Preliminary Investigation On The Effect Of Extracorporeal Shock Wave Combined With Manual Traction On The Improvement Of Joint Dysfunction And PTEN-PI3K/AKT Signaling Pathway In A Rat Model Of Extending Knee Joint Contracture

Objective:The aim of this study was to investigate the interventional effect of extracorporeal shock wave combined with manual traction on extension fixation-induced joint capsule contracture in rats and the effect on PTEN-PI3K/AKT signaling pathway.Methods:The knee joints of rats were fixed by external fixation with a brace.36 SD male rats were randomly divided into 6 groups.The control group(C group)had no fixation of the left knee joint.In the other groups,in order to induce joint contracture.The left knee joints of rats in other groups were straightened at 0°and fixed with brace.After 4 weeks of braking,the rats were randomly divided into 5 groups:Model group(M group),Natural recovery group(NR group),Extracorporeal shock wave therapy group(ET group),and Manual Traction Treatment group(MT group),and Combined therapy group(CT group).Arthrometry was used to assess the left knee joint mobility(ROM);Hematoxylin-eosin(HE)staining and Masson staining were used to assess the number of inflammatory cells and the expression of collagen deposition in the left anterior knee capsule,respectively;immunohistochemical staining and western blot assay were used to assess the phosphatase and Tensin homolog(PTEN),phosphatidylinositol 3-kinase(PI3K)and protein kinase B(AKT)protein levels.Results:1.The measurement results of knee joint ROM of rats in each group showed that the ROM of knee joint in M group was significantly lower than that in C group(P<0.05);Compared with NR group,the ROM of knee in ET group,MT group and CT group were significantly improved(P<0.05).The ROM of knee in CT group was significantly higher than that in ET group and MT group(P<0.05).2.HE and Masson staining results showed that the number of cells and the collagen deposition in M group were significantly higher than those in C group(P<0.05);There was no significant difference between NR group and M group(P>0.05);Compared with NR group,the number of cells and the collagen deposition in ET group,MT group and CT group decreased(P<0.05);Compared with ET group or MT group,CT group had statistical significance(P<0.05).3.The results of immunohistochemical staining showed that the optical density of PTEN in M group was significantly lower than that in C group(P<0.05);There was no significant difference between NR group and M group(P>0.05);The PTEN optical density value of ET group,MT group and CT group increased compared with NR group(P<0.05),while the PTEN optical density value of CT group increased compared with ET group and MT group(P<0.05).The optical density of PI3K/AKT in M groupwas higher than that in C group(P<0.05);There was no significant difference between NR group and M group(P>0.05);The PI3K/AKT optical density value of ET group,MT group and CT group was lower than that of NR group(P<0.05),and the PI3K/AKT optical density value of CT group was lower than that of ET group and MT group(P<0.05).4.Western blot showed that compared with C group,the expression of PTEN in M group decreased(P<0.05)and the expression of PI3K/AKT increased(P<0.05);Compared with M group,the expression of PTEN,PI3K/AKT protein in NR group had no significant difference(P>0.05);Compared with NR group,the expression level of PTEN in ET group,MT group and CT group increased(P<0.05),and the expression level of PI3K/AKT decreased(P<0.05);Compared with ET group and MT group,PTEN expression level in CT group increased(P<0.05)and PI3K/AKT expression level decreased(P<0.05).Conclusion:Extracorporeal shock wave combined with manual traction can effectively 5 alleviate the histopathological changes of joint capsule fibrosis in rat joint contracture model,up-regulate the protein expression of PTEN in fibrotic joint capsule and down-regulate the protein expression of PI3K and AKT.