| Objective:By establishing the rats' rib fracture model, the differences of fracture healing and the changes of CD4+, CD8+T lymphocytes and IL-17 amounts in peripheral blood were compared in different groups administrating simvastatin to discuss the effect of Sim on immune function in fracture rats primary. Methods:1. With reference to relevant literatures, an incision was operated on the back of the trunk to expose the sixth rib, which was then fractured 1.5cm from the vertebral column. An SD(Sprague-Dawley) rat's rib fracture model hereby was established. Observe the fracture healing.2. 48 male SD rats(200±20g) were randomly divided into four groups including test and control in total: administration for 1 week group, reduced administration group, administration for 4 weeks group and control group, 12 rats in each group. After fracture, administer the four groups in the following manners: control group: isovolumetric DMSO as control; administration for 1 week group: Sim 10mg/kg/d in the 1st week, isovolumetric DMSO in the following weeks; reduced administration group: Sim 10mg/kg/d in the 1st week, 7.5mg/kg/d in the 2nd week, 5.0mg/kg/d in the 3rd week, 2.5mg/kg/d in the 4th week; administration for 4 weeks: Sim 10mg/kg/d.3. At 7th, 14 th, 21 th, 28 th day after administration, took blood sample from eyes of rats in each group(approximately 1m L). Then Flow Cytometry(FCM) were applied to detect the content of CD4+/CD8+T cells in peripheral blood. Enzyme linked immunosorbent assay(ELISA) was applied to detect the IL-17 levels in plasma.4. SPSS19.0 statistical analysis software was used to process and analyze the experimental data, which was expressed withsx ±. The sample's means were compared by ANOVA and LSD-t statistical method, the differences were significant when P<0.05. Results: The changes of T lymphocyte subsets over timeCD4+T cells: the content of CD4+T cells in test groups were significantly higher than that in control group in 1w and 2w. In 2w,the amounts of CD4+T cells both in administration for 1 week and administration for 4 weeks reached the maximum value. In 3w, the amount of CD4+T cells in control group reached the maximum, and was higher than that in test groups(P>0.05), with the amounts of administration for 1 week group and administration for 4 weeks group showing a trend of decline and reaching a minimum value in 4w. While CD4+T cells in reduction group showed no obvious fluctuation.CD8+T cells: in 1w, the amounts of CD8+T cells in test groups were higher than that in control group, in 2-4w, which showed the relatively stability. CD8+T cells in control group increased gradually.The ratio of CD4+/CD8+: in 1w, there were no significant differences between test groups and control group, in 2w, the ratio in each group began to show a decline trend, simultaneously this ratio in test groups were higher than that in control group. The change of inflammatory cytokine IL – 17 over timeIn 1w, the plasma IL-17 level in test groups was higher than that in control group(P<0.05). In 2-4w, the IL-17 level in each group was in fluctuation, but the expression of IL-17 in test groups was higher than in control group(except for the administration for 4 week group in 3w). Conclusion:Sim may promote fracture healing through raising the peripheral blood T lymphocyte subsets and the expression of inflammatory cytokine IL – 17, improving the fracture body's immune response in early period, enhancing the immune effect of cellular immunity. |
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