Changes of Slit1 expression in spinal cord after the section of dorsal root in rats

English Keywords:Dorsal root transection  Spinal cord  Slit1

English Abstract:

  【Abstract】 Objectives: To investigate the changes of Slit1 expression in spinal cord after the section of dorsal root in rats, and to provide evidence for the role of Slit1 in nerve regeneration． Methods: The left dorsal roots of L5 and L6 spinal nerve were transected from 80 2-month-old Sprague-Dawley rats, and the changes of Slit1 expression were detected with RT-PCR, Western blotting and immunohistochemical methods in the related spinal cord at 1d, 3d, 7d and 14d, respectively． The left halves of these L5/6 spinal cords were included in test group, the right halves of these L5/6 spinal cords were included in self-control group and the L5/6 spinal cords from sham operation rats(which were anaesthetized and the L5 and L6 spinal nerves were exposed, but without section operation, n=20) in blank control group. Then the number of Slit1 positive cells and the average integral optical density value(AIODV) were determined with image analysis． Results: The numbers of Slit1 positive cells in test group at 1d, 3d, 7d and 14d were 5.78±1.53, 15.85±2.65, 23.93±1.53 and 8.78±1.78; the numbers in self-control group were 2.31±1.63, 2.57±1.89, 3.20±2.16 and 3.02±2.15, respectively． The number of Slit1 positive cells in test group was significantly higher than that in blank control groups(2.89±1.26) or that in self-control group(P＜0.05). Western blotting showed the relative expressions of Slit1 in test group at 1d, 3d, 7d and 14d were 0.326±0.09, 0.448±0.05, 0.638±0.07 and 0.304±0.07; the numbers in self-control group were 0.038±0.02, 0.038±0.01, 0.035±0.02 and 0.046±0.03 respectively. Compared with blank control group(0.038±0.03) and self-control group, the relative expression of Slit1 in test group were significant(P＜0.05). RT-PCR showed the relative expressions of Slit1 mRNA in test group at 1d, 3d, 7d and 14d were 0.380±0.03, 0.425±0.04, 0.768±0.05 and 0.605±0.04; the numbers in self-control group were 0.210±0.04, 0.265±0.03, 0.292±0.02 and 0.261±0.02 respectively. Compared with blank control group(0.231±0.03) and self-control group, the relative expression of Slit1 mRNA in test group was significantly higher(P＜0.05). Conclusions: After the section of dorsal root, Slit1 expression in spinal cord is significantly up-regulated.