An improved liquid nitrogen freezing method for establishing canine models of femoral head necrosis / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish an canine model of femoral head osteonecrosis using an improved liquid nitrogen freezing method.</p><p><b>METHODS</b>Sixteen adult canines were divided into 4 groups at random and subjected to instant freezing of the unilateral femoral head with liquid nitrogen. The dogs were observed at 2, 4, 8, and 16 weeks after the operation for radiographic, gross and pathological changes of the femoral head.</p><p><b>RESULTS</b>Significant radiographic, gross and pathological changes occurred in the femoral head after the freezing.</p><p><b>CONCLUSION</b>Improved liquid nitrogen freezing of the femoral head provides a simple and convenient method for establishing animal models of femoral head osteonecrosis.</p>

Inhibition of growth and angiogenesis of U251 cell xenograft in vivo by short hairpin RNA targeting survivin gene / 中华外科杂志

<p><b>OBJECTIVE</b>To observe the impact of specific short hairpin RNA (shRNA) targeting survivin gene on tumorigenesis and angiogenesis of human brain glioblastoma U251 cells in vivo of nude mice.</p><p><b>METHODS</b>U251 cells, U251-SR cells transfected stably with shRNA eukaryotic expression vector pWH1-SR targeting survivin gene, and U251-P cells transfected stably with blank pWH1 vector, were inoculated respectively into subcutaneous tissue in flank of 15 nude mice (each group 5 mice), and the tumor growth status was observed and measured. Protein expressions of survivin, proliferating cell nuclear antigen (PCNA) and factor VIII related antigen (F VIII RAg) were investigated by immunohistochemistry SABC method, apoptotic cells were screened by TUNEL method, furthermore proliferative index (PI), apoptotic index (AI) and microvessel density (MVD) were measured respectively in each group of tumor specimens.</p><p><b>RESULTS</b>Comparing with those in U251 and U251-P groups, in U251-SR group, the tumorigenesis time delayed, tumor grew slowly, both tumor volume and tumor weight decreased significantly (P < 0.01 for both); Survivin protein expression was down-regulated markedly; PI and MVD decreased significantly, whereas AI increased remarkably (P < 0.01 for all).</p><p><b>CONCLUSIONS</b>The specific shRNA targeting survivin gene can inhibit significantly tumorigenesis and angiogenesis of U251 cells in vivo.</p>

Research on relationship of survivin gene expression with malignant proliferation and apoptosis of brain glioma / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the expression level of inhibitor of apoptosis protein survivin gene in human brain glioma and its role in malignant proliferation and antiapoptosis of brain glioma.</p><p><b>METHODS</b>Eighty-three cases of brain glioma specimen was chosen, protein expression of survivin and proliferating cell nuclear antigen (PCNA) was investigated by immunohistochemistry streptavidin-biotin complex (SABC) method, the immunoreactivity score (IRS) of survivin and the proliferative index (PI) were counted. Apoptotic cells were screened by TdT-mediated dUTP-biotin nick-end labeling (TUNEL) method, and the apoptotic index (AI) of brain glioma was calculated.</p><p><b>RESULTS</b>The survivin IRS, PI and AI of brain glioma were 3.8 +/- 3.9, (28.4 +/- 19.5)% and (1.0 +/- 0.8)% respectively, and all of them were elevated with the increase of pathological grade of brain glioma (P < 0.01 for all). PI in survivin positive group was significantly higher than that in survivin negative group (P < 0.01), and PI was positively correlated with survivin IRS (r = 0.740, P < 0.01). There was no significant difference between AI in survivin positive group and that in survivin negative group (P > 0.05), however, AI was negatively correlated with survivin IRS (r = -0.307, P < 0.01).</p><p><b>CONCLUSIONS</b>Survivin is overexpressed in brain glioma, and which may play important roles in malignant proliferation and antiapoptosis of brain glioma.</p>

Construction and biological activity study of human osteoprotegerin expressing adenoviral system / 生物工程学报

Using the isolated total RNA from osteosacoma cell line MG63, the cDNA encoding human OPG was amplified by RT-PCR. A recombinant adenoviral vector carrying cDNA of OPG was constructed and OPG expression in mouse myoblast C2C12 cells was confirmed by Western blot and ELISA. The secreted expression of OPG protein persisted more than 6 weeks in vitro, and the growth of C2C12 cells infected by recombinant adenoviral were in good state. Osteoclasts derived from mouse bone marrow cells infected with recombinant adenoviral made less number of TRAP positive cells and resorption pits formed on dentine slices.