Effect of resveratrol on cartilage protection and apoptosis inhibition in experimental osteoarthritis of rabbit

To observe the effect of resveratol on cartilage,chondrocyte apoptosis, and nitric oxide in experimental osteoarthritis (OA) of rabbit and to study the mechanism of resveratol in the treatment of osteoarthritis. Thirty New Zealand rabbits were randomly divided into 5 groups: group A (normal control group), group B (model control group), group C (resveratrol intervention high-dosage group), group D (resveratrol intervention middle dosage group), and group E (resveratrol intervention low-dosage group). The model of OA of the knee was established using Hulth technique in groups B, C, D, and E. After 4?weeks, group A and group B rabbits were administered daily a knees injection of dimethylsulfoxide (DMSO), whereas groups C, D, and E were administered daily a knees injection of resveratrol in DMSO in different dosages for 2?weeks. Daily dosage for rabbits of groups C, D, and E was fixed at 50, 20, and 10?μmol/kg, respectively. Then, the rabbits were killed, and the lateral cartilage sections of right femoral medial condyle were evaluated using a histological scoring system (H&E and safranin-O staining) and analyzed by TUNEL for apoptosis. Nitric oxide (NO) in synovial fluid was measured by nitrate reduction method. Histological evaluation of cartilage tissue revealed a significantly reduced cartilage destruction; the evaluation also revealed the loss of matrix proteoglycan content in cartilage in resveratrol intervention groups compared to the model control. Resveratrol reduced the apoptosis rate of chondrocyte and level of NO in the synovial fluid. In the above experiments of OA rabbits, the protective effects of resveratrol were enhanced with increased resveratrol dosage. Resveratrol controls the progression of experimental OA. One of the mechanism(s) responsible for this effect would include lowering of the apoptosis rate of chondrocyte and reducing the production of NO in experimental OA.     

Effect of dehydroepiandrosterone on cartilage and synovium of knee joints with osteoarthritis in rabbits

The aim of this study was to investigate the effects of intra-articular injection of dehydroepiandrosterone (DHEA) on cartilage and synovium of knee joints with osteoarthritis (OA) in rabbits and the underlying mechanism. Forty rabbits underwent unilateral anterior cruciate ligament transaction and were divided into two groups. Rabbits were injected with 100 μmol/l DHEA dissolved in the dimethylsulphoxide (DMSO) in the knee joints 5 weeks after transaction, once a week for 5 weeks. Rabbits injected with DMSO under the same condition were served as a control. All rabbits were killed 1 week after the last injection. The knee joints were evaluated by gross morphology, histology, and gene expression analysis. Gross morphologic inspection and histological evaluation showed that the DHEA group appeared less damage in cartilage and synovium as compared with the control. Gene expression analysis revealed that the mRNA expression of matrix metalloproteinase-3 (MMP-3) in cartilage and synovium decreased significantly in the DHEA group and that of tissue inhibitor of metalloproteinase-1 (TIMP-1) increased. No significant difference of interleukin-1 beta (IL-1β) mRNA expression was found in the cartilage between two groups while the mRNA expression of IL-1β in the synovium was largely suppressed in the DHEA group. The study suggests that DHEA plays a protective role against cartilage degradation and synovium inflammation in rabbits with OA. This role may be achieved through the regulation of the MMP-3, TIMP-1, and IL-1β gene expression in the cartilage and synovium.     

壳聚糖膝关节腔内注射疗法对兔骨关节炎关节软骨的影响

目的观察关节内注射羧甲基壳聚糖(CMCTS)对兔骨关节炎(OA)关节软骨退变及软骨基质金属蛋白酶(MMP)-1,-3mRNA表达的影响。方法24只大耳白兔行单侧膝关节前交叉韧带切断术,术后5周将动物随机分为3组,A组关节内注射2%CMCTS0.3ml,每2周1次;B组关节内注射1%透明质酸钠(HA)0.3ml,每周1次;C组关节内不注射药物。术后11周处死动物,观察各组股骨内髁关节软骨的大体变化,采用反转录-聚合酶链反应(RT-PCR)方法检测股骨内髁退变软骨中MMP-1和MMP-3的mRNA表达。结果CMCTS和HA注射组软骨退变程度较不用药组明显减轻,CMCTS注射组软骨MMP-1、MMP-3的mRNA表达明显低于HA注射组和不用药组。HA注射组软骨MMP-1和MMP-3的mRNA表达与不用药组比较,差异没有显著性意义。结论CMCTS能够明显抑制OA软骨MMP-1和MMP-3的mRNA表达,明显减轻软骨退变的程度,CMCTS对早期OA软骨有修复保护作用。     

Astaxanthin ameliorates cartilage damage in experimental osteoarthritis

Abstract

Purpose. Astaxanthin is a red-pigment carotenoid found in certain marine animals and plants. Astaxanthin has been shown to inhibit matrix metalloproteinases (MMPs) expression in vitro. However, the effect of astaxanthin on cartilage is still unclear. The aim of this study was to investigate the effects of astaxanthin on cartilage in experimental osteoarthritis (OA).

Methods. New Zealand rabbits underwent anterior cruciate ligament transection to induce OA in right knee. Rabbits received intra-articular injection containing 0.3 ml of vehicle (dimethyl sulfoxide) or astaxanthin (50 μM). Injection was started on the day of operation, and the injection were performed once weekly for six consecutive weeks. Then, rabbits were sacrificed and the right knees were harvested for study.

Results. Cartilage degradation was reduced by astaxanthin, as assessed by morphological and histological examination. Astaxanthin inhibited the gene expression of MMP-1, MMP-3, and MMP-13 in cartilage as compared with the vehicle group.

Conclusions. The results suggest that astaxanthin may be considered as pharmaceutical agent in OA treatment.     

Expression of MMP-1 in cartilage and synovium of experimentally induced rabbit ACLT traumatic osteoarthritis: immunohistochemical study

To observe the level and the distribution of MMP-1 in cartilage and synovium over the progression of OA in rabbit ACLT model, and to explore the relationship between the amount of MMP-1 expression and the degree of OA cartilage degradation. OA was induced in 20 rabbits by anterior cruciate ligament transection (ACLT) and ten rabbits were killed at 4 and 8 weeks after the operation, respectively. A further ten rabbits received unilateral knee arthrotomy as controls. Cartilage degradation was observed under dissecting microscope, immunohistochemical, and morphometric analysis were adopted to record the tissue level and distribution of MMP-1 in cartilage and synovium. Cartilage degradation in both ACLT groups was more severe than that in control group, and the degradation in 8-week ACLT group was more severe than that in 4-week ACLT group. MMP-1 was expressed predominantly in the superficial and upper intermediate layers of cartilage and in the lining layer of synovium. Its expression was increased steadily over the progression of OA both in cartilage and in synovium, but there was a little difference in the increase pattern between them: increase of MMP-1 in synovium lagged behind that in cartilage in early stage of OA. Conclusion: MMP-1 was involved in OA development in rabbit ACLT model and the amount of its expression was related with the degree of cartilage degradation. The increase of MMP-1 expression in synovium lagged behind that in cartilage, suggesting OA pathology was originated from cartilage, but synovitis may also paticipate in cartilage degradation, especially in middle and late stage of OA. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

透明质酸钠对兔骨关节炎软骨诱导型NO合酶基因表达的影响

目的观察透明质酸钠(Na—HA)关节腔注射对骨关节炎(OA)模型关节软骨中诱导型NO合酶(iNOS) mRNA表达水平的影响。方法16只大耳白兔行单侧前交叉韧带切断术，术后5周将动物随机分为实验组和对照组，实验组关节腔注射1％Na—HA 0.3ml，每周1次，连续5周，对照组则注射等量生理盐水。术后10周处死动物，观察两组股骨内髁关节软骨的大体形态学和组织学病理改变，采用反转录一聚合酶链反应(RT—PCR)方法检测软骨iNOS mRNA的表达。结果实验组软骨退变程度较对照组明显减轻，实验组软骨中iNOS mRNA的表达水平与对照组比较差异无统计学意义。结论Na—HA能有效地减轻早期OA关节软骨的退变程度，Na—HA对早期OA软骨中的iNOS的表达没有下调作用。     

高脱乙酰度羧甲基壳聚糖对兔膝骨关节炎软骨诱导型一氧化氮合酶表达的影响

目的观察高脱乙酰度羧甲基壳聚糖(HD-CMC)经关节腔注射后对兔膝骨关节炎(OA)软骨诱导型一氧化氮合酶(iNOS)的mRNA和蛋白表达的影响,探讨其用于OA防治的机制及可能性。方法36只日本大耳白兔,行右侧膝关节前交叉韧带切断术(ACLT),术后随机分为2组,实验组于术后当天开始关节腔内注射2%HD-CMC 0．15mg/kg,每2周给药1次,对照组同一时间点关节腔内注射0．9%生理盐水0．15mg/kg。实验组与对照组于第6周分别随机处死大白兔各9只,剩余大白兔于第12周处死,对比两组大白兔股骨髁关节软骨的大体改变,用反转录聚合酶链反应(RT-PCR)及免疫组织化学的方法检测iNOS在软骨中的mRNA和蛋白的表达。结果实验组退变软骨的大体评分轻于对照组,NOS的mRNA和蛋白表达水平均低于对照组。结论HD-CMC能够降低OA退变软骨iNOS的表达,并延缓软骨的退行性变,对OA退变软骨具有修复保护作用。     

Osteoprotegerin inhibits cartilage degradation through an effect on trabecular bone in murine experimental osteoarthritis

OBJECTIVE: To characterize bone microarchitectural changes and to test the hypothesis that disrupting local cytokine equilibrium could modify cartilage degradation in a murine model of experimental osteoarthritis (OA). METHODS: Ten-week-old male C57BL/6 mice underwent medial meniscectomy of their right knees and a sham operation of their left knees. The mice received intraperitoneal injections of osteoprotegerin (OPG) (10 mg/kg), interleukin-1 receptor antagonist (IL-1Ra) (100 mg/kg), or phosphate buffered saline for 6 weeks. The microarchitecture of the trabecular bone, the OA score, and expression of ADAMTS-4 and ADAMTS-5 were assessed. Proteoglycan release was measured in cartilage explant cultures in the presence of IL-1Ra and OPG. RESULTS: In the meniscectomized knees, bone volume/tissue volume (BV/TV) was lower, whereas trabecular separation, the OA score, and aggrecanase expression were higher than in the sham-operated knees. After treatment with OPG, BV/TV was significantly increased and trabecular separation was reduced in the knees that underwent meniscectomy. The OA score and the number of ADAMTS-positive cells were significantly decreased by treatment with OPG but were not affected by IL-1Ra. Moreover, OPG did not directly reduce the release of proteoglycans from cartilage explant cultures. CONCLUSION: In an experimental model of OA, meniscectomy induced bone loss and cartilage degradation at 6 weeks. Systemic administration of OPG prevented bone and cartilage degradation in vivo but had no effect on cartilage in vitro. These data collectively indicate that bone could be a contributor in the early stages of OA pathogenesis. They further suggest that disruption of RANKL/OPG balance might result in the degradation of cartilage subjected to mechanical loading. Specific targeting of the bone cytokine network might help to prevent OA.     

Up regulation of cathepsin K expression in articular chondrocytes in a transgenic mouse model for osteoarthritis

Objectives: To study the expression of cysteine proteinases, particularly cathepsin K, and their extracellular inhibitor cystatin C in articular cartilage of transgenic Del1 mice which harbour a short deletion mutation in a type II collagen transgene and are predisposed to early onset osteoarthritis.

Methods: Northern analysis was used to measure mRNA levels of cathepsins B, H, K, L, and S, and cystatin C in total RNA extracted from knee joints of Del1 mice, using their non-transgenic litter mates as controls. Immunohistochemistry and morphometry was used to study the distribution of cathepsin K and cystatin C in the knee joints.

Results: Up regulation of cathepsin K mRNA expression was seen in the knee joints of transgenic Del1 mice at the onset of cartilage degeneration. Cathepsin K was found near sites of matrix destruction in articular chondrocytes, particularly in clusters of proliferating cells, and in calcified cartilaginous matrix. In intact articular cartilage of control animals, cathepsin K was only seen in a small number of chondrocytes. Upon aging, control animals also developed osteoarthritis, which was accompanied by increased cathepsin K expression. Cystatin C was mostly localised in and around chondrocytes located in calcified cartilage, with no obvious association with the onset of cartilage degeneration.

Conclusion: The temporospatial distribution of cathepsin K in osteoarthritic cartilage suggests a role for this enzyme in the pathogenesis of osteoarthritis. Because cathepsin K can digest cartilage matrix components it may contribute to the development of osteoarthritic lesions. These data may provide new clues for the development of treatments aimed at preventing cartilage degeneration.

     

Femorotibial subchondral bone area and regional cartilage thickness: A cross‐sectional description in healthy reference cases and various radiographic stages of osteoarthritis in 1,003 knees from the Osteoarthritis Initiative

Objective

To identify structural differences in total subchondral bone area (tAB) and cartilage thickness between healthy reference knees and knees with radiographic osteoarthritis (OA).

Methods

Baseline magnetic resonance images from 1 knee of 1,003 Osteoarthritis Initiative participants were studied: 112 healthy reference knees without radiographic OA, symptoms, or risk factors; 70 preradiographic OA knees (calculated Kellgren/Lawrence [K/L] grade 0/1); and 821 radiographic OA knees (calculated K/L grade ≥2). Means and standard (Z) scores (SD unit differences compared with normal subjects) of the tAB and regional cartilage thickness were assessed in the weight‐bearing femorotibial joint and compared between groups.

Results

In men, tAB was 8.2% larger in preradiographic OA knees and 6.6%, 8.1%, and 8.5% larger in calculated K/L grade 2, 3, and 4 radiographic OA knees, respectively, than in reference knees. In women, the differences were +6.8%, +7.3%, +9.9%, and +8.1%, respectively. The external medial tibia showed the greatest reduction in cartilage thickness (Z scores ?5.1/?5.6 in men/women) with Osteoarthritis Research Society International medial joint space narrowing (JSN) grade 3, and the external lateral tibia (Z scores ?6.0 for both sexes) showed the greatest reduction with lateral JSN grade 3. In all subregions of end‐stage radiographic OA knees, ≥25% of the average normal cartilage thickness was maintained. An overall trend toward thicker cartilage was found in preradiographic OA and calculated K/L grade 2 knees, especially in the external central medial femur.

Conclusion

tABs were larger in preradiographic OA and radiographic OA knees than in healthy reference knees, and the difference did not become larger with higher calculated K/L grades. Specific subregions with substantial cartilage thickening or thinning were identified in pre‐, early, and late radiographic OA.

     

Rates of change and sensitivity to change in cartilage morphology in healthy knees and in knees with mild, moderate, and end-stage radiographic osteoarthritis: results from 831 participants from the Osteoarthritis Initiative

Objective

To study the longitudinal rate of (and sensitivity to) change of knee cartilage thickness across defined stages of radiographic osteoarthritis (OA), specifically healthy knees and knees with end‐stage radiographic OA.

Methods

One knee of 831 Osteoarthritis Initiative participants was examined: 112 healthy knees, without radiographic OA or risk factors for knee OA, and 719 radiographic OA knees (310 calculated Kellgren/Lawrence [K/L] grade 2, 300 calculated K/L grade 3, and 109 calculated K/L grade 4). Subregional change in thickness was assessed after segmentation of weight‐bearing femorotibial cartilage at baseline and 1 year from coronal magnetic resonance imaging (MRI). Regional and ordered values (OVs) of change were compared by baseline radiographic OA status.

Results

Healthy knees displayed small changes in plates and subregions (±0.7%; standardized response mean [SRM] ±0.15), with OVs being symmetrically distributed close to zero. In calculated K/L grade 2 knees, changes in cartilage thickness were small (<1%; minimal SRM ?0.22) and not significantly different from healthy knees. Knees with calculated K/L grade 3 showed substantial loss of cartilage thickness (up to ?2.5%; minimal SRM ?0.35), with OV1 changes being significantly (P < 0.05) greater than those in healthy knees. Calculated K/L grade 4 knees displayed the largest rate of loss across radiographic OA grades (up to ?3.9%; minimal SRM ?0.51), with OV1 changes also significantly (P < 0.05) greater than in healthy knees.

Conclusion

MRI‐based cartilage thickness showed high rates of loss in knees with moderate and end‐stage radiographic OA, and small rates (indistinguishable from healthy knees) in mild radiographic OA. From the perspective of sensitivity to change, end‐stage radiographic OA knees need not be excluded from longitudinal studies using MRI cartilage morphology as an end point.

     

Effect of hyaluronan on chondrocyte apoptosis and nitric oxide production in experimentally induced osteoarthritis

OBJECTIVE: Nitric oxide (NO) plays an important role in cartilage degeneration, and NO donors induce chondrocyte apoptosis. This study evaluated the effect of intraarticular injections of hyaluronan (HA) on chondrocyte apoptosis and NO production using an experimental osteoarthritis (OA) model. METHODS: Thirty-six New Zealand white rabbits underwent unilateral anterior cruciate ligament transection (ACLT), and were divided into 3 groups. Four weeks after ACLT, the HA group started intraarticular HA injections once a week for 5 weeks; the vehicle group started to receive the carrier of HA; the no injection group received no treatment. All ACLT knees were harvested at Week 9 and evaluated for OA severity. Culture supernatants of the cartilage were analyzed for nitrite concentration. Cartilage sections were analyzed by TUNEL for apoptosis and by immunohistochemistry for nitrotyrosine. RESULTS: OA in the HA group was less severe than the other 2 groups. The number of apoptotic chondrocytes was significantly lower in the HA group. HA injection did not influence NO production in cartilage. CONCLUSION: HA protects against chondrocyte apoptosis during the development of OA, while it may not have definite effects on NO production in the joints. These inhibitory effects of HA on chondrocyte apoptosis may play a role in its mechanism of action in chondroprotection.     

羧甲基壳聚糖对兔骨关节炎软骨一氧化氮合酶表达的影响

目的探讨关节腔注射羧甲基壳聚糖(CMCTS)对骨关节炎(OA)软骨诱导型一氧化氮合酶(iNOS)表达的影响。方法大耳白兔32只,每只兔单侧膝关节行前交叉韧带切断术,术后5周将兔随机分为4组,每组8只,A组：关节腔注射2%高相对分子质量的CMCTS 0．3ml,每2周重复1次；B组：同等条件下注射2%低相对分子质量的CMCTS 0．3ml；C组：关节腔注射1%透明质酸钠(Na-HA)0．3ml,每周重复1次；D组：关节腔不注射任何药物。术后11周处死动物。采用免疫组织化学、反转录聚合酶链反应(RT-PCR)方法检测软骨iNOS的表达。结果免疫组织化学及RT-PCR显示CMCTS注射组软骨iNOS的表达水平显著低于Na-HA注射组和不用药组,不同相对分子质量CMCTS注射组之间、Na-HA注射组和不用药组之间比较,iNOS的表达差异无统计学意义。结论CMCTS能够明显抑制OA软骨i NOS的表达,Na-HA对OA软骨iNOS的表达没有显著下调作用。     

Cysteine protease cathepsins in atherosclerosis-based vascular disease and its complications

Atherosclerosis-based vascular disease is an inflammatory disease characterized by extensive remodeling of the extracellular matrix architecture of the arterial wall. Although matrix metalloproteinases and serine proteases participate in these pathological events, the discovery of cysteine protease cathepsins, such as cathepsins K, S, L, and B, and cystatin C, and their tissue distribution has suggested that at least some of them participate in cardiovascular disease. Studies on vascular cells have shown that atherosclerosis-associated inflammatory cytokines augment cysteinyl cathepsin expression and activity. Novel insight into cathepsin functions has been made possible by the generation and in-depth analysis of knockout and transgenic mice. These studies have provided direct evidence implicating cathepsins in atherosclerosis-based vascular disease through the activation, liberation, and modification of angiogenic growth factors, cytokines, and proteases associated with lipid metabolism, cell events (migration, invasion, proliferation, and apoptosis), angiogenesis, and matrix protein remodeling. Furthermore, evaluation of the feasibility of cathepsins as a diagnostic tool has revealed that the serum cathepsins S and L and the endogenous inhibitor cystatin C hold promise as biomarkers of coronary artery disease and aneurysm formation. The goal of this review is to summarize the available information regarding the mechanistic contributions of cathepsins in atherosclerosis-based vascular disease.     

Comparative analysis of cathepsin l,cathepsin d,and collagenase messenger rna expression in synovial tissues of patients with rheumatoid arthritis and osteoarthritis,by in situ hybridization

Objective. To compare the expression of cathepsin L, cathepsin D, and collagenase messenger RNA (mRNA) in synovial specimens from patients with rheumatoid arthritis (RA) and osteoarthritis (OA). Methods. The expression of cathepsins L and D as well as collagenase mRNA in synovial tissues from 8 patients with RA, 6 patients with OA, and 2 patients with noninflamed joints was evaluated using in situ hybridization with digoxigenin-labeled RNA probes. Results. Both RA and OA synovial tissue expressed cathepsins L and D as well as collagenase mRNA. The expression of the cathepsins was markedly higher in interstitial regions and, to some extent, in perivascular infiltrates of RA synovial tissue compared with OA specimens. Conclusion. Cathepsins L and D mRNA are expressed differently in RA and OA synovial tissues, supporting the concept that these enzymes may contribute to the influx of mononuclear cells into RA synovium. Moreover, the data reveal that the expression of collagenase and cathepsins in RA and OA synovial lining is otherwise largely similar, and suggest that the adhesion of synovial cells to cartilage mediates the invasive destructive process in RA.     

Role of apoptotic and matrix-degrading genes in articular cartilage and meniscus of mature and aged rabbits during development of osteoarthritis

OBJECTIVE: To determine expression patterns of apoptotic and matrix-degrading genes during aging and development of osteoarthritis (OA), using a rabbit model of induced OA. METHODS: Six mature and 6 aged rabbits underwent anterior cruciate ligament transection and were killed 4 and 8 weeks after surgery, respectively, to create early-grade and advanced-grade OA. RNA from articular cartilage and menisci was examined for expression of the genes caspase 8, Fas, Fas ligand, p53, aggrecanase, matrix metalloproteinase 1 (MMP-1), and MMP-3. A second cohort of animals that had undergone no intervention in the joint was also killed. Parametric data were analyzed with analysis of variance and Student's t-tests, while nonparametric data were assessed with the Mann-Whitney U test. RESULTS: Expression levels of Fas, caspase 8, FasL, and MMP-1 were significantly higher (>100%) in aged cartilage compared with mature cartilage (P < 0.05). After induction of OA, expression of apoptotic genes in aged rabbits remained high, while significant up-regulation of Fas and caspase 8 (nearly 150% increase) was observed in mature rabbits (P < 0.05). No significant up-regulation of these genes was observed in the menisci of aged or mature rabbits prior to or after induction of OA. Development of OA occurred more rapidly in aged cartilage compared with mature cartilage (P < 0.05). CONCLUSION: Differential expression of apoptotic and matrix-degrading genes occurs in aged compared with mature cartilage, both at baseline and during development of OA. This may be responsible for faster degradation of aged cartilage and its predisposition for developing OA.