Figure 4
A. Fundus photograph of an adult Bmp4+/- mouse. The retinal vessels and optic nerve are obscured by white vitreous opacities of varying size and by diffuse vitreous haze. B. Fluorescein angiogram of a wild type C57BL/6J mouse. Both the retinal vessels and the retinal capillary network are sharply defined with the retinal vessels radiating from around the optic nerve. C. Fluorescein angiogram of aBmp4+/- mouse. The retinal vasculature is abnormal consisting of large and small vessels that lie on the retinal surface. Abnormal vessels are also present in the vitreous and have areas of leakage (arrows). D. Wild type adult retina. All layers of the retina (R) are normal, the vitreous (V) is clear, and the lens (L) normal. H&E x 400. E. In this adult Bmp4+/- heterozygote, many persistent hyaloid vessels are located directly posterior to the lens (arrows). The hyaloid vessels appear attached to the retinal surface (arrowheads). H&E x 400. F. In this wild type P10 mouse (when hyaloid vessel involution begins), macrophages (arrowheads) are arranged parallel to the hyaloid vessels (arrows). H&E x 630. G. In this P10 Bmp4+/- mouse, macrophages are absent and the hyaloid vessels (arrows) are larger than normal. H&E x 630. H-I. Optic nerve nerve phenotypes were variable in adult Bmp4+/- heterozygotes. H. The optic nerve is normal. The nasal and temporal nerve fibers (arrows) are present beneath the internal limiting membrane (arrowhead) and enter a well-formed optic nerve (N). The peripapillary retina appears normal. H&E x 200. I. In this heterozygote, there is no clearly formed optic nerve and no nerve fibers are evident in the scleral canal through which the nerve normally exits the eye. The retina has extended into the canal H&E x 200. J. In another heterozygote, the optic nerve is absent and the canal contains pigmented cells and loose connective tissue. H&E x 200. K-N. Retinal phenotypes are also variable in Bmp4+/- eyes. K. Peripapillary retina from a heterozygous eye with a similar optic nerve phenotype to that in I. The internal limiting membrane is present (arrow), but there is no nerve fiber layer. The position marked by an asterisk corresponds to that in H where there is an obvious nerve fiber layer. The inner nuclear layer (arrowhead) is thinner than in H and L. H&E x 200. L. In this heterozygote, the retina appears normal (compare to D). H&E x 200. M. In this heterozygote, persistent hyaloid vessels are attached to both retina and lens and are exerting vitreous traction (arrow), pulling the retina toward the lens. A focus of retinal dysplasia (D) has disrupted the outer nuclear layer. H&E x 400. N. In another Bmp4+/- mouse, there is abnormal retinal lamination and a clump of photoreceptor nuclei (arrows) abuts directly onto the retinal pigment epithelium. H&E x 200.