ObjectiveTo investigate the expression changes and the repair effect of mitogen and stress- activated protein kinase 1 (MSK1) on spinal cord injury (SCI) in rats.MethodsOne hundred and twenty male Sprague Dawley (SD) rats (weighing 220-250 g) were used for the study, 70 of them were randomly divided into sham-operation group and SCI group (n=35), the rats in SCI group were given SCI according to Allen’s method, and the sham-operation group only opened the lamina without injuring the spinal cord; spinal cord tissue was collected at 8 hours, 12 hours, 1 day, 2 days, 3 days, 5 days, and 7 days after invasive treatment, each group of 5 rats was used to detect the expression of MSK1 and proliferating cell nuclear antigen (PCNA) by Western blot assay. Another 20 SD rats were grouped by the same method as above (n=10). In these rats, a negative control lentiviral LV3NC dilution was injected at a depth of approximately 0.8 mm at the spinal cord T10 level. The results of transfection at 1, 3, 5, 7, and 14 days after injection were observed under an inverted fluorescence microscope to determine the optimal transfection time of the virus. The other 30 SD rats were randomly divided into group A with only SCI, group B with a negative control lentiviral LV3NC injected after SCI, and group C with MSK1 small interfering RNA (siRNA) lentivirus injected after SCI, with 10 rats each group. The Basso, Beatlie, Bresnahan (BBB) score of hind limbs was measured at 1, 3, 5, 7, and 14 days after treatment; spinal cord tissue collected at the optimal time point for lentivirus transfection was detected the expression changes of MSK1 and PCNA by Western blot and the localization by immunofluorescence staining of MSK1 and PCNA proteins.ResultsWestern blot assay showed that there was no significant changes in the expression of MSK1 and PCNA at each time points in the sham-operation group. In the SCI group, the expression of MSK1 protein was gradually decreased from 8 hours after injury to the lowest level at 3 days after injury, and then gradually increased; the expression change of PCNA protein was opposite to MSK1. The expression of MSK1 in SCI group was significantly lower than that in the sham-operation group at 1, 2, 3, and 5 days after injury (P<0.05), and the expression of PCNA protein of SCI group was significantly higher than that of the sham-operation group at 8 hours and 1, 2, 3, 5, and 7 days after injury (P<0.05). The fluorescence expression of both the SCI group and the sham-operation group has be found and peaked at 7 days. There was a positive correlation between fluorescence intensity and time in 7 days after transfection. With the prolongation of postoperative time, the BBB scores of groups A, B, and C showed a gradually increasing trend. The BBB score of group C was significantly lower than those of groups A and B at 5, 7, and 14 days after treatment (P<0.05). After transfection for 7 days, Western blot results showed that the relative expression of MSK1 protein in group C was significantly lower than that in groups A and B (P<0.05); and the relative expression of PCNA protein was significantly higher than that in groups A and B (P<0.05). Immunofluorescence staining showed that MSK1 was expressed in the nuclei of the spinal cord and colocalized with green fluorescent protein, neuronal nuclei, and glial fibrillary acidic protein (GFAP). The relative expression area of MSK1 positive cells in group C was significantly higher than that in group B (P<0.05), and the relative expression areas of PCNA and GFAP positive cells were significantly lower than those in group B (P<0.05).ConclusionLentivirus-mediated MSK1 siRNA can effectively silence the expression of MSK1 in rat spinal cord tissue. MSK1 may play a critical role in the repair of SCI in rats by regulating the proliferation of glial cells.
Objective To evaluate the cl inical effectiveness and advantages of one-stage posterior debridement, bone graft, and internal fixation for thoracic tuberculosis. Methods The data were retrospectively analysed, from 21 cases of thoracic tuberculosis undergoing one-stage posterior debridement, bone graft, and internal fixation between June 2007 andNovember 2009. There were 16 males and 5 females with an average age of 42.2 years (range, 22-73 years). The average disease duration was 13.2 months (range, 7-21 months). The lesions were located at the level of T5, 6 (1 case), T6, 7 (1 case), T8, 9 (4 cases), T9, 10 (3 cases), T10, 11 (5 cases), T11, 12 (6 cases), and T9-11 (1 case). According to the Frankel grading criterion, the neurological function was rated as grade B in 2 cases, grade C in 6 cases, grade D in 10 cases, and grade E in 3 cases. The preoperative Cobb angle was (26.3 ± 9.2)°. The erythrocyte sedimentation rate (ESR) was (35.9 ± 11.2) mm/ 1 hour. Results Thoracic tuberculosis was confirmed in postoperative pathological examination in all 21 cases. All incisions healed primarily without fistules formation. The average follow-up time for 21 patients was 16.2 months (range, 1-3 years). Bony fusion was achieved within 7-12 months (mean, 9 months) without pseudoarthrosis. No loosening and breakage of internal fixation were found, and no local recurrence occurred. The ESR decreased to (25.1 ± 8.9) mm/1 hour at 1 week postoperatively, showing significant difference when compared with preoperative value (t=5.935, P lt; 0.01); it decreased to (14.1 ± 4.6) mm/1 hour at 3 months postoperatively. According to Frankel grade, the neurological function was significantly improved at 1 year after operation (χ2=13.689, P=0.003). The average Cobb angle was (17.1 ± 4.5)° at 1 years postoperatively, showing significant difference when compared with preoperative value (t=7.476, P lt; 0.01). Conclusion One-stage posterior debridement, bone graft, and internal fixation has a good cl inical effectiveness for thoracic tuberculosis with less injury and complete focal cleaning, as well as a goodeffectiveness of spinal canal decompression and kyphosis deformity correction.