12th Ljudevit Jurak International Symposium on
Comparative Pathology
June 1-2, 2001

F. Buliæ-Jakuš, G. Juriæ-Lekiæ*, T. Belovari**, S. Mariæ***, D. Ježek*, M. Vlahoviæ, D. Šerman
Department of Biology,  *Department of Histology and Embryology, Medical Faculty, Zagreb, Croatia
**Department of Histology and Embryology,
***Department of Biology, Medical Faculty, Osijek, Croatia
Previously,  it was shown that rat embryonic retina could survive in a chemically-defined medium in vitro (Juri?-Leki? et al. 1994). The aim of this study was to subject such ex-plants to more detailed ultrastructural analysis and to determine the posibility for  survival of isolated rat embryonic retina in subcapsular kidney transplants.
Embryonic neural retina was microsurgically isolated from the eyes of 20-day-old Fisher rat embryos and cultivated in organ culture dishes on a metal grid. Protein-free Eagle’s Minimum Essential Medium was used with no other additives, enriched with transferrin (50?g/ml) or 50% rat serum. After  culture the explants were embedded in Durcopan. For analysis by transmission electron microscope, ultrathin sections were contrasted with lead citrate and uranyl acetate. In the second experiment, isolated 20-day-old embryonic neural retinas were transplanted under the kidney capsule of adult rats. After 7 or 14 days the transplants were fixed in St.Marie fixative, embedded in paraffin and subjected to routine histologycal procedures. Serial sections were stained with HE.
Ultrastructural analysis of neural retina cultivated in vitro confirmed the survival of retinal cells even in the simplest protein-free chemically-defined medium. Although they have lost their normal spatial relationships and rosettes were formed, neural and glia cells could be distinguished. Moreover, in medium with transferrin and in medium with serum, photo-receptors were present. In transplants, similarly as in vitro, embryonic neural retina survived and its cells have lost their normal spatial relationships. Survival of embryonic retina in transplants presents a contrast to previous results with isolated adult rat neural retina which was absorbed after transplantation to the kidney subcapsular space (Juri?-Leki? et al., 1992).
Model for cultivation of mammalian neural retina described here is in line with recent efforts to grow tissues in vitro for purposes such as therapeutical transplantation or for development  of alternatives to in vivo investigation of neurotoxic substances.
  1. Juriæ-Lekiæ, G., Buliæ-Jakuš, F., Vlahoviæ, M., Wiman, K. G., Bygdeman, M. and Klein,G. (1994) : Mammalian neural retina in different experimental systems, Period. Biol. 96, 67-68
  2. Juriæ-Lekiæ G., Buliæ-Jakuš F.(1992): Fate of the retina as an isograft. Ophthalmol. Croat 1 (3): 119-124