Changes in the weight, collagen concentration and content of the uterus and cervix of the ewe during pregnancy

Abstract

The dry and wet weights of the uterus (caruncular and intercaruncular areas) and cervix were measured in non-pregnant (n = 5) and pregnant (n = 25) ewes post mortem; for the latter, five were obtained for each of the 5 months of gestation. The total collagen tissue content was measured in both areas of the uterus and cervix by hydroxyproline analysis and image analysis of Haematoxylin-Van Gieson stained tissue sections. Both wet and dry uterine weights increased significantly with gestational age (P < 0·001). The water content of uterine and cervical tissue remained constant, at between 83 per cent to 85 per cent and 76 per cent to 80 per cent, respectively. There was a close correlation between the two methods used to determine the collagen content (r = 0·96, P < 0·001), and between the increasing weight of the uterus during pregnancy and the total collagen content of tissues (r = 0·97, P < 0·001). At all stages, the total collagen content of the cervix [mean (SEM) 96·2 (5·4) mg g–1] was significantly greater (P < 0·001) than that of the caruncular mean [mean (SEM) 24·3 (1·4) mg g–1], and the intercaruncular areas [mean (SEM) 29·0 (1·0) mg g–1]. The changes in uterine and cervical weights and collagen content of the tissues were similar to those reported in other related species.