Rapid cell death and cell population recovery in mouse skin epidermis after freezing.

Abstract

Abstract Rapid cell death and cell population recovery in mouse skin epidermis were investigated after freezing. 1. 1. All epidermal cells frozen at −40 °C manifest pycnosis immediately after thawing. The pycnotic cells began to disappear after a latent period of 16 hr. All of the frozen cells disappeared within 24 hr, and the frozen skin area manifested ulceration. 2. 2. The repair of ulceration caused by freezing was initiated by the proliferation of epidermal cells located in the nonfrozen periphery of the skin ulcer. The speed of ulcer decrements is constant irrespective of the type of frozen area. 3. 3. Cytokinetically, the decrement of ulcer was achieved by cell proliferation in the periphery of the ulcer accompanied by shortening of the cell cycle. The cell proliferation was restricted to the 1.25 mm width of the hyperplastic zone adjacent to the ulcer. 4. 4. After re-epithelialization of the ulcer, the hyperplastic zone rapidly recovered to normal cellularity, i.e., density.