A preliminary study of the heterogeneity in endometrial morphology and glycosylation in the uterine horns of the non-pregnant impala (Aepyceros melampus)

Abstract

Placentation commences only in the right uterine horn in impala (Aepyceros melampus). To investigate possible differences in morphology or glycosylation between the two horns, right and left uterine horns from six non-pregnant, wild impala were examined morphometrically and histochemically using a panel of 23 lectins and an avidin-biotin revealing system. The presence of ovarian 3ß hydroxysteroid dehydrogenase (3ßHSD) and aromatase was also investigated using immunocytochemistry. There were few detectable differences in morphology and glycosylation between right and left uterine horns in five of the specimens, but the sixth had deep clefts and plentiful exocrine secretions in the right horn, and not the left. Heavily glycosylated clusters of supranuclear granules were present in the epithelial cells, which had many classes of O-linked glycans. The serum progestagen was not markedly different, however, from that of the other specimens. In five of the six specimens, the height of luminal epithelium was greater on the right than that on the left, and the height of the gland epithelium was also greater on the right side in four of these. The 3ßHSD and aromatase activities were present in the ovaries and were similar in impala with or without progestagen concentrations >1 ng/ml in peripheral blood. No corpus haemorrhagicum or corpus luteum could be discerned. These findings indicate there are morphological and biochemical differences between right and left uterine horns in the impala and further studies are needed on both impala and other species in which placentation commences only in one uterine horn, to establish the cyclical hormone changes which induce them.