Low-intensity ultrasound stimulates proteoglycan synthesis in rat chondrocytes by increasing aggrecan gene expression
Low-intensity ultrasound stimulates proteoglycan synthesis in rat chondrocytes by increasing aggrecan gene expression
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DOI：
10.1002/jor.1100170405
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发表时间：
1999-07-01
影响因子：
2.8
通讯作者：
Bolander, ME
中科院分区：
文献类型：
--
作者：
Parvizi, J;Wu, CC;Bolander, ME
我们使用两种不同的1.0 MHz超声信号（空间和时间平均强度分别为50或120 mW/cm（2））评估了低强度脉冲超声刺激对体外大鼠软骨细胞的影响。脉冲的持续时间为200微秒，每毫秒重复一次，相应的平均峰值压力幅度分别为230或360 kPa。从接种后第三天开始，每天刺激细胞一次、三次或五次，持续10分钟。一组细胞暴露于假超声作为对照。评价培养物的细胞增殖（通过[H-3]胸苷掺入和DNA测量）、α（1）（I）和α（II）前胶原和聚集蛋白聚糖的稳态mRNA水平（通过北方印迹法）和蛋白聚糖合成（通过[S-35]硫酸盐掺入）。结果表明，超声处理3次和5次后，聚集蛋白聚糖mRNA水平（p <0.05）和蛋白聚糖合成（p <0.03）增加。α（1）（II）前胶原的mRNA表达随时间增加，但超声没有刺激作用。α（1）（I）前胶原的mRNA表达最初较低，并随时间保持不变。尽管两组的细胞增殖都随着时间的推移而增加，但超声处理的培养物与对照组之间没有统计学显著差异（p = 0.1）。体外实验结果支持了我们先前的体内研究结果，即低强度超声刺激软骨细胞的聚集蛋白聚糖mRNA表达和蛋白聚糖合成，这可能解释了超声在推进软骨内骨化、增加骨折的机械强度和促进骨折修复中的作用。
We evaluated the effect of low intensity-pulsed ultrasound stimulation on rat chondrocytes in vitro using two different 1.0-MHz ultrasound signals with spatial and temporal average intensities of 50 or 120 mW/cm(2). The pulses had a duration of 200 microseconds and were repeated every millisecond, with corresponding average peak-pressure amplitudes of 230 or 360 kPa, respectively. Cells were stimulated one, three; or five times for 10 minutes each day starting the third day after plating. One group of cells was exposed to sham ultrasound as a control. The cultures were evaluated for cell proliferation (by [H-3]thymidine incorporation and DNA measurement), steady-state mRNA levels of alpha(1)(I) and al(II) procollagens and aggrecan (by Northern blotting), and proteoglycan synthesis (by [S-35]sulfate incorporation). The results revealed that ultrasound causes increases in the level of aggrecan mRNA (p < 0.05) and in proteoglycan synthesis (p < 0.03) after three and five treatments. Expression of mRNA for alpha(1)(II) procollagen increased over time, but ultrasound had no stimulatory effect. Expression of mRNA for alpha(1)(I) procollagen was initially low and remained unchanged with time. Although cell proliferation increased with time in both groups, there was no statistically significant difference between the cultures treated with ultrasound and the controls (p = 0.1). The in vitro results support our previous in vivo findings that low-intensity ultrasound stimulates aggrecan mRNA expression and proteoglycan synthesis by chondrocytes, which may explain the role of ultrasound in advancing endochondral ossification, increasing the mechanical strength of fractures, and facilitating fracture repair.