| objective:To observe the effect on axonal regeneration and functional recovery with intrathecal administration of a low weight molecular polypeptide of ROCKII Inhibitor after spinal cord injury in rats.Methods:280healthy adult female SD rats were randomly divided into7groups(40rats/group), among of them, Group A as normal control group, group B as sham operation group and rats in group C-G were inserted a soft catheter into cavitas subarachnoidealis at L4level and subjected to complete paraplegic at levels of T8-T10by weight-drop impact. Group C as control group and group D-G were injected with20μL PBS,20μL Liposomes,20μL (30μM) Y-27632,20μL PBS and8μg low weight molecular polypeptide of ROCKII Inhibitor at1h after SCI respectively, for14consecutive days. The counts of apoptotic cells of neruon were measured at8h,24h,72h,1w and the expression of growth protein-43(GAP-43) was tested at24h,72h,lw,2w after SCI in each group respectively. SEP and BBB scale were examined at of3w,6w,8w after SCI in each group respectively.Anterograde tracing and retrograde tracing of regenerative axon were evaluated at6w after SCI in each group respectively. Al1the results were analyzed by one-way variance and there was a significant statistically difference when P<0.05.Results:The counts of apoptosis cell was7.86±1.45,9.33±2.44,49.67±5.83,50.27±3.80,50.53±4.69,42.2±6.20,39.33±5.35at8h after SCI in each group respectively.It was8.60±1.12,10.27±2.76,54.87±4.61,54.87±4.96,54.73±4.33,45.13±3.72,40.47±4.75at24h. It was8.47±1.46,9.33±1.84,45.67±3.39,46.27±5.18,45.93±6.91,38.00±5.93,31.53±4.96at72h.It was7.40±1.30,7.80±1.08,15.73±1.79,15.60±1.84,15.53±2.03,12.27±1.90,10.33±2.79at1w. The counts of apoptosis cells in Group G and group F were significant less than it in group C、D、E respectively and it in Group G was less than it in group F at8h,24h,72h and1w after SCI.There was no difference of the counts of apoptosis cells in group C、D、E at8h,24h,72h and lw after SCI respectively. The expression of GAP-43in Group A-G was31.04±1.51,32.05±1.43,43.17±2.00,42.90±2.64,43.13±1.84,74.70±2.36,82.92±3.08at24h respectively. It was31.61±1.11,32.72±2.13,52.30±1.97,53.33±2.07,53.23±3.13,85.07±2.78,94.40±3.30at72h. It was31.37±1.48,34.07±2.74,85.5±4.11,86.31±3.45,86.21±3.73,106.75±5.94,113.33±7.29at lw. It was31.11±1.50,34.86±3.70,45.24±4.93,45.57±11.8,48.54±4.08,158.05±5.78,169.37±7.96at2w. The expression of GAP-43in group G and group F was more than it in group C、D、E and it in group G was more than it in group F at8h,24h,72h,lw and2w after SCI respectively.There were no significant difference of the expression of GAP-43in group C、D、E and it in group A、 B respectively.Latency of SEP in each group (ms) was16.10±1.39,15.96±3.60,37.44±5.12,36.84±5.46,36.52±4.36,37.56±4.90,38.30±1.46at24h.It was14.44±0.64,16.02±3.46,35.74±3.87,35.60±5.32,35.46±3.56,31.52±4.79,26.52±1.65at3w. It was14.68±0.22,16.26±1.38,31.48±1.63,29.07±4.56,30.72±0.66,26.76±1.78,23.28±2.10at6w.It was14.36±0.88,14.40±0.57,28.60±0.84,29.07±4.56,28.96±3.72,23.86±2.99,19.12±1.87at8w. The latency in Group G and group F were less than it in group C、D、E and it in Group G were less than it in group F at3w、6w、8w after SCI. There was no significant difference of the latency in group C、D、E respectively. Wave amplitude of SEP in each group was15.40±1.67,14.88±0.99,1.26±0.25,1.30±0.63,1.08±0.33,1.36±0.56,1.22±0.43at24h;It was14.96±3.39,16.06±3.00,1.46±0.48,1.36±0.42,1.32±0.56,4.84±0.49,6.92±0.36at3w.It was15.36±1.75,16.52±0.94,2.62±0.75,2.28±0.25,2.68±0.43,5.86±0.86,9.48±3.19at6w.It was15.12±0.94,16.18±2.46,2.82±0.39,2.92±0.44,3.22±0.54,6.96±0.78,10.09±3.27at8w. The wave amplitude of SEP in Group G and group F were higher than it in group C、D、E and it in Group G were higher than it in group F at3w、6w、8w after SCI respectively. There was no significant difference of the wave amplitude in group C、D、E respectively. The BBB scale in each group was5.4±0.55,5.0±1.87, 5.2±0.84,8.0±1.87,10.0±2.0at3w.It was5.6±1.34,5.8±1.92,5.8±1.79,9.4±1.52,12.0±2.35at6w.It was8.0±1.58,8.2±2.28,8.0±1.58,13.4±1.34,15.8±1.79at8w. The BBB scale in Group G and group F was more than it in group C、D、E and it in Group G was more than it in group F at3w、6w、8w after SCI respectively.There was no significant difference of the BBB scale in group C、D、E respectively. The mean fluorescent area of anterograde tracing in injuryed segment was219.60±10.39,142.5±5.39,34.06±1.78,35.96±3.29,35.18±2.85,76.48±1.11,84.68±2.45.Segment below the injuryed in group A-G was (mm2):219.60±10.24,110.80±3.49,14.18±2.04,14.48±3.33,14.02±1.71,33.46±2.77,43.20±1.54.The mean fluorescent area in Group G and group F were more than it in group C、D、E and it in Group G was more than it in group F, there was significant statistically difference between them (P<0.01).There was no significant statistically difference between group C、D、E and between group A、B (P>0.05) respectively. Retrograde tracing:The mean fluorescent area of injuryed segment in groupA-G was (mm2):192.78±6.14,153.88±4.12,23.86±2.69,23.50±1.70,24.90±2.25,58.16±1.91,65.02±3.10. Segment above the injuryed in group A-G was (mm2):192.78±6.14,147.16±4.25,11.32±1.47,11.48±1.39,11.64±1.39,25.60±2.26,32.28±2.49.The mean fluorescent area in Group G and group F was more than it in group C、D、E and it in Group G was more than it in group F (P<0.01), there was significant statistically difference between them (P<0.01). There was no significant statistically difference between group C、D、E and between group A、B (P>0.05).Conclusion: The low weight molecular polypeptide of ROCKII Inhibitor can improve the regeneration of axon and functional recovery and it’s function is more effective than Y-27632after SCI in rats. |
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