The Frequencies of Spontaneous and Cortisone-treated Open Eyelid and the Relationship with Cleft Palate between A/WySn and C3H/He Mice

Abstract

During embryo development in mammals, the primary eyelids grow and flatten over the eyes and temporarily fuse in a closed position. Failure of this normal developmental process in mice leads to the defect of open eyelid at birth. The purpose of this study was to investigate the frequency of open eyelid occurring spontaneously and in cortisone-treated mice during pregnancy between the A/WySn and C3H/He inbred mice. METHODS: A/WySn and C3H/He mice were used. Pregnant mice were injected on days 11 through 14 of gestation with 100 mg of cortisone per kg of body weight. As a control group pregnant mice were not treated with cortisone. The frequency of open eyelid was noted among embryos that attained at least Day 18 of development. RESULTS: The frequency of mice treated with cortisone and which developed open eyelid (21.9%) was significantly higher than that in mice where this occurred spontaneously (11.6%) in the A/WySn strain. In the C3H/He mice, open eyelid was not found to occur spontaneously or in those treated with cortisone. In contrast, in A/WySn mice, the frequency of open eyelid alone showed no difference when occurring spontaneously (10.8%) or in mice treated with cortisone (8.1%). However, the frequency of open eyelid and cleft palate occurring together in mice treated with cortisone was significantly higher than in instances when these occurred spontaneously. CONCLUSION: The results suggested that the occurrence of open eyelid appears to be a complex genetic trait, and the A/WySn mice may serve as a model for the genetic analysis of open eyelid thought genetic crosses between the A/WySn and C3H/He mice.