ObjectiveTo observe the effect of acupotomy on the piezoelectric mechanical gating ion channel component 1（Piezo1）/glutathione peroxidase 4（GPX4）/long-chain acyl coenzyme A synthetase（ACSL4）signaling axis of knee osteoarthritis（KOA）rabbits knee chondrocytes，so as to explore the mechanism of acupotomy in the treatment of KOA.MethodsTwenty-four male New Zealand rabbits were randomly divided into blank group， model group and acupotomy group， with 8 rabbits in each group. The KOA rabbits model was established by immobilizing the left hind limb in an extended position using the modified Videman method with a plaster cast for 6 weeks. After modeling， the blank group was not fixed， the blank group and the model group were not intervened. The acupotomy group selected the left knee meridian lesion points ' Hedingci '， ' Shangwaishang '， ' Shangneishang '， ' Chengfeijian '， ' Weiyangci '， ' Yinlingci ' for acupotomy treatment， once a week for 4 weeks. Behavioral changes in the affected knee joint of the rabbits were observed to evaluate the symptoms and signs and activity function before and after the intervention and the Lequesne MG score were recorded. Histopathological changes of rabbits chondrocytes were observed after HE staining. The mitochondrial structure of rabbits chondrocytes were observed using transmission electron microscopy. The mRNA expression levels of Piezo1， GPX4 and ACSL4 in rabbits cartilage tissue were detected by real-time qPCR. The protein expression of Piezo1， GPX4 and ACSL4 in rabbits cartilage tissue was detected by Western blot.ResultsCompared with the blank group， the model group showed increase in the Lequesne MG score （P<0.01）， the mRNA and protein expression levels of Piezo1 and ACSL4（P<0.01）， and a decrease in the mRNA and protein expression levels of GPX4（P<0.01， P<0.05）. Compared with the model group， the acupotomy group showed decrease in the Lequesne MG score（P<0.05）， the mRNA and protein expression levels of Piezo1 （P<0.01， P<0.05）， the mRNA and protein expression levels of ACSL4（P< 0.01）， and a increase in the mRNA and protein expression levels of GPX4（P<0.01， P<0.05）.The results of HE staining showed that the cartilage surface of the knee joint of the model group was rough， the nucleus shrank， ruptured or disappeared， the number was rare， the arrangement was scattered， and the level was uneven. The surface of the cartilage of the knee joint of the rabbit in the acupotomy group was relatively flat， the nucleus was clear， the number was increased， the arrangement was more orderly， and the levels were neat.The results of transmission electron microscopy showed that the chondrocytes in the model group were shrunk and irregular in shape， the cell membrane was ruptured， the cytoplasm was dissolved in many places， vacuoles were formed， the mitochondria were round or oval， the number was reduced， the matrix was dissolved in a large area， the ridge was shortened， or even broken and disappeared. The shape of chondrocytes in the acupotomy group was more regular， the cell membrane was more complete， the cytoplasm was more uniform， the mitochondria were round or oval， the number was more， the matrix was more uniform， and there were more ridges.ConclusionAcupotomy can inhibit chondrocyte ferroptosis by regulating he Piezo1/GPX4/ACSL4 signaling axis，and improve KOA rabbits cartilage injury.

Knee osteoarthritis;Acupotomy;iron death;Piezo1/GPX4/ACSL4 signaling axis