Topical doxycycline can induce expression of BDNF in transduced retinal pigment epithelial cells transplanted into the subretinal space

Abstract

PURPOSE. To determine whether topical doxycycline (DOX) induces the expression of brain-derived neurotrophic factor (BDNF) by BDNF-transduced retinal pigment epithelial (RPE) cells transplanted into the subretinal space of rats. METHODS. A rat RPE cell line that can express BDNF by exposure to DOX was created (Tet-BDNF-RPE). The expression of BDNF was examined by ELISA, Western blot analysis, and real-time PCR. The expression of BDNF was controlled by exposure to DOX in vitro. Tet-BDNF-RPE cells were transplanted into the subretinal space of rats, and the rats were exposed to constant light 1 day or 1 month after the transplantation. The rats were followed with or without topical DOX and examined electrophysiologically and histologically. RESULTS. The expression of BDNF was upregulated by exposure of Tet-BDNF-RPE cells to DOX in vitro. The optimal concentration for inducing BDNF expression was 0.5 to 1.0 μg/mL DOX. BDNF expression was also increased in vivo by topical DOX after subretinal transplantation of Tet-BDNF-RPE cells. Statistically significant protection of the electroretinogram amplitudes were found 3 days or 1 month after transplantation, and the outer nuclear layer was better preserved 7 days or 1 month after transplantation in the rats treated by 5 or 10 mg/mL/d topical DOX than rats treated by other conditions or shamoperation rats. CONCLUSIONS. The expression of BDNF can be significantly increased by topical DOX after Tet-BDNF-RPE subretinal transplantation. Better photoreceptor protection against phototoxicity was achieved by DOX eye drops after the cell transplantation. Copyright © Association for Research in Vision and Ophthalmology.