动物模型,视网膜新生血管 z-bo 2020-08-08 468

　　(1) Reproduction method

　　①C57BL/6N mice born 7 days old were placed in 75% oxygen environment, controlled at room temperature (23±2) ℃, and returned to air environment after 5 days. ② 7-day-born rats enter a semi-enclosed oxygen box made of plexiglass. The oxygen box is filled with medical oxygen, and the oxygen saturation in the box is maintained at 75% for 5 days. The oxygen box is opened every other day to clean, add food, and change water. The time is about 5 minutes. After 5 days, the rats were moved into a normal oxygen environment and kept for another 7 days.

　　(2) Model characteristics At 19 days, the mice were perfused with fluorescein to perfuse the retinal vasculature, showing that the morphology and distribution of retinal blood vessels have changed significantly, losing the normal and regular network distribution, large blood vessels are significantly expanded, large areas without perfusion, and a large number of neovascular buds form. Histopathological section of the retina showed that the surface of the retina lost its normal smooth interface, and many capillaries broke through the inner limiting membrane of the retina and grew into the vitreous body, forming a large number of neovascular buds in the front and superficial layers of the retina, even accompanied by vitreous hemorrhage.

　　(3) Comparative medicine The appearance of new blood vessels in the mature retina often leads to decreased vision and even vision loss. Retinal neovascularization is more common in diabetic retinopathy, retinopathy of prematurity, ischemic retinal vein thrombosis, etc. The cause is complicated. It is generally believed that the mechanism of neovascularization is mainly due to breaking the balance regulation of angiogenesis under pathological conditions. In normal eye tissue, the growth of blood vessels is controlled by two opposite regulatory systems. They are factors that promote blood vessel proliferation and inhibit blood vessel growth. Under certain pathological conditions, such as diabetes, premature infants, and ocular trauma, they break This balance increases the content of vascular endothelial growth factor (VEGF) in the retina, leading to the formation of new blood vessels. Newborn rats return to normal oxygen environment after a few days in a hyperoxic environment. Hypoxia promotes angiogenesis by releasing VEGF, and its retina may have hemangioma proliferation and other changes similar to human retinopathy of premature infants, so it can become ideal Animal model of experimental retinal neovascularization.