Early regenerative responses of amputated limbs of the newt, Notophthalamus viridescens to culture conditions

Abstract

Newt forelimbs were removed at the shoulder, amputated slightly proximal to the elbow, and explanted to a gelled medium which was based on chick embryo extract, Holtfreter's salt solution, water and agar. In some groups this medium was supplemented with a porcine STH preparation or cortisone or both. Limb stumps were explanted either with the short segment of spinal cord bearing spinal nerves 3, 4 and 5 intact, or the nerves were cut and no nerve cell bodies were included in the explant. Stumps on medium supplemented with the STH preparation showed better maintenance of the epidermis, otherwise no consistent differences were noticed between any experimental groups during the culture period of 8 or 10 days. Both cultured and in vivo stumps showed distal closure by epidermis, which became thickened and demonstrated phagocytic activities. Muscle, also in both cases, either retained the appearance of the normal tissue, or underwent dissolution to block-like fragments with nuclei resembling those of blastema cells.