Autoradiographic study using 3H-thymidine on rat incisal pulp cells in vitro.

An autoradiographic study using 3H-thymidine (3H-TdR) was carried out to investigate which cells migrate from the pulp explant of the rat incisor in vitro. The cells close to the arterioles (perivascular cells) were especially labeled after 3H-TdR incubation following the dissection of the pulp explant. In tracing these 3H-TdR-labeled perivascular cells, about 15 per cent of the outgrowth cells were the perivascular cells after 2 days of culture and these perivascular cells had a high mitotic activity in vitro. On the other hand, it was ascertained that the odontoblasts in the pulp explant underwent necrotic changes and that the odontoblasts had no ability to migrate from the pulp explant.