Effect Of Cyclosporine A On Expression Of INOS And Apoptosis After Acute Spinal Cord Injury In Rats

Objective:To investigate the effect of cyclosporine A on expression of iNOS and apoptosis after spinal cord injury in rats .Methods: An experimental rat model of acute spinal cord injury was established. 108 rats were randomly divided into the control group, the injury group and the CsA-treated after injury group, 36 rats respectively. Rats were anesthetize,sacrificed and intubated for reperfusion at different time points after modeling. The injury segmental spinal cord was isolated, fixed overnight, embedded and sliced. The structure of the rat spinal cord was shown by HE staining. The expression of iNOS in the rat spinal cord was detected by immunohistochemistry staining and apoptotic cells in the tissue sections were detected by terminal deoxynucleotidyl transferase—mediated dUTP nick end labeling (TUNEL) method . The expression of iNOS was analyzed quantitatively by HPIAS-2000 high-resolution color graphic pathology report management system.The apoptotic index among the three groups was evaluated.Results: 1. HE staining showed white matter, gray matter, the anterior horn and the posterior horn,central tunel in the control group. Blooding, but without necrosis was shown in the injury rat spinal cord and CsA treated after injury rat spinal cord within 6h after injury. Widespread blooding and capsular space formed after blooding, neuronal degeneration and necrosis, gitter cell proliferation and neutrophil infiltration were showed in the injury rat spinal cord subsequently. Local blooding, some neuronal degeneration and necrosis were showed in the CsA treated after injury rat spinal cord subsequently. However, blooding, neuronal degeneration and necrosis, gitter cell proliferation and neutrophil infiltration in the CsA treated after injury rat spinal cord were less than that in the injury rat spinal cord. 2. For iNOS, suspicious expression was shown in normal rat spinal cord, strong expression in injury rats spinal cord and weak expression in CsA treated after injury rats spinal cord. The expression of iNOS could be detected 6h after injury in the injury group and the CsA treated after injury group. In the injury group ,the expression of iNOS reached its peak at 7d after injury and declined at 10d after injury. In the CsA-treated after injury group, the expression of iNOS was less than that in the injury group. and reached its peak at 3d after injury.The differences among the three groups at different time point were statistical significance (6h:F=89.449,P<0.01;12h:F=24.640,P<0.01;24h:F=72.699,P<0.01;3d:F=190.527,P<0.01;7d:F=160.347,P<0.01;10d:F=328.885,P<0.01)3. For apoptotic cells, a little TUNEL–positive cells were scattered present in the control group, a large number of TUNEL–positive cells were present in injury rats spinal cord and middling present in CsA treated after injury rats spinal cord. The apoptotic cells could be detected 6h after injury in the injury group and the CsA treated after injury group. The apoptotic cells reached flood tide at 7d after injury and declined at 10d after injury. In the CsA-treated after injury group, the apoptotic cells were less than that in the injury group, in flood tide at 3d after injury. The apoptotic index among the three groups at different time point were statistical significance (6h:F=180.432,P<0.01;12h:F=491.523,P<0.01;24h:F=594.093,P<0.01;3d:F=1110.324,P<0.01;7d:F=837.660,P<0.01;10d:F=389.124, P<0.01)Conclusions:CsA depresses significantly the expression of iNOS and apoptosis after spinal cord injury in rats and relieves the secondary spinal cord injury.