Embryonic Fibroblast-Conditioned Medium Enhances Viability and Proliferation of Chick Circulating Primordial Germ Cells (cPGCs) in Suspension Culture

Abstract

Primordial germ cells circulating in the embryonic vascular system (cPGCs) were isolated from 2.5-day-old chick embryos and cultured individually in suspension for 5 days in embryonic stem-cell medium (ESM) adjusted to pH 8.0 supplemented with fetal bovine serum. Most cells died within 5 days, during which time only a few cells (16-23%) underwent mitosis once, and only a very few cells (less than 3%) twice. The use of conditioned medium (CM) derived from embryonic fibroblasts enhanced the viability and proliferation of the cPGCs, resulting in survival of up to one-third of the cells for 5 days. A fraction of the cells (3-5%) even divided 3 times. The in vitro cultured cPGCs maintain the capacity to migrate into the gonadal area. The chick cPGCs cultured in vitro for up to 5 days in the CM produced germ-line chimeras upon injection into the bloodstream of 2-day-old quail embryos.