| Research Abstract |
1. To examine the effectiveness of a gene transfer procedure for the delivery of BMP-2, we constructed a human BMP-2-expressing replication-deficient adenoviral vector, AxCAOBMP-2, and evaluated its osteoinductive actiyity in vitro and in vivo.
2. C2C12 myoblasts were infected in vitro with this viral vector or an Escherichia coli LacZ gene-expressing control adenovirus vector (AxCALacZ). Twenty-four hours after the infection, indirect immunofluorescence was performed. On day 5 after the infection, alkaline phosphatase (ALP) in the cells and osteocalcin in the culture medium were measured. Furthermore, to examine the effectiveness of gene transfer of BMP-2 in vivo, we evaluated osteoinduction by AxCAOBMP-2, under transient immunosuppression with cyclophosphamide, given at a dose of 125 mg/kg intraperitoneally the day before injection of the adenoviral vector. Twenty-five microliters of AxCAOBMP-2 (8.75 x 10^8 plaque-forming units [pfu], Group I) and AxCALacZ (1.75 x 10^8 pfu, control group) and 5 microl of AxCAOBMP-2 (1.75 x10^8 pfu, Group II) were injected into a right calf muscle of Wistar rats. On day 21, bone formation in each group was investigated radiologically and histologically.
3. Abundant BMP-2 expression in C2C12 cells infected with this viral vector was confirmed by immunofluorescence. C2C12 cell transferred with the BMP-2 gene by this vector produced ALP in the cells and also produced and secreted osteocalcin in the culture medium. Osteoinduction was found only in the AxCAOBMP-2 treated groups with immunosuppression. Osteoinduction activity was higher in Group I than in Group II.
4. This study demonstrated the osteoinductive activity in vitro and in vivo by an adenoviral vector carrying the BMP-2 gene. Gene therapy with AxCAOBMP-2 under transient immunosuppression may be useful for bone reconstruction.
Reference: Okubo Y, Bessho K, Fujimura K, Iizuka T, Miyatake SL, J Bone Joint Surg Am. 83-A Suppl 1 (Pt 2) : S99-104.2001.)
|
