Abstract:

BACKGROUND: The decline of insulin-like growth factor-1 (IGF-1) levels has been proven to be an important reason leading to osteoporosis. Gene therapy for osteoporosis and other bone metabolic diseases has becoming a direction of the research, but the viral vector may cause serious immune response. Therefore, the recombinant plasmid pEGFP-N1-IGF-1 in vivo transfection of osteoporosis rats may be a more effective treatment way.
OBJECTIVE: To study the IGF-1 expression during recombinant plasmid pEGFP-N1-IGF-1 in the osteoporosis rats in vivo.
METHODS: Female Sprague Dawley rats were randomly assigned to sham-surgery group, pEGFP-N1 group and pEGFP-N1-IGF-1 group. Bilateral ovariotomy was performed in pEGFP-N1 group and pEGFP-N1-IGF-1 group. At 12 weeks following surgery, the three groups were given saline, pEGFP-N1 vector and recombinant plasmid pEGFP-N1-IGF-1 complex liposomes hydrodynamic injection, respectively. Fluorescence in vivo imaging and liver biopsy were observed at 48 hours following transfection. Serum concentrations of IGF-1 were determined at regular intervals.
RESULTS AND CONCLUSION: After transfection, rats of pEGFP-N1 group and pEGFP-N1-IGF-1 group developed noticeable fluorescence expression not only in the whole body but also liver biopsy, especially in the liver and tail. IGF-1 levels were significantly decreased in rats undergoing ovariotomy (P < 0.05). The expression level of serum IGF-1 in rats of pEGFP-N1-IGF-1 group were significantly increased (P < 0.05), and then reduced over time (P < 0.05). Results indicated that recombinant plasmid pEGFP-N1-IGF-1 can be successfully transfected and expressed IGF-1 protein in osteoporosis rats, which can be a substantial foundation for further application of IGF-1 gene therapy to osteoporosis.