Physiological effects of hypoxia and trypan blue in 17-day chick embryos.

Seventeen-day chick embryos were divided into 5 groups and treated as follows: (1) untreated, (2) yolk-sac injected with 0.1 ml of saturated trypan blue solution solution in sterile saline, (3) saline, (4) hypoxia, i.e., 10.5% oxygen, and (5) hypoxia plus trypan blue. After 5 h hypoxia-treated embryos had an increased mortality rate, severe hypoglycemia, reduced blood pH, elevated plasma potassium, and reduced CO2 content. Trypan blue treatment induced few deaths and few physiological imbalances. Hypoxia plus trypan blue was without synergistic effects and had effects that did not differ significantly from hypoxia alone. This lack of response of 17-day chick embryos to high doses of trypan blue may be related to a marked decline in oxygen consumption by the yolk at this age.