Apoptosis and nitric oxide in an experimental model of osteoarthritis in rabbit after hyaluronic acid treatment

The Synergistic Effects of Hyaluronic Acid and Platelet-Rich Plasma for Patellar Chondropathy

Musculoskeletal disorders are increasingly prevalent worldwide, causing significant socioeconomic burdens and diminished quality of life. Notably, patellar chondropathy (PC) is among the most widespread conditions affecting joint structures, resulting in profound pain and disability. Hyaluronic acid (HA) and platelet-rich plasma (PRP) have emerged as reliable, effective, and minimally invasive alternatives. Continuous research spanning from laboratory settings to clinical applications demonstrates the numerous advantages of both products. These encompass lubrication, anti-inflammation, and stimulation of cellular behaviors linked to proliferation, differentiation, migration, and the release of essential growth factors. Cumulatively, these benefits support the rejuvenation of bone and cartilaginous tissues, which are otherwise compromised due to the prevailing degenerative and inflammatory responses characteristic of tissue damage. While existing literature delves into the physical, mechanical, and biological facets of these products, as well as their commercial variants and distinct clinical uses, there is limited discussion on their interconnected roles. We explore basic science concepts, product variations, and clinical strategies. This comprehensive examination provides physicians with an alternative insight into the pathophysiology of PC as well as biological mechanisms stimulated by both HA and PRP that contribute to tissue restoration.

Effect of intra-articular injection of a hyaluronic acid-alendronate conjugate on post-traumatic osteoarthritis induced by destabilization of the medial meniscus in rats

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by pain and cartilage damage. Intra-articular (i.a) viscosupplementation with hyaluronic acid (HA) is frequently used for the management of OA. Preclinical studies have reported that bisphosphonates (BPs) may have a therapeutic potential to slow down or reverse the progression of OA. Among these, alendronate (ALN) has demonstrated chondroprotective effects in both in vitro and vivo experiments. This study evaluated the effects of a novel alendronate-hyaluronic acid (ALN-HA) conjugate on an OA in vivo model induced by medial meniscus destabilization (DMM). DMM surgery was performed on the knees of Sprague Dawley rats that received, after four weeks, one intra-articular (i.a.) injection of: (1) ALN-HA; (2) HA; (3) sodium chloride (NaCl). Sham-operated rats were used as control. Allodynia was assessed by Von Frey test. Joint degeneration was evaluated eight weeks after treatment by micro-computed tomography (micro-CT), histology, and immunohistochemistry. Collagen cross-linked C-telopeptides (CTX-I and CTX-II) serum levels were determined by ELISA. Paw withdrawal threshold increased in ALN-HA group when compared to rats treated with NaCl or HA. Micro-CT did not show differences between ALN-HA, HA and NaCl groups. ALN-HA injection produced significant improvements in articular cartilage degeneration showing an OARSI score lower than those of HA and NaCl, and reduced matrix metalloproteinase (MMP)-13, MMP-3, interleukin-6, vascular endothelial growth factor and Caspase-3 expression. CTX-I was reduced after ALN-HA treatment when compared to NaCl. Our results indicate that i.a. use of ALN after conjugation with HA limits OA development and progression in the rat DMM model, and may lead to the development of novel therapeutic strategies in OA management.

Intra-Articular Hyaluronic Acid in Osteoarthritis and Tendinopathies: Molecular and Clinical Approaches

Musculoskeletal diseases continue to rise on a global scale, causing significant socioeconomic impact and decreased quality of life. The most common disorders affecting musculoskeletal structures are osteoarthritis and tendinopathies, complicated orthopedic conditions responsible for major pain and debilitation. Intra-articular hyaluronic acid (HA) has been a safe, effective, and minimally invasive therapeutic tool for treating these diseases. Several studies from bedside to clinical practice reveal the multiple benefits of HA such as lubrication, anti-inflammation, and stimulation of cellular activity associated with proliferation, differentiation, migration, and secretion of additional molecules. Collectively, these effects have demonstrated positive outcomes that assist in the regeneration of chondral and tendinous tissues which are otherwise destroyed by the predominant catabolic and inflammatory conditions seen in tissue injury. The literature describes the physicochemical, mechanical, and biological properties of HA, their commercial product types, and clinical applications individually, while their interfaces are seldom reported. Our review addresses the frontiers of basic sciences, products, and clinical approaches. It provides physicians with a better understanding of the boundaries between the processes that lead to diseases, the molecular mechanisms that contribute to tissue repair, and the benefits of the HA types for a conscientious choice. In addition, it points out the current needs for the treatments.

Pharmacokinetics and four-week repeated-dose toxicity of hyaluronic acid and ketorolac combination following intra-articular administration in normal rats

Intra-articular (IA) injection of hyaluronic acid (HA) in combination with nonsteroidal anti-inflammatory drugs, such as ketorolac (KL), have been clinically investigated to provide more rapid and profound pain relief in patients with osteoarthritis. However, its safety, local tolerance, and potential for pharmacokinetic interaction have not been assessed. In this study, the pharmacokinetics and toxicity of a combination of HA and KL were evaluated in normal rats following four-week repeated-dose injection. Rats received HA or KL alone at 4 mg/kg or 16 mg/kg, respectively, or HA/KL combination at 4/4 mg/kg, 4/8 mg/kg, or 4/16 mg/kg on a weekly basis. The rats exhibited temporal, reversible changes in hematology, serum chemistry, and urinalysis caused primarily by KL treatment. No deleterious effects were observed on the joint following repeated IA HA/KL administration, which showed only minimal to mild levels of temporary inflammatory changes in synovial membrane. The plasma KL level following IA injection rose as fast as that of intra-muscular injection, with no alteration with the co-administered HA. In conclusion, repeated IA administration of HA/KL combination was tolerated well in normal rats, encouraging future studies of IA injection of HA/KL combination on osteoarthritis-induced animal models and even patients.

Effects of Hesperidin on H₂O₂-Treated Chondrocytes and Cartilage in a Rat Osteoarthritis Model

Background

The purpose of this research was to investigate the effects of hesperidin on hydrogen peroxide (H₂O₂)-induced chondrocytes injury and cartilage degeneration in a rat model of osteoarthritis (OA).

Material/Methods

Chondrocytes were isolated from rat knee joints and treated with hesperidin alone or combined with H₂O₂. Then, Cell Counting Kit-8 (CCK-8) assay was used to assess cell viability. Activity of reactive oxygen species (ROS) and levels of malondialdehyde (MDA) were estimated. Cell apoptosis was assessed by flow cytometry assay. In addition, gene expression levels were measured for caspase 3, tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), collagen type II (Col2a1), aggrecan, (sex-determining region Y)-box 9 (SOX9), matrix metalloproteinase (MMP)-13, and inducible nitric oxide synthase (iNOS) through quantitative real-time polymerase chain reaction (qPCR). To examine the effects on cartilage destruction in vivo, hesperidin or vehicle control were orally administrated in a surgically-induced osteoarthritis (OA) model.

Results

The results indicated that hesperidin pretreatment of chondrocytes reduce H₂O₂-induced cytotoxicity and apoptosis. Hesperidin pretreatment decreased the formation of MDA and intracellular ROS, including chondrocyte apoptosis. Hesperidin also reversed the activity of H₂O₂ on inhibiting the Col2a1, aggrecan, and SOX9 gene expression and increasing the gene expression of caspase 3, IL-1β, TNFα, iNOS, and MMP13. In addition, hesperidin administration markedly attenuated cartilage destruction and reduced IL-1β and TNF-α levels in a surgically-induced OA model.

Conclusions

Our study suggests that hesperidin can prevent H₂O₂-induced chondrocytes injury through its antioxidant effects in vitro and reduce cartilage damage in a rat model of OA.

Comparison of Intra-articular Injection of Hyaluronic Acid and N-Acetyl Cysteine in the Treatment of Knee Osteoarthritis: A Pilot Study

Objective To compare the relative effectiveness of intra-articular N-acetyl cysteine (NAC) and hyaluronic acid (HA) on pain, function and cartilage degradation markers in patients with mild to moderate knee osteoarthritis (OA). Design We prospectively conducted a clinical trial with 20 patients having a diagnosis of Kellgren-Lawrence grade 2-3 knee OA, and randomly allocated to the HA or NAC groups. Groups were matched on age, sex, and body mass index. Injections of 3-mL HA (Hylan G-F 20) or 3-mL NAC (Asist ampoule) were administered as a single shot. Functional status and pain were evaluated before and after injection, using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the visual analogue scale (VAS) scores. Pre- and posttreatment concentrations of serum C-reactive protein (CRP), synovial fluid chondroitin-6-sulfate (C-6S), matrix metalloproteinase-3 (MMP-3), cross-linked C-terminal telopeptide of type 2 collagen (CTX-II), total oxidant status (TOS), and total antioxidant concentration (TAC) were obtained. Results WOMAC, VAS scores, and CRP levels were comparable between groups prior to treatment. Both HA and NAC produced comparable reductions in TOS and MMP-3. NAC was more effective in reducing C-6S and CTX-II ( P < 0.05). No effects on TAC were noted. Conclusions NAC is effective in lowering some cartilage degradation markers, with comparable outcomes to HA for pain and function. NAC could provide a cheaper alternative to HA for intra-articular injection treatment of mild to moderate knee OA. Future placebo controlled trials are warranted to evaluate effectiveness in a larger patient population with a wider range of age and OA severity.

Intracellular Delivery of Poorly Soluble Polyphenols: Elucidating the Interplay of Self-Assembling Nanocarriers and Human Chondrocytes

Increased molecular understanding of multifactorial diseases paves the way for novel therapeutic approaches requiring sophisticated carriers for intracellular delivery of actives. We designed and characterized self-assembling lipid-core nanocapsules for coencapsulation of two poorly soluble natural polyphenols curcumin and resveratrol. The polyphenols were identified as high-potential therapeutic candidates intervening in the intracellular inflammation cascade of chondrocytes during the progress of osteoarthritis. To elucidate the interplay between chondrocytes and nanocapsules and their therapeutic effect, we pursued a complementary analytical approach combining label-free visualization with biological assays. Primary human chondrocytes did not show any adverse effects upon nanocapsule application and coherent anti-Stokes Raman scattering images visualized their intracellular uptake. Further, by systematically blocking different uptake mechanisms, an energy independent uptake into the cells could be identified. Additionally, we tested the therapeutic effect of the polyphenol-loaded carriers on inflamed chondrocytes. Treatment with nanocapsules resulted in a major reduction of nitric oxide levels, a well-known apoptosis trigger during the course of osteoarthritis. For a more profound examination of this protective effect on joint cells, we pursued studies with atomic force microscopy investigations. Significant changes in the cell cytoskeleton as well as prominent dents in the cell membrane upon induced apoptosis were revealed. Interestingly, these effects could not be detected for chondrocytes which were pretreated with the nanocapsules. Overall, besides presenting a sophisticated carrier system for joint application, these results highlight the necessity of establishing combinatorial analytical approaches to elucidate cellular uptake, the interplay of codelivered drugs and their therapeutic effect on the subcellular level.

Cellular supplementation technologies for painful spine disorders

Low back pain affects more than 80% of adults. A proportion of these adults develops chronic low back pain (CLBP) and becomes disabled by their condition. CLBP is expensive to diagnose and treat and in terms of associated loss of productivity in the work place setting by affected individuals. Although challenging, the source of CLBP can be identified. Contemporary literature contains several studies that have established prevalence estimates for various structural sources of CLBP. In young adults, the intervertebral disk is a common source of CLBP, once it incurs annular injury that heals incompletely. Effective treatment for painful disks currently is an unmet clinical need. In older adults, the facet and sacroiliac joints are more commonly responsible for CLBP. Although certain minimally invasive techniques do exist for these painful joints, an effective restorative intervention has yet to be established. Annular injury precipitates a physiologic response that can lead to a catabolic state within the disk that impairs disk restoration. Cell loss is a feature of this process as well as the pathophysiology associated with painful facet and sacroiliac joints. Cellular supplementation is an attractive treatment strategy to initiate the repair of an injured lumbosacral structure. The introduction of exogenous cells may lead to increased extracelluar matrix production and reduced pain and disability in diskogenic CLBP. Compelling data in animal studies have been produced, stimulating Food and Drug Administration-regulated trials in humans. Numerous questions remain regarding cell viability and sufficient native nutrients to support these cells. Clinical research protocols have focused predominantly on diskogenic CLBP, and very few have addressed painful facet and/or sacroiliac joints.

The mechanism of action for hyaluronic acid treatment in the osteoarthritic knee: a systematic review

BACKGROUND

Knee osteoarthritis (OA) is one of the leading causes of disability within the adult population. Current treatment options for OA of the knee include intra-articular (IA) hyaluronic acid (HA), a molecule found intrinsically within the knee joint that provides viscoelastic properties to the synovial fluid. A variety of mechanisms in which HA is thought to combat knee OA are reported in the current basic literature.

METHODS

We conducted a comprehensive literature search to identify currently available primary non-clinical basic science articles focussing on the mechanism of action of IA-HA treatment. Included articles were assessed and categorized based on the mechanism of action described within them. The key findings and conclusions from each included article were obtained and analyzed in aggregate with studies of the same categorical assignment.

RESULTS

Chondroprotection was the most frequent mechanism reported within the included articles, followed by proteoglycan and glycosaminoglycan synthesis, anti-inflammatory, mechanical, subchondral, and analgesic actions. HA-cluster of differentiation 44 (CD44) receptor binding was the most frequently reported biological cause of the mechanisms presented. High molecular weight HA was seen to be superior to lower molecular weight HA products. HA derived through a biological fermentation process is also described as having favorable safety outcomes over avian-derived HA products.

CONCLUSIONS

The non-clinical basic science literature provides evidence for numerous mechanisms in which HA acts on joint structures and function. These actions provide support for the purported clinical benefit of IA-HA in OA of the knee. Future research should not only focus on the pain relief provided by IA-HA treatment, but the disease modification properties that this treatment modality possesses as well.

Does L-arginine availability during the early pregnancy alters the immune response of Trypanosoma cruzi infected and pregnant Wistar rats?

Chagas disease induces a strong immune response and L-arginine is an essential amino acid which plays an important role in homeostasis of the immune system. The aims of this study were to evaluate parasitemia, corticosterone levels, production of nitric oxide (NO), fetal morphological measurements, and histology of heart and placenta. Twenty pregnant Wistar rats (180-220 g) were grouped in: pregnant control (PC), pregnant control and L-arginine supplied (PCA), pregnant infected (PI), pregnant infected and L-arginine supplied (PIA). Females were infected with 1×10(5) trypomastigotes of the Y strain (3rd day of pregnancy). Animals were supplied with 21 mg of L-arginine/kg/day during 14 days. PIA showed significant decreased levels of corticosterone and parasitemia. For control groups, any alteration in NO production was found with L-arginine supplementation; for PIA, enhanced nitrite concentrations were observed as compared to PI. Weights and lengths of fetuses were higher in L-arginine treated and infected pregnant rats as compared to untreated ones. Placental weight from the PIA group was significantly increased when compared to PI. In L-arginine treated animals, cardiac tissue showed reduced amastigote burdens. PIA and PI displayed similar placental parasitism. Based on these results, L-arginine supplementation may be potentially useful for the protection against Trypanosoma cruzi during pregnancy.

Noxa in rheumatic diseases: present understanding and future impact

Impaired programmed cell death is an important contributing mechanism in the development of chronic inflammatory and autoimmune diseases. Overexpression of Bcl-2 family proteins in such diseases has led to the concept of targeted suppression of these proteins as a primary therapeutic strategy. However, limited success with this approach has prompted pharmacologists to look at the other side of the coin, with the aim of reactivating jeopardized pro-apoptotic proteins that may neutralize Bcl-2 or other anti-apoptotic molecules. In this effort, BH3-only proteins have gained recent attention as endogenous molecules for the sensitization of resistant cells to undergo apoptosis. Among the BH3-only family, Noxa stands out as exceptional for its specificity to bind Mcl-1 and Bcl-2 and blunt their biological properties. Noxa is now being tested as a promising therapeutic target in cancer biology. Nonetheless, its role and clinical application still lack validation in autoimmune diseases, including rheumatic conditions. This is partly attributed to the significant gap in our understanding of its regulatory role and how either overexpression of Noxa or delivery of BH3 mimetics could be therapeutically exploited. In this review we highlight some recent studies in RA, OA, SLE and SS suggesting that Noxa may be used as a potential therapeutic target to circumvent invasive and tissue destructive processes in these rheumatic diseases.

A review of translational animal models for knee osteoarthritis

Knee osteoarthritis remains a tremendous public health concern, both in terms of health-related quality of life and financial burden of disease. Translational research is a critical step towards understanding and mitigating the long-term effects of this disease process. Animal models provide practical and clinically relevant ways to study both the natural history and response to treatment of knee osteoarthritis. Many factors including size, cost, and method of inducing osteoarthritis are important considerations for choosing an appropriate animal model. Smaller animals are useful because of their ease of use and cost, while larger animals are advantageous because of their anatomical similarity to humans. This evidence-based review will compare and contrast several different animal models for knee osteoarthritis. Our goal is to inform the clinician about current research models, in order to facilitate the transfer of knowledge from the "bench" to the "bedside."

Effect of a solution of hyaluronic acid-chondroitin sulfate-N-acetyl glucosamine on the repair response of cartilage to single-impact load damage

OBJECTIVE

To investigate effects of 1% hyaluronic acid-chondroitin sulfate-N-acetyl glucosamine (HCNAG) on the damage repair response in equine articular cartilage.

SAMPLE

Articular cartilage from 9 clinically normal adult horses.

PROCEDURES

Full-thickness cartilage disks were harvested from the third metacarpal bone. Cartilage was single-impact loaded (SIL) with 0.175 J at 0.7 m/s and cultured in DMEM plus 1 % (vol/vol) HCNAG or fibroblastic growth factor (FGF)-2 (50 ng/mL). Histologic and immunohistochemical techniques were used to identify tissue architecture and apoptotic cells and to immunolocalize type I and II collagen and proliferating nuclear cell antigen (PCNA).

RESULTS

Type II collagen immunoreactivity increased in SIL cartilage, compared with control samples. At days 14 and 28 (day 0 = initiation of culture), control samples had significantly fewer repair cells than did other treatment groups. In control samples and SIL + HCNAG, there was a significant decrease in apoptotic cell number, compared with results for SIL and SIL + FGF-2 samples. At days 14 and 28, there was a significant increase in chondrocytes stained positive for PCNA in the control samples.

CONCLUSIONS AND CLINICAL RELEVANCE

1% HCNAG significantly affected apoptotic and repair cell numbers in an SIL damage-repair technique in adult equine articular cartilage. However, HCNAG had no effect on the number of PCNA-positive chondrocytes or on type II collagen immunohistochemical results. The inclusion of 1% HCNAG in lavage solutions administered after arthroscopy may be beneficial to cartilage health by increasing the number of repair cells and decreasing the number of apoptotic cells.

Procyanidin B3 prevents articular cartilage degeneration and heterotopic cartilage formation in a mouse surgical osteoarthritis model

Osteoarthritis (OA) is a common disease in the elderly due to an imbalance in cartilage degradation and synthesis. Heterotopic ossification (HO) occurs when ectopic masses of endochondral bone form within the soft tissues around the joints and is triggered by inflammation of the soft tissues. Procyanidin B3 (B3) is a procyanidin dimer that is widely studied due to its high abundance in the human diet and antioxidant activity. Here, we evaluated the role of B3 isolated from grape seeds in the maintenance of chondrocytes in vitro and in vivo. We observed that B3 inhibited H(2)O(2)-induced apoptosis in primary chondrocytes, suppressed H(2)O(2)- or IL-1ß-induced nitric oxide synthase (iNOS) production, and prevented IL-1ß-induced suppression of chondrocyte differentiation marker gene expression in primary chondrocytes. Moreover, B3 treatment enhanced the early differentiation of ATDC5 cells. To examine whether B3 prevents cartilage destruction in vivo, OA was surgically induced in C57BL/6J mice followed by oral administration of B3 or vehicle control. Daily oral B3 administration protected articular cartilage from OA and prevented chondrocyte apoptosis in surgically-induced OA joints. Furthermore, B3 administration prevented heterotopic cartilage formation near the surgical region. iNOS protein expression was enhanced in the synovial tissues and the pseudocapsule around the surgical region in OA mice fed a control diet, but was reduced in mice that received B3. Together, these data indicated that in the OA model, B3 prevented OA progression and heterotopic cartilage formation, at least in a part through the suppression of iNOS. These results support the potential therapeutic benefits of B3 for treatment of human OA and heterotopic ossification.

Management of articular cartilage defects of the knee

Articular cartilage injuries of the knee present a difficult clinical dilemma and their treatment is controversial. Hyaline articular cartilage is an avascular, low-friction, and wear-resistant weightbearing surface that has limited capacity for self-repair. The optimal treatment for cartilage lesions has yet to be established. Various treatment methods are employed to reestablish a stable cartilage surface, including microfracture, autologous and allograft osteochondral transplantation, autologous chondrocyte implantation, matrix-associated chondrocyte implantation, and scaffold-assisted methods. Treatment algorithms help to guide physicians' decision making in the care of these injuries. In this article, results from outcomes studies as well as prospective randomized clinical trials comparing treatment methods are reviewed, and current practice guidelines are summarized.

New Frontiers for Cartilage Repair and Protection

OBJECTIVE

Articular cartilage injury is common after athletic injury and remains a difficult treatment conundrum both for the surgeon and athlete. Although recent treatments for damage to articular cartilage have been successful in alleviating symptoms, more durable and complete, long-term articular surface restoration remains the unattained goal. In this article, we look at both new ways to prevent damage to articular surfaces as well as new techniques to recreate biomechanically sound and biochemically true articular surfaces once an athlete injures this surface. This goal should include reproducing hyaline cartilage with a well-integrated and flexible subchondral base and the normal zonal variability in the articular matrix.

RESULTS

A number of nonoperative interventions have shown early promise in mitigating cartilage symptoms and in preclinical studies have shown evidence of chondroprotection. These include the use of glucosamine, chondroitin, and other neutraceuticals, viscosupplementation with hyaluronic acid, platelet-rich plasma, and pulsed electromagnetic fields. Newer surgical techniques, some already in clinical study, and others on the horizon offer opportunities to improve the surgical restoration of the hyaline matrix often disrupted in athletic injury. These include new scaffolds, single-stage cell techniques, the use of mesenchymal stem cells, and gene therapy.

CONCLUSION

Although many of these treatments are in the preclinical and early clinical study phase, they offer the promise of better options to mitigate the sequelae of athletically induced cartilage.

Intra-articular hyaluronic acid: potential treatment of younger patients with knee injury and/or post-traumatic arthritis

Anterior cruciate ligament (ACL) and meniscal injuries are common in both athletes and the general population. Such injuries may lead to early-onset post-traumatic osteoarthritis (OA) in 50% to 60% of patients, regardless of whether patients had reconstruction performed. In younger patients, intra-articular (IA) injection of hyaluronic acid (HA) may be useful for improving short-term outcomes and possibly slowing or arresting the progression of OA. Hyaluronic acid has anti-inflammatory, anabolic, and chondroprotective effects, which have been demonstrated in in vitro and animal models of meniscal and ACL injury. Results from several clinical trials and patient series have demonstrated the benefit of IA HA injection in younger patients with acute knee damage, including symptomatic meniscal tears and isolated ACL injury with chondral injury, although evidence for this is less extensive than the large database supporting the use of IA HA injection in older patients with knee OA. Administration of HA has been shown to improve outcomes in patients undergoing knee arthroscopy, and IA HA also has direct antinociceptive effects that may contribute to its benefit in patients with patellofemoral pain. However, the use of IA HA in patients with ACL injury or early OA has been evaluated in only a few studies. Thus, there is a need for larger-scale randomized controlled trials with longer durations of follow-up to provide more definitive evaluation of the efficacy and safety of IA HA in these patients. Such studies provide an opportunity to further elucidate the benefits of IA HA in younger patients with knee damage and may result in appropriate expansion of use in this large population, which has a substantial need for new treatment alternatives.

Esterified hyaluronic acid improves cartilage viability in experimental tracheal reconstruction with an auricular graft

OBJECTIVE: The aim of this study was to determine the efficacy of esterified hyaluronic acid (HYAFF) on the vitality of auricular cartilage grafts used for tracheoplasty, with respect to macroscopic and microscopic parameters.

STUDY DESIGN: Prospective, controlled.

SETTING: Academic research laboratory.

SUBJECTS AND METHODS: The study included 14 New Zealand rabbits acquired specifically for the study. The rabbits were divided into two groups: the control group, in which free cartilage grafts were not exposed to any materials or additional procedures (n = 7), and the hyaluronic acid (HA) treatment group, in which auricular grafts and anastomosis lines were covered with HYAFF (n = 7). Free auricular cartilage grafts used for the reconstruction of experimentally created tracheal defects were anastomosed extraluminally. All the rabbits were sacrificed two months post surgery. Samples were collected and examined histopathologically. The sections were stained with hematoxylineosin, Masson's trichrome, and inducible nitric oxide synthase (iNOS) and examined under a light microscope.

RESULTS: Fibrosis and cartilage mass significantly differed between the control and HYAFF group ( P < 0.05). Immunohistochemical examination showed that more chondrocytes stained with iNOS in the control group than in the HYAFF group, according to histologists' observations.

CONCLUSION: HYAFF catalyzed wound healing with less fibrous tissue formation, had chondroprotective and stimulatory effects on chondrocyte metabolism, and decreased nitric oxide production and apoptosis via improving the nourishment of free auricular cartilage grafts, subsequently preventing hypoxia and oxidative stress, particularly in the early postimplantation period.

The protective effect of tetramethylpyrazine on cartilage explants and chondrocytes

AIMS OF STUDY

Ligusticum wallichi Franchat (chuanxiong) is a very common traditional Chinese herbal medicine in China. Tetramethylpyrazine (TMP) is a major active ingredient extracted from Ligusticum wallichi Franchat. We investigated the protective effect of TMP on interleukin-1β (IL-1β) induced proteoglycan (PG) degradation and apoptosis in rabbit articular cartilage and chondrocytes.

MATERIALS AND METHODS

Rabbit articular cartilage explants and chondrocytes were cultured with 10 ng/ml IL-1β for 72 h in the absence or presence of various concentrations of TMP (50, 100 or 200 μM). Cartilage and chondroprotective effects of TMP were determined by evaluating (1) the degree of PG degradation by measuring the amount of glycosaminoglycan (GAG) released into the culture media with 1,9-dimethylmethylene blue (DMMB) assay in cartilage explants; (2) gene expression of MMP-3 and TIMP-1 by real-time quantitative reverse transcription-polymerase chain reaction analysis in cartilage explants; (3) chondrocytes viability with MTT assay; (4) the production of intracellular reactive oxygen species (ROS) with laser scanning confocal microscopy (LSCM). Anti-apoptotic effects of TMP were determined by measuring (1) apoptosis with flow cytometric analysis; (2) mitochondrial membrane potential assay with LSCM; (3) caspase-3 activity with special assay kit.

RESULTS

IL-1β treatment increased the level of GAG released into the culture media, and induced the gene expression of MMP-3 and inhibited the gene expression of TIMP-1 in cartilage explants. Moreover, IL-1β treatment decreased the cell viability and mitochondrial membrane potential, and enhanced the level of intracellular ROS, apoptosis rate, and caspase-3 activity in chondrocytes. However, simultaneous treatment with TMP attenuated the IL-1β-induced cartilage and chondrocyte destruction in a dose-dependent manner. TMP showed the decrease of GAG degradation and MMP-3 mRNA production, and the enhancement of TIMP-1 mRNA production in cartilage explants. TMP also increased the cell viability in chondrocytes. Furthermore, TMP inhibited the chondrocytes apoptosis through suppression of ROS production, maintaining of mitochondrial membrane potential and downregulation of caspase-3 activity.

CONCLUSION

These results demonstrate that TMP has the cartilage and chondroprotective effect, which suggest that TMP could act as an agent for pharmacological intervention in the progress of OA.

The OARSI histopathology initiative - recommendations for histological assessments of osteoarthritis in the rabbit

AIM

The primary goal of this body of work is to suggest a standardized system for histopathological assessment of experimental surgical instability models of osteoarthritis (OA) in rabbits, building on past experience, to achieve comparability of studies from different centres. An additional objective is to review methodologies that have been employed in the past for assessing OA in rabbits with particular reference to the surgical anterior cruciate ligament transection (ACLT) model.

METHODS

A panel of scientists and clinician-scientists with recognized expertise in assessing rabbit models of OA reviewed the literature to provide a critical appraisal of the methods that have been employed to assess both macroscopic and microscopic changes occurring in rabbit joint tissues in experimental OA. In addition, a validation of the proposed histologic histochemical grading system was performed.

RESULTS

The ACLT variant of the surgical instability model in skeletally mature rabbits is the variation most capable of reproducing the entire range of cartilage, synovial and bone lesions recognized to be associated with OA. These lesions can be semiquantitatively graded using macroscopic and microscopic techniques. Further, as well as cartilage lesions, this ACLT model can produce synovial and bone lesions similar to that of human OA.

CONCLUSIONS

The ACLT variant of the surgical instability model in rabbits is a reproducible and effective model of OA. The cartilage lesions in this model and their response to therapy can be graded according to an adapted histological and histochemical grading system, though also this system is to some extent subjective and, thus, neither objective nor entirely reproducible.

Effects of hyaluronan on carrageenan-induced synovitis in rat TMJ

Nitric oxide is one of many proinflammatory mediators that are involved in temporomandibular joint (TMJ) inflammatory disorder and is synthesized by inducible nitric oxide synthase (iNOS). iNOS is transcriptionally regulated by nuclear factor-κB (NF-κB) in cases of inflammation, proliferation, and apoptosis. It has also been reported that nitric oxide is positively regulated by carrageenan and negatively regulated by hyaluronan in the knee joint. The aim of this study was to histologically evaluate how inflammation and cell proliferation of the synovial membrane are affected by the exogenous administration of carrageenan and hyaluronan in the rat TMJ by investigating iNOS, NF-κB, and anti proliferating cell nuclear antigen (PCNA) immunoreactivity. As results, immunoreactive cells to iNOS, NF-κB, and PCNA were normally localized only in the synovial membrane of wild type TMJs. The numbers of immunoreactive cells were extensively larger in the carrageenan-injected synovial membranes exhibiting excessive folding, and smaller in the hyaluronan-injected synovial membranes showing a few folds. These results indicate that a carrageenan injection induced inflammation and cell proliferation especially in the synovial membrane and that hyaluronan relieved the inflammation by decreasing inflammatory molecules in the synovial membrane.

N-acetylcysteine prevents nitric oxide-induced chondrocyte apoptosis and cartilage degeneration in an experimental model of osteoarthritis

We investigated whether N-acetylcysteine (NAC), a precursor of glutathione, could protect rabbit articular chondrocytes against nitric oxide (NO)-induced apoptosis and could prevent cartilage destruction in an experimental model of osteoarthritis (OA) in rats. Isolated chondrocytes were treated with various concentrations of NAC (0-2 mM). Apoptosis was induced by 0.75 mM sodium nitroprusside (SNP) dehydrate, which produces NO. Cell viability was assessed by MTT assay, while apoptosis was evaluated by Hoechst 33342 and TUNEL staining. Intracellular reactive oxygen species (ROS) and glutathione levels were measured, and expression of p53 and caspase-3 were determined by Western blotting. To determine whether intraarticular injection of NAC prevents cartilage destruction in vivo, cartilage samples of an OA model were subjected to H&E, Safranin O, and TUNEL staining. NAC prevented NO-induced apoptosis, ROS overproduction, p53 up-regulation, and caspase-3 activation. The protective effects of NAC were significantly blocked by buthionine sulfoximine, a glutathione synthetase inhibitor, indicating that the apoptosis-preventing activity of NAC was mediated by glutathione. Using a rat model of experimentally induced OA, we found that NAC also significantly prevented cartilage destruction and chondrocyte apoptosis in vivo. These results indicate that NAC inhibits NO-induced apoptosis of chondrocytes through glutathione in vitro, and inhibits chondrocyte apoptosis and articular cartilage degeneration in vivo.

Therapeutic trajectory of hyaluronic acid versus corticosteroids in the treatment of knee osteoarthritis: a systematic review and meta-analysis

OBJECTIVE

To compare the efficacy of intraarticular hyaluronic acid with corticosteroids for knee osteoarthritis (OA).

METHODS

Our data sources were Medline, EMBASE, CINAHL, BIOSIS, and the Cochrane database, as well as hand- searched reviews, manuscripts, and supplements. For unpublished data we used author contacts. Randomized trials that reported effects of intraarticular hyaluronic acid versus corticosteroids on knee OA were selected based on inclusion criteria. Two reviewers extracted data independently. Using a random-effects model, we computed effect sizes for pain change from baseline at 2, 4, 8, 12, and 26 weeks. We also performed multivariate analyses accounting for within and between-study covariance. We performed sensitivity analyses for trials that reported intent-to-treat (ITT) analysis and blinding, and directly compared Hyalgan with methylprednisolone.

RESULTS

The 7 eligible trials included 606 participants. Five reported ITT analyses. At week 2 the effect size was -0.39 (95% confidence interval [95% CI], -0.65, -0.12) favoring corticosteroids; at week 4 it was -0.01 (95% CI -0.23, 0.21) suggesting equal efficacy. At week 8 the effect size was 0.22 (95% CI -0.05, 0.49) favoring hyaluronic acid, and at week 12 it was 0.35 (95% CI 0.03, 0.66) favoring hyaluronic acid. At week 26 the effect size was 0.39 (95% CI 0.18, 0.59), favoring hyaluronic acid. The multivariate analyses and sensitivity analyses generated consistent results.

CONCLUSION

From baseline to week 4, intraarticular corticosteroids appear to be relatively more effective for pain than intraarticular hyaluronic acid. By week 4, the 2 approaches have equal efficacy, but beyond week 8, hyaluronic acid has greater efficacy. Understanding this trend is useful to clinicians when treating knee OA.

The role of different hyaluronic acids in the articular cartilage of rabbit

Purpose:

To elucidate if the differences found in the physico-chemical and rheological behaviour of Hyaluronic Acids result in different in vivo activity. For this purpose two Hyaluronic Acids (HA), HA-1 and HA-2, with similar molecular weight but different percentage of concentration variation, were compared through an osteoarthritis model.

Methods and Materials:

Osteoarthritis was induced in white New Zealand rabbits by anterior cruciate ligament section. After the induction period, the animals were allocated to receive HA-1 or HA-2 intra-articularly in one knee whereas the contralateral knee was used as Operated Control. An additional group of non-operated animals was used as Healthy Controls. Samples of cartilage were taken for different measures: apoptosis, nitric oxide (nitrites) and hyaluronic acid in synovial fluid.

Results:

The administration of HA-1 had a significant inhibitor effect on apoptosis of the chondrocytes compared to operated untreated animals (p = 0.0089), whereas this difference was not observed in the HA-2 knees. Levels of nitrites determined by HPLC in the HA-1 knees were similar to those in the Healthy group (p = 0.6551) whereas they were significantly higher in Operated Control and HA-2 groups (p = 0.0001). The comparison between HA-1 and HA-2 also revealed significantly lower levels of nitrites in the HA-1 knees (p = 0.0001). Values of hyaluronic acid in synovial fluid did not show statistical differences between the different study groups.

Conclusions:

HA-1 and HA-2 showed different physico-chemical characteristics and these differences have resulted in different in vivo behaviour. As a consequence, not all the HA with similar molecular weight can be considered as equivalent.

Prospective pilot study of painful lumbar facet joint arthropathy after intra-articular injection of hylan G-F 20

OBJECTIVE

To examine changes in pain, disability, and medication usage over time from baseline to up to 12 months after facet joint injection of hylan G-F 20.

DESIGN

Prospective, uncontrolled, pilot study.

SETTING

University spine center.

PARTICIPANTS

Fifteen patients (12 females), mean age of 57 years (standard deviation = 12.5), with a median duration of low back pain of 24 months (interquartile range = 11-66).

METHODS

Patients who fulfilled inclusion criteria underwent diagnostic blocks with local comparative anesthetics at one unilateral facet joint (FJ). Those with a true positive response underwent 2 1.0-mL intra-articular hylan G-F 20 injections, 10 days apart, into the painful FJ. A third hylan G-F 20 injection was offered to patients dissatisfied with the results obtained with the first 2 injections.

MAIN OUTCOME MEASURES

Visual analog scale (VAS) (average, standing, walking), Oswestry Disability Index (ODI), SF-36, finger to floor distance (FTF), tolerance (standing, sitting, walking), analgesic usage, and patient satisfaction collected at baseline, 7-10 days, and at 1-, 3-, 6-, and 12-months follow-up.

RESULTS

Repeated measures mixed-models indicated that VAS (average, standing, walking [P all < .005]), ODI (P = .029), SF-36 (P = .013), FTF (P = .032), and sitting tolerance (P = .020) all showed significant changes from baseline up to 6 months and were not sustained at 12 months; with the exception of the baseline to 12-month difference for FTF. There was not evidence of changes over time in standing (P = .085) or walking (P = .084) tolerance. Satisfaction initially increased from baseline (0%) to 7-10 days (64%) but declined over time (36% at 12 months). As compared with baseline (80%), analgesic usage decreased nominally over time showing significant decreases at 6 months (33%, P = .0253) and increased slightly at 12 months (45%).

CONCLUSIONS

Viscosupplementation for lumbar FJ arthropathy with hylan G-F 20 is associated with modest efficacy that predominately lasts up to 6 months. Limitations include a small sample size and lack of both a control and blinding. Larger, randomized, controlled studies are indicated to better clarify its clinical safety, efficacy, and utility.

Intra-articular magnesium sulfate (MgSO4) reduces experimental osteoarthritis and nociception: association with attenuation of N-methyl-D-aspartate (NMDA) receptor subunit 1 phosphorylation and apoptosis in rat chondrocytes

OBJECTIVE

To study the effects of intra-articular injection of magnesium sulfate (MgSO(4)) on the development of osteoarthritis (OA) and to examine concomitant changes in the nociceptive behavior of rats.

METHODS

OA was induced in Wistar rats with intra-articular injection of collagenase (500 U) in the right knee; the left knee was left untreated. In the OA+MgSO(4) group (n=7), the treated knee was injected with 500-microg (0.1-ml) MgSO(4) twice a week for 5 consecutive weeks starting at 1 week after collagenase injection; in the OA group (n=7), the same knee was injected with the same amount of physiological normal saline. In the MgSO(4) group (n=6), naïve rats received only MgSO(4) injections; in the control group (n=6), naïve rats received only physiological normal saline injections. Nociceptive behavior (mechanical allodynia and thermal hyperalgesia) on OA development was measured before and at 1, 2, 4, 6, and 8 weeks after collagenase injection, following which the animals were sacrificed. Gross morphology and histopathology were examined in the femoral condyles, tibial plateau, and synovia. Immunohistochemical analysis was performed to examine the effect of MgSO(4) on N-methyl-D-aspartate (NMDA) receptor subunit 1 phosphorylation (p-NR1) and apoptosis in the articular cartilage chondrocytes.

RESULTS

OA rats receiving intra-articular MgSO(4) injections showed a significantly lower degree of cartilage degeneration than the rats receiving saline injections. MgSO(4) treatment also suppressed synovitis. Mechanical allodynia and thermal hyperalgesia showed significant improvement in the OA+MgSO(4) group as compared to the OA group. Moreover, MgSO(4) attenuated p-NR1 and chondrocyte apoptosis in OA-affected cartilage.

CONCLUSIONS

Our results indicate that local intra-articular administration of MgSO(4) following collagenase injection in an experimental rat OA model (1) modulates chondrocyte metabolism through inhibition of cell NMDA receptor phosphorylation and apoptosis, (2) attenuates the development of OA, and (3) concomitantly reduces nociception.

Hyaluronic acid viscosupplementation and osteoarthritis: current uses and future directions

Intra-articular hyaluronic acid viscosupplementation is gaining popularity as a treatment option in the nonoperative management of patients with osteoarthritis. Recent clinical studies have demonstrated that the anti-inflammatory, anabolic, and chondroprotective actions of hyaluronic acid reduce pain and improve patient function. With evidence mounting in support of the efficacy of this treatment modality for patients with osteoarthritis, its potential use in additional patient populations and for other pathologies affecting the knee is being investigated. The current article reviews the use of intra-articular hyaluronic acid viscosupplementation in the management of knee osteoarthritis and presents the potential for expanding its indications for other joints and alternative patient subpopulations. Additionally, future directions for the use of hyaluronic acid and areas of active research are discussed.

The effect of hyaluronic acid on IL-1beta-induced chondrocyte apoptosis in a rat model of osteoarthritis

The purpose of this article was to study the effect of hyaluronic acid (HA) on chondrocyte apoptosis in a rat osteoarthritis in vitro model (exposure to IL-1beta) and explore its mechanism. A rat in vitro model of osteoarthritis (OA) was established using 10 ng/mL IL-1beta as a modulating and chondrocyte apoptosis inducing agent. Different doses of HA (10, 20, and 40 microg/mL) were added 1 h prior to the addition of IL-1beta to a monolayer culture of freshly isolated juvenile rat chondrocytes. The ratio of apoptotic cell death was surveyed by Annexin V-FITC and propidium iodide double-labeling FACS analysis. The mitochondrial membrane potential of chondrocytes was evaluated by rhodamine-123 fluorescence. The mitochondrial function was evaluated through detecting the ATP production by a luciferase assay. The reverse transcription polymerase chain reaction (RT-PCR) was performed to measure mRNA expression levels of inducible oxide synthase (iNOS). HA could inhibit IL-1beta-induced chondrocyte apoptosis in our cell culture model system. It was showed that addition of HA to the medium was able in a dose-dependent way to reduce the impairment of the mitochondrial membrane potential and to restore mitochondrial ATP production. This study shows that HA could suppress in a dose-dependent way chondrocyte apoptosis in our IL-1beta-induced osteoarthritis model. The suppression of inflammatory cytokine activity within the joint might be one important mechanism of the clinical action of intraarticular injection of HA in the treatment of OA.

Intra-articular injection of hyaluronan diminishes loss of chondrocytes in a rat immobilized-knee model

Joint immobilization is a useful and common treatment modality in orthopedics. However, it also causes unfavorable outcome such as articular cartilage degeneration. Intra-articular injection of hyaluronan has been accepted as a treatment of osteoarthritis, but its effects on immobilized joint remain to be clarified. Hyaluronan is a polysaccharide, distributed ubiquitously in various tissues. In this study, we examined the effect of hyaluronan on the articular cartilage in immobilized joints. The unilateral knee joints of adult male rats were immobilized at 150 degrees in flexion with an internal plate and screws for 1, 2, 4, 6, 8, 12, or 16 weeks (n = 84). Hyaluronan or saline (50 microl/each injection) was administered intra-articularly on the day of surgery and once a week. The articular cartilage from the medial midcondylar region of the knee was obtained, and divided into non-contact, contact and transitional areas (between the non-contact and the contact areas). In each area, a degree of degeneration was evaluated by histomorphometric grading, and measurements of thickness and number of chondrocytes. Histological grading scores in the hyaluronan group were smaller at 12 and 16 weeks compared with those in the saline group. The thickness of the articular cartilage increased in the transitional area in both groups. The number of chondrocytes in the contact and transitional areas gradually decreased, but their number in the hyaluronan group was greater at 12 and 16 weeks compared with that in the saline group. Hyaluronan showed chondroprotective effects on the articular cartilage in a rat immobilized-knee model.

One intra-articular injection of hyaluronan prevents cell death and improves cell metabolism in a model of injured articular cartilage in the rabbit

The purpose of this study was to determine the effect of one intra-articular injection of hyaluronan on chondrocyte death and metabolism in injured cartilage. Twenty-three 6-month-old rabbits received partial-thickness articular cartilage defects created on each medial femoral condyle. In order to examine the effect on articular cartilage surrounding iatrogenic cartilage lesions, which can occur during arthroscopic procedures, Study 1 was performed: in 14 rabbits both knees were immediately rinsed with 0.9% NaCl. Experimental knees were treated with hyaluronan. Six rabbits were sacrificed at 2 days; eight rabbits 3 months postoperatively. Histomorphometric analysis was used for studying cell death in cartilage next to the defect. In order to examine the effect on longer lasting lesions, more reflecting the clinical situation, Study 2 was performed: after 6 months knee joints of nine rabbits were (i) irrigated with 0.9% NaCl, (ii) treated with hyaluronan after irrigation with 0.9% NaCl, or (iii) sham-treated. After 7 days patellas were used to study the chondrocyte metabolism by measuring the [(35)S]sulfate incorporation. Study 1: Two days postoperatively, in hyaluronan-treated cartilage the percentage of dead cells was 6.7%, which was significantly lower compared to 16.2% in saline-treated cartilage. After 3 months the percentages of dead cells in both groups were statistically similar. Study 2: Hyaluronan treatment resulted in significantly higher [(35)S]sulfate incorporation compared to knees irrigated with 0.9% NaCl. These results suggest a potential role for hyaluronan in preventing cell death following articular cartilage injury. One injection of hyaluronan improved cartilage metabolism in knees with 6-month-old cartilage defects.

Intra-articular injection of collagenase induced experimental osteoarthritis of the lumbar facet joint in rats

We aimed to establish an animal model to investigate primary osteoarthritis of the lumbar facet joints after collagenase injection in rats and its effects on chondrocyte apoptosis. We hypothesized that osteoarthritic-like changes would be induced by collagenase injection and that apoptosis of chondrocytes would increase. Collagenase (1, 10, or 50 U) or saline (control) was injected into the lumbar facet joints. The histology and histochemistry of cartilage, synovium, and subchondral bone were examined at 1, 3, and 6 weeks after surgery. Apoptotic cells induced by 1 U of collagenase were quantified using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay. Degeneration of the cartilage and changes to the synovium and subchondral bone were dependent on both the doses of collagenase and the time after surgery. There were significantly more apoptotic chondrocytes in collagenase-treated joints than in control (P < 0.001 at 1 and 3 weeks and P < 0.05 at 6 weeks). Thus, lumbar facet joints subjected to collagenase developed osteoarthritic-like changes that could be quantified and compared. This model provides a useful tool for further study on the effects of compounds that have the potential to inhibit enzyme-associated damage to cartilage.

Detection and distribution of apoptotic cell death in normal and diseased canine cranial cruciate ligaments

One of the possible initiating factors in canine cranial cruciate ligament (CCL) rupture could be an abnormal pattern of ligament cell death. This study compared apoptotic cell death in sections of ruptured CCLs and normal controls, and examined nitric oxide (NO) production in joint tissues and correlated this to apoptosis. CCLs and cartilage from the lateral femoral condyle were harvested from 10 healthy dogs and 15 dogs with CCL rupture and ligaments were further processed to detect cleaved caspase-3 and to determine supernatant NO production in explant cultures. Apoptotic activity was greater in ruptured ligaments compared to controls. NO in ligaments showed a moderate but significant positive correlation with caspase-positive cells. The results suggest that increased apoptosis has a role in CCL rupture and that apoptosis may be influenced by local NO production.