Changes in mitotic activity of the corneal epithelium of albino rats cooled at different times of day

Abstract

The effect of moderate hypothermia on mitotic activity of the corneal epithelium of albino rats was studied. The animals were cooled to 28°C by a contact method for 1 h. Cooling was carried out in the early morning (6 a.m.), at noon, and in the evening (6 p.m.). The response of the epithelium to cooling was found to depend on the time of day. The most marked inhibition of mitotic activity (by 14 times) occurred in the afternoon, 3 h after cooling at noon. A tendency toward restoration of normal cell division was observed 6 and 12 h later. The number of mitoses was reduced 3 h after cooling in the evening, but no changes in mitotic activity were discovered 6 and 12 h later. No changes were found 3 and 6 h after cooling in the morning, but 12 h later cell division was inhibited.