Effect of needle knife on mTOR/Atg/ULK1/Beclin-1 axis and chondrocyte autophagy in rats with knee osteoarthritis / 中国针灸

OBJECTIVE@#To observe the effect of needle knife on chondrocyte autophagy and expressions of autophagy-related protein and mammalian target of rapamycin (mTOR) in rats with knee osteoarthritis (KOA), and to explore the possible mechanism of needle knife for KOA.@*METHODS@#A total of 42 SD rats were randomly divided into a normal group, a model group and a needle knife group, 14 rats in each group. Except for the normal group, the other two groups were injected with the mixture of papain and L-cysteine into the left hind knee joint to establish the KOA model. After modeling, the rats in the needle knife group were treated with needle knife at strip or nodule around the quadriceps femoris and medial and lateral collateral ligament on the affected side, once a week for 3 times (3 weeks). The changes of left knee circumference in each group were observed; the chondrocytes and ultrastructure of left knee joint were observed by HE staining and electron microscope; the mRNA and protein expressions of autophagy-related genes (Atg5, Atg12, Atg4a), Unc-51 like autophagy activated kinase 1 (ULK1), autophagy gene Beclin-1 and mTOR in left knee cartilage were detected by real-time fluorescence quantitative PCR and Western blot.@*RESULTS@#After modeling, the left knee circumferences in the model group and the needle knife group were increased compared with those before modeling and in the normal group (P<0.05); after intervention, the left knee circumference in the needle knife group was smaller than that in the model group and after modeling (P<0.05). Compared with the normal group, the number of chondrocytes was decreased, and a few cells swelled, nuclei shrank, mitochondria swelled and autophagosomes decreased in the model group; compared with the model group, the number of chondrocytes was increased , and most cell structures returned to normal, and autophagosomes was increased. Compared with the normal group, the mRNA and protein expressions of Atg5, Atg12, Atg4a, Beclin-1 and ULK1 in the knee cartilage in the model group were decreased (P<0.05); compared with the model group, the expressions of the above indexes in the needle knife group were increased (P<0.05). Compared with the normal group, the mRNA and protein expressions of mTOR in the knee cartilage in the model group were increased (P<0.05); compared with the model group, the expressions of the above indexes in the needle knife group were decreased (P<0.05).@*CONCLUSION@#The needle knife intervention could improve knee cartilage injury in rats with KOA, and its mechanism may be related to reducing the expression of mTOR and up-regulating the expressions of Atg5, Atg12, Atg4a, ULK1 and Beclin-1, so as to promote chondrocyte autophagy and delay the aging and degeneration of chondrocytes.

Repair impact of vibration exercise with different frequencies on articular cartilage of rats with early knee osteoarthritis and its JNK/NF-κB, SOX9 mechanisms / 中国应用生理学杂志

Objective: To investigate the repair effect and JNK/NF-κB,SOX9 mechanisms of vibration exercise with different frequencies on articular cartilage in rats with early knee osteoarthritis. Methods: Forty-eight adult male SD rats were randomly divided into six groups(n=8):model control group(MC),high frequency vibration group 1 (GP1,60 Hz),high frequency vibration 2 group (GP2,40 Hz),medium frequency vibration group (ZP,20 Hz),minor frequency group(DP,10 Hz)and normal control group(NC). Except for NC group,the rats in each group were made into early knee osteoarthritis model after six weeks of knee joint cavity injection of papain solution and 2% mixture l-cysteine on the 1st,4 th and 7th day. Each exercise group was subjected vibration to 40 minutes a day with amplitude of 2～5 mm and 5 days a week. Four weeks later, the articular cartilage of the lateral femoral condyle of the both back leg knee joints were detected by HE staining,serine O staining and Mankin scores for morphological observation. The expression levels of JNK,NF-κB p65 and Sox9 mRNA in articular cartilage of the medial femoral condyle were detected by RT-qPCR,and the protein expressions of JNK,NF-κB p65 and Sox9 were detected by Western blot. Results: Compared with the NC group,the Mankin score in other groups was significantly higher (P＜0.01). Compared with the MC group,the Mankin score of each vibration group was significantly lower(P＜0.05),the mRNA and protein expressions of JNK and NF-κB p65 in each vibration training group were significantly lower (P＜0.01),the expressions of Sox9 mRNA and protein in vibration training group were increased significantly (P＜0.01). Compared with the higher frequency group,the Mankin score,the mRNA and protein expressions of JNK and NF-κB p65 of lower frequency group were significantly lower (P＜0.05 or P＜0.01). But the expressions of Sox9 mRNA and protein were significantly higher (P＜ 0.05 or P＜0.01). Conclusion: Vibration exercise of different frequencies may present varying degrees of cartilage repair impact in rats with early knee osteoarthritis,and the cartilage repair by low-frequency vibration training is better than that by high-frequency vibration. This can be one of the mechanisms on controlling collagen synthesis by down-regulating JNK/NF-κB expression and increasing SOX9 activity of OA articular cartilage.

Different sources of mesenchymal stem cells for the treatment of cartilage repair in knee joint / 中国骨伤

As propose of organ repair stem cell therapy technology, articular cartilage cannot be repaired by itself has become one of the research hotspots, repair of articular cartilage with mesenchymal stem cells has shown obvious advantages for the treatment. The scholars have made a preliminary study on the role of mesenchymal stem cells from different sources in the repair of knee articular cartilage, and with the combination of transplantation and cartilage tissue engineering, these technologies improved the human cartilage repair effect of bone marrow, adipose, synovium, cord blood derived stem cells, which achieved good clinical curative effect. Due to the different sources, the dominant and recessive factors, each stem cell will have certain advantages and disadvantages. At present, the clinical research is still in the experimental stage, there is no definite conclusion on which kind of stem cell or technology is more suitable for human cartilage repair. This requires the validation of large-scale or combining with new processing technology clinical trials and the long-term clinical effect, it also provides for the basis for further clinical research.