THE UTILIZATION OF SOME CARBOHYDRATES BY IN VITRO CULTURED CHICK BLASTODERMS IN WOUND HEALING

¹ Department of Zooloqy, University of Minnesota, Minneapolis, Minnesot

1. Wounds produced in the pellucid area of chick embryos cultured on a non-nutrient medium failed to heal within 20 hours. Although there was little or no change in the dimensions of the holes after 8 hours, differentiation of the head region continued beyond this time.

2. On media of 100 mg%, 50 mg% and 10 mg% glucose the blastoderms healed, for the most part, within 8 hours, while development continued in the embryo proper. On a medium containing glucose in concentration of 5 mg%, however, about one half of the wounds did not heal, correlated with degenerative changes in the embryos, principally at the node, occurring between 8 and 20 hours after injury.

3. Fructose and galactose were found to be quite ineffective as carbohydrate sources for the closure of wounds and for development in general. Results using these media were comparable to those when 5 mg% glucose was utilized.

4. By pretreating the blastoderms for 5 and 10 hours on saline-agar prior to wounding, with subsequent transfer to media containing glucose, it was determined that 5 mg% glucose was approximately the minimal concentration required by the embryo for wound closure.

5. In view of the observation that embryonic development continued beyond the time when healing stopped, and because it was assumed that more carbohydrate must be required for the former to take place, it was postulated that there is a greater concentration of endogenous substrate localized in the axial tissues than in the outlying pellucid region.