The Study Of Thrombospondins-1 And Neuroligin-1 Expression Curve After Spinal Cord Injury In Rats

Objective To observe the expression of TSP1 and NL1 fluctuation in spinal cord injured rats and know their impression on synaptic regeneration.Methods A total of 90 adult female Sprague-Dawley rats were randomly divided into control group（n=45）and experiment group（n=45）,and both groups were further arranged into 3 days,7 days,14 days,21 days,and 28 days subgroups.The control group accepted T_9-11-11 laminectomy,while the experiment group injured T₁₀0 spinal cord hit by Allen’s technique（10 g×25 mm）.The Basso,Beattie&Bresnahan locomotor rating scale（BBB scale）was applied to make a assessment to the hindlimb motor function of rats in every subgroup included in both the control and the injury,then made a comparison among the scores;Golgi-Cox staining was used to observe the variation of dendrites and density of dendritic spine in the white matter located at upper end of spinal cord injured center.Immunofluorescence staining and western blot were used to detect the expression of TSP1 and NL1 at 3 days,7 days,14 days,21days and 28 days after spinal cord injury,and their photo results were analysed successively by softwares ImageJ 1.50i and Graphpad Prism 6 to get the mean density and relative gray value respectively.Results 1.The BBB scale scores of every subgroup rats in the injured are below corresponding subgroup rats in the control（n=6,P<0.001）.2.Compared to the control,both dendrites and density of dendritic spine in the white matter were decreasing gradually after injury（n=6,P<0.001）.3.The results of TSP1immunofluorescence staining and semi quantitative analysis showed that the level of NL1 increased from injured 3d to 7d,but decreased in injured 14d,then increased in injured 21d and decreased in injured 28d;The results of NL1 immunofluorescence staining and semi quantitative analysis showed that the level of NL1 increased gradually after injured 3d,peaked at 14d post injury and then began to reduced.4.The western blot and analysis of relative gray value of TSP1 and NL1 consisted with corresponding immunofluorescence staining and semi quantitative analysis results.Conclusion TSP1 and NL1 increases spontaneously within 28 days after spinal cord injury,which is not enough to promote synaptic regeneration.