疾病动物模型,辐射性白内障 z-bio 2022-10-10 539

　　[Modeling mechanism] Ultraviolet rays (UV) in nature are divided into UVA (315-400m), UVB (280-315m) and UVC (100-280m). Ozone in the atmosphere can absorb ultraviolet light with a wavelength of less than 280m, and inject UVB and UVA into the ground. The most sensitive ultraviolet wavelength of the lens is 300nm. Ultraviolet rays destroy the membrane proteins of lens epithelial cells, disrupt their ion balance, affect subepithelial fibroblasts through cell-to-cell connections, increase intracellular osmotic pressure, and cause cell edema and cataracts. In addition, tryptophan absorbs ultraviolet light and is then converted into N-formylkynurenine and 3-hydroxyquinine. The latter reacts with O2 to form an oxidant, which ultimately leads to the denaturation of lens protein.

　　[Modeling method] Adult guinea pigs, rats and rabbits can be used. The pupils can be dilated with 1% atropine solution at least twice a week. Rats should use Shuangxingming eye drops and phenylephrine eye drops to dilate pupils. The molding time is related to the irradiation method, dose and irradiation time. Generally, 5 kJ/m2 of 300 kN UV is regarded as the threshold dose for permanent damage to the lens of rabbit eyes. After the rats were irradiated with 36 kJ/m2300m ultraviolet rays for 30 minutes every day, obvious lens opacity was observed one week later. However, if the guinea pig is placed in an environment surrounded by an ultraviolet lamp emitting a wavelength of 300-400m, it should be kept for 2-14 months before observing the development of cataract.

　　[Model Function] As time goes by, the lens will show varying degrees of turbidity. The opaque areas are mainly located in the center of the lens and the anterior and posterior cortex. They are small dots, vacuoles, flakes or feathers. Under an optical microscope, the normal lens epithelial layer is very thin, and the lens fibers are arranged in a square brick shape, but the cataract lens irradiated by ultraviolet light shows the swelling of the lens fibers, and the difference in distribution thickness is obvious. It is an obvious lesion with almost no fibers, layers, vacuole degeneration and laceration, and it is obviously fused with each other, accompanied by clusters of eosinophils and follicular cells. The core of the lens is dirty and uneven. The lens epithelium is obviously thickened. The electron microscope also showed that the lens fibers were significantly swollen, and the fiber gaps were significantly widened.

　　[Model Evaluation and Application] Using indoor UV diffuse reflection to model guinea pigs is simple and easy to use, and is close to the state of cataract formation in normal high latitude areas. Pupil size and radiance are the keys to successful modeling. A large amount of direct radiation saves test time and is currently used in many applications. It is suitable for studying the oxidative damage of presbyopia and cataract.