Organotypic retinal cultures constitute a useful tool to perform preclinical drug testing. The aim of the present study was characterize the morphologic changes in macro- and microglial cells in this culture system.Methods
Retinas were isolated from 7-day-old Crl:CD(SD) rats with the retinal pigment epithelium attached. Retinal explants were cultured for 4, 10, and 14 days (DIV4, DIV10, and DIV14). Cryosections and whole-mounts of age-matched control and cultured retinas were used to analyze macro- and microglial cells by immunostaining using antibodies against GFAP, vimentin and CD11-b.Results
In comparison with in vivo, in DIV4 and DIV10 cultures, GFAP-positive astrocytes were more robust, the astrocytic network being thicker in some retinal areas while in other regions astrocytes were sparsely distributed. Few thin GFAP-positive astrocytes were observed at DIV14. Müller cells in the cultures exhibited GFAP up-regulation in comparison with in vivo retinas. CD11-b+ microglial cells at DIV4 and DIV10 showed more robust somas and thicker and more retracted processes than in vivo. Overall, at DIV14 CD11-b+, microglial cells exhibited a rounded morphology.Conclusion
In rat organotypic culture both macro- and microglial cells showed progressive changes: i) reactive macrogliosis, ii) rearranged astrocytic distribution, iii) GFAP up-regulation in Müller cells, and iv) microglial activation. Given that this glial response is a hallmark of several retinal diseases, organotypic retinal culture is a valuable resource for future investigations in retinal degenerative processes and therapy.