Figure 4: Transmission electron microscopy (TEM) identifies lens capsule fenestrae in E16.5 Adamts9^del/+ eyes.

(a) The anterior and posterior lens capsule were of comparable appearance in Adamts9^del/+ and Adamts9^+/+ eyes through most of their extent. Arrowheads indicate endothelial cells of microvessels in the pupillary membrane (anterior) or the tunica vasculosa lentis (posterior). Panels are representative of 4 eyes of each genotype. Scale bar = 500 nm. (b) Anterior, equatorial and posterior lens capsule thickness was similar in Adamts9^del/+ and Adamts9^+/+eyes. (c) A defect in the posterior lens capsule associated with a lens fiber extrusion in an Adamts9^del/+ eye (left-hand panel). The right-hand panel shows that the extruded material lying in the vitreous is membrane-bound. Scale bar = 2 μm. (d) In Adamts9^del/+ eyes, lens epithelial cells traversed the discontinuous anterior lens capsule (white arrowhead) and formed nests of cells surrounded by basement membrane similar to the lens capsule. Higher magnifications of the indicated regions are shown as framed panels on the right. The asterisk in the upper panel shows the extraneous anterior layer of lens capsule formed by the ectopic cells, the center panel shows a local duplication or folding of the lens capsule, and the lower panel shows a lens epithelial cell (arrowhead) penetrating the fenestrated lens capsule. Scale bar = 2 μm. (e) In an Adamts9^del/+ eye, Peters anomaly was identified by continuity of the lens with surface ectoderm across a discontinuous cornea (left-hand panel). The right-hand panel shows the resulting corneal edge at high magnification to indicate the interrupted corneal endothelium. Scale bar = 2 μm. L = lens, C = cornea, Lc = lens capsule, Le = lens extrusion, Lf = lens fibers, Ce = corneal endothelium. Significance was determined using a 2-tailed student’s t test.