The Effect Of Low-intensity Pulsed Ultrasound On Chondrocytes Under The Action Of Adipokines Through The Integrin-FAK-p38 MAPK Pathway

Objective:To observe the effect of low intensity pulsed ultrasound(LIPUS)on the chondrocytes induced by adipokines via integrin-focal adhesion kinase(FAK)-mitogen activated protein kinase 38(p38 MAPK)pathway.Methods:24 cases of knee infrapatellar fat pad and cartilage from female patients after acute trauma were provided by orthopedics operating room.These fat pads were cut and made fat conditioned medium(FCM).The chondrocytes were isolated from the integrate surface of cartilage and cultured in vitro,and were randomly divided into four groups,i.e.,normal chondrocytes group(the normal group),normal chondrocytes+FCM group(the model group),normal chondrocytes+FCM+LIPUS group(the treatment group),normal chondrocytes+FCM+LIPUS+integrin inhibitor(GRGDSP)group(the inhibitor group).The chondrocytes in the normal group and model group were compared and identified by type ? collagen and aggrecan immunohistoehemical staining.The treatment group and the inhibitor group received LIPUS radiation,which were exposed to 40 mW/cm2 radiation for 20 min once a day.The rest of groups were accepted false LIPUS radiation.Cells were collected after six days.The expressions of type ? collagen,aggrecan,matrix metalloproteinase(MMP)-13,integrin ?1,p-FAK and p-p38 were examined by Western blot.In addition,effects of LIPUS on the level of leptin and IL-6 in FCM were also studied.Results:? type ? collagen and aggrecan immunohistochemical test:the expressions of type ? collagen and aggrecan in model group were significantly lower than that in normal group.? type ? collagen,aggrecan,MMP-13:Compared with the normal group,the expressions of type ? collagen and aggrecan in model group were lower,while the expression of MMP-13 was higher(P<0.05).Compared with the model group,the expressions of type ? collagen and aggrecan in the treatment group increased(P<0.05)and that of MMP-13 decreased(P<0.05);while the expressions of type ? collagen,aggrecan and MMP-13 in the inhibitor group had no significant difference with the model group(P>0.05).Compared with the treatment group,the expressions of type ? collagen and aggrecan in the inhibitor group decreased(P<0.05)and that of MMP-013 increased(?<0.05).?integrin ?1,p-FAK,p-p38:Compared with the normal group,the expressions of integrin ?1,p-FAK and p-p38 in the model group were higher(P<0.05),Compared with the model group,the expressions of integrin ?1 and p-FAK increased in the treatment group(P<0.05)and that of p-p38 decreased(P<0.05);while the expressions of integrin ?1,p-FAK and p-p38 in the inhibitor group had no significant difference with the model group(P>0.05).Compared with the treatment group,the expressions of integrin ?1 and p-FAK in the inhibitor group decreased(P<0.05)and that of p-p38 increased(P<0.05).?IL-6,leptin:Compared with the nomal group,the expressions of IL-6 and leptin in the model group cell supermatant were significantly higher(P<0.05).Compared with the model group,the expression of IL-6 in the treatment group and the inhibitor group decreased(P<0.05),but the leptin expression had no significant difference(P>0.05);Compared with the treatment group,the expressions of IL-6 and leptin in the inhibitor group had no significant difference(P>0.05).Conclusions:LIPUS provided a protective effect on destructive chondrocytes indueed by adipokines through inhibiting the expression of MMP-13 and degradation of type ? collagen artd aggrecan,which may acted through activating integrin-FAK-p3 8 MAPK pathway.