The Experimental Study On The Recovery Of Motor Function Induced By Astragalus Polysaccharides In Spinal Cord Injury

ObjectiveIn this study,we observed the effects of Astragalus Polysaccharides(APS)on motor function and pathological changes in rats with spinal cord injury(SCI).To observe the effect of APS on axonal regeneration after spinal cord injury in rats and identify its therapeutic target on spinal cord injury,and then explore the effect of Astragalus Polysaccharide on spinal cord injury.Methods1.The repair effect of Astragalus Polysaccharide on motor function and pathological changes after spinal cord injurySeventy adult Sprague-Dawley rats were randomly selected as normal group(n=10),injury group(n=30)and astragalus polysaccharide treatment group(n=30).The injury group and the astragalus polysaccharide treatment group had 3 time points(7 days,14 days,28 days)and were established with Allen’s mode at T10(10mg×25mm).After modeling,the injury group received no treatment and astragalus polysaccharide treatment group was injected astragalus polysaccharide(Sigma)10 mg/Kg.The hindlimbs function of rats was rated with Basso-Beattie-Bresnahan(BBB)scores at 7 days,14 days and 28 days.The cell morphology was observed with HE staining.Nylon body was observed with Nissl staining.Myelin sheath was observed with eriochrome cyanine staining.2.The effect of Astragalus Polysaccharides on Expression of GAP-43 and MAP2 in Spinal Cord Injury RatsImmunofluorescence and western blot were used to detect the expression of GAP-43 and MAP protein,and to explore the target of APS in the treatment of spinal cord injury.Results1.The injury group and treatment group rats’ BBB scores were between 1-3 points and the hindlimds function recovery was slow at the 7th day after modeling.Between 7-28 days the rats’ BBB scores increased rapidly and their hindlimbs function recovery fastly.The treatment group rats’ BBB score was significantly higher than that in the injury group at each time point(P <0.05).HE staining was observed:there was a large number of necrotic tissue in the injury center of rats between the 7th day and 14 th day and cystic cavity begans to form and gradually increased.Cystic cavity formed basically and the surrounding of cavity is dense scar at the 28 th day.With the injury comparsion,the number of necrotic tissue decreased in the treatment group rats at each time point and the effective area of cystic cavity was significantly reduced.Eriochrome cyanine staining was observed: spinal cord appeared demyelination and myelin sheaths loose in 7 days after injury,and aggravated with the passage of time.On the 28 th day,there was a cystic cavity in trauma center.With the injury comparsion,the demyelination and remyelination of loosely arranged situation had improved in the treatment group rats.In the injured group,the Nissl bodies began to accumulate on the 7th days after injury,agglutination increased on the 14 th days after injury,and almost completely disintegrated on the 28 th days after injury.With the injury comparsion,Nissl body coalesced alleviativly in the treatment group at each time point.2.Immunofluorescence and western blot showed that in the spinal cord of normal rats,GAP-43 was expressed highly in the gray matter of the spinal cord,but not in the white matter of the spinal cord.The expression of GAP-43 in the gray matter of the spinal cord was significantly decreased after spinal cord injury,and decreased gradually with the time after injury.The expression of GAP-43 was the lowest at 28 days.The expression trend of GAP-43 in the APS group was the same as that in the injury group The expression of GAP-43 was significantly higher than that of the injury group(P <0.05).MAP2 was expressed mainly in the gray matter of the normal group and was not expressed in the white matter.MAP2 began to decrease on the 7th days after injury.The expression of MAP2 decreased gradually with the prolongation of time after injury.The expression of MAP2 also showed a decreasing trend after treatment with APS.Compared with the injury group,the expression level of MAP2 was significantly higher in the treatment group,and the difference was statistically significant(P <0.05).ConclusionAstragalus polysaccharide may reduce the pathological damage after spinal cord injury,and promote the improvement of motor function.The possible mechanism of its action is by increasing the expression of GAP-43 and MAP2 proteins,delaying the downregulation of its expression.