Insulin-like growth factor-I cDNA Gene transfer in vitro and in vivo

Our hypothesis is that gene transfer of an IGF-I CMV-cDNA with cholesterol containing cationic liposomes is an efficient tool for transient transfecti on of growth factors in vitro and in vivo. In vitro, we transiently cotrans fected IGF-I cDNA with a CMV construct and a Lac Z beta-galactosidase cDNA/ CMV construct using cholesterol containing cationic liposomes and measured beta-galactosidase and IGF-I mRNA and protein. In vivo, we subcutaneously i njected 3-month-old male Sprague-Dawley rats with IGF-I cDNA and beta-galac tosidase cDNA into rat skin. After IGF-I and beta-galactosidase were cotran sfected into PC12 cells, Northern blot analysis showed that the peak time o f IGF-I expression was 2 days for mRNA and 5 days for protein. In vivo, a c DNA/liposome ratio of 1:2 was most effective. IGF-I protein expression in I GF-I-transfected skin resulted in significant transfection from day 5 to da y 7. In situ determination of beta-galactosidase activity confirmed that tr ansfections resulted in a restricted expression area.