Corrosion cast demonstration of choroidal vasculature in normal Wistar Kyoto rat

No previous attempt has been made so to demonstrate the details of the chor oid vascularization in the rat. This paper describes the choroidal vascular pattern of the normal Wistar Kyoto rat using the corrosion cast method. 6-month-old normal Wistar Kyoto rats were used. Vascular casts prepared by our previously described technique were observed with a Hitachi S-2360N sca nning electron microscope. Corrosion casts of the entire choroidal vasculature showed that the ophthal mic artery branched into two main ciliary arteries: the nasal and temporal arteries, which extend forward to form the iridociliary circle. Further the inferior ciliary artery arises from the temporal ciliary artery. In the po sterior eye segment these arteries form four to seven branches supplying th e adjacent choriocapillaris. There are different arrangements of choriocapi llaris. The larger veins formed four vortex veins, one in each quadrant, dr aining blood from the anterior region of the choroid or iris. Venous blood from the central region, peripapillary choroid and sometimes optic nerve he ad is drained by smaller veins, which run more or less directly into the po sterior ciliary veins. In conclusion corrosion casts and SEM can show the details of the choroidal vascular architecture. These three-dimensional (3-D) findings of choroidal vessels of the rat are very useful for the study of choroid vascular abnor malities in various pathological conditions.