To compare efficacy on scar formation of G-CSF & GM-CSF after spinal cord injury in rats

초록

PURPOSE : G-CSF suppressed neuronal apoptosis after SCI and promoted hindlimb functional recovery in the rat. The authors have already reported GM-CSF led to the functional recovery in a rat SCI model, effectively inhibiting scar formation in vitro. This study investigated the difference of scar formation between GM-CSF and G-CSF in rat SCI injury model. MATERIALS AND METHODS : For spinal cord injury, vascular clip on the T9 level of the spinal cord for 10 min (30-40g/N) was applined on Male Sprague–Dawley rats (280~300g). Recombinant GM-CSF and G-CSF were treated immediately after injury once either intraperitoneally (IP) . The group subjected only with SCI was treated IP with phosphate buffered saline (PBS) alone. The sham group received laminectomy alone without SCI. In all experiments except the behavior analysis, three rats per time point (n = 3/time point/group) was used in the four experimental groups of Sham, SCI, SCI + G-CSF (IP) and SCI + GM-CSF. The motor activity was performed at days 1, 3, 7, 14, 21 and 28 after SCI by the Basso–Beattie–Bresnahan (BBB) locomotor rating system. The rat at 3, 7, and 28 weeks were sacrified to confirm sacr formation in the injured spinal cord by using Immnuohistochemical staining for GFP, Neurocan and NG2. RESULTS : BBB ratings was improved at 3-4 weeks on G-CSF and GM-CSF treated groups. The administration of GM-CSF and G-CSF significantly reduced the cavity size and glial scar formation at 3–4 weeks after SCI. However, the size of scar formation in GM-CSF group was not difference in both groups. GM-CSF and G-CSF also reduced the expression of core proteins of chondroitin sulfate proteoglycans (CSPGs) such as neurocan and NG2 but not phosphacan.However, the intensive expression of glial fibriallary acidic protein (GFAP) and neurocan found around the cavity at 1 week and 4 weeks were obviously suppressed by GM-CSF but can be inhibited at 4 weeks only by G-CSF . CONCLUSION : These results