engleski

TRANSPLANTATION OF THE RAT FETAL NEURAL RETINA TO AN ECTOPIC SITE IN VIVO

Fetal neural retina of the rat can differentiate in vitro in a three-dymensional organ culture model with chemically defined culture medium, although the normal tissue architecture is lost and rosettes are formed (Bulić-Jakuš et al., 2000). To investigate the developmental potential of the fetal neural retina in an ectopic site in vivo, transplantation under the kidney capsule was performed. Neural retinas were isolated from 20-days-old Fischer rat fetuses under the dissecting microscope. Adult Fischer males were anaesthetized with ether and the skin and muscle cut to approach the kidney. A small "pocket" was done under the kidney capsule to place the transplant. Each rat received one transplant. After 50 days, transplants were fixed and histologically processed. Indirect immunohistochemistry on 5ľm thick slides was applied for detection of various antigens. Primary antibodies were: goat polyclonal anti-Sema3A antibody ; CS-56, mouse monoclonal IgM anti-chondroitin sulfate ; monoclonal anti-PCNA. Biotinilated anti-goat and anti-mouse secondary antibodies for immunoperoxidase staining were used respectively from Vectastain ABC kit following the manufacturer's protocol. 3, 3-diaminobenzidine with metal enhancer was used for visualization of positive signals. In transplants, retinal cells forming rosettes were detected. Among them, few cells expressing strongly the proliferating cell nuclear antigen (PCNA) were found. Semaphorin IIIA, a guidance molecule, was scattered throughout the tissue in a punctiforme manner. Sometimes it was found to decorate cells. Chondroitin sulfate was positive in the cell cytoplasm and in the extracellular matrix. Fibronectin was absent from the retina but was found in the kidney capsule. These results show that even after the period of 50 days, in neural retina transplants which have lost their normal cell interactions, some cells are proliferating and therefore still contained in the cycling compartment.

neural retina; transplantation; growth; differentiation

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