Abstract
Abstract: :
Purpose: Preclinical testing has to analyse the bioactivity, safety, and efficacy of a specific compound. Drug tests in animals are costly and time consuming whereas conventional cell culture systems fail to reproduce many important features of an intact tissue, in particular when complex neuronal interactions have to be considered, e.g. in hereditary and age related retinal degeneration, diabetic retinopathy, and glaucoma. To overcome these limitations, we developed an organotypic culture system of the vascularized mammalian retina in which the influence of drugs could be studied in vitro under conditions in which cellular interactions and three–dimensionality of the tissue are preserved during the whole culturing period. Methods: Under sterile conditions the eyes from neonatal rats were enucleated and the retinas dissected free, with or without the adhering retinal pigment epithelium. The entire tissue was transferred onto a polycarbonate membrane of a Costar’s Transwell cell culture insert and maintained in a medium/gas interface with adjusted atmosphere, humidity, and temperature. The medium was changed at regular intervals. Results: Retinas were kept in the organ culture system for up to three weeks, offering the possibility of long–term drug testing with defined concentrations by adding the compounds directly to the medium. To validate the efficiency of a certain compound apoptosis rate, cell viability, LDH, reactive gliosis, and several immunohistochemical parameters were assayed. Exposure to neurotrophic factors showed an enhanced survival and reduced apoptosis rate of neurons. Exposure to ethanol, mimicking conditions of fetal alcohol syndrome, showed an upregulation of GABA and glutamate receptors. Exposure to glutamate induced a dose dependent intoxication that could be rescued by glutamate antagonists. Conclusions: The data obtained under these experimental conditions indicate that our organotypic retinal culture is a valid model for testing drug efficacy and safety on the neuronal retina.
Keywords: retinal culture • drug toxicity/drug effects