| Objective To investigate the function and effect of the TGF-β/Smads pathway in the form of glial scar after rats suffering acute spinal cord injury through checking the effect of Decorin on the expression of GFAP、 TGF-β1、Smad3and Smad7as well as research the relations between them at different time points.Methods Ninety female SD rats. Those animals were randomly divided into sham group:only removed the vertebral lamina, the spinal cord was untouched, pure spinal cord injury group(control group), spinal cord injury with Decorin interventing group (intervention group), with30animals in each group. which pure spinal cord injury group and intervention group, the spinal cord was hit according to the improved Allen’s method to establish rat acute spinal cord injury model. The Motor Function Assessment (BBB) was taken at each time points after injury, then sacrificed rats and obtained materials; following by HE staining, immunohistochemical staining(IHC) of GFAP、TGF-β1, Smad3and Smad7, observation and calculation of the GFAP positive cells area and the color rendering index (CRI) of TGF-β1, Smad3and Smad7under light microscope. The number of positive cells area and CRI of injured spinal cord tissue were compared at every time points among groups and within groups. Then correlation between GFAP positive cells area and the CRI of TGF-β1and Smad7as well as between TGF-β1and Smad7within pure injury group were analyzed. The experimental data was analyzed by SPSS16.0statistical software.Results The result of the BBB score:the score of control group and intervention group at every time points were significantly decreased compared to sham group, while the score of intervention group was higher than control group at all the time points after3days(P<0.05), among which the score of the two groups were apparently different at14,28days time pionts(P<0.01). The result of GFAP IHC:There was a low expression of GFAP at all time pionts in sham group. In control group, GFAP highly expressed in the injured area and its periphery after spinal cord injury, obviously expressed at7d、14d and still expressed at28d. While in intervention group, the expression of GFAP apparently lessen at all time pionts compared to control group (P<0.01). The result of IHC of the TGF-β1、Smad3and Smad7: A weak positive expression of TGF-β1、Smad3were observed at every time points in sham group, The expression of TGF-β1、Smad3could be observed obviously Id after spinal cord injury in the control and intervention groups. and its gradually increased after injury, reached the peak at5d,7d, decreased after that. the CRI of TGF-β1、Smad3in intervention group was significantly lower at1d、3d、5d、7d、4d and28d when compared to control group, which was significantly different (P<0.05), among which it was apparently different at1d、5d、7d and28d time pionts (P<0.01). While, there was a strong positive expression of Smad7at every time points in sham group, and its CRI apparently higher at all time pionts compared to the control and intervention groups (P<0.01). The expression of Smad7could be observed obviously Id after spinal cord injury in the control group. and its gradually reduced after injury as time goes on, reached the lowest at7d, a litter rised after that. The Smad7CRI of intervention group was higher than control group at all the time points (P<0.05), among which the CRI of the two groups was apparently different at3、7、14、28days time pionts (P<0.01). The correlation between GFAP positive cells area and the CRI of TGF-β1and Smad7at all time points of pure injured group was analyzed, and the result was that the expression of GFAP was positively correlate with the TGF-β1at these time points (correlation index r=0.74202, P<0.01), and a negatively correlate with the Smad7(correlation index r=-0.86, P<0.01). there was also a negatively correlate between the TGF-β1and Smad7(correlation index r=-0.5928, P<0.01)Conclusions①The expression of GFAP arised after acute spinal cord injury and the glial scar was obvious hyperplasia.②Decorin can promote the function of neural recovery by inhibiting the expression of GFAP, and reduced the hyperplasia of glial scar.③There was a proportional relations between the quantity of glial scar after acute spinal cord injury and the expression of TGF-β1, Smad3and Smad7:a positively correlate with the TGF-β1and Smad3; a negatively correlate with the Smad7.④TGF-β/Smads pathway has a important function and effect in the form of glial scar after acute spinal cord injury. |
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