Effect of electrothermic needle on synovial inflammation and chondrocyte apoptosis in rats with knee osteoarthritis by regulating the Wnt/PPARγ signaling pathway

YANG Kun; HU Feng; MIN Hui

doi:10.3969/j.issn.1002-7386.2025.08.004

Abstract：Objective To investigate the effects of electrothermic needle on synovial inflammation and chondrocyte apoptosis in rats with knee osteoarthritis by regulating the Wnt/PPARγ signaling pathway.Methods Forty Sprague-Dawley(SD)male rats in the specific pathogen free(SPF)grade were randomly divided into control(NOR)group,model(MOD)group,electrothermic needle(EHN)group and PPARγ agonist(AGO)group,with 10 rats in each group.Knee osteoarthritis model was established by injections of type Ⅱ collagenase into the knee space of rats in MOD,EHN and AGO groups,and rats in the NOR group were treated with blank control.After the modeling was successfully created,rats in the EHN group were treated with electrothermic needle,and those in the AGO group were intrabitoneally injected with 30mg/kg Wnt/PPARγ signaling pathway agonist pioglitazone.Rats in the NOR group and MOD group were given the same volume of normal saline via oral gavage.Knee joint activity and swelling were recorded,and the pathological morphology of the synovial tissue was detected by hematoxylin and eosin(H&E)staining.Synovial inflammation was detected by enzyme-linked immunosorbent assay(ELISA),and chondrocyte apoptosis was detected by the terminal deoxynucleotidyl transferase dUTP nick-end labeling(TUNEL)assay.Protein levels of relevant genes in the Wnt/PPARγ signaling pathway were detected by Western blot.Results Compared with those of NOR group,rats in the MOD group presented significantly decreased knee joint activity and increased knee joint swelling(P＜0.05).Compared with those of MOD group,rats in the EHN group and AGO group presented significantly increased knee joint activity and decreased knee joint swelling(P＜0.05).In the NOR group,rats had normal synovial tissue with neat arrangement of synovial cells,no pannus formation and no obvious inflammatory cell infiltration.Rats in the MOD group had synovial cell proliferation,pannus formation and obvious inflammatory cell infiltration.Compared with those of MOD group,the pathological structures of key joint in rats of EHN group and AGO group were significantly alleviated.Compared with those of NOR group,relative levels of TGF-β1,IL-1α and IL-21 in synovial tissue of rats in MOD group were significantly elevated(P＜0.05),while TGF-β1,IL-1α and IL-21 in synovial tissue of rats in EHN and AGO groups were significantly reduced compared with those of MOD group(P＜0.05).Compared with that of NOR group,the apoptotic rate of chondrocytes in the MOD group was significantly elevated(P＜0.05).Compared with that of MOD group,the apoptotic rate of chondrocytes in EHN group and AGO group was significantly reduced(P＜0.05).Compared with those of NOR group,rats in the MOD group had significantly upregulated Wnt4 and β-catenin,and downregulated PPARγ in knee tissue(P＜0.05).Downregulated Wnt4 and β-catenin,and upregulated PPARγ were observed in knee tissue of rats in EHN group and AGO group(P＜0.05).Conclusion Electrothermic needle can effectively inhibit synovial inflammation and chondrocyte apoptosis in rats with knee osteoarthritis by regulating the Wnt/PPARγ signaling pathway.