The Study Of Spinal Cord Contusion Injury Induces Cognitive Impairment And Relative Mechanisms In Adult Rats

ObjectiveThis study explored the effects of spinal cord injury on learning,memory and mood and other cognitive functions in rats,and the pathologic changes of brain-related areas.The activation of endoplasmic reticulum stress-related molecules in the brain in order to gain a better understanding of spinal cord injury.The influence of the function and the possible mechanism.Methods1.120 adult female S-D rats were divided into sham operation group and injury group(n = 60).The Allens method was used to prepare the spinal cord T10 segment(20 g × 25 mm).The sham operation group was treated with laminectomy without any damage.2.Behavioral BBB score was used to evaluate the success of SCI modeling and the recovery of motor function after injury.The Morris maze test the anxiety and fear of rats and so on.The test and memory ability of the rats were measured by the platform test.Morris water Maze to detect the spatial cognition and learning and memory of rats.3.Histology The morphological and quantitative changes of neuronal cells in the hippocampus and cortex of the brain were observed by Nissl’s staining.The dendritic spine density of hippocampal neurons in the brain was detected by rapid Golgi staining.4.The expression of phosphorylated IRE1 in rat hippocampus was detected by immunofluorescence.The expression of GRP78,phosphorylated IRE1 and Caspase-12 protein in rat hippocampus was detected by Western blot.Results1.One day after surgery,SCI rats BBB scores more than 1 minute,indicating that bilateral lower limbs completely paralyzed,modeling success.After SCI,the lower limbs of rats had some functional recovery but not completely.BBB score was significantly lower than that of sham operation group at each time point.2.The results showed that the number of open arms,residence time and activity in the labyrinth of the rats were significantly decreased at the 8th week after SCI.The results showed that the number of learning errors in SCI was significantly increased The level of the relevant latency was significantly reduced;Mirros water maze found that the damage of rats swimming latency,the target quadrant residence time and the number of target platforms were significantly decreased.The above behavioral changes occurred eight weeks after SCI.3.The results showed that the number of neurons in the forebrain cortex and hippocampus of SCI rats was decreased and the morphological abnormalities were observed.The dendritic spine density of hippocampus was decreased.4.Immunofluorescence showed that the expression of p-IRE1 protein was significantly up-regulated at 4w and 8w after 4 weeks of SCI.Western blot showed that GRP78,p-IRE1 and Caspase related to endoplasmic reticulum stress-12 and other protein eggs up-regulation.Conclusion1.SCI not only causes the following exercise dysfunction in rats,but also causes cognitive impairment in rats,memory impairment and anxiety,depression and so on.2.Persistent pathological changes in the hippocampus and forebrain cortical neurons after SCI showed that secondary injury to spinal cord injury could lead to damage to the central nervous system.3.The cognitive impairment of SCI rats may be related to the stress of the brain caused by injury.