Acute embryonic exposure to isotretinoin during gastrulation (gestational day 7) in the mouse results in delay or failure of separation of the lens vesicle from the surface ectoderm. During normal lens vesicle detachment, laminin is localized within the lens, keratolenticular stalk and adjacent surface ectoderm. The mesenchyme surrounding the stalk stains positively for fibronectin. In contrast, isotretinoin-exposed embryos at the same stage of gestation exhibit reduced staining for both extracellular matrix components. Persistent keratolenticular attachment observed later in gestation in the exposed embryos is associated with increased production of laminin by the keratolenticular stalk and anterior lens epithelium. A delay in the sequence of production of extracellular matrix may be causally associated with persistence of the keratolenticular stalk
