Opaque eyes developed in transgenic mice with T-cell receptor delta gene

During the generation of transgenic mice (TGs) introduced with mouse T-cell receptor delta (TCR delta) gene, the authors found a TG line with corneal opacity that coincided with the presence of the transgene. The authors investigated the pathogenesis and molecular mechanisms of this corneal opacity in this line.

The pathologic features and pathogenesis of the corneal opacity in TGs were examined histologically using transmission and scanning electron microscopy, as well as light microscopy. DNA and RNA blot analyses were performed to examine the copy number and the expression of the transgenes, respectively.

Histologically, edema of the corneal epithelium and adhesion of the iris to the cornea were observed in adult TGs. In the developmental analysis, the authors first observed relative hypoplasia of the ciliary body on day 18 of gestation and dysgenesis of the anterior chamber angle from postnatal day 2. Corneal opacity was observed from postnatal day 8, coinciding with the histologic vesicular change of the epithelium. No inflammation was observed through its life. In the sublines that have different copy numbers of the transgene, the occurrence of the opacity depended on the copy number of the transgene. Expression of the transgene in the thymus was consistent with the number of the introduced transgene.

In a TCR delta TG line, the overexpression of transgenes coincided with abnormal development of the ocular anterior segment and the corneal opacity. Pathogenesis is described, and possible molecular mechanisms are discussed.