histological assessment. RESULTS: The total distance and number of rearing times in the open field were significantly reduced in a time-dependent manner. Micro-CT revealed intervertebral osteophytes and irregularities in the endplates at 12 weeks. The bone volume/tissue volume (BV/TV) around the endplates significantly increased from 6 weeks onward. Safranin-O staining revealed severe degeneration of IVDs and endplate disorders in a dose- and time-dependent manner. Calcitonin gene-related peptide-positive nerve fibers significantly increased from 6 weeks onward. However, the number of osteoclasts decreased over time. CONCLUSION: Our rat EPL model showed progressive morphological vertebral endplate changes in a time- and concentration-dependent manner, similar to the degenerative changes in human IVDs. This model can be used as an animal model of severe IVD degeneration to better understand the pathophysiology of EPL.

Platelet-rich plasma alleviates neuropathic pain in osteoarthritis by downregulating microglial activation.

BACKGROUND: The development of neuropathic pain (NP) is one of the reasons why the pain is difficult to treat, and microglial activation plays an important role in NP. Recently, platelet-rich plasma (PRP) has emerged as a novel therapeutic method for knee osteoarthritis (KOA). However, it's unclarified whether PRP has analgesic effects on NP induced by KOA and the underlying mechanisms unknown. PURPOSE: To observe the analgesic effects of PRP on NP induced by KOA and explore the potential mechanisms of PRP in alleviating NP. METHODS: KOA was induced in male rats with intra-articular injections of monosodium iodoacetate (MIA) on day 0. The rats received PRP or NS (normal saline) treatment at days 15, 17, and 19 after modeling. The Von Frey and Hargreaves tests were applied to assess the pain-related behaviors at different time points. After euthanizing the rats with deep anesthesia at days 28 and 42, the corresponding tissues were taken for subsequent experiments. The expression of activating transcription factor 3 (ATF3) in dorsal root ganglia (DRG) and ionized-calcium-binding adapter molecule-1(Iba-1) in the spinal dorsal horn (SDH) was detected by immunohistochemical staining. In addition, the knee histological assessment was performed by hematoxylin-eosin (HE) staining. RESULTS: The results indicated that injection of MIA induced mechanical allodynia and thermal hyperalgesia, which could be reversed by PRP treatment. PRP downregulated the expression of ATF3 within the DRG and Iba-1 within the SDH. Furthermore, an inhibitory effect on cartilage degeneration was observed in the MIA + PRP group only on day 28. CONCLUSION: These results indicate that PRP intra-articular injection therapy may be a potential therapeutic agent for relieving NP induced by KOA. This effect could be attributed to downregulation of microglial activation and reduction in nerve injury.

[Hematological toxicity of disinfection by-product iodoacetic acid].

OBJECTIVE: To clarify the effect of iodoacetic acid(IAA) on the blood system and electrolyte balance, hence further study the intrinsic relation of blood routine parameters and electrolyte levels, major hematological toxicity effects and their pattern after IAA treatment. METHODS: Forty-eight 21-day-old male SPF grade Sprague-Dawley(SD) rats were gavaged with 0, 6.25, 12.5 and 25 mg/kg IAA for 31 days. After detections of blood routine and plasma inorganic ion levels, Spearman correlation coefficients were performed to evaluate their relationship. Changes in ferritin, transferrin, hepcidin, C-reactive protein and glyceraldehyde-3-phosphate dehydrogenase(GAPDH) were assessed by enzyme-linked immunosorbent assays. The EDock bioinformatics tool was applied to docking model of IAA and GAPDH. RESULTS: Compared to the control, high-dose IAA exposure had obvious inhibition effect on rat leukocytes with the total number declined by 51.12%, and neutrophils were particularly sensitive to IAA with the number reduced by 73.66%(P<0.01), and rat erythrocytes exhibited a small cell low pigment effect with hemoglobin and hematocrit decreased by 8.60% and 8.70%, respectively(P<0.05). But IAA had little effects on the platelet. Plasma iron, phosphorus, zinc and potassium levels were repressed significantly, while chlorine, sodium and magnesium levels were elevated obviously through IAA exposure. However, plasma calcium levels were hardly affected by IAA. In comparison with the control, iron levels declined by 67.09%, whereas magnesium levels increased by 131.82% in the high-dose group(P<0.01). Overall, correlation analyses uncovered that plasma iron metabolism was most strongly and positively correlated with levels of leukocyte, erythrocyte and platelet system parameters after IAA exposure, and the correlation coefficients of leukocyte number, mean hemoglobin content and mean erythrocyte volume were 0.637, 0.410 and 0.365, respectively(P<0.05). Compared to the control, in the high-dose IAA group, the plasma content of C-reactive protein was significantly upregulated by 13.30%(P<0.05), and plasma levels of transferrin and ferromodulin were also respectively elevated by 12.73% and 11.02%(P<0.05). But plasma levels of ferritin and GAPDH did not differ between groups. The docking model exhibited that IAA could bind to the 150 Cys active site of rat GAPDH did. CONCLUSION: IAA not only had toxic effects on rat leukocytes and the plasma electrolyte balance, but also generated inflammation and iron deficiency, leading to smaller erythrocytes and lower pigment.

Transcranial Direct Current Stimulation Attenuates the Chronic Pain of Osteoarthritis in Rats via Reducing NMDAR2B Expressions in the Spinal Cord.

OBJECTIVES: Osteoarthritis (OA) has been the common cause to lead to chronic pain. Transcranial direct current stimulation (tDCS) is effective in the treatment of chronic pain, but its analgesic mechanism is still unclear. This study observed the analgesic effects of tDCS in rats to explore the top-down analgesic modulation mechanism of tDCS. METHODS: Monosodium iodoacetate (MIA) was used to establish OA chronic pain model. After 21 days, the rats received tDCS for 14 consecutive days (20 min/day). We assessed the pain-related behaviors of rats at different time points. Western blot and Immunohistochemistry were performed to observe the expression level of NMDAR2B in the spinal cord after tDCS treatment. RESULTS: After MIA injection, rats developed apparent mechanical hyperalgesia and thermal hyperalgesia. However, the pain-related behaviors of rats were significantly improved after tDCS treatment. In addition, the expression of NMDAR2B and the proportion of positive stained cells of NMDAR2B were reversed by tDCS treatment. CONCLUSIONS: The results demonstrated that tDCS can attenuate OA-induced chronic pain in rats via reducing NMDAR2B expressions in the spinal cord. We believe that this may be the result of tDCS participating in the top-down modulation of pain pathway in the endogenous analgesic system.

Potentiating TRPA1 by Sea Anemone Peptide Ms 9a-1 Reduces Pain and Inflammation in a Model of Osteoarthritis.

Progressive articular surface degradation during arthritis causes ongoing pain and hyperalgesia that lead to the development of functional disability. TRPA1 channel significantly contributes to the activation of sensory neurons that initiate neurogenic inflammation and mediates pain signal transduction to the central nervous system. Peptide Ms 9a-1 from the sea anemone Metridium senile is a positive allosteric modulator of TRPA1 and shows significant anti-inflammatory and analgesic activity in different models of pain. We used a model of monosodium iodoacetate (MIA)-induced osteoarthritis to evaluate the anti-inflammatory properties of Ms 9a-1 in comparison with APHC3 (a polypeptide modulator of TRPV1 channel) and non-steroidal anti-inflammatory drugs (NSAIDs) such as meloxicam and ibuprofen. Administration of Ms 9a-1 (0.1 mg/kg, subcutaneously) significantly reversed joint swelling, disability, thermal and mechanical hypersensitivity, and grip strength impairment. The effect of Ms 9a-1 was equal to or better than that of reference drugs. Post-treatment histological analysis revealed that long-term administration of Ms9a-1 could reduce inflammatory changes in joints and prevent the progression of cartilage and bone destruction at the same level as meloxicam. Peptide Ms 9a-1 showed significant analgesic and anti-inflammatory effects in the model of MIA-induced OA, and therefore positive allosteric modulators could be considered for the alleviation of OA symptoms.

Drinking water disinfection byproduct iodoacetic acid affects thyroid hormone synthesis in Nthy-ori 3-1 cells.

Iodoacetic acid (IAA) is an emerging and the most genotoxic iodinated disinfection byproduct to date. IAA can disrupt the thyroid endocrine function in vivo and in vitro, but the underlying mechanisms remain unclear. In this work, transcriptome sequencing was used to investigate the effect of IAA on the cellular pathways of human thyroid follicular epithelial cell line Nthy-ori 3-1 and determine the mechanism of IAA on the synthesis and secretion of thyroid hormone (TH) in Nthy-ori 3-1 cells. Results of transcriptome sequencing indicated that IAA affected the TH synthesis pathway in Nthy-ori 3-1 cells. IAA reduced the mRNA expression of thyroid stimulating hormone receptor, sodium iodide symporter, thyroid peroxidase, thyroglobulin, paired box 8 and thyroid transcription factor-2, inhibited the cAMP/PKA pathway and Na+-K+-ATPase, and decreased the iodine intake. The results were confirmed by our previous findings in vivo. Additionally, IAA downregulated glutathione and the mRNA expression of glutathione peroxidase 1, leading to increased reactive oxygen species production. This study is the first to elucidate the mechanisms of IAA on TH synthesis in vitro. The mechanisms are associated with down-regulating the expression of genes related to TH synthesis, inhibiting iodine uptake, and inducing oxidative stress. These findings may improve future health risk assessment of IAA on thyroid in human.

Rotator cuff muscle degeneration in a mouse model of glenohumeral osteoarthritis induced by monoiodoacetic acid.

BACKGROUND: Osteoarthritis (OA) is a disease of joint degeneration and impaired function. Muscle atrophy, fatty infiltration, and fibrosis are degenerative features of muscle injury and predict poor outcomes in some degenerative and exercise-related injuries. Patients with glenohumeral joint OA usually have rotator cuff muscle degeneration, even though the rotator cuff is intact. However, the mechanism and correlation between OA and degeneration of muscles around joints are still unknown. METHODS: Forty-five 12-month-old C57BL/6J mice received a single injection of monoiodoacetic acid into the right glenohumeral joint. The sham group was injected with saline on the same day in the right glenohumeral joint. Three and 6 weeks after the operation, gait analysis was conducted to evaluate the function of the forelimb. Then, the shoulder joint and supraspinatus muscle were collected for histologic staining, reverse transcription quantitative polymerase chain reaction, and biomechanics test. Correlations between fat area fraction in muscle, percentage wet muscle weight change or Osteoarthritis Research Society International score, and gait analysis/muscle mechanics tests were assessed using Pearson's correlation coefficient or Spearman's correlation coefficient. RESULTS: Compared with the sham group, the monoiodoacetic acid group developed significant glenohumeral joint OA and the supraspinatus muscle developed significant fatty infiltration and muscle atrophy. Shoulder function correlated with glenohumeral joint OA/rotator cuff muscle severity, weight loss, and fatty infiltration. CONCLUSION: In mice, glenohumeral joint OA can lead to rotator cuff degeneration and inferior limb function. The small animal model could be a powerful tool to further study the potential mechanisms between glenohumeral OA and rotator cuff muscle degeneration.

Soluble CCR2 gene therapy controls joint inflammation, cartilage damage, and the progression of osteoarthritis by targeting MCP-1 in a monosodium iodoacetate (MIA)-induced OA rat model.

BACKGROUND: Osteoarthritis (OA) is the most common type of degenerative arthritis and affects the entire joint, causing pain, joint inflammation, and cartilage damage. Various risk factors are implicated in causing OA, and in recent years, a lot of research and interest have been directed toward chronic low-grade inflammation in OA. Monocyte chemoattractant protein-1 (MCP-1; also called CCL2) acts through C-C chemokine receptor type 2 (CCR2) in monocytes and is a chemotactic factor of monocytes that plays an important role in the initiation of inflammation. The targeting of CCL2-CCR2 is being studied as part of various topics including the treatment of OA. METHODS: In this study, we evaluated the potential therapeutic effects the sCCR2 E3 gene may exert on OA. The effects of sCCR2 E3 were investigated in animal experiments consisting of intra-articular injection of sCCR2 E3 in a monosodium iodoacetate (MIA)-induced OA rat model. The effects after intra-articular injection of sCCR2 E3 (fusion protein encoding 20 amino acids of the E3 domain of the CCL2 receptor) in a monosodium iodoacetate-induced OA rat model were compared to those in rats treated with empty vector (mock treatment) and full-length sCCR2. RESULTS: Pain improved with expression of the sCCR2 gene. Improved bone resorption upon sCCR2 E3 gene activation was confirmed via bone analyses using micro-computed tomography. Histologic analyses showed that the sCCR2 E3 gene exerted protective effects against cartilage damage and anti-inflammatory effects on joints and the intestine. CONCLUSIONS: These results show that sCCR2 E3 therapy is effective in reducing pain severity, inhibiting cartilage destruction, and suppressing intestinal damage and inflammation. Thus, sCCR2 E3 may be a potential therapy for OA.

Analgesic dorsal root ganglion field stimulation blocks both afferent and efferent spontaneous activity in sensory neurons of rats with monosodium iodoacetate-induced osteoarthritis.

OBJECTIVES: Chronic joint pain is common in patients with osteoarthritis (OA). Non-steroidal anti-inflammatory drugs and opioids are used to relieve OA pain, but they are often inadequately effective. Dorsal root ganglion field stimulation (GFS) is a clinically used neuromodulation approach, although it is not commonly employed for patients with OA pain. GFS showed analgesic effectiveness in our previous study using the monosodium iodoacetate (MIA) - induced OA rat pain model. This study was to evaluate the mechanism of GFS analgesia in this model. METHODS: After osteoarthritis was induced by intra-articular injection of MIA, pain behavioral tests were performed. Effects of GFS on the spontaneous activity (SA) were tested with in vivo single-unit recordings from teased fiber saphenous nerve, sural nerve, and dorsal root. RESULTS: Two weeks after intra-articular MIA injection, rats developed pain-like behaviors. In vivo single unit recordings from bundles teased from the saphenous nerve and third lumbar (L3) dorsal root of MIA-OA rats showed a higher incidence of SA than those from saline-injected control rats. GFS at the L3 level blocked L3 dorsal root SA. MIA-OA reduced the punctate mechanical force threshold for inducing AP firing in bundles teased from the L4 dorsal root, which reversed to normal with GFS. After MIA-OA, there was increased retrograde SA (dorsal root reflex), which can be blocked by GFS. CONCLUSIONS: These results indicate that GFS produces analgesia in MIA-OA rats at least in part by producing blockade of afferent inputs, possibly also by blocking efferent activity from the dorsal horn.

Ameliorative Effect of Curcumin Nanoparticles against Monosodium Iodoacetate-Induced Knee Osteoarthritis in Rats.

Aim: This study is aimed at evaluating the use of curcumin-loaded polylactic-co-glycolic acid nanoparticles (CUR-loaded PLGA NPs) as a treatment against monosodium iodoacetate- (MIA-) induced knee OA. Materials and Methods: Eighteen rats were assigned to three groups (n = 6), namely, normal control group that received intra-articular injections (IAIs) of saline, an OA control group that received an IAIs of MIA (2 mg/50 µL), and a treatment group (MIA+CUR-loaded PLGA NPs) that received IAIs of CUR-loaded PLGA NPs (200 mg/kg b.wt). Results: The CUR NP treatment against knee OA alleviated radiographic alternations and histopathological changes and inhibited the upregulation in the serum levels of interleukin-1ß, tumor necrosis factor-α, interleukin-6, and transforming growth factor-beta and the downregulation in interleukin-10. CUR NP-treated joints also decreased the mRNA expression of nuclear factor-kappa B and inducible nitric oxide synthase and the protein expression of matrix metalloproteinase-13 and caspase-3. Finally, CUR-loaded PLGA NP treatment mitigated the loss of type II collagen, which resulted in a significant reduction in malondialdehyde level and increased the glutathione content and superoxide dismutase activity compared with that of the OA group. Conclusion: This study demonstrated that the administration of CUR NPs could provide effective protection against MIA-induced OA and knee joint histological deteriorated changes due to its anti-inflammatory, antioxidant, and antiapoptotic properties.

Intra-articular injection of monoiodoacetate induces diverse hip osteoarthritis in rats, depending on its dose.

BACKGROUND: Monoiodoacetate (MIA)-induced arthritis models are used widely in osteoarthritis (OA) research to develop effective conservative treatments for hip OA, as an alternative to joint replacement surgery. In joint OA models, such as the MIA-induced knee OA model, various doses of MIA are utilized, depending on the purpose of the research. So far, only 2 mg of MIA has been used for MIA-induced hip OA research. We hypothesized that the amount of MIA should be adjusted according to the osteoarthritis model under investigation. We performed radiographic and histological evaluations in rats for hip OA models induced by different doses of MIA. METHODS: One hundred and eighty right hips of six-week-old, male Sprague-Dawley rats (n = 30 rats per group) were treated with either a single intra-articular injection of various doses of MIA (0.25, 0.5, 1.0, 2.0, and 4.0 mg) dissolved in 25 µl of sterile saline (MIA group), or with 25 µl of sterile saline alone (Sham group). Radiographic and histological evaluations of the hip joint were performed at one, two, four, eight, and 12 weeks after administration (n = 6 rats per group per time point). RESULTS: OA changes progressed from 1 week after administration in the 1.0-mg, 2.0-mg, and 4.0-mg MIA groups. The degree of OA changes increased as the dose of MIA increased. The 0.25-mg and 0.5-mg MIA groups presented fewer OA changes than the 2.0-mg and 4.0-mg MIA groups during the entire study period (up to 12 weeks). The administration of 0.25 mg and 0.5 mg of MIA-induced both radiographic and histological OA changes in a time-dependent manner, whereas more than 2 mg of MIA provoked end-stage OA at 8 weeks after injection. Absolute, dose-dependent histopathological OA changes were observed 4 weeks after MIA administration. CONCLUSIONS: Intra-articular MIA injection to the hip joints of rats induced diverse OA changes dose-dependently. Research for developing novel conservative treatments for hip OA and intractable pain should consider the pathological condition when determining the dose of MIA to be employed.

Iodoacetic acid exposure alters the transcriptome in mouse ovarian antral follicles.

Iodoacetic acid (IAA) is an unregulated water disinfection byproduct that is an ovarian toxicant. However, the mechanisms of action underlying IAA toxicity in ovarian follicles remain unclear. Thus, we determined whether IAA alters gene expression in ovarian follicles in mice. Adult female mice were dosed with water or IAA (10 or 500 mg/L) in the water for 35-40 days. Antral follicles were collected for RNA-sequencing analysis and sera were collected to measure estradiol. RNA-sequencing analysis identified 1063 differentially expressed genes (DEGs) in the 10 and 500 mg/L IAA groups (false discovery rate FDR < 0.1), respectively, compared to controls. Gene Ontology Enrichment analysis showed that DEGs were involved with RNA processing and regulation of angiogenesis (10 mg/L) and the cell cycle and cell division (500 mg/L). Pathway Enrichment analysis showed that DEGs were involved in the phosphatidylinositol 3-kinase and protein kinase B (PI3K-Akt), gonadotropin-releasing hormone (GnRH), estrogen, and insulin signaling pathways (10 mg/L). Pathway Enrichment analysis showed that DEGs were involved in the oocyte meiosis, GnRH, and oxytocin signaling pathways (500 mg/L). RNA-sequencing analysis identified 809 DEGs when comparing the 500 and 10 mg/L IAA groups (FDR < 0.1). DEGs were related to ribosome, translation, mRNA processing, oxidative phosphorylation, chromosome, cell cycle, cell division, protein folding, and the oxytocin signaling pathway. Moreover, IAA exposure significantly decreased estradiol levels (500 mg/L) compared to control. This study identified key candidate genes and pathways involved in IAA toxicity and can help to further understand the molecular mechanisms of IAA toxicity in ovarian follicles.

Inhibition of fibrotic changes in infrapatellar fat pad alleviates persistent pain and articular cartilage degeneration in monoiodoacetic acid-induced rat arthritis model.

OBJECTIVE: We have reported that fibrotic changes in infrapatellar fat pad (IFP) after acute joint inflammation are closely associated with persistent pain in rats. In this study, to examine the effects of anti-fibrotic treatment on persistent pain, we used C-type natriuretic peptides (CNP) at the recovery phase after acute joint inflammation. DESIGN: Thirty-two male Wistar rats were used in this study. Monoiodoacetic acid (MIA) was injected intra-articularly to induce IFP fibrosis and persistent pain. CNP was injected after acute inflammatory phase in the same knee joint. Time-course pain-avoidance behavior tests and histological analyses were performed to examine the effects of CNP. RESULTS: Histological evaluations indicated that intra-articular injection of CNP inhibited fibrotic changes in IFP after acute inflammation. Incapacitance tests indicated that MIA injection into rat knee joint quickly decreased the percent weight on ipsilateral limb. In the vehicle group, the decrease was maintained up to day 28, suggesting that pain persistence occurred after acute inflammation (Day 0/Day 28, Est Dif -8.15, CI -10.78∼-5.53, Linear mixed-effect model). In contrast, the pain was alleviated in the CNP group after day 14 (Day0/Day 14, -0.51, -2.62-1.59). In addition, we observed significant improvement in the degree of articular cartilage degeneration at day 14 in the CNP group (OARSI score: vehicle 16.14 ± 4.37 vs CNP 6.87 ± 3.44, P < 0.01; Wilcoxon rank sum test). CONCLUSION: Fibrotic changes in IFP may play important roles in both persistent pain and articular cartilage degeneration.

Aldehyde dehydrogenase 2 alleviates monosodium iodoacetate-induced oxidative stress, inflammation and apoptosis in chondrocytes via inhibiting aquaporin 4 expression.

BACKGROUND: Knee osteoarthritis (KOA) is a common cause of disability among the elderly. We aimed to explore the effects of aldehyde dehydrogenase (ALDH) 2 on the progression of KOA and identifying the potential mechanisms. METHODS: First, ALDH2 expression in knee joint effusion of patients with KOA and the levels of oxidative stress-related markers were determined. After ALDH2 overexpression in monosodium iodoacetate (MIA)-treated SW1353 cells, cell viability was tested with CCK-8 assay. Subsequently, oxidative stress and inflammation-associated factors were measured. Meanwhile, cell apoptosis was assessed with TUNEL staining and expression of apoptosis-related proteins was detected by western blotting. To analyze the mechanism of ALDH2 in KOA, aquaporin 4 (AQP4) expression was determined using western blotting following ALDH2-upregulation. Subsequently, AQP4 was overexpressed to evaluate the changing of oxidative stress, inflammation and apoptosis in SW1353 cells exposed to MIA with ALDH2 overexpression. RESULTS: Results indicated that knee joint effusion with higher ALDH2 expression displayed lower oxidative stress. In addition, significantly upregulated ALDH2 expression was observed in MIA-treated SW1353 cells. ALDH2 overexpression oxidative stress, inflammation and apoptosis in SW1353 cells exposed to MIA. Moreover, MIA-triggered elevated expression of AQP4, which was reduced by ALDH2 overexpression. By contrast, AQP4-upregulation abrogated the inhibitory effects of ALDH2 on oxidative stress, inflammation and apoptosis in MIA-induced SW1353 cells. CONCLUSIONS: ALDH2 inactivates the expression of AQP4, by which mechanism the MIA-induced oxidative stress, inflammation and apoptosis injuries were alleviated, which provides a novel insight for understanding the mechanism of KOA and a promising target for the treatment of this disease.

Inhibition effect of Caragana sinica root extracts on Osteoarthritis through MAPKs, NF-κB signaling pathway.

Osteoarthritis (OA) is a common joint disease characterized by degradation and inflammation of cartilage extracellular matrix. We aimed to evaluate the protective effect of Caragana sinica root (CSR) on interleukin (IL)-1ß-stimulated rat chondrocytes and a monosodium iodoacetate (MIA)-induced model of OA. In vitro, cell viability of CSR-treated chondrocytes was measured by MTT assay. The mRNA expression of Matrix metallopeptidases (MMPs), a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs) and extracellular matrix (ECM) were analyzed by quantitative real-time PCR (qRT-PCR). Moreover, the protein expression of MAPK (phosphorylation of EKR, JNK, p38), inhibitory kappa B (IκBα) and nuclear factor-kappa B (NF-κB p65) was detected by western blot analysis. In vivo, the production of nitric oxide (NO) was detected by Griess reagent, while those of inflammatory mediators, MMPs and ECM were detected by ELISA. The degree of OA was evaluated by histopathological analyses, Osteoarthritis Research Society International (OARSI) score and micro-CT analysis. CSR significantly inhibited the expression of MMPs, ADAMTSs and the degradation of ECM in IL-1ß-stimulated chondrocytes. Furthermore, CSR significantly suppressed IL-1ß-stimulated of MAPKs, NF-κB signaling pathway. In vivo, CSR and Indomethacin inhibited the production of inflammatory mediators, MMPs and degradation of ECM in MIA-induced model of OA. In addition, CSR improved the severity of OA. Taken together, these results suggest CSR is a potential therapeutic active agent in the treatment of OA.

Local Administration of Low-Dose Nerve Growth Factor Antibody Reduced Pain in a Rat Osteoarthritis Model.

Systemic injection of a nerve growth factor (NGF) antibody has been proven to have a significant relevance in relieving osteoarthritis (OA) pain, while its adverse effects remain a safety concern for patients. A local low-dose injection is thought to minimize adverse effects. In this study, OA was induced in an 8-week-old male Sprague-Dawley (SD) rat joint by monoiodoacetate (MIA) injection for 2 weeks, and the effect of weekly injections of low-dose (1, 10, and 100 µg) NGF antibody or saline (control) was evaluated. Behavioral tests were performed, and at the end of week 6, all rats were sacrificed and their knee joints were collected for macroscopic and histological evaluations. Results showed that 100 µg NGF antibody injection relieved pain in OA rats, as evidenced from improved weight-bearing performance but not allodynia. In contrast, no significant differences were observed in macroscopic and histological scores between rats from different groups, demonstrating that intra-articular treatment does not worsen OA progression. These results suggest that local administration yielded a low effective NGF antibody dose that may serve as an alternative approach to systemic injection for the treatment of patients with OA.

Biosynthesis of gold nanoparticles for the treatment of osteoarthritis alone or in combination with Diacerein® in a rat model.

Gold (Au) compounds were used as an effective therapeutic agent for various inflammatory diseases; however, the use of Au compounds becomes limited because of its association with several side effects. Hence, gold nanoparticles (AuNPs) were developed as a new option for the medical proposes. However, the safety evaluation of gold nanoparticles (AuNPs) in osteoarthritis (OA) treatment remains vague. This study aimed to biosynthesize, characterize and evaluate the therapeutic effects of biosynthesized AuNPs and/or Diacerein® (DIA) in experimental OA. OA was induced by a single injection of monosodium iodoacetate (3 mg/joint) in the intra-articular knee of female rats. Normal rats (N-rats) and OA-rats were treated orally for 5 weeks as follow: untreated N-rats; untreated OA-rats; N-rats received DIA (50 mg/kg b.w); N-rats received AuNPs (30 µg/kg b.w.); N-rats received AuNPs plus DIA; OA-rats received DIA; OA-rats received AuNPs, and OA-rats received AuNPs plus DIA. Blood, knee cartilage, liver and kidney samples were collected for biochemical and histological analysis. The synthesized AuNPs were nearly spherical with average size of 20 nm and zeta potential of 33 mV. AuNPs and DIA induced a significant improvement in serum inflammatory cytokines, biochemical parameters, estrogen level, hepatic and renal oxidative markers, hepatic DNA fragmentation, genomic template stability and cartilage joint histology of OA-rats. AuNPs were more effective than DIA and the combined treatment was more effective than the single treatment. It could be concluded that AuNPs are promising for the treatment of OA alone or in combination with DIA.

Use of magnetic capture to identify elevated levels of CCL2 following intra-articular injection of monoiodoacetate in rats.

PURPOSE: Synovial fluid biomarkers help evaluate osteoarthritis (OA) development. Magnetic capture, our new magnetic nanoparticle-based technology, has proven to be effective for determining extracellular matrix fragment levels in two rat OA models. Here, the feasibility of magnetic capture for detecting monocyte chemoattractant protein-1 (MCP-1 or CCL2) is demonstrated after intra-articular injection of monoiodoacetate (MIA) in the rat knee. METHODS: Forty-eight male Lewis rats received a right hind limb, intra-articular injection of MIA (1 mg in 25 µl of saline) or 25 µl of saline. Magnetic capture and lavage were performed at 7 days after injection (n = 6 per treatment per procedure), with magnetic capture additionally performed at 14 and 28 days post-injection (n = 6 per treatment per time point). CCL2 was also assessed in serum. RESULTS: Serum CCL2 levels revealed no difference between MIA and saline animals (p = 0.0851). In contrast, magnetic capture and lavage detected a significant increase of CCL2 in the MIA-injected knee, with the MIA-injected knee having elevated CCL2 compared to contralateral and saline-injected knees (p = 0.00016 (contralateral) and p = 0.00016 (saline) for magnetic capture; p = 0.00023 (contralateral) and p = 0.00049 (saline) for lavage). CONCLUSIONS: Magnetic capture of CCL2 was successfully developed and applied to determine levels of CCL2 in a rat knee. Magnetic capture detected a statistically significant increase of CCL2 in MIA-injected knees compared to controls, and CCL2 levels stayed relatively stable from week 1 through week 4 post-MIA injection.

Alterations in Anandamide Synthesis and Degradation during Osteoarthritis Progression in an Animal Model.

Osteoarthritis (OA) is a degenerative joint disease manifested by movement limitations and chronic pain. Endocannabinoid system (ECS) may modulate nociception via cannabinoid and TRPV1 receptors. The purpose of our study was to examine alterations in the spinal and joint endocannabinoid system during pain development in an animal model of OA. Wistar rats received intra-articular injection of 3mg of sodium monoiodoacetate (MIA) into the knee joint. Animals were sacrificed on day 2, 7, 14, 21, 28 after injection and lumbar spinal cord, cartilage and synovium were collected. Changes in the transcription levels of the ECS elements were measured. At the spinal level, gene expression levels of the cannabinoid and TRPV1 receptors as well as enzymes involved in anandamide synthesis and degradation were elevated in the advanced OA phase. In the joint, an important role of the synovium was demonstrated, since cartilage degeneration resulted in attenuation of the changes in the gene expression. Enzymes responsible for anandamide synthesis and degradation were upregulated particularly in the early stages of OA, presumably in response to early local joint inflammation. The presented study provides missing information about the MIA-induced OA model and encourages the development of a therapy focused on the molecular role of ECS.

Molecular Targets of Natural Products for Chondroprotection in Destructive Joint Diseases.

Osteoarthritis (OA) is the most common type of arthritis that occurs in an aged population. It affects any joints in the body and degenerates the articular cartilage and the subchondral bone. Despite the pathophysiology of OA being different, cartilage resorption is still a symbol of osteoarthritis. Matrix metalloproteinases (MMPs) are important proteolytic enzymes that degrade extra-cellular matrix proteins (ECM) in the body. MMPs contribute to the turnover of cartilage and its break down; their levels have increased in the joint tissues of OA patients. Application of chondroprotective drugs neutralize the activities of MMPs. Natural products derived from herbs and plants developed as traditional medicine have been paid attention to, due to their potential biological effects. The therapeutic value of natural products in OA has increased in reputation due to their clinical impact and insignificant side effects. Several MMPs inhibitor have been used as therapeutic drugs, for a long time. Recently, different types of compounds were reviewed for their biological activities. In this review, we summarize numerous natural products for the development of MMPs inhibitors in arthritic diseases and describe the major signaling targets that were involved for the treatments of these destructive joint diseases.