Expression of CD90 decreases with progression of synovial chondromatosis in the temporomandibular joint

Objectives: The aim of the present study was to investigate the factors that contribute to the progression of synovial chondromatosis in the temporomandibular joint (TMJ).

Methods: The authors investigated the expression of CD105 and CD90 in specimens from 17 patients with synovial chondromatosis in the TMJ, using immunohistochemical staining, and expression of CD105 and CD90 in cartilaginous nodules was scored semiquantitatively.

Results: The expression of CD105 and CD90 was found in almost all the cases. In particular, the expression of CD90 in cartilaginous nodules significantly decreased with the progression of synovial chondromatosis.

Discussion: The factors that determine progression of synovial chondromatosis are not fully understood. The results of this study suggest that CD90 may play an important role in the progression of synovial chondromatosis in the TMJ.     

不同频率的周期性压力对兔软骨细胞影响的生物学研究

目的：通过观察不同频率的周期性压力对兔软骨细胞增殖及整合素α1β1分泌量的影响,研究不同频率的力学刺激对软骨细胞产生的生物学影响。方法：取兔四肢关节的软骨细胞,在体外进行培养。表型稳定的第3代细胞进行研究,设置常压培养A组和周期性压力B组,并将B组在压力为172kPa按照加压频率分组,加压频率B1组为0．2Hz,B两组0．5Hz ,B3组1Hz,B4组2Hz,B5组5Hz。 B组每天干预2h,连续干预3d。检测A和B组软骨细胞增殖情况和整合素α1β1的含量。结果：OD值A组为1．08±0．13,B1组为1．19±0．11,B两组为1．23±0．08,B3组为1．35±0．06,B4组为1．45±0．09,B5组为1．37±0．12。加压各组与对照组比较OD值升高,差异有统计学意义。 B组各组间差异有统计学意义,峰值出现在B4组。 A组整合素α1β1水平为3．02±0．26pg/mL,B1组为3．28±0．19pg/mL, B两组为3．43±0．11pg/mL,B3组为3．77±0．24pg/mL,B4组为4．01±00．9 pg/mL,B5组为3．94±0．13pg/mL。加压各组与对照组比较整合素α1β1含量均有升高,差异有统计学意义差异（ P＜0．05）。 B组各组间整合素差异有统计学意义,峰值出现在B4组。结论：相同大小（172kPa）不同频率的周期性压力刺激兔软骨细胞,均能促进软骨细胞增殖和增加整合素含量的作用,但并非频率越高作用越强。本实验中以2Hz频率的周期性压力作用最强。     

Requirement of mitogen-activated protein kinase for collagenase production by the fibronectin fragment in human articular chondrocytes in culture

Abstract

Fibronectin fragments have been shown to up-regulate matrix metalloproteinase production in chondrocytes. We investigated the roles of mitogen-activated protein kinase (MAPK) pathways activated by the COOH-terminal heparin-binding fibronectin fragment (HBFN-f) in collagenase production by human chondrocytes in culture. In articular cartilage explant culture, HBFN-f stimulated type II collagen cleavage by collagenase in association with increased secretion of MMP-1 and MMP-13. In human articular chondrocytes, HBFN-f induced the collagenases with activation of the extracellular signal-regulated kinase (ERK), p38, and the c-Jun NH₂-terminal kinase (JNK). PD98059 that inhibits the ERK pathway blocked HBFN-f-stimulated production of MMP-1 and MMP-13 in explant culture. SB203580 at 1?µM, the concentration that inhibits p38 only, partially suppressed HBFN-f-induced collagenase production, whereas at 10?µM, the inhibitor that blocks both p38 and JNK almost completely inhibited collagenase induction. PD98059 and SB203580 individually blocked HBFN-f-increased cleavage of type II collagen in the explant culture, although 10?µM SB203580 strongly inhibited the collagen cleavage compared with 1?µM of the inhibitor. These results indicate that collagenase production leading to type II collagen cleavage in cartilage explants requires ERK, p38, and JNK.     

Protective effects of ginsenoside Rg3 on human osteoarthritic chondrocytes

Objectives

To explore whether Rg3, a major and especially potent ginsenoside, modulates human osteoarthritic (OA) chondrocyte senescence.

Methods

Isolated chondrocytes were cultured in medium containing interleukin-1 beta (IL-1β) with or without Rg3. The expression levels of mRNAs encoding aggrecan (ACAN), a major structural proteoglycan, type II collagen (COL2A1), and metalloproteinases (MMP) -1, -3, and -13, respectively, were determined using real-time PCR. Cellular senescence was detected by measuring senescence-associated β-galactosidase (SA-β-Gal) activity. Chondrocyte telomerase activity also served as a senescence marker.

Results

Chondrocytes stimulated by IL-1β showed increased MMP-1, MMP-3, and MMP-13 levels, whereas the expression of COL2A1 and ACAN decreased. However, in cells co-treated with IL-1β and Rg3, the levels of MMP-1 and MMP-13 were lower than in cells treated with IL-1β alone, and COL2A1 and ACAN expression levels recovered from the low values seen when cultured only in the presence of IL-1β. Also, compared to vehicle-treated controls, IL-1β stimulation alone resulted in an increased number of SA-β-Gal-positive cells, while co-incubation with IL-1β and Rg3 significantly suppressed the expression of this senescence marker. Chondrocytes cultured with Rg3 showed significantly higher proliferative and telomerase activities than did control cells.

Conclusions

These findings indicate that Rg3 protects the cell against the development of chondrocyte senescence in osteoarthritis.     

低剂量T-2毒素对大鼠体外培养软骨细胞影响的超微结构观察

目的观察低剂量T-2毒素对大鼠体外培养软骨细胞的影响。方法单层原代培养的软骨细胞加入不同浓度T-2毒素(0．5、1．0μg／L)培养24h，用透射电子显微镜观察软骨细胞超微结构。结果0．5μg/L T-2毒素组软骨细胞细胞质内细胞器数量明显减少，核固缩，染色质形成斑块状散布核内，核膜增厚，双层膜结构不清；粗面内质网数量减少且不扩张；部分线粒体空泡变性和髓样变。1．0μg/L T-2毒素组软骨细胞表面微绒毛脱失，细胞核改变非常明显，可见许多畸形核；胞质内可见大量空泡变性的线粒体，并可见线粒体的髓样变；粗面内质网扩张成囊状，脱颗粒，偶见凋亡的软骨细胞，细胞核固缩，形成高密度斑块。结论0．5μg/L T-2毒素即可对体外培养软骨细胞造成损害，剂量越大．损害越严重。     

成人骨髓基质干细胞体外定向诱导分化为软骨细胞的实验研究

目的 建立临床成人骨髓基质干细胞(MSCs)体外培养、定向诱导分化为软骨细胞的途径。方法抽取成人骨髓，Percol密度梯度离心法进行体外培养，贴壁细胞传代，取第3代细胞在培养基中添加软骨分化诱导剂地塞米松、维生素C和不同剂量转化生长因子-β(TGF-β)，培养16d后,在倒置显微镜观察细胞形态，甲苯胺蓝染色蛋白多糖，逆转录一聚合酶链反应(RT-PCR)、免疫细胞化学(SABC法)检测Ⅱ型胶原表达，诱导后MSCs与新型材料聚乳酸和羟基乙醇共聚物(PL-GA)复合。结果 Percoll密度梯度离心法培养可获得均一的。MSCs；5、10ng TGF-β诱导分化的MSCs生长迅速。呈典型的软骨细胞形态，甲苯胺蓝染色阳性，Ⅱ型胶原表达阳性，MSCs对材料PL-GA黏附力强。结论 可以从成人骨髓中培养出MSCs，并可定向诱导分化为软骨细胞，5～10ng TGF-β为最佳诱导剂量，成人MSCs可用作临床自体软骨组织工程种子细胞。     

Inhibition of nitric oxide can ameliorate apoptosis and modulate matrix protein gene expression in bacteria infected chondrocytes in vitro.

Bacterial infection stimulates nitric oxide (NO) production in chondrocytes. However, the role of NO in chondrocyte apoptosis after infection remains unclear. The purpose of the study was to test if inhibition of NO could ameliorate apoptosis and modulate matrix protein gene expression in bacteria-infected chondrocytes. It was shown that pre-treating chondrocytes with L-NAME (1 mM) significantly decreased the release of NO (from 72 to 14 microM) and the extent of apoptosis (from 52.9% to 18.9%). Pre-treatment with L-NAME also counteracted the bacteria-induced downregulation of Type II collagen (from 26% to 79%) and aggrecan (from 63% to 105%) mRNA levels. Inhibition of NO after the induction of infection could not decrease the extent of apoptosis and modulate matrix protein gene expression. The results of this study support the hypothesis that NO has an important role in bacteria-induced chondrocyte apoptosis. Pre-treatment but not post-treatment could ameliorate the extent of apoptosis and reestablish the cartilage matrix protein gene expression. This study suggests that in addition to NO, other mechanisms may be responsible for the sustained destruction of articular cartilage in the post-infectious arthropathy.     

Cell culture of rabbit meniscal fibrochondrocytes: proliferative and synthetic response to growth factors and ascorbate

This study was undertaken to determine whether the cells of the fibrocartilaginous meniscal substance are capable of proliferation and matrix synthesis. Cells were isolated from the fibrocartilaginous menisci of young New Zealand white rabbits, and grown in two alternative culture regimens differing only in the basal nutrient medium used to initiate primary monolayer growth. Under each culture regimen, the cells attached and proliferated both initially and after passage into secondary (2 degrees) culture. Differences were noted in cell morphology and time to reach confluence in primary (1 degrees) culture. Upon passage into 2 degrees culture, the fibrochondrocytes assumed two distinct morphologies depending upon the type of medium used for 1 degree culture. These morphological changes were accompanied by differences in the population doubling time and incorporation of 35SO4 into sulfated proteoglycans. The proliferation of both fibrochondrocyte subtypes was stimulated by the addition of either pituitary fibroblast growth factor (FGF) or human platelet lysate in a dose-dependent manner. Both FGF (10 ng/ml) and ascorbate (40 micrograms/ml) decreased 35-sulfate incorporation, whereas only ascorbate was found to alter the amount of sulfated glycosaminoglycan in the pericellular coat. We conclude that the fibrochondrocytes of the meniscal substance are capable of replication and synthesis of matrix macromolecules if given the proper stimuli. Additionally, there may be two subpopulations of fibrochondrocytes that can be distinguished by their in vitro behavior.     

Osteochondritis dissecans of the talus treated by the transplantation of tissue-engineered cartilage

Management of osteochondral lesions of the joint has been difficult, because articular cartilage has a poor healing capacity as a result of its lack of vessels, nerve supply, and its isolation of systemic regulation. Although a lot of basic research and surgical treatments for cartilage repair have focused on osteochondral lesions in the knee joint, orthopedic surgeons have recently diverted their attention to osteochondral lesions in the ankle joint, partly because of the widespread introduction of arthroscopy in ankle surgery. There have been many attempts to treat articular cartilage defects in the ankle joint as well as in the knee joint. However, no treatment has achieved efficient healing with hyaline cartilage. Recently, tissue engineering technique for cartilage repair has been gaining much attention in the orthopedic field. In this study, we reported on a patient with osteochondritis dissecans of the talar dome, successfully treated by transplantation of tissue-engineered cartilage made ex vivo using atelocollagen gel and low tibial osteotomy.     

Characterization of growth plate mitochondria

The growth plate chondrocyte plays a central role in growth plate function. The purpose of this study was to characterize the respiratory and calcium transport properties of isolated mammalian growth plate chondrocytes and mitochondria obtained from these cells and to quantitate the mitochondrial weight and volume fraction in each zone of the growth plate. A new method was developed for isolation of mitochondria from chondrocyte suspensions. Isolated chondrocyte mitochondria demonstrated an eightfold increase in oxygen consumption in response to calcium and a two- to threefold increase in oxygen consumption in response to adenosine diphosphate. Similar responses were observed in chondrocytes treated with digitonin. The mitochondrial protein content of the growth plate and hyaline cartilage chondrocytes is significantly less than hepatocytes. Conversely, the chondrocyte mitochondrial cytochrome aa3 content is similar to mitochondria from a wide variety of sources. A zonal analysis of the growth plate demonstrates an increase in the mitochondrial weight (protein) fraction from the reserve to the hypertrophic zone whereas the mitochondrial volume fraction decreases from the reserve to the hypertrophic zone. The findings of this study emphasize the dependence of chondrocytes on glycolysis as a prime energy source and support the concept that chondrocyte mitochondria have become specialized in the process of matrix calcification.