ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effects of olfactory ensheathing cells (OECs) transplantation and treadmill training in improving hindlimb motor function of spinal cord injury(SCI) rats and explore its possible mechanism.</p><p><b>METHODS</b>A total of 80 male SD rats were randomly divided into four groups: media untrained (group A), OECs untrained (group B), media trained (group C) and OECs trained(group D). Each group had 20 rats and all rats were made the model of spinal cord injury. The rats of group C and D underwent treadmill exercise in 3 days after operation, the rats of group B and D underwent OECs transplantation in 7 days after operation (each rat was injected a total of 4 μl, cell concentration was 1.0×10₆/μl), at the same time, the rats of group A received the corresponding dose of saline. Then observed was continued for 4 weeks totally. BBB scores in each group were measured weekly. The expression of Bax, Bcl-2, NF-200 were observed by immunohistochemisty staining. Mallory staining was used to the regeneration of nerve fibers and TUNEL staining was used to observe neuronal apoptosis.</p><p><b>RESULTS</b>(1)The BBB scores in group D in the 4th week was significantly higher than of other three groups(<0.05). (2)On the Bcl-2 protein expression, there was interaction between OECs and treadmill training, the two mutually reinforcing;while OECs transplantation can significantly reduce the Bax protein expression without significant interaction with treadmill training(>0.05). TUNEL staining showed that OECs transplantation, treadmill training, the time factor had an interaction and significantly inhibited the apoptosis(<0.05). (3)It was showed in immunohistochemisty staining of NF-200 and Mallory staining that OECs transplantation, treadmill training with the time factor were an interaction among the three with significant regeneration of nerve fibers(<0.05).</p><p><b>CONCLUSIONS</b>OECs transplantation combined with treadmill training can significantly improve hindlimb motor function of SCI rats, which may be achieved by the following ways. OECs transplantation and treadmill training can collaborate with each other, significantly increasing the expression of Bcl-2 gene, which significantly inhibit neuronal apoptosis;at the same time it can promote neuronal axonal regeneration, increase the number of nerve fibers, and this effect may be more remarkable with time.</p>
ABSTRACT
Objective: To explore the law of apoptosis of lumbar spinal cord neurons in cauda equina syndrome (CES). Methods: Cauda equina of rats was compressed by a piece of silica gel stick. From day 1 to day 28, the lumbar spinal cord specimens were harvested and assessed by Nissl's staining and TUNEL staining. Results: Compression of cauda equina caused lesion and apoptosis of neurons in lumbar spinal cord, and the extent of apoptosis reached the peak on 7th day after compression. Conclusion: Apoptosis of neurons in lumbar spinal cord might be one of the reasons why patients with CES get poor prognosis.
ABSTRACT
<p><b>OBJECTIVE</b>To observe the expressions of nestin and glial fibrillary acidic protein (GFAP) and their association with reactive astrocytes following spinal cord injury in adult rats.</p><p><b>METHODS</b>Adult rats with compression injury of the spinal cord were divided into 7 groups (n=6) and examined at 1, 3, and 5 days and at 1, 2, 4 and 8 weeks after the injury. The recovery of the locomotor function after the injury was evaluated with Basso, Beattie and Bresnahan (BBB) scale, and the degree and scope of the spinal injury were assessed using toluidine blue staining. Immunohistochemistry, double immunofluorescent labeling and an image analysis system were employed to observe nestin and GFAP expression and cell proliferation in different regions of the spinal cord.</p><p><b>RESULTS</b>The bilateral hind limb locomotor function of the rats declined severely 24 h after the spinal cord injury and underwent substantial recovery in 1 or 2 weeks after the injury, but followed by rather slow recovery afterwards. Toluidine blue staining of the spinal cord 24 h after the injury showed significant pathological changes in the neurons. The extension of the tissue injury increased with time till 1 week after the spinal cord injury. The site of injury and the adjacent tissues presented with markedly increased nestin and GFAP expressions 24 h after the injury, and nestin+/GFAP(-) cells dominated in the ependymal region around the central canal, whereas nestin+/GFAP+ dominated in the in other regions, showing significant difference from the control group. Nestin and GFAP expression reached the peak level 3 to 7 days after the injury and declined gradually till reaching nearly the control level at 2 weeks.</p><p><b>CONCLUSION</b>Compression injury of the spinal cord induces up-regulated expressions of nestin and GFAP, and nestin expression is positively correlated to the reactive astrocytes, which, along with the neural stem cells, respond to spinal nerve injury and possibly play a role in repair of the central nervous system injury.</p>