Effects of 2,2',5,5'-tetrachlorobiphenyl (PCB52) on migration of chicken primordial germ cells

Polychlorinated biphenyls cause developmental and physiological anomalies in the reproductive system. This study investigated the effects of 2,22,5,52-tetrachlorobiphenyl (PCB52), which can produce oestrogenic effects on the homeostasis of chicken primordial germ cells from the initial stage until completion of their settlement in the gonadal primordium. The blastoderm of chicken embryos was injected with 1 (1/4)L PCB52 (10 micromol/L) and oestradiol (100 micromol/L) before incubation, and the number of primordial germ cells was determined during their migration and development. The number of primordial germ cells in germinal crescents in PCB52-treated groups was slightly decreased (P = 0.068), but it was reduced significantly at stages 13-15 and 28-30 (P < 0.01, respectively) compared with controls. No obvious effects on primordial germ cell migration were observed with oestradiol treatments. The present results suggest that the influence of PCB52 on chicken primordial germ cell migration and proliferation may be via its toxic effect, not its oestrogen-mimicking effect, and provide information on the sensitivity of primordial germ cells to the direct action of PCB52.