| ObjectiveSpinal cord injury(SCI)is a severe traumatic disease and currently lack of effective therapeutics.Activation and proliferation of astrocytes play a pivotal role in maintaining the structural integrity of spinal cord after SCI.Excessive astrocytic proliferation hampers axonal outgrowth and secrets neural growth inhibitory factors to reduce neural survival and impede neuroregeneration.In this study,we investigated the effects of gastrodin(GAS)on suppressing glial scar formation and promoting neurologic functions after SCI in rat model.Methods1.Eighty adult male SD rats,weighing 220g-240g,were randomly divided into 5 groups:(1)Sham group(saline,n=16),(2)SCI group(saline,n=16),(3)SCI + low dose GAS group(50mg/d,n=16),(4)SCI + moderate dose GAS group(100mg/d,n= 16)and(5)SCI + high dose GAS group(150mg/d,n=16).SCI was induced by application of 70g aneurysm clip to the T10 segment of spinal cord for 30 seconds.Sham group only received laminectomy.Gastrodin or saline were given for 7 consecutive days post-injury.Basso Beattie Bresnahan motor function score(BBB score)and Rivlin oblique plate test(Rivlin socre)were performed at 1,3,7,14,21,28 day after SCI.2.Routine perfusion and sampling 4 weeks after injury.Observe the morphological changes of injured spinal cord,and routine dehydration,embedding and frozen section were performed.Quantitative analysis of the image was performed to determine the expression of glial fibrillary acidic protein(Glial Fibrillary Acidic,GFAP)and the area of glial scar after immunofluorescence staining.3.HE staining was used to detect the morphology of spinal cord and the area of syringomyelia 4 weeks after injury,and nissl's(Nissl)staining was used to detect the number and morphology of Nissl bodies.4.In each group,4 rats were randomly selected and injected stereo positioning with fluorescein labeled BDA nerve fiber 2 weeks after injury.Observe the number of axons and evaluate the recovery of spinal nerve conduction pathway under fluorescence microscope.Results1.The BBB score and Rivlin score were decreased in all groups,and increased gradually as the post-injury time goes on.The score of Sham group at each time point were higher than other groups(P<0.05),the scores of GAS treatment group were significantly higher than SCI group after 3d and each time point(P<0.05),the score of SCI+GAS(M)group were higher than other two treatment group(P<0.05).2.The expression of GFAP in GAS treatment group and SCI group was higher than Sham group 4 weeks post-SCI(P<0.05),but the GAS treatment group was dramatically reduced than that in the SCI group,and was inhibited obviously in the SCI+GAS(M)group(P<0.05).The positive staining area of glial scar was significantly reduced in GAS treatment group,and the SCI+GAS(M)group was significantly smaller than that of SCI group(P<0.05).3.The structure of spinal cord tissue disorded,syringomyelia formatted in SCI group,GAS treatment significantly alleviated structural disorganization,diminished tissue cavitation and increased number of neurons in the lesion site of the spinal cord at 4 weeks post-SCI(P<0.05).The number of Nissl bodies in SCI+GAS(M)group was significantly higher than that in SCI group(P<0.05).4.Fluorescein-conjugated BDA labeling fibers were the most in Sham group 4 weeks post-SCI,and were significantly higher in each GAS treatment group than that of SCI group in the lesion site of the spinal cord,and was more positive in SCI+GAS(M)group than the other two groups(P<0.05).Conclusions1.Gastrodin could reduce GFAP at damage area expressed by astrocytes,inhibit the activation of astrocytes and suppress glial formation after spinal cord injury.2.Gastrodin could protect the injured neurons in the SCI area,reduce the formation of spinal cord,increase neuronal survival,and promote the repair of spinal nerve conduction pathway.3.Gastrodin could improve SCI-induced neurologic deficits and the behavioral score of rats after SCI.Optimized dosage of gastrodin(100mg/d)may generate optimal therapeutic effects against spinal cord injury. |
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