Successful in utero gene transfer using a gene gun in midgestational mouse fetuses.

ABSTRACT

BACKGROUND/PURPOSE: In utero gene therapy offers a number of potential advantages over postnatal gene therapy. A latest method of gene transfer to fetuses in utero uses a new tool called a gene gun. The gene gun is less invasive and simpler than other in utero methods. The current study was designed to determine whether the gene gun is an effective tool for transferring genes to mouse fetuses in utero. METHODS: Using a gene gun, we transferred plasmids that included enhanced green fluorescent protein (EGFP) genes and cytomegalo virus promoters to the abdominal skin of 40 A/J fetal mice at each of 3 gestational ages (13, 14, or 15 days). Four or 5 days after gene transfer, the number of surviving fetuses was counted, and a color image of EGFP in the skin was analyzed for gene transfer rates by fluorescence microscopy. Survival rates were analyzed using Fisher's Exact test. RESULTS: The mean survival rate was 89.2% (107 of 120) in gene transfer fetuses and 91.7% (55 of 60) in controls. There is no difference in survival rate between gene transfer fetus and control. The highest gene transfer rate was 100% (37 of 37) at the gestational age of 14 days. The rate was 97.1% (34 of 35) at gestational ages of 13 and 15 days. CONCLUSIONS: The results of this study show that in utero gene transfer by gene gun is a less-invasive technique, and the gene gun is an effective tool transferring genes to mouse fetuses in utero.