Hyaluronan modulates accumulation of hypoxia-inducible factor-1 alpha, inducible nitric oxide synthase, and matrix metalloproteinase-3 in the synovium of rat adjuvant-induced arthritis model

The effects of a galectin-3 inhibitor on bladder pain syndrome in mice with cyclophosphamide-induced cystitis

AIMS

To explore the effect of blocking galectin-3 in the bladder pain syndrome associated with interstitial cystitis.

METHODS

A galectin-3 inhibitor was used to treat mice with cyclophosphamide-induced cystitis. The expression of galectin-3 in bladder tissues and urine was examined by immunohistochemistry and enzyme-linked immunosorbent assay (ELISA), respectively. Suprapubic-pelvic pain, bladder voiding, bladder pain-like nociceptive behavior, and referred hyperalgesia were assessed. The weights of the bladders were also measured, and inflammatory cell infiltration and inflammatory cytokine levels were examined by histopathological evaluation. The inflammatory cytokines interleukin 1β (IL-1β), nerve growth factor (NGF), IL-6, and tumor necrosis factor α (TNF-α) were measured by ELISA.

RESULTS

Increases in galectin-3 levels, inflammation, bladder weight, and bladder pain-related symptoms were observed in bladders with cyclophosphamide-induced cystitis. Administration of the galectin-3 inhibitor significantly mitigated bladder pain-related symptoms and inflammatory response. In response to the 500 μM dose of the galectin-3 inhibitor, nociceptive behaviors, nociceptive score, and bladder-to-body weight ratios were reduced by 65.1%, 65.3%, and 40.3%, respectively, while 500 μM Gal-3 inhibitor increased pelvic pain threshold by 86.7%. Moreover, galectin-3 inhibitor treatment inhibited the inflammation. Compared to untreated CYP-induced mice, there were significant changes in the levels of IL-1β (41.72 ± 2.05 vs. 18.91 ± 2.26 pg/mg tissues), NGF (9.64 ± 0.38 vs. 1.88 ± 0.05 pg/mg tissues), IL-6 (42.67 + 1.51 vs. 21.26 + 2.78 pg/mg tissues, and TNF-α (22.02 ± 1.08 vs. 10.70 ± 0.80 pg/mg tissues) in response to the highest dose of the Gal-3 inhibitor subgroup (500 μM), and 500 μM Gal-3 inhibitor reduced mast cell infiltration ratios by 71.8%.

CONCLUSIONS

The galectin-3 inhibitor relieved pelvic pain, urinary symptoms, and bladder inflammation in mice with cyclophosphamide-induced cystitis. Thus, galectin-3 inhibitors may be novel agents in interstitial cystitis treatment.

Risk of Infection After Total Knee or Hip Arthroplasty After Receipt of Multiple Corticosteroid or Hyaluronic Acid Injections

BACKGROUND

Few studies have assessed the relationship between the quantity of preoperative corticosteroid injections (CSIs) or hyaluronic acid injections (HAIs) and postoperative infection risk after total knee or hip arthroplasty (TKA, THA). We aimed to (1) determine whether the number of injections administered before TKA/THA procedures is associated with postoperative infections and (2) establish whether infection risk varies by injection type.

METHODS

This retrospective cohort study included 230,487 THAs and 371,511 TKAs from the 2017 to 2018 Medicare Limited Data Set. The quantity of CSI or HAI, defined as receiving either CSI or HAI ≤2 years before TKA/THA, was identified and categorized as 0, 1, 2, or >2. The primary outcome was 90-day postoperative infection. Multivariable regression models measured the association between the number of injections and 90-day postoperative infection. Odds ratios and 95% confidence intervals were reported.

RESULTS

The percentage of THA patients receiving 1, 2, and >2 preoperative CSIs was 6.1%, 1.6%, and 0.8%, respectively. Receiving >2 CSIs within 2 years before THA was associated with higher odds of 90-day postoperative infection (odds ratios = 1.74, 95% CI = 1.11 to 2.74, P = 0.02). The percentage of TKA patients receiving 1, 2, and >2 CSIs was 3.0%, 1.2%, and 1.1%, respectively. For HAIs in TKA patients, percentage receiving injections was 98.3%, 0.6%, 0.2%, and 0.9%, respectively. Quantity of CSIs or HAIs administered was not associated with postoperative infection among TKA patients.

CONCLUSION

Patients receiving >2 injections before THA had higher odds of 90-day postoperative infection. This finding was not observed in TKA patients. These results suggest that the use of >2 injections within 2 years of THA should be avoided.

Do preoperative intra-articular injections of corticosteroids or hyaluronic acid increase the risk of infection after total knee arthroplasty? A meta-analysis

Aims

There is conflicting evidence on the safety of intra-articular injections of hyaluronic acid (HA) or corticosteroids (CSs) before total knee arthroplasty (TKA). We performed a meta-analysis of the relationship between intra-articular injections and subsequent infection rates after TKA.

Methods

We searched PubMed, EMBASE, and the Cochrane Library for cohort studies that assessed the effect of preoperative injection of drugs into the joint cavity on the infection rate after TKA. The outcomes analyzed included the total infection rate, as well as those for different preoperative injection time periods and different drugs.

Results

Eight studies, including 73,880 in the injection group and 126,187 in the control group, met the inclusion criteria. The injection group had a significantly higher postoperative infection rate than the control group (risk ratio (RR) 1.16; 95% confidence interval (CI) 1.07 to 1.27; p < 0.001; I² = 32%). For patients who received injections up to three months preoperatively, the postoperative infection risk was significantly higher than that in the control group (RR 1.26; 95% CI 1.18 to 1.35; p＜0.001; I² = 0%). There was no significant difference in the infection rates between the four-to-six-month injection and control groups (RR 1.12; 95% CI 0.93 to 1.35; p = 0.240; I² = 75%) or between the seven-to-12-month injection and control groups (RR 1.02; 95% CI 0.94 to 1.12; p = 0.600; I² = 0%).

Conclusion

Current evidence suggests that intra-articular injections of CSs or HA before TKA increase the risk of postoperative infection. Injections administered more than three months before TKA do not significantly increase the risk of infection.

Cite this article: Bone Joint Res 2022;11(3):171–179.

Shentong Zhuyu Decoction Inhibits Inflammatory Response, Migration, and Invasion and Promotes Apoptosis of Rheumatoid Arthritis Fibroblast-like Synoviocytes via the MAPK p38/PPARγ/CTGF Pathway

INTRODUCTION

The current study is aimed at exploring the effect of Shentong Zhuyu Decoction on the proliferation, migration, invasion, and apoptosis of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS) and its underlying molecular mechanism.

MATERIALS AND METHODS

The type II collagen-induced arthritis (CIA) model was established. Subsequently, the RA-FLS were isolated from the CIA rat model and identified by immunohistochemistry. The viability, apoptosis, cell cycle, migration, and invasion of RA-FLS were detected by the cell counting kit 8 (CCK-8) assay, flow cytometry, wound-healing assay, and transwell invasion assay, respectively. The levels of MAPK p38, PPARγ, CTGF, Bcl-2, Bax, caspase-3, IL-1β, MMP-3, CDK4, and cyclin D1 were determined by qRT-PCR and western blotting, respectively.

RESULTS

After treatment with Shentong Zhuyu Decoction medicated serum, the OD570 value, migrative and invasive abilities, and the secretion of IL-1β, MMP-3 were remarkably decreased in RA-FLS, while the apoptosis rate was increased. Further, results showed that Shentong Zhuyu Decoction inhibited the transition from the G1 phase to S phase. Additionally, Shentong Zhuyu Decoction significantly inhibited the expression of Bcl-2, CDK4, cyclin D1, MAPK p-p38, and CTGF, whereas elevated the levels of Bax, caspase-3, and PPARγ. Importantly, the effects of Shentong Zhuyu Decoction were consistent with the trends of MAPK P38 inhibitor (SB203580) and PPARγ agonist (GW1929).

CONCLUSIONS

Shentong Zhuyu Decoction inhibited viability, inflammatory response, migration, invasion, and transition from the G1 phase to S phase and promoted apoptosis of RA-FLS via the MAPK p38/PPARγ/CTGF pathway.

Downregulation of Hypoxia-Inducible Factor-1α by RNA Interference Alleviates the Development of Collagen-Induced Arthritis in Rats

Rheumatoid arthritis (RA) is the most common type of autoimmune arthritis. Hypoxia-inducible factor-1α (HIF-1α) as a transcription factor in response to hypoxia suggests that it could be a potential therapeutic target for the treatment of RA. In this study, we assessed whether the HIF pathway blockade attenuates the manifestations of RA in the collagen-induced arthritis (CIA) rat model. We constructed a short hairpin RNA (shRNA) lentiviral expression vector targeting HIF-1α (pLVX-shRNA-HIF-1α) and to achieve HIF-1α RNA interference. Quantitative RT-PCR, immunofluorescence staining, and western blot were used to detect the expressions of HIF-1α, vascular endothelial growth factor (VEGF), phsopho (p)-p65, and p-IКBɑ mRNA and protein, respectively. Micro-computed tomography was used to investigate joint morphology at different time points after CIA induction. Moreover, enzyme-linked immunosorbent assay (ELISA) was used to monitor the expression of inflammatory cytokines. In vitro analyses revealed that pLVX-shRNA-HIF-1α effectively inhibited the expression of HIF-1α and VEGF and led to the activation of p-65 and p-IКBɑ, as well as decreased proinflammatory cytokine expression in cell culture. Inhibition of HIF-1α in rats decreased signs of a systemic inflammatory condition, together with decreased pathological changes of RA. Moreover, downregulation of HIF-1α expression markedly reduced the synovitis and angiogenesis. In conclusion, we have shown that pharmacological inhibition of HIF-1 may improve the clinical manifestations of RA.

Magnesium oil enriched transdermal nanogel of methotrexate for improved arthritic joint mobility, repair, and reduced inflammation

Aim: Methotrexate (Mtx) is prescribed to reduce pain and inflammation in arthritis patients; however, improved repair and mobility of joints still are the major concerns. Magnesium oil (MO) improves joint mobility and repair; therefore, MO-assisted transdermal delivery of Mtx was aimed.Methods: MO integrated Mtx nanoemulsion (Mtx-MONE) was prepared with uniform size (175 ± 35.4 nm), pH (6.15 ± 0.3) near to skin pH, and high entrapment efficiency (65 ± 8.6%). Mtx-MONE was transformed to nanogel (Mtx-MONEG) with semisolid consistency (43,408 ± 77.72 cP) and good spreadability (3.63 ± 0.033 mJ).Results: Mtx-MONEG showed significant reduction in oedema, arthritic scores, level of inflammatory cytokines, and improved walking as compared to diseased control. MO offered additional improvements in joints, mobility, and repair.Conclusion: Transdermal delivery of Mtx has been successfully achieved by Mtx-MONEG. Tremendous recovery from inflammation, improved joints mobility and repair, and reduced pain strongly support the use of MO as an adjutant of Mtx for improved transdermal application.

Integrative Population and Physiological Genomics Reveals Mechanisms of Adaptation in Killifish

Adaptive divergence between marine and freshwater (FW) environments is important in generating phyletic diversity within fishes, but the genetic basis of this process remains poorly understood. Genome selection scans can identify adaptive loci, but incomplete knowledge of genotype-phenotype connections makes interpreting their significance difficult. In contrast, association mapping (genome-wide association mapping [GWAS], random forest [RF] analyses) links genotype to phenotype, but offer limited insight into the evolutionary forces shaping variation. Here, we combined GWAS, RF, and selection scans to identify loci important in adaptation to FW environments. We utilized FW-native and brackish water (BW)-native populations of Atlantic killifish (Fundulus heteroclitus) as well as a naturally admixed population between the two. We measured morphology and multiple physiological traits that differ between populations and may contribute to osmotic adaptation (salinity tolerance, hypoxia tolerance, metabolic rate, body shape) and used a reduced representation approach for genome-wide genotyping. Our results show patterns of population divergence in physiological capabilities that are consistent with local adaptation. Population genomic scans between BW-native and FW-native populations identified genomic regions evolving by natural selection, whereas association mapping revealed loci that contribute to variation for each trait. There was substantial overlap in the genomic regions putatively under selection and loci associated with phenotypic traits, particularly for salinity tolerance, suggesting that these regions and genes are important for adaptive divergence between BW and FW environments. Together, these data provide insight into the mechanisms that enable diversification of fishes across osmotic boundaries.

Comparison of Infection Risk with Corticosteroid or Hyaluronic Acid Injection Prior to Total Knee Arthroplasty

BACKGROUND

Recent studies have shown that intra-articular injections ≤3 months before total knee arthroplasty increase the risk of periprosthetic joint infection. We are aware of no previous study that has differentiated the risk of periprosthetic joint infection on the basis of the type of medication injected. In addition, we are aware of no prior study that has evaluated whether hyaluronic acid injections increase the risk of infection after total knee arthroplasty. In this study, we utilized pharmaceutical data to compare patients who received preoperative corticosteroid or hyaluronic acid injections and to determine whether a specific injection type increased the risk of periprosthetic joint infection.

METHODS

Patients undergoing unilateral primary total knee arthroplasty were selected from a nationwide private insurer database. Ipsilateral preoperative injections were identified and were grouped by medication codes for corticosteroid or hyaluronic acid. Patients who had received both types of injections ≤1 year before total knee arthroplasty were excluded. The outcome of interest was periprosthetic joint infection that occurred ≤6 months following the total knee arthroplasty. The risk of periprosthetic joint infection was compared between groups (no injection, corticosteroid, hyaluronic acid) and between patients who received single or multiple injections. Statistical comparisons were performed using logistic regression controlling for age, sex, and comorbidities.

RESULTS

A total of 58,337 patients underwent total knee arthroplasty during the study period; 3,249 patients (5.6%) received hyaluronic acid and 16,656 patients (28.6%) received corticosteroid ≤1 year before total knee arthroplasty. The overall infection rate was 2.74% in the no-injection group. Multivariable logistic regression showed independent periprosthetic joint infection risk for both corticosteroid (odds ratio [OR], 1.21; p = 0.014) and hyaluronic acid (OR, 1.55; p = 0.029) given ≤3 months before total knee arthroplasty. There was no increased risk with injections >3 months prior to total knee arthroplasty. Direct comparison of corticosteroid and hyaluronic acid showed no significant difference (p > 0.05) between medications or between single and multiple injections.

CONCLUSIONS

Preoperative corticosteroid or hyaluronic acid injection ≤3 months before total knee arthroplasty increased the risk of periprosthetic joint infection. There was no difference in infection risk between medications or between multiple and single injections. On the basis of these data, we recommend avoiding both injection types in the 3 months prior to total knee arthroplasty.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Nitric oxide alters hyaluronan deposition by airway smooth muscle cells

Asthma is a chronic inflammatory disease that is known to cause changes in the extracellular matrix, including changes in hyaluronan (HA) deposition. However, little is known about the factors that modulate its deposition or the potential consequences. Asthmatics with high levels of exhaled nitric oxide (NO) are characterized by greater airway reactivity and greater evidence of airway inflammation. Based on these data and our previous work we hypothesized that excessive NO promotes the pathologic production of HA by airway smooth muscle cells (SMCs). Exposure of cultured SMCs to various NO donors results in the accumulation of HA in the form of unique, cable-like structures. HA accumulates rapidly after exposure to NO and can be seen as early as one hour after NO treatment. The cable-like HA in NO-treated SMC cultures supports the binding of leukocytes. In addition, NO produced by murine macrophages (RAW cells) and airway epithelial cells also induces SMCs to produce HA cables when grown in co-culture. The modulation of HA by NO appears to be independent of soluble guanylate cyclase. Taken together, NO-induced production of leukocyte-binding HA by SMCs provides a new potential mechanism for the non-resolving airway inflammation in asthma and suggests a key role of non-immune cells in driving the chronic inflammation of the submucosa. Modulation of NO, HA and the consequent immune cell interactions may serve as potential therapeutic targets in asthma.

Establishment of a Novel Autoimmune Experimental Model of Bladder Pain Syndrome/Interstitial Cystitis in C57BL/6 Mice

The aim of this study is to identify whether vaccinating twice with bladder homogenate can establish a new model of experimental autoimmune cystitis (EAC) in C57BL/6 strain mice. C57BL/6 mice were vaccinated with bladder homogenate in complete Freund's adjuvant (CFA) and boost immunized with bladder homogenate in incomplete Freund's adjuvant (IFA) after 2 weeks were used as the EAC model. Mice immunized with phosphate-buffered saline (PBS) in CFA or IFA were used as the control. Micturition habits and suprapubic-pelvic pain threshold were measured 4 weeks after primary immunization. Bladder to body weight ratios and expression of inflammatory cytokines and neurokinin 1 receptor (NK1R) were then examined. Histologic and immunohistochemical examination of the bladder was carried out, and IL-1β, IFN-γ, and TNF-α production by the kidneys, liver, and lungs was also tested. Double-immunized mice were extensively sensitive to pressure applied on the pelvic area (P < 0.001). Compared to single-immunized mice or controls, double-immunized mice showed more micturition frequency, lower urine output per micturition, higher bladder to body weight ratio, and significant elevation in the expression of inflammatory cytokines, including IL-1β, IL-4, IL-6, IL-10, IFN-γ, and TNF-α (all P < 0.05). NK1R gene expression was significantly increased in double-immunized mice compared to the other three groups (P < 0.001). A nonspecific immune response occurred in the liver but was much weaker than bladder inflammation. Our dual immunization EAC model in C57BL/6 mice can effectively mimic the symptoms and pathophysiologic characteristics of BPS/IC and thus can be widely used to investigate the pathogenesis and therapeutic strategies of BPS/IC.

The Disease-Modifying Effects of Hyaluronan in the Osteoarthritic Disease State

Hyaluronic acid (HA) has been a treatment modality for patients with knee osteoarthritis (OA) for many years now. Since HA was first introduced for the treatment of painful knee OA, much has been elucidated regarding both the etiology of this disease and the mechanisms by which HA may mitigate joint pain and tissue destruction. The objectives of this article are to (1) describe the etiology and pathophysiology of OA including both what is known about the genetics and biochemistry, (2) describe the role of HA on disease progression, (3) detail the antinociceptive and anti-inflammatory actions of HA in OA, and (4) present evidence of disease-modifying effects of HA in the preservation and restoration of the extracellular matrix. These data support that HA is not only just a simple device used for viscosupplementation but also a biologically active molecule that can affect the physiology of articular cartilage.

Anti-rheumatic effects of Aconitum leucostomum Worosch. on human fibroblast-like synoviocyte rheumatoid arthritis cells

The aim of the present study was to investigate the effects of Aconitum leucostomum Worosch. crude drug, processed products and monomer components on human fibroblast-like synoviocyte rheumatoid arthritis (HFLS-RA) cells, and its associated mechanisms. Following drug treatment, cell proliferation was assessed using a Cell Counting Kit-8 assay. Cellular apoptosis and cell cycle were evaluated using flow cytometry. Levels of hypoxia-inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF) and toll-like receptor 4 (TLR4) mRNA and protein were evaluated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis, respectively. Levels of pro-inflammatory cytokines were evaluated using ELISA. Analysis of cell proliferation indicated that crude drug and processed products markedly inhibited the cell proliferation. Compared with the control group, the apoptosis rates were significantly elevated in all treatment groups (all P<0.05). Furthermore, the proportion of cells in G0/G1 phase was significantly decreased in all treatment groups compared with the control group (all P<0.05). RT-qPCR and western blotting indicated that, compared with the control group, mRNA and protein expression levels of HIF-1α, and TLR4 were significantly downregulated in all treatment groups (P<0.05). The mRNA and protein expression levels of VEGF in all treatment groups were decreased compared with those in the control group, but the difference was not significant. Results from ELISA demonstrated that the levels of interleukin (IL)-6, IL-1β and tumor necrosis factor-α in the cell culture supernatant were all significantly decreased following drug treatment in HFLS-RA cells (all P<0.05). Therefore, A. leucostomum Worosch. crude drug, processed products and monomer components may exert anti-rheumatic effects on HFLS-RA cells, inhibiting cell proliferation and enhancing cellular apoptosis. These effects may be attributable to the downregulated expression of HIF-1α and TLR4, as well as decreased levels of pro-inflammatory cytokines.

Thiamine and riboflavin inhibit production of cytokines and increase the anti-inflammatory activity of a corticosteroid in a chronic model of inflammation induced by complete Freund's adjuvant

BACKGROUND

The effects induced by thiamine and riboflavin, isolated or in association with corticosteroids, in models of chronic inflammation are not known. Thus, we evaluated the effect induced by these B vitamins, isolated or in association with dexamethasone, on the mechanical allodynia, paw edema and cytokine production induced by complete Freund's adjuvant (CFA) in rats.

METHODS

Chronic inflammation was induced by two injections of CFA. Nociceptive threshold, paw volume and body temperature were evaluated for 21days. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) contents were determined in paw tissue. Riboflavin (125, 250 or 500mg/kg) or thiamine (150, 300 or 600mg/kg) were administered per os (po), twice daily. Dexamethasone (0.5mg/kgday, po) was administered every three days.

RESULTS

CFA induced long lasting mechanical allodynia and paw edema. Elevation of body temperature was observed for a short period. Riboflavin reduced neither paw edema nor mechanical allodynia. Thiamine did not change paw edema, but partially inhibited mechanical allodynia. Riboflavin (500mg/kg) and thiamine (600mg/kg) exacerbated the anti-inflammatory activity of dexamethasone. Riboflavin, thiamine and dexamethasone reduced TNF-α and IL-6 production. The association of dexamethasone with thiamine induced greater inhibition of IL-6 production when compared with that induced by dexamethasone.

CONCLUSIONS

Riboflavin and thiamine exacerbate the anti-inflammatory activity of dexamethasone and reduce production of TNF-α and IL-6.

The fluence effects of low-level laser therapy on inflammation, fibroblast-like synoviocytes, and synovial apoptosis in rats with adjuvant-induced arthritis

OBJECTIVE

The aim of this study was to evaluate the effect of low-level laser therapy (LLLT) operating at low and high fluences on joint inflammation, fibroblast-like synoviocytes (FLS), and synovial apoptosis in rats with adjuvant-induced arthritis.

BACKGROUND DATA

Rheumatoid arthritis (RA) is characterized by pronounced inflammation and FLS proliferation within affected joints. Certain data indicate that LLLT is effective in patients with inflammation caused by RA; however, the fluence effects of LLLT on synovium are unclear.

METHODS

Monoarthritis was induced in adult male Sprague-Dawley rats (250-300 g) via intraarticular injection of complete Freund's adjuvant (CFA) into the tibiotarsal joint. Animals were irradiated 72 h after CFA administration with a 780 nm GaAlAs laser at 4.5 J/cm2 (30 mW, 30 sec/spot) and 72 J/cm2 (80 mW, 180 sec/spot) daily for 10 days. After LLLT, the animals were euthanized and their arthritic ankles were collected for histopathological analysis, immunoassays of tumor necrosis factor (TNF)-α, matrix metallopeptidase (MMP)3 and 5B5, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays.

RESULTS

LLLT at a fluence of 4.5 J/cm2 significantly reduced infiltration of inflammatory cells and expressions of TNF-α-, MMP3- and 5B5-like immunoreactivities, as well as resulting in more TUNEL-positive apoptotic cells in the synovium. No significant changes were observed in these biochemicals and inflammation in arthritic animals treated with 72 J/cm2.

CONCLUSIONS

LLLT with low fluence is highly effective in reducing inflammation to sites of injury by decreasing the numbers of FLS, inflammatory cells, and mediators in the CFA-induced arthritic model. These data will be of value in designing clinical trials of LLLT for RA.

Relationship between PI3K pathway and angiogenesis in CIA rat synovium

To investigate the expression of hypoxia inducible factor (HIF-1α) and vascular endothelial growth factor (VEGF) in the synovium of collagen-induced arthritis (CIA) joint, and whether the PI3K pathway regulates angiogenesis in rheumatoid arthritis or not. A randomized controlled according to the principle of the rats were divided into normal control group (10 rats) and the experimental group (40 rats). The experimental group rats were established as type II collagen plus adjuvant Freund's complete adjuvant-induced arthritis model. HIF-1α and VEGF proteins' expression in serum of CIA rats group and normal control group were detected by ELISA. Microvessel density (MVD) in synovial tissue of CIA rats group and normal control group were detected by immunohistochemistry (IHC) staining. The protein expression of PTEN, PI3K, and AKT in synovial tissue were detected by Western Blot. Compared with normal control group, toes and ankle swelling and arthritis index (AI) of CIA rat increased, and the expression of VEGF and HIF-1α proteins in peripheral serum increased, IHC showed that MVD was significantly higher than that of the control group, and the difference was statistically significant (p<0.05). Western Blot results showed that PI3K and AKT proteins expression in CIA synovial tissue of rats increased, while the expression of PTEN protein decreased. Correlation analysis showed that VEGF and HIF-1 levels in the peripheral serum of CIA rats were positively correlated with arthritis index (AI); the contents of HIF-1α and VEGF in the peripheral serum of CIA rats were positively correlated with MVD in synovium tissue. The CIA rat model regulated the expression of HIF-1α and VEGF proteins in peripheral serum by PI3K signaling pathway, and then regulated neovascularization in RA.

Weekly injections of Hylan G-F 20 delay cartilage degeneration in partial meniscectomized rat knees

Background

Cross-linked hyaluronan—also called Hylan G-F 20—is a medical device developed to treat osteoarthritis of the knee. However, it is still controversial whether Hylan G-F 20 has a cartilage protective effect in trauma-induced osteoarthritis. We investigated whether Hylan G-F 20 delayed osteoarthritis progression in a partial meniscectomized rat model.

Methods

Lewis rats were used for the experiments. The anterior medial meniscus was resected at the level of the medial collateral ligament in both knees. From 1 week after the surgery, 50 μl of Hylan G-F 20 was injected weekly into the left knee and phosphate buffered saline was injected into the right knee. Cartilage was evaluated for macroscopic findings, histology with safranin-o, and expression of type II collagen at 2, 4, and 8 weeks. Synovitis was also evaluated, and immunohistochemical analysis was performed for ED1.

Results

Macroscopic findings demonstrated that India ink positive area, representing fibrillated cartilage, was significantly smaller in the Hylan G-F 20 group than in the control group at 2, 4, and 8 weeks (n = 5). There were no significant differences in osteophyte score between the Hylan G-F 20 group and the control group at 2, 4, and 8 weeks.

Histologically, the cartilage in the medial tibial plateau was destroyed at 8 weeks in the control group, while type II collagen expression was still observed at 8 weeks in the Hylan G-F 20 group. OARSI score for cartilage histology was significantly lower in the Hylan G-F 20 group than in the control group at 4 and 8 weeks (n = 5). There were no significant differences in synovial cell number or modified synovitis score between the Hylan G-F 20 group and the control group at 2, 4, and 8 weeks (n = 5). In the Hylan G-F 20 group, foreign bodies surrounded by ED1 positive macrophages were observed in the synovium.

Conclusion

Weekly injections of Hylan G-F 20 starting 1 week after surgery delayed cartilage degeneration after meniscectomy in a rat model. Synovitis induced by meniscectomy was not alleviated by Hylan G-F 20. Insoluble gels were observed in the synovium after the Hylan G-F 20 injection.

Effects of high molecular weight hyaluronic acid on induced arthritis of the temporomandibular joint in rats

High molecular weight hyaluronic acid (HMWHA) has been used to treat temporomandibular joint (TMJ) disorders, but controversial results have been described. This study aimed to characterize the morphological and biochemical actions of HMWHA on induced arthritis of the TMJ. Twenty-four male Wistar rats were used, and arthritis of the TMJ was induced through an intra-articular injection of Complete Freund's Adjuvant (CFA) (50 μl). One week after arthritis induction, the animals were treated with HMWHA (once per week for three weeks). Histological analyses were performed using sections stained with hematoxylin-eosin, toluidine blue and Picrosirius. Were also performed histomorphometric analysis and birefringence of collagenous fibers (polarization microscopy). Biochemical analyses of TMJ tissues were carried out through measurements of sulfated glycosaminoglycans and zymography for evaluation of metalloproteinase-2 and -9 (MMP-2 and -9). Data were analyzed using paired t-test and unpaired t-test, with a 5% significance level. HMWHA reduced histologic changes and thickness of the articular disc, led to a greater arrangement of collagenous fibers, lower concentration of sulfated glycosaminoglycans and lower activity in all isoforms of MMP-2 and -9 in TMJs with induced arthritis. These findings suggest that HMWHA may exert a protective effect on the TMJ.

Preventing effects of joint contracture by high molecular weight hyaluronan injections in a rat immobilized knee model

PURPOSE

To elucidate preventive effects of high molecular weight hyaluronan (HMWHA) on the joint capsule of immobilized knees in rats.

MATERIALS AND METHODS

Unilateral knee joints of rats were immobilized with an internal fixator. Either 50 μl of HMWHA (Im-HA group) or 50 μl of saline (control group) was administered intra-articularly once a week after surgery. Sagittal sections were prepared from the medial midcondylar region of the knee joints and assessed by histological, histomorphometric, and immunohistochemical methods. Gene expressions related to inflammation, fibrotic conditions, and hypoxia were evaluated by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Tissue elasticity of the capsule from both groups was examined using a scanning acoustic microscope (SAM).

RESULTS

CD68 positive cells decreased in adhesion areas of the synovial membrane after 1 week in both groups. The length of the superficial layer in the synovial membrane of the Im-HA group was significantly longer than those in the control group over a period of 4 to 8 weeks with significantly small numbers of CD68 positive cells. The gene expressions of IL-6, IL-1β, TGF-β, CTGF, COL1a1, COL3a1, SPARC, and HIF1-α were significantly lower in the Im-HA group compared to those in the control group. The sound speed of the anterior and posterior synovial membrane increased significantly (a reduction in elasticity) in the control group compared to those in the Im-HA group during weeks 1 to 4.

CONCLUSIONS

This study demonstrated that HMWHA injections suppressed inflammatory, fibrotic, and hypoxic conditions observed in the immobilized joint capsule.

Sorbitol-modified hyaluronic acid reduces oxidative stress, apoptosis and mediators of inflammation and catabolism in human osteoarthritic chondrocytes

OBJECTIVE AND DESIGN

Our study was designed to elucidate the precise molecular mechanisms by which sorbitol-modified hyaluronic acid (HA/sorbitol) exerts beneficial effects in osteoarthritis (OA).

METHODS

Human OA chondrocytes were treated with increasing doses of HA/sorbitol ± anti-CD44 antibody or with sorbitol alone and thereafter with or without interleukin-1beta (IL-1β) or hydrogen peroxide (H2O2). Signal transduction pathways and parameters related to oxidative stress, apoptosis, inflammation, and catabolism were investigated.

RESULTS

HA/sorbitol prevented IL-1β-induced oxidative stress, as measured by reactive oxygen species, p47-NADPH oxidase phosphorylation, 4-hydroxynonenal (HNE) production and HNE-metabolizing glutathione-S-transferase A4-4 expression. Moreover, HA/sorbitol stifled IL-1β-induced metalloproteinase-13, nitric oxide (NO) and prostaglandin E2 release as well as inducible NO synthase expression. Study of the apoptosis process revealed that this gel significantly attenuated cell death, caspase-3 activation and DNA fragmentation elicited by exposure to a cytotoxic H2O2 dose. Examination of signaling pathway components disclosed that HA/sorbitol prevented IL-1β-induced p38 mitogen-activated protein kinase and nuclear factor-kappa B activation, but not that of extracellular signal-regulated kinases 1 and 2. Interestingly, the antioxidant as well as the anti-inflammatory and anti-catabolic effects of HA/sorbitol were attributed to sorbitol and HA, respectively.

CONCLUSIONS

Altogether, our findings support a beneficial effect of HA/sorbitol in OA through the restoration of redox status and reduction of apoptosis, inflammation and catabolism involved in cartilage damage.

Importance of synovitis in osteoarthritis: evidence for the use of glycosaminoglycans against synovial inflammation

OBJECTIVES

After detailing the different aspects of synovial inflammation (i.e., cellular, biochemical, and vascular) and based on the current knowledge, the aim of this review was to collect the available in vitro and in vivo data regarding the potency of some glycosaminoglycan (GAG) compounds to target synovial inflammation, an important aspect of osteoarthritis.

METHODS

The first part of the review corresponds to a qualitative review of the inflammatory status of OA synovial membrane. The second part corresponds to a systematic review of the literature regarding the potential effects of some GAGs on the previously described phenomenon.

RESULTS

The synovial aspect of the inflammatory status of OA has been detailed. Chondroitin sulfate has demonstrated to control the three aspects of synovial membrane inflammation: cell infiltration and activity, biochemical mediators release, and angiogenesis. Glucosamine is also active on both cellular and molecular aspects of the inflammatory reaction. Hyaluronic acid seems to be anti-inflammatory in its native form, while products of degradation are reported to be pro-angiogenic.

CONCLUSION

Much evidence suggests that some of the studied GAG compounds could target different aspects of synovitis. Some of them could be considered in combination therapy since they exhibit complementary properties. Most of the studies have concentrated on articular cartilage and chondrocytes. In order to achieve a structure modification, one may now consider all joint tissues and investigate the drug potency on all of them. Potent treatment should trigger the most important features of OA: cartilage degradation, subchondral bone sclerosis, and all aspects of synovial inflammation.

Muscle wasting associated with pathologic change is a risk factor for the exacerbation of joint swelling in collagen-induced arthritis in cynomolgus monkeys

BACKGROUND

Not only joint destruction but also muscle wasting due to rheumatoid cachexia has been problem in terms of quality of life of patients with rheumatoid arthritis (RA). In the present study, we performed histopathological examination and assessed relationships between characteristic parameters relating to muscle and joint swelling in a collagen-induced arthritis (CIA) model using cynomolgus monkeys (CMs).

METHODS

Female CMs were used and CIA was induced by twice immunizations using bovine type II collagen with Freund's complete adjuvant. Arthritis level was evaluated from the degree of swelling at the peripheral joints of the fore and hind limbs. Food consumption, body weight, and serum biochemical parameters were measured sequentially. Five or 6 animals per time point were sacrificed at 2, 3, 5 and 9 weeks after the first immunization to obtain quadriceps femoris specimens for histopathology. Pimonidazole hydrochloride was intravenously administered to determine tissue hypoxia in skeletal muscle.

RESULTS

Gradual joint swelling was observed and the maximum arthritis score was noted at Week 5. In histopathology, necrosis of muscle fiber in the quadriceps femoris was observed only at Week 2 and the most significant findings such as degeneration, atrophy, and regeneration of muscle fiber were mainly observed at Week 5. Food consumption was decreased up to Week 4 but recovered thereafter. Body weight decreased up to Week 5 and did not completely recover thereafter. A biphasic increase in serum cortisol was also observed at Weeks 2 and 5. Histopathology showed that muscle lesions were mainly composed of degeneration and atrophy of the muscle fibers, and ATPase staining revealed that the changes were more pronounced in type II muscle fiber than type I muscle fiber. In the pimonidazole experiment, mosaic pattern in skeletal muscle was demonstrated in the intact animal, but not the CIA animal. Increased arthritis score was accompanied by a decrease in serum creatinine, a marker that reflects muscle mass.

CONCLUSIONS

Muscle wasting might exacerbate joint swelling in a collagen-induced arthritis model of cynomolgus monkeys.

Tumor oxygen measurements and personalized medicine

Tumor hypoxia is probably the most important not yet measurable factor that predicts the outcome of cancer therapy. Hypoxic tumors are resistant to radiation, chemotherapy, and surgery. They signal tumor cells to grow, invade, survive cytotoxic-factor assault, and increase metastatic activity. Therapies aimed at reversing hypoxia-related treatment resistance or normalizing hypoxia are proven effective with level 1 evidence. The weak link remains the lack of satisfactory methods of measurement of tumor oxygenation.

Low-level laser therapy alleviates neuropathic pain and promotes function recovery in rats with chronic constriction injury: possible involvements in hypoxia-inducible factor 1α (HIF-1α)

Nerve inflammation plays an important role in the development and progression of neuropathic pain after chronic constrictive injury (CCI). Recent studies have indicated that hypoxia-inducible factor 1α (HIF-1α) is crucial in inflammation. Low-level laser therapy has been used in treating musculoskeletal pain, but rare data directly support its use for neuropathic pain. We investigated the effects of low-level laser on the accumulation of HIF-1α, tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) in controlling neuropathic pain, as well as on the activation of vascular endothelial growth factor (VEGF) and nerve growth factor (NGF) in promoting functional recovery in a rat CCI model. CCI was induced by placing four loose ligatures around the sciatic nerve of rats. Treatments of low-level laser (660 nm, 9 J/cm(2)) or sham irradiation (0 J/cm(2)) were performed at the CCI sites for 7 consecutive days. The effects of laser in animals with CCI were determined by measuring the mechanical paw withdrawal threshold, as well as the sciatic, tibial, and peroneal function indices. Histopathological and immunoassay analyses were also performed. Low-level laser therapy significantly improved paw withdrawal threshold and the sciatic, tibial, and peroneal functional indices after CCI. The therapy also significantly reduced the overexpressions of HIF-1α, TNF-α, and IL-1β, and increased the amounts of VEGF, NGF, and S100 proteins. In conclusion, a low-level laser could modulate HIF-1α activity. Moreover, it may also be used as a novel and clinically applicable therapeutic approach for the improvement of tissue hypoxia/ischemia and inflammation in nerve entrapment neuropathy, as well as for the promotion of nerve regeneration. These findings might lead to a sufficient morphological and functional recovery of the peripheral nerve.

Chronic inflammation and pain in a tumor necrosis factor receptor (TNFR) (p55/p75-/-) dual deficient murine model

Many aspects of tissue damage after acute or chronic inflammatory reactions can be attributed directly to the concomitant biosynthesis and release of inducible early proinflammatory cytokine tumor necrosis factor alpha (TNFα). Conversely, systemic inflammation is impacted by the consequences of tissue damage. Dysregulated TNFα contributes to numerous pathophysiologic conditions including inflammatory bowel disease (IBD) and arthritis. Inflammatory stimuli trigger proteolytic cleavage and shedding of extracellular domains of TNFα receptors giving rise to 2 soluble fragments (p55 soluble tumor necrosis factor receptor 1 (sTNFR1) and p75 sTNFR2) that block the additional binding, activity, and synthesis of TNFα. We hypothesized that absence of sTNFR inhibitory feedback control would result in accumulated high levels of TNFα and other inflammatory factors promoting the cardinal signs of chronic inflammation and pain. The current study reports a translational murine model of chronic arthritis precipitated by 2 consecutive inflammatory insults. The "double hit" procedures provoke a chronic inflammatory response and pain-related behaviors in mice that are dually deficient in p55 (TNFR1) and p75 (TNFR2). The inflammation- and pain-related behaviors are transient in similarly treated wild-type (WT) mice. The complete Freund's adjuvant (CFA) method was used initially to induce knee joint inflammation, tactile mechanical and heat hypersensitivity, and gait disturbance. After these transient effects of the insult were resolved, a recrudescence persisting at least through 23 weeks was promoted by gastrointestinal (GI) insult with dilute intracolonic mustard oil (MO) only in the mutant mice and was reversed by a P2X7 antagonist. A serum proteome profiling analysis revealed high levels of serum inflammatory factors TNFα, regulated upon activation normally T-cell expressed and secreted (RANTES), chemokine (C-X-C motif) ligand 9 [CXCL9 (MIG)], chemokine (C-X-C motif) ligand 10 [CXCL10 (IP-10)], and chemokine (C-C motif) ligand 2 [CCL2 (MCP-1)]. These data suggest that impaired signaling of TNFα as a result of the deficit of the 2 protective soluble p55 and p75 sTNFR inhibitory factors plays a pivotal role in the reactivation of the immune response to GI insult that can produce recrudescence of inflammatory injury and a chronic pain state through promotion of high levels of serum inflammatory factors.