래트의 척수 손상 모델에서 저산송증으로 유발되는 유전자 발현 체계에 관한 연구

초록

Purpose: To limit the risk of unwanted overexpression of VEGF geners, we developed a hypoxia-inducible gene therapy system using the erythropoietin (Epo) enhancer and the RTP 801 promotor. Methods: he VEGF expression plasmids (pEpo-SV-VEGF, pRTP801 -VEGF and pSV-VEGF) were constructed. The plasmids were introduced to N2a neuroblastoma cells using polyethylmeimine (PEI) and directly to the injured rat spinal cord produced by contusion model.The expression of VEGF was examined in N2a cells and rat spinal cord by RT-PCR and ELISA. The therapeutic effect of VEGF on the recovery from SCI was examined by the Basso-Beattie-Bresnehan locomotor rating system.The VEGF expressing cells were identified by the cells co-expressing the neural markers and VEGF. Results: In vitro gene expression assay showed that hypoxia increases the VEGF expression in the cells treated with pRTP801-VEGF orpEpo-SV-VEGF than pSV-VEGF. However, in the SCI model, higher expression of VEGF in the rat spinal cord was found on pEpo-SV-VEGF than pRTP801-VEGF or pSV-VEGF treated group. Immunohistochemical staining showed that VEGF expression is found on astrocytes as well as neurons. The neurologic functions of the injured rats were also improved significantly inthe pEpo-SV-VEGF administered group than the pSV-VEGF and pRTP801-VEGF group. Conclusion: The VEGF gene therapy using hypoxia inducible expression system such as the pEpo-SV-VEGF and the pRTP801-VEGF may be useful to eventually treat spinal cord injury model. Futerhmore, the EPo-SV-VEFG and pRTP801-VEGF system could improve neurologic functions in a rat SCI model. These finfings suggest that gene therapy using an hypoxia-inducible gene expression system is one of the important therapeutic prociples in treating SCI.