Experimental Study Of Cationic Lipsome-medicated Insulin-like Growth Factor-1 Gene Transfer In Vivo On Acute Spinal Cord Injury In Rats

Objective: To study the effect of cationic liposome mediated IGF-1 gene transfer and its potential mechanism in vivo on neurological recovery of acute spinal cord injury in rats. Methods: The recombinant plasmids pEGFP-N1-IGF-1 was injected into adult rats thoracic spinal cord mediated by Transfectam Reagent. The expression of IGF-1 mRNA was measured by real time PCR (Q-PCR) in the rat injuried spinal cord at one week after gene transfer in vivo. Nervous functional evaluation was observed by nervous function, immunohistochemistry, TUNEL in situ hybridization and activity of the content nitric oxide synthase and inducible nitric oxide synthase with different time after postinjury administration. Results: IGF-1 gene in the recombinant plasmids pEGFP-N1-IGF-1 was exactly confirmed with DNA electrophoresis after enzyme-incise and DNA sequencing. Quantitative analysis of IGF-1 mRNA showed that the expressions of IGF-1 mRNA in pEGFP-N1-IGF-1 group were of significantly higher than other two groups'. Along with continuous observation in 4 weeks by immunohistochemistry, TUNEL in situ end-labeling and hindlimb locomotor scale, there was difference between pEGFP-N1-IGF-1 group and IGF-1 group or between IGF-1 group and SAL control group (P<0.05). There was significantly difference on the activity of NOS and NOS between IGF-1 group and SAL control group or between pEGFP-N1-IGF-1 group and SAL control group at different time after SCI(P<0.01). Conclusions: IGF-1 gene transfection medicated by cationic liposome can suppress apoptosis and necrosis of nerve cell, nervous locomotor function can be improved too. The damage of nervous tissue caused by secondary lesion can be reduced. The recovery of neurofunction furtherly proved the reliability of IGF-1 gene transfer in vivo by lateral surface.