Abstract
Abstract: :
Purpose: We previously demonstrated that overexpression of biglycan under the control of the keratocyte-specific keratocan promoter (Kerapr) lead to eyelid dysplasia including aplasia of Meibomian gland. The present study is to further elucidate the cellular events of eyelid morphogenesis during development of wild type and KeraprBgn/+ mice. Methods: Time-mated pregnant female non-transgenic mice crossed with male Bgn-tg mice at different gestations (from E14.5 through E18.5) were I.P. injected with BrdU (100 µg/g body weight) 2 h prior to sacrifice. The embryos obtained by caesarian section were fixed in 3% glutalaldehyde for morphological analysis by Scan EM and TEM, or in 4% paraformaldehyde and were subsequently subjected to immunohistcehmistry for ECM components, αSMA. cDNA micro-array was used to analyze gene expression patterns of eyelids from E17.5 embryos. Result: In Bgn-tg mice, the number of stromal cells of eyelid decreases in comparison to that of wild type littermates. However, % BrdU labeled remains constant between transgenic mice and their wild type littermates. TUNNEL assay does not identify apoptotic cells in either transgenic or non-transgenic mice. In addition, the eyelid stromal cells are of myofibroblast characteristics, expressing αSMA. Scanning EM demonstrates that eyelid epithelial cell migration is disturbed in Bgn-tg mice. The eyelid of transgenic mice fuses by E16.5, but it subsequently undergoes non-infectious ulceration that leads to premature eye opening at postnatal day 1. Micro-array analysis of RNA from transgenic and wild type mice reveals down regulation of IQGAP1, a protein modulating cell migration. Conclusion: Excess biglycan expression inhibits eyelid stromal cell migration and differentiation during development in transgenic mice.