ABSTRACT
Objective To investigate the role of SDF-1/CXCR4 axis on the apoptosis of human degenerative nucleus pulposus cells (NPCs) and its potential molecular mechanism .Methods The intervertebral disces tissues from clinical discectomy were divided into normal group and intervertebral disc degeneration ( IVD) group according to Pfirrmann classification.The different expression of SDF 1 and CXCR4 in human IVDs was tested by immunohistochemistry, quantify polymerase chain reaction (q-PCR) and Western blot.The primary degenerative NPCs were primary cultured.The generation Ⅲ~Ⅴ NPCs was treated with 10 ng/mL SDF-1, in the presence of or in the absence of CXCR4 siRNA transfection and 20 μmol/L NF-κB inhibitor (pyrrolidine dithiocar bamate,PDTC).The transfection efficiency and target protein of signal pathway were verified by Western blot , the apoptosis of NPCs were tested by Annexin V /PI, the nucleus transferlocation of P65 from NF-κB were tested by immunofluorescent method.Results SDF-1and CXCR4 were both expressed in all donor tissues, however, there was a significantly increased in the degenerative IVDs .The apoptosis of degenerative NPCs was expedited by SDF -1 stimulation,which was significantly suppressed by CXCR 4 silencing by siRNA (P<0.05).Furthermore, with SDF-1 stimulation,the expressions of phosphorylated P 65 was significantly increased and the P65 perssad transferred to the nucleuses,which could be suppressed by the NF-κB inhibitor, PDTC(P<0.05).Conclusions The expression levels of SDF-1 and CXCR4 are increased in degenerative NP tissue.The SDF-1/CXCR4 axis is considered to induce apoptotic of human degenerative NPCs via the NF-κB signaling pathway.
ABSTRACT
BACKGROUND: A Lenke3 type adult idiopathic scoliosis finite element model was established successfully using Mimics software. However, whether the model fits the actual conditions of individualized patients still requires a further revision and validation.OBJECTIVE: To modify and validate the Lenke3 type adult idiopathic scoliosis finite element model by finite element analysis software.METHODS: Based on the characteristics of Lenke3 adult idiopathic scoliosis model, the three-factor and three-level orthogonal experiment was used to optimize the finite element model, making it more close to the actual one. The vertebrae at T1-T4, T5-T8 and L6-S1 levels (sacral lumbarization) were loaded to simulate left and right lateral flexion,as well as extension and flexion, and the range of motion when left and right rotation were compared with Busscher and Yamamoto experiments in vitro.RESULTS AND CONCLUSION: (1) According to the orthogonal experiment, the mean difference and range of each factor and each level were calculated, and finally A1B2C3 combination was the optimal one that can make the model largely consistent with the real situation. The difference in Cobb angles between the clinical lateral flexion test and the parameter pre-modified model simulation was 54.44°, which was decreased to 2.11° after modification. Moreover, the maximum difference in each scoliosis Cobb angle of the modified model was 4.29°. (2) The simulation results of the modified model when compared with the X-ray images when left and right lateral flexion, the two data obeyed normal distribution, so the paired t test was used: left lateral flexion, P =0.082 (P > 0.05); right lateral flexion, P=0.421 (P > 0.05);supine position, P=0.160 (P > 0.05). (3) The range of motion at T1-T4 segments was as followings: left flexion, 3.25°;right flexion, 3.32°; anteflexion 2.52°; extension, 2.89°; left rotation, 3.73°; right rotation 3.76°; the range of motion at T5-T8 segments: left flexion, 1.39°; right flexion, 1.43°; anteflexion 1.35°; extension, 1.34°; left rotation 2.09°; right rotation 2.11°; the range of motion at L6/S1: left flexion: 5.17°; right flexion: 5.19°; anteflexion: 8.92°; extension: 7.35°; left rotation: 1.41°; right rotation: 1.42°. The results were almost consistent with Busscher and Yamamoto experimental results. (4) To conclude, the model is in good agreement with the patient's actual properties after modification. The modified model has good reliability and validity, and provides valid data platform for simulating clinical operation in the future.