Effect of traction on the vasculature of chorioallantoic membranes of chick embryos.

In order to investigate the effect of traction of the vasculature on induction or acceleration of neovascularization, the chorioallantoic membranes (CAMs) of the developing chick embryo were placed under tension with 10-0 nylon sutures and subsequently examined histologically. In the initial phase of the study, CAMs from 6- to 8-day-old chick embryos were placed under traction and sampled serially. The cell proliferation and migration from the ectoderm to the mesoderm were observed from half a day to 3 days after the initiation of traction, and increase in the density of the mesodermal vessels was initially observed after 3 days. In the second study, CAMs from embryos at each age from 7 to 16 days were placed under traction and sampled after 1 day. As the CAMs developed, the ectodermal cell proliferation and migration decreased. This may be related with the increase of desmosomes among the ectodermal cells during the CAM development. The above results suggest that traction can induce the changes of the vasculature, and the effect of traction varies with the development of CAMs.