ABSTRACT
BACKGROUND:The mechanism underlying Wal erian degeneration fol owing peripheral nerve injury is complex. Immune regulation on Wal erian degeneration is beneficial for early repair of perpheral nerve injury. OBJECTIVE:To investigate the effects of Tol-like receptor 4 (TLR4) antagonist on Wal erian degeneration and axonal regeneration after early peripheral nerve injury in rats. METHODS:Fifty male Wistar rats were recruited and randomly divided into treatment group (n=20), model group (n=20) and sham group (n=10). The right sciatic nerves of rats in treatment and model groups were cut and sutured end-to-end, while the sciatic nerves of rats in sham group were only exposed. In the treatment group rats were intravenously injected with 0.15 mg/kg TAK-242 via tail vein 1 hour preoperatively and 7 days postoperatively, and the rats in the other two groups were given intravenous injection of the same volume of normal saline. The sciatic nerves were removed at 24 hours, 3, 4 and 7 days after surgery. RESULTS AND CONCLUSION:Real-time PCR indicated that the mRNA expressions of interleukin-1βand monocyte chemoattractant-1 were significantly increased in the model group compared with the sham group at 24 hours after surgery (both P<0.001), while the expressions were significantly decreased after TAK-242 injection (both P<0.001). Immunofluorescence showed that compared with the model group, down-regulated expression of CD68+and iba1+cel s appeared in the treatment group at 3 days after surgery (P<0.01, P<0.05). Luxol fast blue staining revealed that demyelination at the sciatic nerve stump appeared in both model and treatment groups at postoperative 7 days, but myelin debris clearance in the treatment group was significantly reduced compared with the model group (P<0.05). Hematoxylin-eosin staining showed that a lot of inflammatory cel s, Schwann cells and regenerated nerve fibers at the sciatic nerve stump were found in the model group, while there were few inflammatory cells, Schwann cel s and regenerated nerve fibers in the treatment group at 7 days after surgery. Immunohistochemistry found that the expression of growth-associated protein-43 in the treatment group was significantly lower than that in the model group at 4 days postoperatively (P<0.05). Besides, compared with the model group, a significantly decreased sciatic functional index was found in the treatment group at 20, 30 and 40 days after surgery (P<0.05). These results show that TLR4 antagonists delay early nerve regeneration in rats after sciatic nerve injury probably by inhibiting the TLR4 signaling pathway.
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BACKGROUND:The sodium alginate film, jointly developed by our research team and the Institute of Polymer Material of Qingdao University, has good biocompatibility and is often used for the preparation of a variety of composite materials. OBJECTIVE: To observe the effect of sodium alginate film wrapping and covering nerve anastomotic stoma on the regeneration of injured sciatic nerve in rats. METHODS: A total of 36 male Wistar rats were randomly divided into two groups after the right sciatic nerve was cut. Control group: The nerve stump was sutured through epineurial end-to-end anastomosis; Experimental group: The nerve stump was sutured through epineurial end-to-end anastomosis, and wrapped with sodium alginate film, forming a regenerative environment for sciatic nerve regeneration. The degradation and absorption of sodium alginate film, as wel as the adhesion at suture site were observed post-operation. Interleukin-2 and interleukin-4 positive expression was detected with immunohistochemistry method. The histological sections were also detected with hematoxylin-eosin staining and osmium tetroxide staining. RESULTS AND CONCLUSION:At 4-6 weeks post-operation, sodium alginate film was mostly degraded and absorbed in the experimental group. The experimental group rats had less local adhesion, slighter infiltration of inflammatory cels, and fewer fiber tissue hyperplasia than control group rats. The contents of interleukin-2 and interleukin-4 were almost the same between the control and experimental groups at 1, 7, 14 days post-operation. At 6 weeks, the regenerated nerve fibers were distributed evenly with uniform shape, the number of nerve fibers, axons and myelin sheath were significantly better than the control group (P < 0.05). Sodium alginate film has good biological degradability and histocompatibility and plays an important role in promoting sciatic nerve regeneration.
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BACKGROUND: Cryotherapy of acute soft tissue injury has been widely used in clinical practice.OBJECTIVE: To observe the histological changes and treatment effect of different cryotherapies on the rats' acute damage of soft tissue. METHODS: Neonatal Wistar rats were randomized to normal, model, intermittent cryotherapy and continuous cryotherapy groups. Models of acute damage of soft tissue were established in model, intermittent cryotherapy and continuous cryotherapy groups. In intermittent cryotherapy group, the injury was treated by intermittent cryotherapy with ice bag at 4 °C; in the continuous cryotherapy group, the injury was treated by continuous cryotherapy with ice bag at 4 °C; the model group was not treated. Histological changes were observed at 48 hours. Injury degree was evaluated using injury symptom index.RESULTS AND CONCLUSION: Compared with model group, the scores of injury symptom index and histology were lower, interleukin-1β expression was reduced, and transforming growth factor-β1 (TGF-β1) expression was increased in intermittent cryotherapy and continuous cryotherapy groups (P < 0.05). Compared with intermittent cryotherapy group, the scores of injury symptom index and histology were reduced (P < 0.05), interleukin-1β expression was reduced (P < 0.05), and TGF-β1 expression was increased in continuous cryotherapy group (P < 0.05). Results demonstrated that cryotherapy can cure the acute damage of soft tissue by reducing interleukin-1β expression and raising TGF-β1 expression. Continuous cryotherapy is superior over intermittent cryotherapy.
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BACKGROUND: Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been widely used on clinic; however, there are still few reports addressing rhBMP-2-induced osteogenesis in intervertebral disc.OBJECTIVE: To verify the effect of rhBMP-2 to induce interbody fusion in rabbits.DESIGN, TIME AND SETTING: Randomized controlled animal study and multi-level evaluation, which was performed in Affiliated Hospital of Medical College of Qingdao University from February to July 2007.MATERIALS: 24 adult New-Zealand rabbits weighing 3.5-4.5 kg were used to expose L4-5 and L5-6 intervertebral disc; rhBMP-2 (1 mg/ampoule, purity≥95%) was provided by Beijing Bailingke Biological Products Co., Ltd.METHODS: 24 rabbits were randomly divided into experimental group and control group with 12 rabbits for each. In the experimental group, saline (20 μL, containing 200 μg rhBMP-2) was injected into nucleus pulposus of L4-5 intervertebral disc; equivalent saline was inserted into nucleus pulposus of L5-6 intervertebral disc as controls. Rabbits in the control group were injected with saline (20 μL) into nucleus pulposus of L4-5 intervertebral disc.MAIN OUTCOME MEASURES: Morphological changes of injected segments were observed by hand-feeling check together with histological and imaging tests at 10, 30, 60, and 90 days postoperatively.RESULTS: 24 rabbits were included in the final analysis. ①In the experimental group, the motion range of L4-5 segment was not limited at 10 days postoperatively, and lightly limited at 30 days, but severely limited at 60 days postoperatively; L4-5 segment was fixed tightly at 90 days postoperatively. Moreover, motion range of L5-6,segment and articular motion range in the control group were not changed remarkably. ② L4-5 interbedy space was narrowed at 10 days or even disappeared at 90 days postoperatively, and then osteogenesis fusion was formed. Transmittance of intervertebral space in the L5-6 segment and in the control group was not changed obviously. ③ Nucleus pulposus was gradually shrunk at 10 days postoperatively; partial cartilage endplate transformed into mature woven bone, and collagen fiber structure of annulus fibrosus gradually disappeared at 90 days postoperatively. A lot of mesenchymal cells were aggregated surrounding annulus fibrosus at 10 and 30 days postoperatively. Moreover, mature woven bone was formed in annulus fibrosus near to cartilage endplate at 90 days postoperatively. However, histological and morphological changes were not found in the control group at those four time points.CONCLUSION: rhBMP-2 can induce intervertebral disc osteogenesis so as to achieve interbody fusion.
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Objective To deliver an exogenous therapeutic gene—hTGF ?1 to rabbit lumbar intervertebral disc in vivo by adenovirus vector and observe the expression of the exogenous therapeutic gene. Methods 20?l of 0 01?mol/L PBS, with or without adenovirus (6?10 6pfu) carrying TGF ?1 gene (Ad/CMV hTGF ?1) which were constructed by our laboratory, was injected directly into nucleus pulposus tissues of lumber discs of mature New Zealand white rabbits. Immunohistochemical staining for human transforming growth factor ?1 was performed on the rabbit disc tissues in different periods after operation. A half quantitation for immunohistochemical staining was performed by VIDAS analysis system. Results Discs injected with Ad/CMV hTGF ?1 exhibited extensive and intense positive immunohistochemical staining for transforming growth factor ?1 from 1 week to 12 weeks after operation, and positive pellets in nucleus pulposus cells in 4th day group, while the control groups(intact group and PBS group) showed negative or weakly positive immunohistochemical staining. The OPTDM was significantly increased in the discs injected with Ad/CMV hTGF?1 compared to the contact discs or the discs injected with only PBS( P