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Hexi District, China

Shao H.,Tian Jin Medical University | Shu H.,Tian Jin Hospital | Wang C.,Tian Jin Medical University | Yuan W.,Tian Jin Medical University | Li Y.,Tian Jin Medical University
Anatomical Record | Year: 2013

Despite many experimental and clinical studies conducted on distraction osteogenesis (DO) in the past decade, changes in the surrounding tissues that occur after the procedure remains poorly understood. To study the biochemical changes of recovery in nerve tissues upon DO-induced nerve injury, we prepared a rabbit model of tibia lengthening to observe the expression pattern of nerve growth factor (NGF) and low-affinity NGF receptor (p75NGFR) in the distracted tibial nerve. The distracted tibial nerve was harvested at various time points during the consolidation period of new bone formation and immunohistochemical staining was performed to detect the expression of NGF and p75NGFR. The expression levels of NGF and p75NGFR were found to be different at various times after DO. The changes in expression of these two cellular factors show similar tendencies with significantly elevated expression in Schwann cells at 7 and 14 days after distraction, but low or undetectable levels of expression at 0, 28, and 56 days. These results suggest that NGF and p75NGFR may play important roles in the adaptive process of the distracted nerve. NGF and p75NGFR are autocrine growth factors present in the distracted nerve during the early consolidation period. NGF interacts with p75NGFR to promote damage repair and reconstruction of nerves. Together, this study furthers the understanding of the relative mechanisms of nerve repair, as well as provides a further basis for the clinical application of neurotrophins. © 2012 Wiley Periodicals, Inc.

Wang T.,Tianjin Medical University | Li P.,Tianjin Medical University | Ma X.,Tian Jin Hospital | Tian P.,Tian Jin Hospital | And 4 more authors.
Biochimie | Year: 2015

Background Human nucleus pulposus cell (HNPC) apoptosis plays an important role in the development of intervertebral disc degeneration (IVDD). Our previous research revealed that among all of the dysregulated microRNAs in the degenerated nucleus pulposus tissues of patient with IVDD, miRNA-494 (miR-494) is the most significantly increased. However, the influence of miR-494 HNPC apoptosis has not been confirmed. Objective This study was designed to evaluate the effect of miR-494 on the HNPC apoptosis induced by TNF-α and to explore the possible mechanism of this process. Methods First, HNPCs were stimulated with TNF-α at different concentrations (0 ng/ml, 10 ng/ml, 50 ng/ml, or 100 ng/ml) for 0 h, 8 h, 16 h, or 24 h. Annexin V-PE/7-AAD assays and real-time quantitative PCR were used to detect the cell apoptosis rates and miR-494 expression. Second, we successfully knocked down endogenous miR-494 in HNPCs via lentiviral antigomiR-494 vector infection and then stimulated with TNF-α (100 ng/ml, 16 h). The rates of apoptosis and miR-494 expression were then detected again. Additionally, a dual-luciferase reporter assay and western blotting were used to determine whether JunD is a target of miR-494. Finally, western blotting was used to analyze the expression of cytochrome C. Results We found that the rate of apoptosis increased with concentration, time (p < 0.05) and miR-494 expression (p < 0.05). The rate of apoptosis in the 100 ng/ml, 16 h group appeared to be suitable. After transfection, the apoptosis rate and miR-494 expression were significantly decreased in the antigomiR-494+TNF-α group compared to the controls (p < 0.05). We also revealed that JunD is a target of miR-494. Western blotting analysis demonstrated that treatment with the lentiviral antigomiR-494 vector resulted in increased expression of JunD (p < 0.05) and decreased expression of cytochrome C (p < 0.05). Conclusion These results indicated that miR-494 is a novel regulator of HNPC apoptosis induced by TNF-α. The knock-out of miR-494 expression protected the HNPCs from apoptosis via the up-regulation of JunD, which was possibly mediated via cytochrome C apoptotic signaling. These findings suggest that the miR-494/JunD signaling pathway might represent a novel therapeutic target for the prevention of IVDD. © 2015 Published by Elsevier B.V.

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