[Modeling mechanism] The Royal College of Surgeons (RCS) rat is an autosomal recessive genetic animal model. CS rat retinal pigment epithelial cells (retinal pigment epithelium, RPE) express genes that cannot swallow discrete patches. This leads to the loss of photoreceptor cells after the rat is born. Recessive gene mutations in CS rats have been shown to exist in the Mertek gene of receptor tyrosinase, which is mainly expressed in retinal RPE. This deletion mutation occurs after frameshift and open reading frame (ORH) initiation. The signal at codon 20 is terminated prematurely, RPE cells cannot swallow a separate patch, and this mutation is also present in human retinitis pigmentosa (RP).
[Characteristics of the model] Histological observation of the retina of RCS rats showed that the external debris between the outside of the photoreceptor cells and the retinal pigment epithelium was abnormally aggregated. The appearance is normal at 2 weeks of age, and degeneration of the outer retinal nuclear layer begins 20 to 30 days after birth. After 8 weeks, RPE cells in the posterior pole began to be lost. Ten weeks after PE disappeared, capillary endothelial cells became thicker. , The endothelial window disappears; this degeneration and apoptosis process can last up to 3 months of age. Mutations in CS rats caused progressive apoptosis of rod-shaped cells, followed by pyramidal cells. Some retinal pigment epithelial cells adjacent to degenerated photoreceptors are taller than normal RPE cells of the same age, with significantly increased basal surface folding and increased cytoplasmic mitochondria. After 8 weeks, the RPE cells in the posterior pole began to be lost. When the RPE was lost for 10 weeks, the capillary endothelial cells became thicker and the endothelial window disappeared. Multiple centers of this degenerative change occur in different parts of the retina.
[Model Evaluation and Application] CS rat is the first animal model used to study the etiology and treatment of RP. RP is a more mature animal model of retinal degeneration and has many similarities with human RP. .. This model is widely used in the study of retinal degeneration and experimental treatments aimed at slowing down the process of photoreceptor cell loss.