Xu Yaofeng, Gu Yuguo, Ji Wanbo, Dong Qirong
Department of Orthopedics, the Second Affiliated Hospital of Soochow University, Suzhou, China.
Department of Orthopedics, Suzhou Hospital of Traditional Chinese Medicine Affiliated to Nanjing University of Traditional Chinese Medicine, Suzhou, China.
Ann Transl Med. 2021 Apr;9(8):663. doi: 10.21037/atm-21-1215.
The objectives of this study was to explore the activation of the extracellular-signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling pathway and osteogenesis-related factors in the subchondral bone of patients with knee osteoarthritis (OA).
Ten patients with primary OA who underwent total knee arthroplasty in the Department of Arthritis Surgery of our hospital were enrolled, and subchondral bone tissue samples were obtained during the operation. He staining and saffron staining were used to observe the arrangement of chondrocytes in the patient tissues. The protein expression levels of JNK, p-JNK, ERK, p-ERK, Runx2 and OMD in subchondral bone were detected by Western Blot. Knee osteoarthritis mice were established. He staining was used to observe the arrangement of subchondral bone cells in the knee joint of mice. Cellular mineralized nodules were determined by alizarin red staining.
Firstly, in general and staining, it was observed that the subchondral bone lesions of knee OA participants were obvious. Compared with normal knee joints, the levels of phosphorylation-c-Jun N-terminal kinase (P-JNK) and phosphorylation-extracellular-signal-regulated kinase (P-ERK) in the subchondral bone of knee arthritis participants were significantly increased (P<0.05). The level of osteomodulin (OMD) was significantly reduced (P<0.05). Secondly, compared with normal mice, the levels of JNK, P-JNK, OMD, ERK, and P-ERK in the model group were significantly different (P<0.05). At 2-8 weeks, the JNK and P-JNK levels in the mice model group increased significantly over time (P<0.05), and the OMD level decreased significantly over time (P<0.05). The levels of ERK and P-ERK fluctuated over time. Thirdly, osteoblasts were treated with different concentrations of anisomycin, and stained with alizarin red after continuous culture for 24 and 48 h, respectively. It was found that all the cells were stained with orange-red mineralized nodules. As the concentration of anisomycin was increased, the number of cell mineralization nodules was significantly larger, and the positive rate of chemical nodules increased. Different concentrations of anisomycin were given to interfere with the osteoblasts of mice. When anisomycin was administered at a dose of 25 ng, the OMD level reached the highest level. When the concentration of anisomycin was increased, the osteocalcin (OCN) level also showed an upward trend.
The process by which the JNK signaling pathway regulates OMD may be closely related to the pathological changes of subchondral bone in patients with knee OA, and is involved in the occurrence and development of knee arthritis.
本研究旨在探讨膝骨关节炎（OA）患者软骨下骨中细胞外信号调节激酶（ERK）和c-Jun氨基末端激酶（JNK）信号通路及成骨相关因子的激活情况。
选取在我院关节炎外科接受全膝关节置换术的10例原发性OA患者，术中获取软骨下骨组织样本。采用苏木精-伊红（HE）染色和番红染色观察患者组织中软骨细胞的排列。通过蛋白质免疫印迹法检测软骨下骨中JNK、p-JNK、ERK、p-ERK、Runx2和骨调素（OMD）的蛋白表达水平。建立膝骨关节炎小鼠模型。采用HE染色观察小鼠膝关节软骨下骨细胞的排列。通过茜素红染色检测细胞矿化结节。
首先，在大体及染色观察中，发现膝OA患者的软骨下骨病变明显。与正常膝关节相比，膝关节炎患者软骨下骨中磷酸化c-Jun氨基末端激酶（P-JNK）和磷酸化细胞外信号调节激酶（P-ERK）水平显著升高（P<0.05）。骨调素（OMD）水平显著降低（P<0.05）。其次，与正常小鼠相比，模型组JNK、P-JNK、OMD、ERK和P-ERK水平差异有统计学意义（P<0.05）。在2-8周时，小鼠模型组JNK和P-JNK水平随时间显著升高（P<0.05），OMD水平随时间显著降低（P<0.05）。ERK和P-ERK水平随时间波动。第三，用不同浓度茴香霉素处理成骨细胞，分别连续培养24小时和48小时后进行茜素红染色。发现所有细胞均被染成橙红色矿化结节。随着茴香霉素浓度增加，细胞矿化结节数量显著增多，化学结节阳性率增加。用不同浓度茴香霉素干预小鼠成骨细胞。当茴香霉素剂量为25 ng时，OMD水平达到最高。当茴香霉素浓度增加时，骨钙素（OCN）水平也呈上升趋势。
JNK信号通路调节OMD的过程可能与膝OA患者软骨下骨的病理变化密切相关，并参与膝关节炎的发生发展。
