Low-intensity Pulsed Ultrasound On Cultured Rabbit Chondrocytes In Mmp-13 And Type Ii Collagen

Objective:To study the effects of low intensity pulsed ultrasound (LIPUS) on chondrocytes proliferation and MMP-13 and typeâ…¡collagen of chondrocytes of rabbit's knee in vitro and discuss the effect and Mechanism of LIPUS to chondrocytes activity.Methods: The chondrocytes were obtained from knee joints of six one-month old rabbits. Each rabbit's chondrocytes were divided into 5 groups: control group and four LIPUS groups with the intensity of LIPUS is 20 mW /cm2, 30 mW /cm2, 40 mW /cm2, 50 mW /cm2 respectively. During the second cultured generation, the chondrocytes were irradiated by LIPUS for 20 minutes and cells were counted each day for 10 days. On the 0, 5th and 10th day, chondrocytes were collected and their protein and RNA were extracted for test of MMP-13 and typeâ…¡collagen content with Western-blot and qRT-PCR technique.Result: 1.Contrasting with control groups, the chondrocytes number were higher in each LIPUS groups (p<0.05) and the numbers were significantly higher in the 40 mW /cm2 group (p<0.05). 2. MMP-13 contents were higher in the 5th day and 10th day than in the 0 day (p<0.05). After irradiated 5 days and 10 days, the contents of MMP-13 in each LIPUS group were remarkable lower than control group(p<0.05) and 40 mW /cm2 group was the lowest (p<0.05). 3. After cultured 5 days and 10 days, typeâ…¡collagen contents were lower than the 0 day(p<0.05). The contents of typeâ…¡collagen in each LIPUS groups were remarkable higher than control groups(p<0.05) and 40 mW /cm2 group was the highest (p<0.05). 4. There was significantly negative correlation between MMP-13 and typeâ…¡collagen(r=-0.757,p<0.05).Conclusion: The 4 kinds of intensity of LIPUS could promote the activities of chondrocyte and the effect is related to the chondrocyte proliferation and changes of MMP-13 and typeâ…¡collagen content in chondrocytes.