| Objective:To observe the impact of curcumin on motor function and morphology and structure of tissue after the spinal cord injury of rats, as well as to explore the neuroprotective mechanism of curcumin on spinal cord injury in rats. In order to provide theoretical and experimental evidence for the clinical treatment of curcumin on spinal cord injury.Methodology:Part 1: Using HI-0400 impactor(produced by American PSI Company) to create the animal model of acute hitting spinal cord injury: divide 65 clean and healthy rats into‘sham operation’ group(Sham), ‘spinal cord injury’ group(SCI) and ‘curcumin’ group;and also divide ‘curcumin’ group(SCI+CUR) into three dose group, with 100 mg/kg, 200mg/kg and 400 mg/kg respectively. Then, inject the corresponding medicine into abdominal cavity 30 minutes after creating the spinal cord injury model, and use the neural function of BBB scale(motor function scale) and Rivlin inclined plate disorder rate to evaluate rats’ behavior 3~4 days, 1 week, 2 weeks,3 weeks and 4 weeks after operation. Drawing materials 7 days, 14 days and 28 days after operation, and observe the changes of spinal cord’s tissue morphology through light microscope after HE staining.Part 2: Randomly divide 84 clean and healthy rats into ‘sham operation’ group(Sham), ‘spinal cord injury’ group(SCI) and ‘curcumin’ group(SCI+CUR), inject the corresponding medicine after the spinal cord injury model is created, draw materials 12 hours, 1 day, 3 days and 7 days after operation respectively, and use TUNEL staining method, immunocytochemical method, ELISA assay and Western blot method to detectthe changes of the apoptosis number and the expressions of NF-kB(nuclear factor kappa B), Bcl-2(B-cell lymphoma-2), Bax(apoptosis gene), ATF6(activating transcription factor 6), GRP78(glucose regulate protein 78) and Caspase-3(aspartic acid specific cysteine proteinase 3).Results:1. Obeservation of rats’ behavior: 1 week after rats’ spinal cord injury, both of the BBB scale and inclined plate rate had increased, and the ‘curcumin’ group was middle than the ‘spinal cord injury’ group, the difference was significant(P<0.05). And the improvement of the middle dose of 200 mg/kg curcumin group was more obvious than small dose groups of 100 mg/kg and larger 400 mg/kg.2. HE staining method(three days after the spinal cord injury): when observing the spinal cord injury tissue section of the ‘curcumin’ group rats, only point-to-point flaky bleeding foci were found under the light microscope, the neuronal cell volume was atrophied, and the nucleolus was disappeared. Compared with SCI, the damage degree of each time point was significantly reduced.3. TUNEL staining method: During the 1 day, 3 day and 7 day periods, the fluorescence intensity of ‘SCI’ group and ‘SCI + CUR’ group(200 mg / kg) were significantly higher than ‘Sham’ group, which means they had higher level of cell apoptosis, and ‘SCI’ group was slightly stronger than ‘SCI+CUR’ group; however, as time goes on, the fluorescence intensity of ‘SCI+CUR’ group weakened gradually, which indicates that curcumin can distinctly inhibit apoptosis.4. The expression of inflammatory factor NF- kappa B: which was significantly increased 12 hours, 1 day, 3 days and 7 days after spinal cord injury, and the expression of inflammatory factor B kappa NF- in the curcumin group was significantly weaker at every time point than it was in the pure spinal cord injury group.5. The activity of SOD and the content of MDA: The SOD activity in rats of ‘SCI’ and‘SCI+CUR’ groups decreased after spinal cord injury, while MDA increased. Also,compared ‘Sham’ group with ‘SCI+CUR’ group, the content of MDA increasedsignificantly.6. The expression of apoptosis related protein: The sham operation group had no obvious protein staining of Bax and Bcl-2, which indicated that the sham operation group had no obvious cell apoptosis. Within the spinal gray of ‘SCI’ group, the staining of the two pro-apoptosis factors-Caspase-3 and Bax were obviously increased than curcumin group, while its anti-apoptosis factor was decreased compared to curcumin group. The expression of apoptosis started to increase 1day after spinal cord injury, and reached peak in day 3, then began to decline later after.7. The expression of endoplasmic reticulum stress related protein: The endoplasmic reticulum stress related protein GRP78 and ATF6 were significantly increased after spinal cord injury, and the curcumin intervention group was obviously lower than that in the spinal cord injury group.Conclusion:1. Curcumin can improve the recovery of neural tissue morphology and structure of spinal cord injured rats, and promote their recovery of motor function, which has protective actions on rats’ spinal cord injury.2. Curcumin has inhibited the infiltration of nuclear factor kappa B(NF-κB), and promoted the recovery of neural function to a certain extent.3. Curcumin can enhance the vitality of SOD in rats by inhibiting the generating of MDA, which indirectly inhibits the lipid peroxidation reaction of spinal cord tissue.4. Curcumin would inhibit the apoptosis after spinal cord injury through inhibiting the expressions of pro-apoptosis factor Bax and Caspase-3, and promoting the expression of anti-apoptosis factor Bcl-2, so as to accelerate the recovery of spinal cord.5. Curcumin promoted the recovery of spinal cord injury by inhibiting the expressions of ERS related protein ATF6 and GRP78. |
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