engleski

Development of the Fetal Neural Retina in Vitro and in Ectopic Transplants in Vivo

Investigation of the developmental potential of immature tissues is important for novel approaches to human regener- ative medicine. Development of the fetal neural retina has therefore been investigated in two experimental systems. Ret- inas were microsurgically isolated from W-days-old rat fetuses and cultivated in vitro for 12 days or transplanted in vivo under the kidney capsule of adult males for as long as 6 months. Shedding of the photoreceptor outer segment which is a process occurring at the terminal stage of photoreceptor differentiation was observed in culture by transmission electron microscopy (TEM). In transplants, no photoreceptors were found although markers of terminal neural and glial differ- entiation (e.g. synaptophysin, chromogranin and glial fibrilary acidic protein - GFAP) along with the molecules in- volved in the process of differentiation (guidance molecule semaphorin IIIA and chondroitin sulfate proteoglycan) were expressed. Semaphorin was differentially expressed being absent from older transplants. Proliferating cell nuclear anti- gen and nestin (marker of undifferentiated neural cells) were still weakly expressed even in six-months-old transplants. We could conclude that in both our experimental systems fetal neural retina proceeded to differentiate further on. How- ever, even in long-term ectopic transplants a small population of cells still retained the potential for proliferation and has not yet reached the stage of terminal differentiation.

rats; retina; fetal tissue transplantation; in vitro

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