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OBJECTIVE: Aberrant apoptosis of nucleus pulposus cells (NPCs) is one of the most remarkable pathological changes in intervertebral disc degeneration (IDD) development. Albeit the advances in the application of stem cell-based therapy in IDD treatment, the molecular mechanisms underlying the anti-apoptotic actions of mesenchymal stem cell (MSC) remain poorly elucidated. PATIENTS AND METHODS: The expression patterns of apoptosis-related proteins and Wnt/β-catenin-related genes in NP samples isolated from patients with mild or severe IDD were compared by performing immunoblot assay and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. NPCs were in vitro treated with compression to induce apoptosis and then co-cultured with Wharton’s Jelly- derived MSCs without direct interaction. After that, flow cytometry was carried out to detect the apoptosis rate of NPCs and the activity of Wnt/β-catenin pathway was determined. DKK-1 was used to inhibit Wnt signaling, in prior to evaluation of the effects of WJ-MSCs on apoptosis within the co-cultured NPCs. RESULTS: Compared to the mild IDD group, there was a significant increase in the expression of Caspase-3 and Bax in the NP tissues from severe IDD patients, whereas Bcl-2 displayed an opposite result. In addition, the expression of Wnt 3a, Wnt 5a, Wnt 10a, GSK-3β, cyclinD1 and β-catenin was notably augmented in parallel with IDD progression. After compression treatment, the proportion of apoptotic NPCs was increased, which was then dramatically reversed by WJ-MSCs co-culture. Likewise, WJ-MSCs suppressed compression-induced Wnt-related gene expression and blocking Wnt/β-catenin pathway using DKK-1 enhanced the anti-apoptotic impacts of WJ-MSCs. In the presence of DKK-1, there was no significant difference between NPCs co-cultured with WJ-MSCs and those cells cultured alone. CONCLUSIONS: WJ-MSCs attenuate the compression- induced apoptosis in NPCs and inhibit the activation of Wnt/β-catenin signaling. Blocking Wnt/β-catenin pathway further facilitates the actions of WJ-MSCs in anti-apoptosis, indicating that Wnt/β-catenin signaling plays a crucial role in this process and may function as a potential therapeutic target for IDD treatment. [ABSTRACT FROM AUTHOR]

Objective: To investigate the clinical outcomes and radiographic results of artificial cervical disc replacement (ACDR) for cervical adjacent segment disease (ASD). Methods: The clinical data of 28 patients with single-segment cervical ASD treated with ACDR in Xi 'an Honghui Hospital from December 2013 to July 2016 were retrospectively analyzed. There were 19 males and 9 females with a mean age of (46±7) years (36-63 years). Preoperative, postoperative 1 month and postoperative 24 months of clinical and radiographic outcomes were recorded and compared. The clinical outcome mainly includes Japanese orthopedic association (JOA), Neck Disability Index (NDI%), Odom score and complications. Imaging assessment mainly included range of motion (ROM) of cervical spine, surgical segment ROM, Cobb angle of surgical segment, degree of adjacent disc degeneration, heterotopic ossification, and prosthesis related image parameters. Results: In terms of clinical outcome, the average JOA score was 12.7±1.5 before surgery, 14.0±1.0 one month after surgery, 15.8±0.9 24 months after surgery, and the improvement rate of JOA was 75%±19%. The mean NDI% was 27.0%±2.8% before surgery, 20.5%±1.6% one month after surgery, and 15.3%±2.8% 24 months after surgery; the difference before and after treatment was statistically significant ( F= 159.101, P< 0.01). Twenty patients were classified with excellent Odom score and 8 patients with good Odom score at the final follow-up. The total ROM of cervical spine, operation segment ROM, operation segment Cobb angle were all improved significantly after the operation ( F= 4.633, 6.063, 26.952, all P< 0.05). There was a statistical difference in Miyazaki classification between adjacent discs above ACDR and below the fusion segment 24 months after surgery (μ(c)=2.12, P= 0.034). The incidence of heterotopic ossification was 14.3%. The results of displacement degree of prosthesis were as follow: coronal plane (0.30±0.11) mm, sagittal plane (0.28±0.10) mm; subsidence of the prosthesis: (0.27±0.09) mm. No prosthesis loosening was observed. Conclusions: The clinical outcome of revision of cervical ASD by ACDR is satisfactory. The risk of intervertebral disc degeneration in adjacent segments is significantly lower than that of ACDF due to the presence of certain motor function postoperatively.

Objective: To observe effect of interleukin(IL)-1β on the expression of signaling pathway of mammalian target of rapamycin(mTOR) of articular cartilage. Methods: Articular cartilage of rats was isolated under sterile technique, cells were digested by type Ⅱ collagenase and trypsin and cultured in vitro, pre-culture the Ⅱ cells for three days, different concentrations of IL-1β were added for 24 hours.The cells were stained with toluidine blue and HE, to observe morphological changes of cells.RT-PCR was used to detect the mRNA expression of typeⅡcollagen gene, aggrecan gene, mTOR gene and P70S6K gene, Western blotting was used to detect the expression of protein related to mTOR. Results: With increasing concentrations of IL-1β, the phenotype of cells appeared polygon into a spindle, the mRNA expression of gene of type Ⅱ collagen (the control group: 0.821±0.014; 1 ng/ml: 0.614±0.014; 10 ng/ml: 0.549±0.009; 100 ng/ml: 0.520±0.008), aggrecan(0.867±0.005; 0.857±0.001; 0.554±0.008; 0.538±0.004) and mTOR(0.845±0.015; 0.785±0.009; 0.569±0.025; 0.518±0.014) reduced, but P70S6K(0.465±0.024; 0.566±0.022; 0.663±0.022; 0.896±0.015) increased by PCR .Expression of protein detected by Western blotting was similar to the trend of PCR. Conclusion: mTOR signaling pathway may play an important role on the degeneration of articular cartilage, regulating mTOR signaling pathway may provides a new idea of delaying the degeneration process of cells.

This study examines the design of a rational stimulation pattern for electrical stimulation and a robust closed-loop control scheme to improve cycling system efficacy for subjects with paraplegia. The stimulation patterns were designed by analyzing gravitation potential needed for the cycling movement of the lower limbs against a frictionless cycling ergometer and the response delay of electrically stimulated muscles. To simplify the cycling control system, the stimulation patterns were fixed and only the single gain of the stimulation patterns was adjusted via a feedback control algorithm. To circumvent the complexity involved with exactly modeling a stimulated muscle and cycling ergometer, a model-free fuzzy logic controller (FLC) was adopted herein for our control scheme. Comparison between FLC and conventional proportional-derivative (PD) controllers demonstrated that the FLC with asymmetrical membership function enabled the subject with paraplegia to maintain varied desired cycling speeds, particularly at lower cycling speed. By incorporating the rational stimulation patterns, the FLC can produce a smooth and prolonged cycling movement deemed necessary for designing various training protocols.