Expression of Semaphorin 3A after spinal cord injury / 中国骨伤

OBJECTIVE@#To investigate expression of Semaphorin 3A in rats after spinal cord injury and explore possible mechanism of inhibiting of axonal regeneration after SCI.@*METHODS@#Forty healthy female SD rats, 8 weeks old, weighing (210.00±9.88) g, were randomly divided into control group(20 rats in group A) and model group(20 rats in group B). In control group, removal of T@*RESULTS@#After a simple spinal cord transection injury, hemorrhagic necrosis, localized edema, neurodegeneration, necrosis, and cyst formation occurred in the injured area, and glial scar formation occurred in glial cells. Semaphorin 3A expression levels in control group was low in the gray matter area. There was no expression of Semaphorin 3A in the injured area of spinal cord injury in model group 3 days after operation. On the 14th day, the expression of Semaphorin 3A in the injured area of spinal cord injury increased significantly and was at a high level. On the 28th day, the expression of Semaphorin 3A was moderate. On the 42th day, the positive expression of Semaphorin 3A returned to normal level.@*CONCLUSION@#The increased expression of Semaphorin 3A after spinal cord injury may be one of the mechanisms that inhibit axonal regeneration.

Effect of lipid accumulation after spinal cord injury in autofluorescence intensity of injury site / 中国骨伤

<p><b>OBJECTIVE</b>To investigate the relationship between lipid accumulation and autofluorescence intensity of injury site after spinal cord injury (SCI), and explore whether CuSO⁴ can eliminate autofluorescence in the injury site after SCI.</p><p><b>METHODS</b>Thirty six Wild Type mice at age of 8 to 12 weeks (weight 18 to 24 g) were randomly divided into normal control group (4) and SCI group (32). Respectively, 8 mice of SCI group were sacrificed randomly at 1 week, 2 weeks, 4 weeks and 8 weeks after injury. Frozen sections of spinal cord tissue with injury site at the center were made to observe autofluorescence under green channel of fluorescence microscope (Specimens of normal control group were taken from the same segment of the spinal cord, and fixed with 4% paraformaldehyde solution). Oil Red O staining was applied to visualize the lipid accumulation in the injury site, and correlation between lipid accumulation and autofluorescence intensity was analyzed. Furthermore, sections were incubated with CuSO⁴ buffer to eliminate autofluorescence, and CuSO⁴ concentration and incubation time was optimized.</p><p><b>RESULTS</b>No obvious autofluorescence or lipid staining was found in normal spinal cord tissue sections. By contrast, autofluorescence appeared in the injury site of spinal cord sections, and the intensity increased with passing time after injury. Oil Red O staining showed that lipid accumulated in the injury site with passing time after injury as well, and the correlation between lipid accumulation and autofluorescence intensity was positive. After incubation with CuSO⁴ buffer, the autofluorescence in the injury site was significantly reduced, especially after optimizing CuSO⁴ concentration and incubation time.</p><p><b>CONCLUSIONS</b>Lipid accumulation may play an important role to determine the autofluorescence intensity of injury site after SCI, and the autofluorescence intensity can be used as a simple index for evaluating lipid peroxidation damage. Optimized method of using CuSO⁴ can significantly reduce the autofluorescence in the injury site after SCI, which will be beneficial to the application of immunofluorescence staining technique in the study of SCI.</p>

Construction of recombinant plasmid pIRES-GM-CSF-IL-21 and its therapeutic effect on orthotopically transplanted liver cancer in mice / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To construct a recombinant plasmid pIRES-GM-CSF-IL-21, and to investigate its antitumor effect on tumors in the mice.</p><p><b>METHODS</b>Fifty Bal b/c mice were included in this study. Cultured hepatoma H22 cells were inoculated in the left lobe of the liver to develop orthotopically transplanted liver tumor models. The mice with orthotopically transplanted liver tumor were randomly divided into 5 groups (n = 10): (1) Each mouse received injection of recombinant plasmid pIRES-GM-CSF-IL-21; (2) Received injection of plasmid pIRES-GM-CSF; (3) pIRES-IL-21; (4) Received injection of ampty plasmid pIRES (H22/neo group); (5) Received injection of PBS (H22 group) via the tail vein, respectively. Therefore, the anti-tumor effect was induced by both GM-CSF and IL-21, or by either of them alone. The serum levels of IFN-γ and IL-2 were detected by ELISA, and the cytotoxicity of spleen NK and CTL cells were tested by MTT colorimetry.</p><p><b>RESULTS</b>Comparing with the H22 and H22/Neo groups, the tumor weight in the mice of H22/GM-CSF group was (0.603 ± 0.223) g, H22/IL21-treated group (0.583 ± 0.290) g and H22/GM-CSF-IL21-treated group (0.303 ± 0.323) g, significantly lower than that in the H22 group [(1.591 ± 0.280) g] and H22/Neo group [(1.489 ± 0.155) g]. Among them the tumor growth was most significantly inhibited in the H22/GM-CSF-IL-21 group (0.303 ± 0.323) g, compared with that of H22 and H22/neo groups (P < 0.01). But there was no significant difference between the tumor weights of the H22/GM-CSF group and H22/IL-21 group, and between the tumor weights of the H22 and H22/Neo groups (P > 0.05). The levels of IFN-γ and IL-2 in peripheral blood of mouse models treated with H22/GM-CSF-IL-21 were significantly increased than that in the H22/GM-CSF group and H22/IL-21 group (all P < 0.01), but significantly decreased in the H22group and H22/Neo group (P < 0.01). The anti-tumor activity of splenic NK cells and CTLs in the H22/GM-CSF-IL21 group was significantly enhanced (P < 0.01), compared with the significantly decreased in the H22 and H22/Neo groups.</p><p><b>CONCLUSIONS</b>Our results demonstrate apparent antitumor effect of the plasmid pIRES-GM-CSF-IL-21 on the orthotopically transplanted liver tumor in mice. The combination of both pIRES-GM-CSF and IL-21 is more effective than that of pIRES/IL21 or pIRES/GM-CSF treatment alone. In addition, the plasmid pIRES-GM-CSF-IL-21 can also promote the secretion of IFN-γ and IL-2 in vivo, and enhance the cytotoxic activity of splenic NK and CTLs against the transplanted liver tumor.</p>