凋亡相关基因Bax和bcl-2在骨关节炎软骨中的作用

目的探讨原发性骨关节炎与继发性骨关节炎发病机制的异同。方法收集原发性骨关节炎、继发性骨关节炎的关节软骨各8例，并以9例正常关节软骨作对照，采用RT—PCR和免疫组化方法分别检测Bax和bcl-2的mRNA和蛋白的表达，应用细胞核荧光染色的方法进行软骨细胞凋亡的检测。结果1．原发性骨关节炎组BaxmRNA表达明显升高，与继发组、对照组差异均有统计学意义（P〈0．01，P〈0．01），而继发性骨关节炎组Bax mRNA的表达与对照组之间的差异没有统计学意义（P〉0．05）；bcl-2mRNA在两类骨关节炎中的表达较对照组均升高（P〈0．01，P〈0．05），而两组间差异没有统计学意义（P〉0．05）。2．免疫组化发现两类骨关节炎中Bax、bcl-2蛋白表达水平与其mRNA表达相一致。3．原发性骨关节炎组、继发性骨关节炎组和正常对照组细胞凋亡率分别为10％～20％，8％～13％，2％～5％。原发性骨关节炎组细胞凋亡比例最高。结论软骨细胞凋亡是骨关节炎发病的重要原因，受Bax和bcl-2的共同调节；Bax表达水平的升高可能是原发性骨关节炎发病的重要原因。     

骨关节炎欠骨细胞凋亡调控基因的研究

目的 比较分析正常人及老年性骨关节炎患者软骨细胞ｂａｘ、ｂｃｌ－２的表达及细胞凋亡状况。方法 取９例骨关节炎患者的关节软骨做实验标本,以６例无骨关节炎病史的意外死亡者关节软骨作为正常对照,采用逆转录／聚合酶链反应（ＲＴ－ＰＣＲ）方法检测dirｂａｘ、ｂｃｌ－２ｍＲＮＡ表达,免疫组化检测ｂａｘ、ｂｃｌ－２蛋白;应用ＴＵＮＥＬ方法进行凋亡细胞原位检查。结果 骨关节炎患者和正常对照软骨细胞都能表达ｂａｘ、     

生长抑素类似物诱导胆管癌细胞凋亡和bcl-2/bax表达的研究

目的探讨生长抑素类似物SMS2 0 1 995 (SMS)对人胆管癌SK ChA 1细胞凋亡和凋亡调控基因bcl 2和bax的影响。方法用DNA凝胶电泳、流式细胞仪检测AnnexinV标记凋亡细胞、免疫组化和原位杂交方法研究SMS(10 0ng/ml)处理 6、12和 2 4h后人胆管癌SK ChA 1细胞凋亡和bcl 2 /bax表达的变化。结果SMS作用SK ChA 1细胞 6h对DNA无明显影响 ,作用 12和 2 4h后DNA凝胶电泳出现呈典型梯状条带。SMS作用 6、12和 2 4h后 ,AnnexinV标记的凋亡细胞分别为 (2 2±5 ) % ,(39± 7) %和 (5 8± 10 ) %。同时 ,SMS可使细胞bcl 2蛋白表达下降 ,使bax蛋白和mRNA表达升高。结论SMS能诱导SK ChA 1细胞发生凋亡 ,bax和bcl 2凋亡基因介导了SMS对SK ChA 1细胞凋亡的发生     

重组人红细胞生成素对大鼠心肌梗死的治疗作用

目的　观察重组人红细胞生成素 (rHu EPO)治疗心肌梗死大鼠心功能和心肌细胞凋亡情况 ,探讨其机制。方法　 3 2只SD大鼠分空白组 (Sham )、心肌梗死组 (MI)和治疗组 (MI EPO) ,结扎左冠前降支制备心肌梗死的模型 ,治疗组每天腹腔注射 5 0 0 0IU /kg体重rHu EPO共 7d ,14d后所有大鼠检测血流动力学指标 ,心脏切片原位末端标记 (TUNEL)检测凋亡 ,免疫组织化学检测bcl 2、bax表达。结果　心肌梗死组凋亡指数 (AI)为 1.65 % ,bcl 2及bax蛋白阳性表达指数 (PEI)分别为 0 .96%和 1.3 4% ,均明显高于空白组 (P <0 .0 5 ) ;治疗组心功能保存较好 ,AI与bax蛋白PEI分别为 0 .84%和 0 .68% ,均下降 (P <0 .0 5 ) ,而bcl 2蛋白PEI增高 (P <0 .0 5 )为 1.43 %。结论　rHu EPO可抑制心肌细胞凋亡 ,保存心功能。可能是通过下调bax表达和上调bcl 表达实现的。     

阻塞性黄疸大鼠肝组织细胞凋亡及相关基因bcl-2、bax的表达

目的　探讨阻塞性黄疸肝损害的调控机制。方法　用末端脱氧核苷酸转移酶介导生物素标记(TUNEL)技术和免疫组织化学方法检测 4 0只阻塞性黄疸大鼠肝脏组织细胞凋亡状态及凋亡相关基因bcl 2和bax蛋白的表达。结果　胆总管结扎后 ,随结扎时间的延长细胞凋亡增加 ,结扎 14d后细胞凋亡达高峰 ,凋亡指数 (AI)达 5 8.2 3± 1.5 8,各组AI差异有显著性 (P <0 .0 5 )。在阻塞性黄疸过程中 ,bcl 2蛋白表达越强 ,bax蛋白表达越弱 ,AI亦越少。结论　bcl 2和bax蛋白均参与了阻塞性黄疸肝组织中细胞凋亡的调节。     

成软骨相关miR-4287调控人软骨细胞聚蛋白多糖酶-1表达的研究

目的探讨成软骨相关miR-4287对人软骨细胞聚蛋白多糖酶-1(a disintegrin and metalloproteinase with thrombospondin motif 4,ADAMTS4)调控作用及其机制。方法取自愿捐赠的膝关节正常及骨关节炎软骨组织,采用实时荧光定量PCR检测miR-4287和ADAMTS4 mRNA表达量;然后分离培养软骨细胞,取第1代骨关节炎细胞,给予IL-1β处理,观察其对软骨细胞miR-4287和ADAMTS4 mRNA表达的影响;分别给予MAPK信号通路抑制剂SP600125以及NF-κB信号通路抑制剂SN50预处理后联合IL-1β刺激,观察IL-1β介导的信号通路对软骨细胞miR-4287和ADAMTS4 mRNA表达的影响;分别转染miR-4287模拟物及其阴性对照、miR-4287抑制物及其阴性对照,观察miR-4287调控软骨细胞ADAMTS4 mRNA及蛋白的表达。荧光素酶报告实验验证miR-4287与ADAMTS4 mRNA 3’非翻译区(untranslated region,UTR)的直接结合效应。结果与正常软骨组织比较,骨关节炎软骨组织miR-4287相对表达量下降,ADAMTS4 mRNA相对表达量上升,比较差异有统计学意义(P0.05)。IL-1β下调软骨细胞miR-4287表达、上调ADAMTS4 mRNA表达,与未经IL-1β处理的软骨细胞相比差异均有统计学意义(P0.05)。经IL-1β介导的信号通路抑制剂预处理后,软骨细胞miR-4287相对表达量上升,ADAMTS4 mRNA相对表达量降低,与未经信号通路抑制剂预处理细胞相比,差异均有统计学意义(P0.05)。转染miR-4287模拟物后,软骨细胞内ADAMTS4 mRNA及蛋白表达均降低(P0.05);而转染miR-4287抑制物后,软骨细胞内ADAMTS4 mRNA及蛋白表达均升高(P0.05)。无论结合位点为野生型或突变型,过表达miR-4287均不能改变报告载体的荧光素酶活性(P0.05)。结论成软骨相关miR-4287可能是一种与软骨退变相关的miRNA。miR-4287能调控人软骨细胞ADAMTS4表达,但不是通过靶向结合mRNA 3’UTR的方式发挥作用,其具体机制有待进一步研究。     

半乳糖化磁性阿霉素白蛋白纳米粒对大鼠移植性肝癌模型bcl-2/bax蛋白表达的研究

目的　半乳糖化白蛋白磁性阿霉素纳米粒 (Gal MADM NP)治疗大鼠移植性肝癌对肿瘤细胞凋亡bcl 2及bax蛋白表达的影响。方法　采用SABC法进行免疫组织化学染色观察bcl 2及bax蛋白的表达。结果　注射Gal MADM NP(肿瘤区加磁场 )组免疫组织化学显示bcl 2蛋白表达阳性率 2 3 .5 3 % ,低于ADM组 5 4.5 5 %及NS组 71.43 % (P <0 .0 1) ,bax蛋白表达阳性率88.2 4% ,高于ADM组 45 .45 %及NS组 2 8.5 7%。结论　Gal MADM NP组在适当外加磁场的作用下 ,能够降低bcl 2蛋白表达 ,增加bax蛋白表达 ,促进移植肝癌肿瘤细胞凋亡。     

肾必宁对大鼠系膜增生性肾小球肾炎肾小球细胞凋亡及bax、bcl-2表达的影响

目的：探讨中成药肾必宁对慢性血清病性系膜增生性肾炎肾小球细胞凋亡与调控基因bax、bcl—2表达的影哨。方法：应用大鼠慢性血清病性系膜增生性肾炎模型；造模第4周起，灌服中成药肾必宁，以等量生理盐水为对照；24h定量测定尿蛋白；TUNEL法检测实验大鼠肾小球细胞凋亡；免疫组化SABC法观察bax、bcl—2表达的改变。结果：肾必宁治疗组肾小球细胞凋亡率较病理组升高(P＜0．01)，bax表达增强(P＜0．01)，bcl—2表达下降(P＜0.01)。结论：肾必宁可能通过影哨凋亡调控基因bax、bcl—2的表达，诱导肾小球细胞凋亡，进而抑制系膜增生性肾小球肾炎系膜细胞增殖。     

Chondrocyte death during murine osteoarthritis

OBJECTIVE: To determine whether chondrocyte apoptosis occurs during the progression of osteoarthritis (OA) in the STR/ort mouse model of OA.METHODS: Serial cryostat sections were cut (10 microns) through the knee joint of young and old male STR/ort mice and graded for the severity of OA lesions. Age- and sex-matched CBA mice were used as controls. Apoptotic chondrocytes were detected using the TUNEL assay. Ultrastructural changes were examined using electron microscopy (EM). Expression of biochemical markers associated with apoptosis (bax, bcl-2 and caspases-3, -8 & -9) was investigated using immunohistochemistry.RESULTS: TUNEL assays on histological sections of STR/ort knee joints showed that the number of TUNEL-positive chondrocytes in the tibial medial articular cartilage correlated with the severity of the OA damage. These cells were located close to the lesional area. Only very occasional TUNEL positive chondrocytes were detected in either morphologically normal STR/ort cartilage or in control CBA cartilage. Ultrastructural analysis of chondrocytes neighboring focal osteoarthritic lesions in STR/ort tibial cartilage revealed an abundance of abnormal cells exhibiting numerous morphological changes. These resembled, but in some cases differed, from changes reported in classical apoptosis. The changes include abnormal distribution of chromatin, cell shrinkage, membrane blebbing and deposition of cell remnants (apoptotic bodies) in the lacuna space. Despite the TUNEL and EM changes, immunohistochemistry failed to detect any changes in the ratio of bax to bcl-2 in tibial chondrocytes of STR/ort mice. Both bcl-2 and bax levels decreased with age in morphologically normal STR/ort and control CBA cartilage. None of the caspases tested for was detected in tibial chondrocytes of either strain.CONCLUSION: Chondrocyte cell death is correlated with the progression of OA in STR/ort mice and has many of the morphological characteristics of classical apoptosis. Absence of changes in bax to bcl-2 ratio in STR/ort chondrocytes indicate that the mitochondrial pathway of apoptosis is unlikely to be involved. Failure to detect caspases could be due to low levels of enzyme expression, expression within a very brief time period, or to a caspase-independent mechanism of cell death.     

FrzB-2: a human secreted frizzled-related protein with a potential role in chondrocyte apoptosis

OBJECTIVE: To characterize a novel secreted frizzled-related protein (SFRP) and determine its tissue distribution at the mRNA and protein level. METHODS: The FrzB-2 gene was identified by expressed sequence tag (EST) analysis of human tissue-derived libraries. Tissue distribution of FrzB-2 mRNA was determined by Northern blot analysis and in situ hybridization. FrzB-2 protein reactivity was localized in human OA articular cartilage by immunocytochemistry, using a polyclonal antibody against a peptide sequence unique to FrzB-2. Apoptosis was detected in articular cartilage sections using Tunel staining. RESULTS: ESTs corresponding to FrzB-2 were found in osteoblast, chondrosarcoma, osteosarcoma, osteoclastoma and synovial fibroblast libraries. FrzB-2 mRNA is expressed in a number of tissues and cell types including bone-related cells and tissues such as primary human osteoblasts and osteoclastoma. In situ hybridization studies showed strong FrzB-2 mRNA expression in human chondrocytes in human osteoarthritic (OA) cartilage but negligible levels in normal cartilage chondrocytes. The FrzB-2 cDNA encodes a secreted 40 kDa protein consisting of 346 amino acids. FrzB-2 is 92. 5% identical to the rat orthologue, DDC-4, which has been shown to be associated with physiological apoptosis. FrzB-2 protein was selectively detected in human OA articular cartilage by immunocytochemistry, using a polyclonal antibody. Consistent with its potential role in apoptosis, positive FrzB-2 staining and Tunel positive nuclei staining were detected in chondrocyte clones in sections of human OA cartilage. CONCLUSION: These data suggest that FrzB-2 may play a role in apoptosis and that the expression of this protein may be important in the pathogenesis of human OA.     

Localization of bone morphogenetic protein-2 in human osteoarthritic cartilage and osteophyte

OBJECTIVES: To examine the localization of bone morphogenetic protein (BMP)-2 mRNA and protein in human osteoarthritic (OA) articular cartilage and osteophyte. DESIGN: Five normal, four growing and 14 OA human cartilage samples, graded histomorphologically by Mankin Score, were studied by in situ hybridization and immunohistochemistry for the expression of BMP-2. RESULTS: BMP-2 mRNA was present in chondrocytes in neonatal growing articular cartilage, but was scarcely present in normal adult articular cartilage. In OA articular cartilage, BMP-2 mRNA and protein were detected in both clustering and individual chondrocytes in moderately or severely damaged OA cartilage. In moderately damaged OA cartilage, BMP-2 mRNA was localized in both upper and middle zone chondrocytes, but was not detected in deep layer chondrocytes. In severely damaged OA cartilage, cellular localization of BMP-2 mRNA was extended to the deep zone. In the area of osteophyte formation, BMP-2 mRNA was intensely localized in fibroblastic mesenchymal cells, fibrochondrocytes, chondrocytes and osteoblasts in newly formed osteophytic tissue. The pattern of BMP-2/4 immunolocalization was associated with that of mRNA localization. CONCLUSIONS: BMP-2 mRNA and BMP-2/4 were detected in cells appearing in OA tissues. BMP-2 was localized in cells of degenerating cartilage as well as osteophytic tissue. Given the negative localization of BMP-2 in normal adult articular cartilage, BMP-2 might be involved in the regenerating and anabolic activities of OA cells, which respond to cartilage damage occurring in osteoarthritis.     

过氧化物酶Ⅰ在骨关节炎软骨组织中的表达与分布及意义

目的观察过氧化物酶Ⅰ（PrxⅠ）在正常和骨关节炎（OA）膝关节软骨组织中的表达和分布特点,探讨PrxⅠ与活性氧歧化物和凋亡等在OA软骨表层聚集现象之间的关联。方法分别从正常膝关节提取正常软骨（NC,n=21）和接受膝关节表面置换术的OA患者提取OA软骨（OA,n=21）,应用Westernblot技术检测PrxⅠ在正常软骨细胞和OA软骨细胞中表达水平的总体差异,并用免疫组织化学技术观察PrxⅠ蛋白在正常与OA软骨表/中/深各层组织表达和分布的特点。结果 Western blot证实PrxⅠ在OA软骨组织中的表达水平较正常软骨组织显著提高2.89倍（t=18.34,P〈0.01）。免疫组织化学显示PrxⅠ在正常软骨组织的表层、中层和深层呈现较均一的表达,但是,在OA软骨组织中,PrxⅠ的表达水平存在显著层间差异。PrxⅠ在软骨组织深层表达水平显著升高,但在浅层细胞中,PrxI的表达水平反而显著减低甚至缺如。结论虽然总体表达水平升高,但PrxⅠ在OA软骨组织表层的表达缺如,可能与OA软骨组织表层活性氧歧化物蓄积和细胞凋亡聚集现象相关。     

Apoptosis of articular chondrocytes in rheumatoid arthritis and osteoarthritis: correlation of apoptosis with degree of cartilage destruction and expression of apoptosis-related proteins of p53 and c-myc

To investigate the relationship of chondrocyte apoptosis and cartilage destruction, we performed in situ nick end labeling (ISNEL), electron microscopy, and im-munohistochemistry against apoptosis-related proteins, p53 and c-myc, in the articular cartilages of patients with rheumatoid arthritis (RA; n = 12) and osteoarthritis (OA; n = 12), and in control articular cartilages from patients with femoral neck fracture (n = 8). The distribution of stained chondrocytes was evaluated semiquantitatively in relation to the degree of cartilage destruction. ISNEL-positive chondrocytes with apoptotic morphological features were identified in a relatively early phase of cartilage destruction, and correlated positively and significantly in a number with the degree of cartilage degeneration. Comparison of RA and OA revealed a significantly greater number of ISNEL-positive chondrocytes in RA cartilage. In contrast, the specimens of normal subjects contained few cells with apoptotic changes. Similarly to the distribution of ISNEL staining, the expression of p53 and c-myc proteins was observed in chondrocytes within the degraded lesions, and showed a positive correlation with the number of ISNEL-stained cells. These results suggest that the degree of chondrocyte apoptosis is closely related to cartilage destruction and that chondrocytes in RA more readily undergo apoptosis than those in OA. The expression of p53 and c-myc proteins in ISNEL-positive areas may reflect the involvement of these proteins in the apoptotic process in articular chondrocytes in inflammatory arthritis. Received for publication on April 28, 1999; accepted on Sept. 22, 1999     

Chondrocyte Differentiation in Human Osteoarthritis: Expression of Osteocalcin in Normal and Osteoarthritic Cartilage and Bone

Osteocalcin (OC), which is a marker of the mature osteoblasts, can also be found in posthypertrophic chondrocytes of the epiphyseal growth plate, but not in chondrocytes of the resting zone or in adult cartilage. In human osteoarthritis (OA), chondrocytes can differentiate to a hypertrophic phenotype characterized by type X collagen. The protein- and mRNA-expression pattern of OC was systematically analyzed in decalcified cartilage and bone sections and nondecalcified cartilage sections of human osteoarthritic knee joints with different stages of OA to investigate the differentiation of chondrocytes in OA. In severe OA, we found an enhanced expression of the OC mRNA in the subchondral bone plate, demonstrating an increased osteoblast activity. Interestingly, the OC protein and OC mRNA were also detected in osteoarthritic chondrocytes, whereas in chondrocytes of normal adult cartilage, both the protein staining and the specific mRNA signal were negative. The OC mRNA signal increased with the severity of OA and chondrocytes from the deep cartilage layer, and proliferating chondrocytes from clusters showed the strongest signal for OC mRNA. In this late stage of OA, chondrocytes also stained for alkaline phosphatase and type X collagen. Our results clearly show that the expression of OC in chondrocytes correlates with chondrocyte hypertrophy in OA. Although the factors including this phenotypic shift in OA are still unknown, it can be assumed that the altered microenvironment around osteoarthritic chondrocytes and systemic mediators could be potential inducers of this differentiation. Received: 20 May 1999 / Accepted: 10 February 2000     

Activation of stress-activated protein kinase in osteoarthritic cartilage: evidence for nitric oxide dependence

OBJECTIVE: We have demonstrated in bovine chondrocytes that nitric oxide (NO) mediates IL1 dependent apoptosis under conditions of oxidant stress. This process is accompanied by activation of c-Jun NH2-terminal kinase (JNK; also called stress-activated protein kinase). In these studies we examined activation of JNK in explant cultures of human osteoarthritic cartilage obtained at joint replacement surgery and we characterized the role of peroxynitrite to act as an upstream trigger. DESIGN: A novel technique to isolate chondrocyte proteins (<10% of total cartilage protein) from cartilage specimens was developed. It was used to analyse JNK activation by a western blot technique. To examine the hypothesis that chondrocyte JNK activation is a result of increased peroxynitrite, in vitro experiments were performed in which cultured chondrocytes were incubated with this oxidant. RESULTS: Activated JNK was detected in the cytoplasm of osteoarthritis (OA) affected chondrocytes but not in that of controls. In vitro, chondrocytes produce NO and superoxide anion. IL-1 (48 h), which induces nitric oxide synthase, resulted in an activation of JNK; this effect was reversed by N-monomethylarginine (NMA). TNFalpha treated chondrocytes at 48 h produce superoxide anion (EPR method). Exposure of cells to peroxynitrite led to an accumulation of intracellular oxidants, in association with JNK activation and cell death by apoptosis. CONCLUSION: We suggest that JNK activation is among the IL-1 elicited responses that injure articular chondrocytes and this activation of JNK is dependent on intracellular oxidant formation (including NO peroxynitrite). In addition, the extraction technique here described is a novel method that permits the quantitation and study of proteins such as JNK involved in the signaling pathways of chondrocytes within osteoarthritic cartilage.     

Microarray analysis reveals the involvement of beta-2 microglobulin (B2M) in human osteoarthritis

OBJECTIVE: To assess whether beta-2 microglobulin (B2M) has effects on articular chondrocytes that would implicate B2M involvement in osteoarthritis (OA) pathogenesis. METHODS: The mRNA levels of B2M in fetal and osteoarthritic chondrocytes were detected by RT-PCR. B2M levels in synovial fluid and tissue cultured media from cartilage explants were tested using B2M ELISA kit. Primary cultured chondrocytes were used for proliferation and microarray experiments. RESULTS: The average B2M level in OA synovial fluid is significantly higher than that found in normal synovial fluid. However, there was no significant difference in B2M synovial fluid levels amongst differing OA stages. The release of B2M by osteoarthritic cartilage was detectable after 24h in culture and continued to increase during the 72 h study period. B2M had an inhibitory effect on chondrocyte growth at 1.0 microg/ml, and became significantly inhibitory at 10.0 microg/ml. Genes regulated by B2M were detected through microarray technology. Twenty genes were found to be up-regulated by B2M, including collagen type III which is known to be up-regulated in OA. Eleven genes were found to be down-regulated at least two-fold by B2M. CONCLUSION: These results indicate that B2M is highly expressed in OA cartilage and synovial fluid compared to normal, and suggest that B2M may have effects on chondrocyte function that could contribute to OA pathogenesis.Copyright 2002 OsteoArthritis Research Society International. Published by Elsevier Science Ltd.