The P27kip1/Jab1 expression and its role in injured spinal cord of rats

English Keywords:Spinal cord injury  P27kip1  Jab1  Glial scar

English Abstract:

  【Abstract】 Objectives: To investigate the expression and distribution of P27kip1 and Jab1 in SD rat models with spinal cord injury(SCI), to explore their functions in the process of spinal cord injury and proliferation of astrocytes followed immediately. Methods: 56 male Sprague-Dawley(SD) rats were randomly divided into two groups: sham group(simple vertebra excision) and spinal cord injury group. And the rats in spinal cord injury group were divided into 6h, 12h, 1d, 3d, 5d, 7d, 14d groups according to the length of time of injury. The adult SD rat SCI models were established by using improved Allen′s method, T9 level of spinal cord was chosen to induce injury. First of all, the temporal expression of P27kip and Jab1 were detected by Western Blot. Then, the P27kip1 positive cell number in 3d group and Jab1 positive cell number in 5d were counted in immunohistochemistry. At the last, the change of cellular localization of Jab1 in 5d group was observed by immunofluorescence. Results: The Western Blot result showed the relative grey value of P27kip1 in 6h, 12h, 1d, 3d, 5d, 7d, 14d groups was 1.00±0.10, 0.82±0.05, 0.27±0.03, 0.34±0.03, 0.25±0.02, 0.28±0.03, 0.57±0.05 respectively, and the 1d, 3d, 5d, 7d, 14d group had obviously lower value than sham group(P<0.05). On the contrary, the relative grey value of Jab1 in 6h, 12h, 1d, 3d, 5d, 7d, 14d groups was 0.58±0.08, 0.53±0.04, 0.89±0.11, 1.06±0.24, 1.22±0.26, 0.85±0.16, 0.25±0.03 respectively, and the 6h, 12h, 1d, 3d, 5d, 7d groups had higher value than sham group(P<0.05). And the positive cell number in 3d spinal cord injury and P27kip1 group was 130.8±29.8, which was lower than sham group(406.8±56.6)(P<0.05). The positive cell number of 5d spinal cord injury and Jab1 group was 383.5±68.8, which was higher than sham group(123.5±42.6)(P<0.05). Moreover, double labeling immunofluorescence of 5d Jab1 group presented that the Jab1 and GFAP double positive cell number was significantly more than that of the sham group(spinal cord injury group: 383.3±39.1, sham group: 114.3±35.6, P<0.05). Conclusions: The up regulation of Jab1 is related to the degradation of P27kip1 in spinal cord injury of rats, which may be involved in the excessive proliferation of astrocytes.