Capability of neurite regeneration of rat retinal explant at different ages

Neurite regeneration from central nervous tissue of mammalian has been demonstrated to occur in early postnatal stage but not in adult stage. To answer when the retinal explant of rat loses the neurite regeneration in vitro after birth, we have used tissue culture to study the neurite regeneration of retinal explant of Wistar rat at different ages. The retinal explants from rat at first postnatal day, 3rd postnatal day, one week, two weeks, three weeks, four weeks old and of the adult were put in tissue culture to observe the neurite growth after four-day incubation. The neurites were also identified by immunochemical staining using monoclonal antibody to neurofilament. The capability of neurite regeneration of retinal explant was decreased with the passage of time after birth, and it was lost after two weeks old. The age of losing retinal regenerative capability coincides with that of eye opening and retinal maturation of Wistar rat (15th-18th postnatal day, mean 16.2 +/- 1.3 days). These results indicate that when the development of retina has been completed, it will lose the capability of regeneration in vitro.