Development of medium size animal models with photoreceptor degeneraion and assessment of visual function from these animals for retinal prosthesis studies

人造眼睛或视网膜假体的开发需要动物来测试视网膜假体装置。这些动物眼睛的大小最好接近人眼的大小。为了评估假眼的安全性，可以将其移植到具有健康眼睛的动物身上。但是当考虑到恢复因视网膜退行性疾病而失去视力的患者的视觉功能的可能性时，最好将假体装置移植到同样失去视力的动物身上，以验证视觉功能的任何可能改善。这需要一个感光细胞受损但神经节细胞功能完好的动物模型。在这项研究中，我们试图创建一个中等大小的动物模型，最初是兔子，其中失明是由光感受器细胞退化引起的。为了实现这一目标，执行了以下三个项目。(1)玻璃体内注射特殊药物引起光感受器变性。(2)系统应用特殊药物引起光感受器变性。(3)通过基因操作诱导光感受器变性。我们特别关注了基因操作诱导光感受器变性。在这种方法中，兔子产生了一个突变的视紫红质基因，这是负责人类视网膜色素变性的基因之一。分离了含紫红质基因的家兔基因组克隆，制备了含紫红质基因突变（Pro347Leu突变）的载体。然后，将这种载体注射到受精卵中。这些动物模型可用于视网膜假体的动物实验。

Development of an artificial eye or retinal prosthesis requires an animal on which the retinal prosthetic device can be tested. Preferably, the size of the eye of these animals should be close to the size of the human eye. For an evaluation of the safety of a prosthetic eye, the transplantation can be made into animals with healthy eyes. But when considering the possibility of restoring visual function to patients who have lost vision to degenerative diseases of the retina, it would be preferable to transplant the prosthetic device into animals that have also lost their vision in order to verify any possible improvements in the visual function. This would require an animal model with damage of their photoreceptor cells, but with the ganglion cells still remaining functionally intact. In this study, we tried to create a medium-sized animal model, initially rabbits, in which the blindness is induced by degeneration of the photoreceptor cells. To accomplish this goal, the following three projects were performed. (1)Injection of special drugs into the vitreous body to cause photoreceptor degeneration. (2)Systemic application of special drugs to cause photoreceptor degeneration. (3)Induction of photoreceptor degeneration through genetic manipulation. Especially, we focused on the genetic manipulation to induce the photoreceptor degeneration. In this method, rabbits were produced with a mutated rhodopsin gene, which is one of the genes responsible for the retinitis pigmentosa in humans. The rabbit genome clone which includes the rhodopsin gene is isolated, and a vector including rhodopsin gene mutations (Pro347Leu mutation) were made. Then, this vector was injected into fertilized eggs. These animal models are thought to be useful for animal experiments for retinal prosthesis.