Ultrasound speed and attenuation in progressive trypsin digested articular cartilage  

作　　者：NIU HaiJun LI LiFeng SUN Feng YAN Yan WANG YueXiang LI DeYu FAN YuBo 

机构地区：[1]State Key Laboratory of Software Development Environment, Key Laboratory of Ministry of Education for Biomechanics and Mechanobiology, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China [2]Department of Ultrasound, People＇s Liberation Army General Hospital, Beijing 100085, China

出　　处：《Science China(Life Sciences)》2011年第11期1029-1035,共7页中国科学（生命科学英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No. 31170896);State Key Laboratory of Software De-velopment Environment (Grant No. SKLSDE-2011ZX-11)

摘　　要：Subtle changes of articular cartilage(AC) can lead to tissue degeneration and even osteoarthritis(OA).The early degeneration of AC is closely related to a change in proteoglycans(PG) content.The observation of PG is therefore an appropriate way of studying OA and evaluating the degree of AC degeneration.In this study,20 cartilage-bone samples were prepared from normal porcine femoral condyle cartilage and 10 samples were digested over 2 h using 0.25% trypsin solution.The dynamic process of PG-digestion was explored using a conventional A-mode ultrasound(US) experimental system with a 10 MHz center frequency.Quantitative acoustic parameters were calculated from ultrasonic radio-frequency echo signals and included US speed(USS),US amplitude attenuation coefficient(UAA) and broadband US attenuation coefficient(BUA).The experimental results showed that the conventional A-mode ultrasound is valuable for tracking the degree of PG-digestion.Histology also confirmed the validity of the ultrasound observations.For every AC sample,the degree of PG-digestion within a given time was different and was affected by individual differences.After two hours of degeneration,USS showed a mean decrease of 0.4%(P<0.05).UAA was significantly lower after a two-hour PG depletion period(from(2.45±0.23) to(2.28±0.41) dB mm?1).BUA showed no significant differences during this process.In conclusion,conventional ultrasound can provide useful information about trypsin-induced progressive PG depletion in AC and can reflect variations of PG content via the quantitative acoustic parameters USS and UAA.The results of this study may be used to identify an indirect indicator of cartilage matrix integrity and OA disease progression.Subtle changes of articular cartilage（AC） can lead to tissue degeneration and even osteoarthritis（OA）.The early degeneration of AC is closely related to a change in proteoglycans（PG） content.The observation of PG is therefore an appropriate way of studying OA and evaluating the degree of AC degeneration.In this study,20 cartilage-bone samples were prepared from normal porcine femoral condyle cartilage and 10 samples were digested over 2 h using 0.25% trypsin solution.The dynamic process of PG-digestion was explored using a conventional A-mode ultrasound（US） experimental system with a 10 MHz center frequency.Quantitative acoustic parameters were calculated from ultrasonic radio-frequency echo signals and included US speed（USS）,US amplitude attenuation coefficient（UAA） and broadband US attenuation coefficient（BUA）.The experimental results showed that the conventional A-mode ultrasound is valuable for tracking the degree of PG-digestion.Histology also confirmed the validity of the ultrasound observations.For every AC sample,the degree of PG-digestion within a given time was different and was affected by individual differences.After two hours of degeneration,USS showed a mean decrease of 0.4%（P〈0.05）.UAA was significantly lower after a two-hour PG depletion period（from（2.45±0.23） to（2.28±0.41） dB mm？1）.BUA showed no significant differences during this process.In conclusion,conventional ultrasound can provide useful information about trypsin-induced progressive PG depletion in AC and can reflect variations of PG content via the quantitative acoustic parameters USS and UAA.The results of this study may be used to identify an indirect indicator of cartilage matrix integrity and OA disease progression.

关 键 词：articular cartilage trypsin degeneration OSTEOARTHRITIS acoustic parameters 

分 类 号：Q954.657[生物学—动物学] P642.14[天文地球—工程地质学]