Comparative morphometric and glycohistochemical studies on the epididymal duct in the donkey (Equus asinus) and dromedary camel (Camelus dromedarius)

The present study was undertaken to compare morphometric and glycohistochemical differences in the epididymal duct of the donkey and the dromedary camel. Paraffin-embedded sections from the different regions of the duct (caput, corpus and cauda) of both species were stained conventionally for general histology and histomorphometry and also with fluorescein isothiocyanate (FITC) conjugated lectins for glycohistochemical mapping. Morphometric data (means ± SE) showed that the luminal diameter was widest (1029.76 ± 15.04 μm) in the donkey cauda and narrowest (179.80 ± 3.27 μm) in the camel corpus. The thickness of the peritubular muscle coat had the highest (74.32 ± 1.85 μm) and the lowest (24.32 ± 0.74 μm) values in the donkey cauda and corpus respectively. The greatest (94.44 ± 2.08 μm) and the least (21.48 ± 0.66 μm) values of epithelial height were reported respectively in the camel caput and in the donkey cauda. The length of stereocilia of principal cells in the camel was greatest (21.88 ± 0.57 μm) and lowest (6.68 ± 0.28 μm) in the caput and cauda. Binding sites for only six out of eight lectins could be found. The distribution pattern of binding sites of different lectins showed significant variations in both a species-specific and also region-specific manner. Distinct labeling was found in the Golgi zone, apical cytoplasm and on stereocilia of principal cells in the camel (WGA and DBA) and donkey (DBA) caput region, while other lectins exhibited variable reactivity in the other regions in both species. The basal cells showed variable binding to most of the lectins, however, they displayed distinct binding to WGA and PSA throughout the duct in camel and donkey respectively. In conclusion, both morphometric and glycohistochemical findings displayed regional species-specific and potentially functional relevant characteristics.