ABSTRACT
<p><b>OBJECTIVE</b>To examine the influence of vascular endothelial growth factors (VEGF) in controlling the growth of an experimental osteosarcoma in mice by performing retrovirus-mediated sFlt-1 gene modification.</p><p><b>METHODS</b>From March to October 2010 human osteosarcoma G-292 cells were in vitro infected with retroviral vectors encoding soluble Flt-1 or LacZ gene before transplanted into proximal tibiae of immune deficient SCID mice to establish experimental orthotopic osteosarcoma. Daily observation and biweekly microCT were performed to monitor tumor development and progression till sacrifice at 8 weeks after tumor cell inoculation for histological and molecular analyses.</p><p><b>RESULTS</b>Successful transgene expression was confirmed in the culture media of sFlt-1 transduced G-292 cells using ELISA, and with positive X-gal staining of the LacZ transduced cells. Noteworthy tumors were grown in all mice on the tibiae receiving G-292 cell inoculation, with clear detection on microCT images starting 2 weeks after inoculation. Over the time period, tumors derived from sFlt-1 transduced G-292 cells were distinctively smaller in size compared to the ones from wide-type G-292 and G-292-LacZ cells. Histology showed typical osteosarcoma characteristics including severe cellular pleomorphism, bone erosions, and neo-vascularization. Real-time polymerase chain reaction indicated significantly higher sFlt-1 expression in sFlt-1 transduced groups than the wild-type G-292 or LacZ treated groups. Strong expression of oncogenes c-myc and c-fos were also obvious, along with the expression of VEGF in the primary tumor tissue.</p><p><b>CONCLUSION</b>Retrovirus-mediated sFLT-1 gene modification decelerates the osteosarcoma tumor growth in this murine model.</p>
Subject(s)
Animals , Female , Humans , Mice , Bone Neoplasms , Genetics , Metabolism , Pathology , Cell Line, Tumor , Genetic Vectors , Lac Operon , Mice, SCID , Neovascularization, Pathologic , Metabolism , Pathology , Osteosarcoma , Genetics , Metabolism , Pathology , Retroviridae , Genetics , Transgenes , Vascular Endothelial Growth Factor A , Metabolism , Vascular Endothelial Growth Factor Receptor-1 , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To observe the effects of cryopreserved olfactory ensheathing cells (OECs) transplantation on axonal regeneration and functional recovery following spinal cord injury in adult rats.</p><p><b>METHODS</b>Twenty-four rats were divided into experimental and control groups, each group having 12 rats. The spinal cord injury was established by transecting the spinal cord at T10 level with microsurgery scissors. OECs were purified from SD rat olfactory bulb and cultured in DMEM (Dulbecco's minimum essential medium) and cryopreserved (-120 degree) for two weeks. OECs suspension [(1-1.4)x10(5)/ul] was transplanted into transected spinal cord, while the DMEM solution was injected instead in the control group. At 6 and 12 weeks after transplantation, the rats were evaluated with climbing test and MEP (moter evoked potentials) monitoring. The samples of spinal cord were procured and studied with histological and immunohistochemical stainings.</p><p><b>RESULTS</b>At 6 weeks after transplantation, all of the rats in both transplanted and control groups were paraplegic, and MEPs could not be recorded. Morphology of transplanted OECs was normal, and OECs were interfused with host well. Axons could regrow into gap tissue between the spinal cords. Both OECs and regrown axons were immunoreactive for MBP. No regrown axons were found in the control group. At 12 weeks after transplantation, 2 rats (2/7) had lower extremities muscle contraction, 2 rats (2/7) had hip and/or knee active movement, and MEP of 5 rats (5/7) could be recorded in the calf in the transplantation group. None of the rats (7/7) in the control group had functional improvement, and none had MEPs recorded. In the transplanted group, histological and immunohistochemical methods showed the number of transplanted OECs reduced and some regrown axons had reached the end of transected spinal cord. However, no regrown axons could be seen except scar formation in the control group.</p><p><b>CONCLUSIONS</b>Cryopreserved OECs could integrated with the host and promote regrowing axons across the transected spinal cord ends.</p>