Growth of Embryonic Mammalian Cartilage after Freezing

Abstract

SINCE the discovery that glycerol will protect cells and tissues against freezing damage¹, considerable progress has been made in developing techniques for the preservation of tissues at very low temperatures. Attempts to establish low-temperature banks of adult human cartilage have unfortunately, so far, proved unsuccessful². Biggers³, however, was able to show that embryonic chick tibiæ will grow and differentiate in vitro, after freezing to −79 ° C., in saline containing 15 per cent glycerol. This communication describes briefly some of the work concerned with freezing embryonic rat tibiæ to −79° C. A fuller account is being given elsewhere⁴. Rat fœtuses of a known age were obtained from the Medical Research Council strain of albino rat, bred in the Department. The occurrence of a vaginal copulation plug, or the presence of sperm in the vaginal smear, was taken as the indication of mating. On the seventeenth day post coitum, the conceptuses were excised, and the embryonic tibiæ were isolated under a dissecting microscope. The bones were cleaned of as much extraneous tissue as possible, with care to avoid injuring the perichondrium. The structure of these tibiæ is being described elsewhere⁵.