Abstract
Purpose :
To examine the effects on embryonic development of eyelids and orbicularis oculi muscles and meibomian glands in Six1 and Six4 (Six1/4) double knockout mice.
Methods :
Six1/4-double knockout (dKO) and littermate wild-type (WT) embryos were used. Paraffin sections or whole-mounted specimens of eyelids were examined at embryonic day (E)15.5 (n = 4), E16.5 (n = 4) and E17.5 (n = 4). Paraffin sections were processed for hematoxylin and eosin (HE) staining or immunohistochemistry for a-smooth muscle actin. Whole-mount eyelid specimens were processed for phalloidin staining and observed under confocal microscopy.
Results :
A dKO mouse died just after birth due to a breathing problem. At and after E16.5 the morphogenesis of eyelid was found to be severely impaired in dKO embryos. Histology and immunohistochemistry showed disturbance of the development of meibomian glands and orbicularis oculi muscles in dKO embryos. Eye including intraocular structures were well formed. Confocal microscopy observation of eyelid samples with phalloidin staining nicely showed severely impaired development of orbicularis oculi muscles in dKO embryos at E16.5 and E17.5 as compared with WT embryos.
A dKO mouse died just after birth due to a breathing problem. At and after E16.5 the morphogenesis of eyelid was found to be severely impaired in dKO embryos. Histology and immunohistochemistry showed disturbance of the development of meibomian glands and orbicularis oculi muscles in dKO embryos. Eye including intraocular structures were well formed. Confocal microscopy observation of eyelid samples with phalloidin staining nicely showed severely impaired development of orbicularis oculi muscles in dKO embryos at E16.5 and E17.5 as compared with WT embryos.
Conclusions :
Deletion of both Six1/4 impaired embryonic development of eyelids and meibomian glands, as well as orbicularis oculi muscles, in mice. Because Six1/4 are known to be involved in growth of striated muscle, morphogenesis of orbicularis oculi muscle might be critical in eyelid development.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.