Effects of electro-acupuncture on remyelinization after compressive spinal cord injury / 中华物理医学与康复杂志

Objective To observe the effects of electro-acupuncture on the expression and inhibition of DNA binding protein 2 (Id2) and myelin basic protein (MBP),and to explore the mechanism of remyelinization after compressive spinal cord injury (CSCI) in rats.Methods Fifty-four SD rats were randomly divided into a control group and a treatment group,and each was further subdivided into 3 time point subgroups:3,7 and 14 days.There were 9 rats in each subgroup.The CSCI models were made with a self-designed method.The acupuncture points Jiaji (EX-B2),bilateral Zusanli (ST36) and Taixi (KI3) were selected for treatment.Electro-acupuncture (continuous wave,2 Hz,1.5 V)was applied to the bilateral Zusanli (ST36) and Taixi (KI3) points.The control group received the injury but no treatment.The changes in the ultrastucture of the nerve fibers＇ white matter were de-termined by transmission electron microscopy (TEM).The alterations in the expression of MBP and Id2 were observed by double labeled immunofluorescence and Western blotting on the 3rd,7th and 14th day after the injury.Results TEM showed that the myelin sheaths in the control group had degenerated,swollen,and even broken down after CSCI.Changes to the myelin sheaths in the treatment group were milder than those in the control group.The immunofluorescence results showed the amount of Id2-immunoreactive oligodendrocytes in the control group to be (20 ±2) on the 3rd day after CSCI,becoming (16 ± 1) on the 14th day.The differences among the 3 control subgroups were not statistically significant.The amount of Id2-immunoreactive oligodendrocytes in the treatment group was (13 ± 1) on the 3rd day,reaching a minimum the 14th day.The differences among the 3 treatment groups were statistically significant.The differences compared with the control group at the same time points were also statistically significant.Western blotting showed that the expression of Id2 in the contrast and treatment groups was (1.12 ±0.12) and (0.67 ±0.01) respectively on the 3rd day after CSCI,and both decreased with time.The expression of Id2 in both groups reached their minima ((0.86 ±0.02) and (0.25 ±0.01) respectively) on the 14th day.The difference between the treatment groups and the contrast group was statistically significant at each time point.The expression of MBP in the contrast and treatment groups at day 3 was (0.44 ± 0.02) and (0.67 ± 0.04) respectively,and these increased with time.The expression of MBP in both groups peaked at the 14th day (at (0.95 ± 0.04) and (1.74 ± 0.09) respectively).These differences were again statistically significant.Conclusion Electro-acupuncture can regulate the expression of Id2 and MBP after CSCI.The down-regulation of Id2 which controls MBP negatively and the up-regulation of MBP may contribute to remyelination in the injured spinal cord.

Expression and role of connective tissue growth factor in the peripheral nerve after chronic compression injury / 中华显微外科杂志

Objective To investigate the effects of connective tissue growth factor (CTGF) on the chronic peripheral nerve compression injury and explore the function of CTGF in peripheral nerve compression injury and repair. Methods From July 2010 to September 2010, fifty aduh male SD rats were randomly divided into group A and B: group A (sham-operated group): only exposed the sciatic nerve; group B (compression group): undergone sciatic nerve entrapment operation on the right hind leg according to the method which Mackinnon adopted when he established the model of chronic sciatic nerve compression.Electron microscopy,immunohistochemistry,RT-PCR and Western-blot were performed to observe the morphological changes of the compressed nerve tissue and to determine the level of CTGF,collagen- Ⅰ,Ⅲ (COL- Ⅰ,Ⅲ),2,4,6,8,10 weeks after the surgery,respectively. Results After sciatic nerve compression,the collagen in nerve increased ; The expression of CTGF and COL- Ⅰ, Ⅲ in sciatic nerve of compressed group increased, which was statistically different compared with the sham-operation group (P ＜ 0.05); In the meanwhile,the contents of CTGF and COL- Ⅰ,Ⅲ were positively correlated in a certain period. Conclusion Peripheral nerve fibrosis can be caused by chronic nerve compression.The expression of COL- Ⅰ,Ⅲ in sciatic nerve increased and CTGF get involved in the pathophysiological process, which suggests that CTGF plays an important role in the process of neural injury and fibrosis.

Neurologic and Histological Study of Clip Compression Model for Rat Thoracic Spinal Cord Injuries

OBJECTIVE: The purpose of this study was to assess the time-response of clip compression model for the relationship between the duration of the injury on the rat thoracic spinal cord, and histological and functional outcome measures. METHODS: After laminectomy at T9 in Sprague-Dawley rats, a modified aneurysm clip with a closing force of 30-gram was applied extradurally around the spinal cord at T9, and then rapidly released with cord compression persisting for 1, 5, and 10 minutes, respectively. The locomotor function, according to the Basso-Beattie-Bresnahan (BBB) scale, was assessed weekly for 4 weeks after the injury. The injured spinal cord was then examined histologically including quantification of cavitation. RESULTS: Spinal cord injury by clip compression resulted in worsened BBB scale scores. However, there was spontaneous functional improvement in times for all 3 injury severities, with the greatest improvement in the 1-minute compression group. From 1 week after the injury, BBB scores in the 1-minute group were significantly higher than in the 5 or 10-minutes groups until the end of the follow-up period (p<0.05). For histological analysis, the cavitation area and cavity volume at 4 weeks was directly proportional to the severity of the injury. CONCLUSION: The results of this study show that the rat thoracic cord clip compression model is a reliable and reproducible spinal cord injury model. The duration of clip compression injury in the rat thoracic cord has been correlated with both functional and histologic outcome measures.

Duplication of animal models for spinal cord injury and its application in experimental therapeutics / 中国药理学通报

The mechanism of spinal cord injury and repair therapy after nerve injury is currently a hotspot of neuroscience research.Duplicating animal models plays a key role in experimental therapeutics of spinal cord injury.This review systematically describes the progress in animal models for spinal cord injury including contusion, compression, transection, ischemic,distraction and chemical-mediated injury,which have been established at home and abroad.Based upon the aforementioned models,some applications in experimental therapeutics are simultaneously enumerated.All these information provides scientific guidance for the experimental novel drugs′screening.

Establishment of a canine spinal cord injury model induced by epidural balloon compression

A model that provides reproducible, submaximal yet sufficient spinal cord injury is needed to allow experiments leading to development of therapeutic techniques and prediction of clinical outcome to be conducted. This study describes an experimental model for spinal cord injury that uses three different volumes of balloon inflation and durations of compression to create a controlled gradation outcome in adult dogs. Twenty-seven mongrel dogs were used for this study. A 3-french embolectomy catheter was inserted into the epidural space through a left hemilaminectomy hole at the L4 vertebral arch. Balloons were then inflated with 50, 100, or 150 microliter of a contrast agent at the L1 level for 6, 12, or 24 h and spinal canal occlusion (SCO) measured using computed tomography. Olby score was used to evaluate the extent of spinal cord injury and a histopathologic examination was conducted 1 week after surgery. The SCO of the 50, 100, and 150 microliter inflations was 22-46%, 51-70%, and 75-89%, respectively (p 50% for 24 h, and > 75% for 12 h induces paraplegia up to a week after spinal cord injury.

The Study of Nerve Conduction Time and TGF-beta After Sciatic Nerve Injury

The peripheral nerves can restore their impaired function after injuries from trauma or surgery. The known factors affecting the recovery of damaged peripheral nerves include the severity of damage, nerve growth factor(NGF) from the damaged area and the concentrations of fibrinogen and thrombin. One of polypeptides, transforming growth factors beta(TGF-beta) has been known to be related to inflammation and healing process of various wound. The TGF-beta has to three subtypes, TGF-beta(1), TGF-beta(2) and TGF-beta(3). This study was performed to explore the effects of TGF-beta subtypes on the recovery phase of damaged nerve. Sciatic nerves of rat were compressed 200 dyne/mm2. The latencies were measured by stimulation of proximal and distal portion of compression injury site and expression of TGF-beta isoforms was studied in proximal and distal nerve of compression site and spinal cord by using avidin-biotin complex immunoperoxidase technique. The latencies were increased at one week after nerve injury and then recovered progressively following 4 weeks. The latencies were restored to almost normal values at 4 weeks after nerve injury. TGF-beta(1) and TGF-beta(3) were expressed weakly at the cytoplasm of Schwann cell in the distal portion after 12 hours of injury. The values of TGF-beta(1) and TGF-beta(3) were increased at 3rd day after injury and lasted till the 4th week which was the end point of nerve regeneration. The changes of proximal portion were different from those of distal portion. TGF-beta(1) and TGF-beta(3) of proximal portion showed stronger positive reaction than that of distal portion and the reaction was peaked at 3rd day after injury. TGF-beta subtypes were rarely present at neuronal cells and astrocytes in spinal cord from 12th hour to 3rd day after injury. The TGF-beta subtypes were weakly appeared at the 1st week after injury and successively increased to 4th week at which the latencies were restored to almost normal value. The patterns of revelation of TGF-beta subtypes showed that TGF-beta(1) was predominant at neuronal cell and TGF-beta(2) was at glial cells. We suggest that TGF-beta subtypes might be related to the regeneration process of nerve injuery.