| Objective This essay aimed to observe the treatment effects of bFGF gene modified bone mesenchymal stem cells(BMSCs )and PLGA composite on the right T7 spinal cord injury hemisection model in rats ,thus providing reliable data for clinical therapy of spinal cord injury(SCI).Methods 240 rats with T7 spinal cord injury by hemisection were randomly divided into four groups: Group A of the rats treated with the transplantation composite of PLGA and bFGF gene modified BMSCs; group B treated with transplantation of modified bFGF gene BMSCs; group C treated with transplantation of BMSCs without genetic modification; and group D as the control group. on third day, in the second week,third week,eighth week and twelfth week after operation ,12 rats in each group, chosen randomly, were graded by the BBB motor functional scale and were measured by SEP; then the rats were killed and the spinal cord injured sections were taken out. Sections from 6 rats were used for RT-PCR analysis to detect the mRNA expression level of bFGF gene, and the other 6 were used for the immunohistochemical examination of NF-200, GAP-43, GFAP expression and the histomorphological observation of HE staining.Results (1)The result of BBB scales: the BBB score in each group, before 2w after operation, was lower than 2 point, and there was no statistical difference among each group(P>0.05). From 3w, it recovered faster and group A was higher than other groups. In 12w, group A got 14 points, group B 11, group C 9 and group D 8, with a significantly statistical difference among each group (P<0.05). (2) The result of SEP: All rats could be monitored by SEP before operation. During operation, the latent period was prolonged more than 10% and the amplitude declined more than 50% of SEP. However, no SEP could be monitored in each group before 3w after operation and only a part of them could be monitored by SEP from 8w after operation in each group. Statistical data could not be collected completely.(3)RT-PCR results: In 2w the bFGF mRNA expression level of group B was higher than that of other groups, reaching its highest point before a falling trend. In 3w the bFGF mRNA expression level of group A was higher than other groups and remaining a high expression level; group C and group D were always at the low expression level. There was significantly statistical difference among each group after 2w (P<0.05). (4)The result of immunohistochemical examination: in 2w the number of NF-200,GAP-43,GFAP immunohistochemical positive cells in group B was larger than that of other groups and reached the top. The similar case happened to group A in 3w. There was significantly statistical difference among each group after 2w (P<0.05). (5) The histomorphological observation of HE staining: before 2w the injury area in each group lacked spinal cord tissue, which was surrounded by splinter hemorrhage and serious inflammation. At the second week after surgery, kinds of inflammatory cells appeared in the damaged zone which surrounded by atrophic neurons, reactive hyperplastic gliacytes and spinal cord cavities. At the third week after surgery,serious structural damage arounded the spinal cord injury zone, nerve fibers were irregularly arranged, visible scar was formated.From the eighth week, obvious glial scar arounded the injury area, group D was more serious than other groups. The histomorphological observation of HE staining: before 2w the injury area in each group lacked spinal cord tissue, which was surrounded by splinter hemorrhage and serious inflammation. A variety of inflammatory cells appeared in the damaged zone and surrounded by atrophic neurons, reactive hyperplastic gliacytes and spinal cord cavities. In 3w, serious structural damage appeared around the spinal cord injury zone, nerve fibers were irregularly arranged, and visible scars were formed. After 8w, obvious glial scars around the injury area were obvious, and this case was more serious in group D than in other groups.Conclusions For the rats with the spinal cord injury by hemisection, the transplantation of BMSCs alone can promote the nerve regeneration and the motor functional recovery to some extent, while the transplantation of bFGF-BMSCs can improve the therapeutic effects. What is worth noticing is that the transplanted bFGF-BMSCs + PLGA composite can improve the therapeutic effects better. |
