A Preliminary Study Of Neuroprotection Or Neurotoxicity In Immune Inflammatory Response After Acute Spinal Cord Injury In Mice

[objective]through compare the Locomotion function behavior and cytomorphology between the two groups mice at Different time points, Explore Neuroprotection or neurotoxicity in immune inflammatory response after acute spinal cord injury in mice, and provide theoretical basis for the Interventing the immune inflammatory response at Different time points to treat the SCI.[method]1.A group of 24 gene knock-out mice, B group of 24 Wild type mice.2.The segments T9 of spinal cord injury in mice were prepared by NewYork university (NYU) impactor.3.Each group of mice were divided into three batch at different time points (1 weeksn 2 weeks、4 weeks), We used Basso Mouse Scale (BMS) to evaluate the loco mo tor recovery of the two groups of mice after SCI, And then, collected 1.Ocm spinal cord tissue from the injury center by operation.4. GFAP was used to assay the morphology and the distribution of activated Astrocytes In the spinal cord;Ibal staining was used to assay the distribution and morphology of activated Microglia;Nissl staining was used to evaluate the neural function:To observe the changes of the nerve cell morphology (including The changes of Nissl body、Nerve nuclei dendrites and axons); ChAT was employed to label the dynamoneure and observe the The survival situation in the spinal cord;5. The collected data were analyzed by SPSS 13.0 software.[Result]Through model of SCI in the mice,We observed that the locomotor of the two groups of mice were improved gradually at the third day after SCI,We used Basso Mouse Scale (BMS) to evaluate the locomotor recovery of the two groups of mice after SCI, At the fifth day,knock-out mice got a higher score (mean=3.625) than Wild type mice (mean=1.5) in Basso Mouse Scale,the differences were statistically significant (P< 0.01, n=8),At the one week after SCI, the locomotor function of the knock-out mice (mean=5.40625) were markly improved than Wild type mice (mean=2.8125),the differences were statistically significant (P< 0.001, n=8),it shows us that the locomotor function of the knock-out mice were better than the wt during the first week after the SCI. After the first week,the trends of locomotor recovery in knock-out mice to be gentle,but wt got a rapidly improvement during the second week after SCI and surpassed the knock-out mice at the third week, it reveals tha the immune inflammatory response maybe drifting to a beneficial way in SCI.We found that the both of Ast and GM were Abnormally activated in the wt after the first week in SCI Through immunohistochemical staining,and observed that the cells were even bigger and in dense arrays,On the contrary, the knock-out mice arrived a mild activation,at the same time,we used Nissl staining and ChAT staining to find that the survival nerve cells in wt were Less than the knock-out mice.Based on the above results,we cognize that the immune inflammatory response May be harmful in the early stage of SCI,and then,the immune inflammatory response played a role in Neuroprotection in the subsequent period of SCI.[Conclusion]1. the excessive activation of immune inflammatory response played a role in neurotoxicity and can be harnessed to recover the neural function in the early stage of SCI.2. the immune inflammatory response may move slowly to a beneficial direction of the recovery in the subsequent period of SCI.3. maybe there is a new strategy to treat the SCI by Interventing the immune inflammatory response at Different time points.