| Objective:Spinal Cord Injury (SCI) is a serious central nervous system injury. It often results in loss of voluntary motor and sensory, and even leads to the dysfunction of urination and defecation. The treatment of SCI is a medical puzzle and tough problem todays. In this experiment, we study the changes of the motor compacity after the combination of SY by intraperitoneal injection and MSCs transplantation on SCI in Rats, discuss the treatment mechanisms of SY and MSCs transplantation on SCI.Methods:MSCs would be collected and expanded in vitro from the bone marrow of S-D yong rat with adherence-separated-culture mothod. Rats would be randomly divided into 5 groups:group A (SY+MSCs), B (saline+MSCs), C (SY+PBS), D (saline+PBS) and E (supplementary group). There were 15 rats in every group. The SCI models could be induced by striking of the spinal cord with modified Allen's device. The MSCs (6×106/60μl) were injected into SCI space in group A and B, the same volume of PBS in group C and D. From 1 to 14 days after SCI, the SY was administered in a dose of 40mg/kg by intraperitoneal injection in group A and C, and the same volume of saline in group B and D. The changes of SOD, MDA and cell apotosis in the lesion site would be observed in 1,2,3,4 and 7 days after SCI. The nerological functional changes were evaluated by BBB scale in 1 day and 1,2,3,4 weeks after SCI. And at the same time point, the injury spinal cord was made into frozen section, histomorphology change was observed by HE staining. During the experiment, if one of rats died in group A,B,C,D, another one would be selected from group E instead of it and the feeding time would be recalculated from beginning.Results:(1) Modified Allen method had accurte and contolled striking. In the SCI model induced with Allen's method, there were tissue bleeding, edema and necrosis early. In the followed stage, there were partial recovery and tissue reconstruction. In the last stage, there were formation of cavity and glial scar, shrinkage of parenchymal cells. The characteristics of tissue damage were in good agreement with which of human spinal cord injury.(2) All rats before the experiment are normal. The BBB scores of each rat were 21 points. All rats had a double flaccid paralysis hind limb after successful modeling, and had 0 piont in BBB scores in 24 hours after modeling. The motor capacity of hind limb was not obvious recovery in every group in 7 days after modeling. However, there was gradually recovery in hind limb function in 3 and 4 weeks. The BBB scores at each time point were significantly higher in group A, B and C than in group D in 14,21,28 days after modeling. It was same in group A than in group B and C. The difference was statistically significant (P<0.05).(3) Histomorphology changes showed:(1) In 1 day after modeling, the regional gray matter was not different from regional white matter. Cell's structure and morphology could not be identified. In the surrounding area there were swelling, degeneration, and a large number of f inflammatory cells and red blood cells. Red blood cells fused into sheets sometimes. there were also some cavity. It is little difference among the groups. (2) After 7 days from modeling, the larger cells can be seen in group A and B, which are different from neurons and glial cells, and could be considered as the transplanted MSCs. The number change of the larger cells in group A and B had same tendency with the BBB scores. The number of the cavity changes inversely with the BBB scores.It is minimum in group A, maximum in group D, middle in group B and C(4) The SOD activity decreased significantly in every groups, but the content of MDA increased significantly. The SOD activity was higher in group A, B and C than in group D (control group) at all time points, and same in group A than in group B and C. The content of MDA was less in group A, B and C than in group D in 3 days,4 days and 7 days after SCI modeling. It was lower in group A than in group B and C in 2 days,3 days and 4 days. The number of apoptotic cells in each time point was less in goup B and C than in group D, and in group A than in group B and C.Conclusion:(1) The rat SCI model induced with modified Allen's method was homogeneous, had similar pathological changes to human SCI. Modified Allen's method had good reproducibility and simple operation. So it meet the requirements of experimentation.(2) SY by intraperitoneal injection can alleviate the pathological changes of rat SCI model; reduce free radicals and adip-peroxidation, decrease apoptosis of nerve cell in the injury site of spinal cord. So it can reduces the secondary injury after Primary injury, promote recovery of motor function after SCI in rat.(3) MSCs transplantation can alleviate the pathological changes of rat SCI model; reduce free radicals and adip-peroxidation, decrease apoptosis of nerve cell in the injury site of spinal cord. So it can reduces the secondary injury after Primary injury, promote recovery of motor function after SCI in rat.(4) The combination of SY by intraperitoneal injection and MSCs transplantation has synergistic effect on SCI in rat.It has more effect than only either SY by intraperitoneal injection or MSCs transplantation when they alleviate the pathological changes, reduce free radicals and adip-peroxidation, decrease apoptosis of nerve cell. |
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