动物造模,药效评价,白内障 z-bio 2024-06-19 553

　　【 Modeling Mechanism 】 Ultraviolet (UV) in nature is divided into UVA (315-400nm), UVB (280-315nm), and UVC (100-280nm). The atmospheric ozone can absorb UV with a wavelength less than 280nm, and what enters the ground are UVB and UVA. The most sensitive UV wavelength of the lens is 300nm. Ultraviolet radiation damages the membrane proteins of lens epithelial cells, leading to ion imbalance and affecting the fibrocytes beneath the epithelium through intercellular connections. This leads to increased intracellular osmotic pressure, cellular edema, and the formation of cataracts. In addition, tryptophan absorbs ultraviolet light and transforms into N-formylcaninurine and 3-hydroxycaninurine, which react with O2 to form oxidants, ultimately leading to lens protein denaturation.

　　【 Modeling Method 】 Adult guinea pigs, rats, and rabbits can all be used. 1% atropine solution can be used to dilate the pupils, at least twice a week. It is recommended to use bisoprolol eye solution and epinephrine eye solution to dilate the pupils in rats. The modeling time is related to the irradiation method, dosage, and irradiation time. It is generally believed that a 300nm UV dose of 5kJ/square meter is the threshold dose for causing permanent damage to the rabbit lens. A daily irradiation of 36kJ/square meter of 300nm UV on rats for 30 minutes resulted in significant lens opacity observed one week later. But if guinea pigs are raised in an environment surrounded by ultraviolet lamps that can generate wavelengths of 300-400nm, it takes 2-14 months to observe the formation of cataracts.

　　【 Model characteristics 】 As time goes on, the lens appears to varying degrees of turbidity. The cloudy area is mainly located in the central part of the lens and the anterior and posterior cortex, appearing as small dots, vacuoles, flakes, or feathers. Under light microscopy, the normal epithelial layer of the lens is relatively thin, and the lens fibers are arranged in a square brick shape; However, ultraviolet induced cataracts present with swelling of lens fibers, significant differences in thickness distribution, and fewer fiber layers in the affected area. Void degeneration and tearing are evident and fuse with each other, and clusters of eosinophilic bodies and vesicular cells can be seen. The staining depth of the lens nucleus is uneven. The epithelial layer of the lens is significantly thickened. Electron microscopy examination also showed significant swelling of lens fibers and widening of fiber gaps.

　　【 Model Evaluation and Application 】 Using indoor ultraviolet diffuse irradiation to create a model for guinea pigs is simple and feasible, close to the normal conditions for cataract formation in high latitude areas. However, the modeling cycle is long, and animal feeding and management are difficult during the experimental process. The size of the pupil and the irradiation dose are the key factors affecting the success of modeling. High dose direct irradiation saves experimental time and is currently widely used. Suitable for research on age-related cataracts and oxidative damage in cataracts.