Enhancement effect of human insulin-like growth factor-1 gene on aggrecan expression of degenerative intervertebral disk in rabbits / 基础医学与临床

ABSTRACT

Objective To study hIGF-1 gene expression and the influence on aggrecan expression of degenerative intervertebral disk. Methods Twenty four male New-Zealand rabbits IDD models were established and randomly divided into Ad/CMV-hIGF-1、hIGF-1 growth factor and PBS group. Twenty five mL of Ad/CMV-hIGF-1(T=80?109 PFU/L), hIGF-1 growth factor(100 ?g/L) and PBS were respectively injected into L4-5, L5-6 intervertebral disk through fluoroscopic guidance. One,two,four and eight weeks after-operation, rabbits were sacrificed, intervertebral disk samples were collected. Total protein of equal mass intervertebral disks were extracted, isolated by SDS-PAGE and transferred to polyvinylidene difluoride (PVDF) Millipore. The hIGF-1 growth factor expression were indentified with Western blot. Aggrecan gene fragments were amplified with RT-PCR,and relative expression was checked with GAPDH as intern control. Results The hIGF-1 interest protein existed at 7.6 kilo-Dalton. One week after injection, its expression quantities were almost equal between Ad/CMV-hIGF-1 and hIGF-1 growth factor group. At two week after injection, it obviously declined in hIGF-1 growth factor group. Four week after injection, it was still expressed in Ad/CMV-hIGF-1 group. Eight week after injection, it did not express in three groups. Aggrecan gene relative expression increased significantly from one to four weeks after injection, declined slightly by the end of eight weeks in Ad/CMV-hIGF-1 group. However, it appeared to decrease continuously in the other two groups with time. Conclusion Ad/CMV-hIGF-1 successfully infected degenerative intervertebral disk. The hIGF-1 gene expression lasted four weeks and could stimulate aggrecan synthesis in Ad/CMV-hIGF-1 group.