Steinmeyer J, Knue S
Department of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany.
Biochem Biophys Res Commun. 1997 Nov 7;240(1):216-21. doi: 10.1006/bbrc.1997.7641.
This study describes the effect of load magnitude, frequency and duration on proteoglycan (PG) biosynthesis and loss in mature bovine articular cartilage explants. Cultured full thickness cartilage discs were subjected to a continuously applied, uniaxial compressive cyclic load. The loads were applied using a sinusoidal waveform of 0.001, 0.01, 0.1 or 0.5 Hz-frequency and a peak stress of 0.1, 1.0, 2.5, or 5.0 MPa for a period of 1, 3 or 6 days. Increasing the load magnitude, as well as the duration of loading, reduced the PG biosynthesis. Reducing the load frequency abolished the inhibitory effect of a given load magnitude on PG biosynthesis, even though explants were more compressed. Increasing the load magnitude stimulated the release of newly synthesized PGs from explants, whereas an elevated duration of loading significantly decreased the release of endogenous PGs. Explants loaded for 1 or 3 days were viable as determined biochemically, whereas 6 days of loading resulted in a slightly diminished viability of explants. This study demonstrates that the duration and intensity of loading influences the inhibition of PG biosynthesis, while PG loss is only modulated by the magnitude and duration of loading.
本研究描述了负荷大小、频率和持续时间对成熟牛关节软骨外植体中蛋白聚糖（PG）生物合成及损失的影响。将培养的全层软骨圆盘置于持续施加的单轴压缩循环负荷下。使用频率为0.001、0.01、0.1或0.5Hz的正弦波形以及峰值应力为0.1、1.0、2.5或5.0MPa施加负荷，持续1、3或6天。增加负荷大小以及负荷持续时间会降低PG生物合成。降低负荷频率消除了给定负荷大小对PG生物合成的抑制作用，即便外植体受到了更大程度的压缩。增加负荷大小会刺激新合成的PG从外植体中释放，而延长负荷持续时间则会显著降低内源性PG的释放。经生化测定，负荷1天或3天的外植体具有活力，而负荷6天则导致外植体活力略有下降。本研究表明，负荷的持续时间和强度会影响PG生物合成的抑制，而PG损失仅受负荷大小和持续时间的调节。
