Study on the platform development for therapeutics of ophthalmic disease
| Autor: | Pei-Yin Su, 蘇佩吟 |
|---|---|
| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 99 Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries. Chronic oxidative stress and the accumulation of lipofuscin with age in retinal pigment epithelial (RPE) cells play pivotal role in the pathogenesis of AMD. Autophagy is a cellular mechanism involved in the elimination of damaged organelles and long-lived proteins via lysosomal machinery, and impaired autophagy in senescent cells can lead to the accumulation of lipofuscin. Therefore, we aimed to establish a drug-screening platform for identification of compounds which can promote autophagy and decrease lipofuscin accumulation in RPE cells, and can rescue retina from degeneration in experimental animals. The in vitro analyses comprised both phenotypic and functional assays. Monodansylcadaverine (MDC) staining of primary bovine RPE cells treated with Chinese herbal extracts was employed to identify potential autophagy activators, and followed by Western blot for microtubule-associated protein 1 light chain 3 (LC3). Three (ephedrine, ViRa35EH2 and BGSC35E) of 18 different extracts of Chinese herbs studied were chosen and tested by Western blot. All of them are enhanced cellular LC3-II protein expression level. The first part of the functional analyses was photoreceptor outer segment binding/internalization assay. The effects of these 3 extracts on autofluorescence of RPE cells fed with either POS or A2E were then determined. BGSC35E decreased the autofluorescence of POS- or A2E-loaded RPE cells in a dose dependent manner. Furthermore, the mRNA expression of proinflammatory cytokines induced to A2E-mediated photooxidation in RPE cells also decreased significantly upon treatment with these extracts. In our murine model of dry AMD, a sublethal dose of sodium iodate, which target RPE cells specifically, was administered intravenously to induce RPE damage. The animals were then exposed to intense light after the RPE impairment had been demonstrated by electroretinogram (ERG). This model may mimic the pathogenesis of dry AMD better than retinal degeneration caused by either sodium iodate or light damage alone. We fed mice, which was damaged by sodium iodate and light damage on mice made of dry AMD, with BGSC35E 40 mg/kg and 160 mg/kg. After 2 weeks, the mice ERG response became much better than the damage group. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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