Low intensity pulsed ultrasound can help protect chondrocytes co-cultured with the infrapatellar fat pad through the integrin-FAK-p38 MAPK pathway / 中华物理医学与康复杂志

ABSTRACT

Objective To observe the effect of low intensity pulsed ultrasound (LIPUS) on chondrocytes co-cultured with infrapatellar fat pads.Methods Twenty-four infrapatellar fat pads and cartilages from female knee trauma patients aged between 25 and 35 were cut and stained using hematoxylin-eosin staining.Chondrocytes were isolated from part of the integrated surface of the cartilages to be cultured in vitro.They were then randomly divided into a normal chondrocyte group (the control group),a normal chondrocyte+FCM (fat conditioned medium) group (the model group),a normal chondrocyte+ FCM + LIP US group (the treatment group),and a normal chondrocyte+ FCM + LIPUS + GRGDSP (an integrin inhibitor) group (the inhibited group).The treatment group and inhibited group received LIPUS at 40 mW/cm2 for 20 min once a day,while the other groups received sham LIPUS treatment.Five days later,the cells were collected and western blotting was used to examine the expression of type Ⅱ collagen (COL2),aggrecan (Acan),matrixmetalloproteinase (MMP)-13,integrin β1,phosphorylation-focal adhesion kinase (p-FAK) and phosphorylation p38 (p-p38).Results Western blotting showed that compared with the control group,the expression of COL2 and Acan was significantly lower in the model group,but that of MMP-13,integrin β1,p-FAK and p-p38 was significantly higher.As compared with the model group,the expression of COL2,Acan,integrin β1 and p-FAK was significantly higher,and that of MMP-13 and p-p38 was significantly lower in the treatment group.The expression of COL2,Acan,MMP-13,integrin β1,p-FAK and p-p38 showed no significant difference between the inhibited and model groups,but that of COL2,Acan,MMP-13,integrin β1,p-FAK and p-p38 was significantly different between the control and treatment groups.Conclusions LIPUS provides a protective effect on chondrocytes through inhibiting the expression of MMP-13 induced by adipokines and the degradation of COL2 and Acan through activating the integrin-FAK-p38 MAPK pathway.