Ultrasound speed and attenuation in progressive trypsin digested articular cartilage

Abstract

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.

Observation of sGAG content of human hip joint cartilage in different old age groups based on EPIC micro-CT

“…This result is consistent with previous studies observing the sGAG content in different layers of human cartilage (34–36). Moreover, the variation tendency of X-ray attenuation in the superficial layer and middle layer is more obvious than that in the deep layer; this result indicates that sGAG content in the superficial layer and middle layer is lost more easily than the deep layer with aging.…”

Progression and prospects of translational medicine in China

“…Most scientists in China had promoted studies focusing on clinical problems. Prof. Feng et al [23] had studied the non-invasive detection of gastric cancers, and Prof. Niu et al [24] had focused on identifying an indirect indicator of cartilage ma-trix integrity and OA disease progression. Prof. Zhou and his colleagues [25] had investigated how to evaluate muscle fatigue to avoid occupational injuries.…”