Olsen A K, Sondergaard B C, Byrjalsen I, Tanko L B, Christiansen C, Müller A, Hein G E, Karsdal M A, Qvist P
Nordic Bioscience Diagnostics A/S, Herlev, Denmark.
Osteoarthritis Cartilage. 2007 Mar;15(3):335-42. doi: 10.1016/j.joca.2006.08.015. Epub 2006 Oct 11.
The aim of the present study was to investigate collagen metabolism after anabolic and catabolic stimulation of chondrocytes ex vivo.
Metabolic activities in ex vivo bovine cartilage explants were stimulated with insulin-like growth factor I (IGF-I) or a combination of tumor necrosis factor alpha (TNFalpha) and oncostatin M (OSM). Supernatants were assessed for changes in biochemical markers, N-terminal propeptide of type II (PIINP) collagen and fragments of C-telopeptide of type II collagen (CTX-II). Matrix metalloproteinases (MMP) were added to metabolic inactivated cartilage and evaluated by the two biochemical markers for formation or degradation, respectively. Finally, urinary CTX-II and PIINP were evaluated for assessment of type II collagen turnover in patients with rheumatoid arthritis (RA).
In the bovine articular cartilage explants, IGF-I induced an increase in PIINP level up to 4.8+/-1.1[ng/ml]/mg cartilage whereas CTX-II remained below 0.1+/-0.1[ng/ml]/mg cartilage. In the catabolic stimulated explants both PIINP and CTX-II were released to the supernatant, reaching concentrations of 9.0+/-1.4 and 9.1+/-2.2[ng/ml]/mg cartilage, respectively. RA patients had significantly lower serum concentrations of PIINP (3.4+/-3.7 ng/ml) compared with those healthy individuals (18.7+/-12.41 ng/ml, P<0.001). In contrast, RA patients had significantly higher urinary CTX-II (0.8+/-0.8 mg/mmol) compared to the healthy controls (0.1+/-0.08 mg/mmol, P=0.004).
This study is the first to demonstrate that precursors and degradation products of type II collagen released into the supernatant can effectively reflect the anabolic and catabolic activities of stimulated cartilage explants.
本研究旨在体外研究软骨细胞在合成代谢和分解代谢刺激后的胶原代谢情况。
用胰岛素样生长因子I（IGF-I）或肿瘤坏死因子α（TNFα）与制瘤素M（OSM）的组合刺激体外培养的牛软骨外植体的代谢活性。评估上清液中生化标志物、II型胶原N端前肽（PIINP）和II型胶原C端肽片段（CTX-II）的变化。将基质金属蛋白酶（MMP）添加到代谢失活的软骨中，并分别通过两种生化标志物评估其形成或降解情况。最后，评估类风湿关节炎（RA）患者尿CTX-II和PIINP，以评估II型胶原的周转情况。
在牛关节软骨外植体中，IGF-I使PIINP水平升高至4.8±1.1[纳克/毫升]/毫克软骨，而CTX-II仍低于0.1±0.1[纳克/毫升]/毫克软骨。在分解代谢刺激的外植体中，PIINP和CTX-II均释放到上清液中，浓度分别达到9.0±1.4和9.1±2.2[纳克/毫升]/毫克软骨。与健康个体（18.7±12.41纳克/毫升）相比，RA患者血清PIINP浓度显著降低（3.4±3.7纳克/毫升，P<0.001）。相反，与健康对照（0.1±0.08毫克/毫摩尔）相比，RA患者尿CTX-II显著升高（0.8±0.8毫克/毫摩尔，P=0.004）。
本研究首次表明，释放到上清液中的II型胶原前体和降解产物能有效反映受刺激软骨外植体的合成代谢和分解代谢活性。
