PURPOSE. To describe the phenotypes of a newly developed Pde6b-deficient rat model of retinal degeneration. METHODS. Pde6b knockout rats were produced by CRISPR-Cpf1 technology. Pde6b knockout rats were evaluated for ocular abnormalities by comparison with wild-type eyes. Eyes were imaged using fundus photography and optical coherence tomography (OCT), stained by hematoxylin and eosin (H&E), and examined by TUNEL assay. Finally, eyes were functionally assessed by electroretinograms (ERGs). RESULTS. Pde6b knockout rats exhibited visible photoreceptor degeneration at 3 weeks of postnatal age. The fundus appearance of mutants was notable for pigmentary changes, vascular attenuation with an irregular vascular pattern, and outer retinal thinning, which resembled retinitis pigmentosa (RP) in humans. OCT showed profound retinal thinning in Pde6b knockout rats; the outer nuclear layer (ONL) was significantly thinner in Pde6b knockout rats, with relative preservation of the inner retina at 3 weeks of postnatal age. H&E staining confirmed extensive degeneration of the ONL, beginning at 3 weeks of postnatal age; no ONL remained in the retina by 16 weeks of postnatal age. Retinal sections of Pde6b knockout rats were highly positive for TUNEL, specifically in the ONL. In ERGs, Pde6b knockout rats showed no detectable a-or b-waves at 8 weeks of postnatal age. CONCLUSIONS. The Pde6b knockout rat exhibits photoreceptor degeneration. It may provide a better model for experimental therapy for RP because of its slower progression and larger anatomic architecture than the corresponding mouse model. Further studies in this rat model may yield insights into effective therapies for human RP.
Bibliographical noteFunding Information:
Supported by grants from the Ministry of Health & Welfare (HI15C2599, 2016; JYL), and Korea Mouse Phenotyping Project (NRF-2013M3A9D5072551; KYS) of the Ministry of Science and ICT through the National Research Foundation and Asan Institute for Life Sciences (2018-484; JYL), Asan Medical Center, Seoul, Republic of Korea. Disclosure: J.H. Yeo, None; B.K. Jung, None; H. Lee, None; I.-J. Baek, None; Y.H. Sung, None; H.-S. Shin, None; H.-K. Kim, None; K.Y. Seo, None; J.Y. Lee, None
The authors thank the core facilities of Genetically Engineered Animal Research (GEAR) and Mammalian Genetics (MG) at the ConveRgence mEDIcine research center (CREDIT), Asan Medical Center, for the use of their shared equipment, services, and expertise. Supported by grants from the Ministry of Health & Welfare (HI15C2599, 2016; JYL), and Korea Mouse Phenotyping Project (NRF-2013M3A9D5072551; KYS) of the Ministry of Science and ICT through the National Research Foundation and Asan Institute for Life Sciences (2018-484; JYL), Asan Medical Center, Seoul, Republic of Korea.
© 2019 The Authors.
All Science Journal Classification (ASJC) codes
- Sensory Systems
- Cellular and Molecular Neuroscience