动物造模,药效评价,视网膜 z-bio 2024-09-03 467

　　Inducing retinal diseases involves the use of drugs or physical methods to alter the structure of the retina, resulting in conditions similar to human retinitis pigmentosa. The animal model of RP disease induced by physical and chemical factors is simpler to operate and more effective than the genetically modified RP model. Here, we introduce the commonly used N-ethyl-N-nitrosourea (ENU) - induced RP disease animal model.

　　ENU is a powerful mutagen that can transfer ethane groups to the oxygen or nitrogen atoms of DNA bases without relying on metabolic processes. It can cause high-frequency point mutations in DNA, leading to genetic abnormalities in the retina and optic disc. It can induce mutations in genes such as Pde6b, Roml, Pax6, Mitf, Egr, etc., causing eye or visual abnormalities. Hart et al. applied ENU to mice and discovered 7 new point mutations in Pde6b, causing photoreceptor death. ENU induces Rom1 gene mutation, leading to disruption of the outer disc membrane and degeneration of photoreceptor cells.

　　The ENU induced RP model has good reproducibility. At present, C57BL/6J and BALB/cAnN mice are frequently used for modeling. Select 8-10 week C57BL/6J male mice and inject 85-100 mg/kg of ENU intraperitoneally twice a week. After screening for eye diseases, mice with retinitis pigmentosa were mated with wild-type female mice in a sterile environment to produce the first generation (F1) offspring. Mating F1 male mice with wild-type female mice, and then backcrossing F2 female mice with F1 male mice, the F3 mice obtained were used for large-scale eye screening to obtain an animal model of hereditary retinitis pigmentosa.

　　[Model features] ENU induced Rom1 mutation had similar retinal structure to the control group at 3 weeks, the outer nuclear layer was 1/3 of the control group at 7 weeks, and only 1-2 layers of the outer nuclear layer remained at 35 weeks. ENU induced Pde6b mutant mice were identified as Pde6b gene by capillary electrophoresis and DNA sequencing methods. Pde6b mutant mice were found to have dynamic vision between 25 days and 10 weeks after birth through cage transfer detection. Pde6b mutant mice showed almost complete death of rod photoreceptor cells after 17 days.

　　[Model Evaluation and Application] ENU induced ophthalmic diseases require whole genome screening in addition to fundus screening and visual function examination to determine the pathogenic genes. The ENU induced RP animal model has a high incidence and good repeatability, but it is difficult to predict the incidence rate of specific genes. The animal model of genetic retinitis pigmentosa induced by ENU overcomes the limitations of spontaneous retinal genetic diseases, and provides a pathway for artificially simulating human genetic RP diseases.