Morphologic characteristics of equine endometrium classified as Kenney categories I, II, and III, using light and scanning electron microscopy
Ferreira-Dias, G.; Nequin, L.G.; King, S.S.
American Journal of Veterinary Research 55(8): 1060-1065
1994
ISSN/ISBN: 0002-9645 PMID: 7978644 Document Number: 428725
Pathologic changes in the endometrium of mares may be rated according to Kenney's method of classification. Category I endometrium contains healthy tissue with no or few widely scattered pathologic changes. At the opposite end, severe widespread pathologic changes are associated with category III. Uterine biopsy specimens were collected aseptically from 16 mares during the estrous and diestrous stages of the cycle. Pathologic changes were evaluated, using light microscopy, and endornetrium was classified as Kenney's category I, II or III. Endometrial tissue of category I (n = 5 mares in estrus; n = 3 in diestrus); category II (n = 3 in estrus; n = 4 in diestrus), and category III (n = 4 in estrus; n = 4 in diestrus) were processed for scanning electron microscopy (SEM). All specimens were fixed immediately after biopsy because it was found that numerous bleb-like projections were formed when fixation was delayed. Category I endometrium had normal glands, and fibrotic tissue was not observed by fight microscopy. Scanning electron microscopy revealed numerous hexagonally shaped cells that were covered with many microviui. Ciliated cells also were observed, and they contained long healthy cilia. Category B endometrium had 2 to 4 nests surrounded by collagen fibers. Of the 4 specimens, 3 had moderate leukocyte infiltration (59 +/- 14.8 WBC/4 high-power fields [450X]). Scanning electron microscopy revealed some inflammatory changes with slight swelling of the cell surface. Several cells in category II endometrium lacked microvilli, but they were interdispersed among many healthy hexagonal cells. Many nests were seen in category III tissue, and 2 specimens had severe infiltration of WBC (232,264 cells/4 fields). These 2 specimens appeared to be swollen when examined by SEM. Degenerative changes were more extensive in category III endometrium. Large areas lacked microviui, and some areas had complete loss of the cell boundaries. Numerous holes and ulcer-like formations also were observed on the surface of this type of endometrium. Morphometric analysis of the ciliated cell population indicated no significant difference in the quantity of cells in normal tissue during estrus vs diestrus. Category III tissue had significantly (P < 0.05) more surface damage than did tissue of the other 2 categories. In conclusion, the degree of surface damage observed, using SEM, paralleled the number of fibrotic nests that were seen by light microscopy. The amount of surface swelling was related to the amount of inflammatory infiltration observed by light microscopy.