Department of Veterinary Anatomy, Faculty of Veterinary Medicine, University of Nigeria Nsukka, Enugu State, Nigeria.
J Morphol. 2020 Nov;281(11):1446-1455. doi: 10.1002/jmor.21258. Epub 2020 Sep 8.
We studied the morphological characteristics and seasonal changes of the bulbourethral gland of Eidolon helvum in a typical African tropical environment. Forty-eight bulbourethral glands were examined using gross anatomical, histological, histochemical, and ultrastructural techniques during the early rainy, late rainy, and peak dry seasons. The pear-shaped bilateral bulbourethral glands were located extra-abdominally in the inguinal region. Trabeculae from the capsule divided the parenchyma into numerous lobules of tubuloalveolar glandular acini. The mucosa was covered by a simple columnar epithelium consisting up of principal secretory cells, columnar dense cells and basal cells, which were progressively pronounced during the dry season. The principal cells contained eosinophilic granules, which were PAS positive while the dense cells did not show affinity for the stains. The mean gross weights, acini diameters, and epithelial heights were greater during the rainy season than the dry season. Ultrastructural evaluation showed that the cytoplasm of the principal cells contained well-developed Golgi complexes, rough endoplasmic reticulum, mitochondria, and secretory vesicles of varying electron densities and sizes. The secretory vesicles were numerous during the early rainy season, decreased during the late rainy season and were scanty during the peak dry season. The simple columnar epithelium observed during the rainy season was replaced by an undefined stratified epithelium during the dry season, and this was associated with cellular degenerations and regenerations. In conclusion, E. helvum has a typical mammalian bulbourethral gland, with a unique cell type, the dense cell whose functions are not well-understood. The gland exhibits cyclical seasonal variation in structure and secretory activity; being active during the early rainy season (breeding season), and showing the lowest activity during the dry season (non-breeding season). Glandular epithelial cell renewal occurs during the dry season in preparation for the next breeding season.
我们在典型的非洲热带环境中研究了非洲蹄兔的尿道球腺的形态特征和季节性变化。在早雨季、晚雨季和旱季高峰期，使用大体解剖学、组织学、组织化学和超微结构技术检查了 48 个尿道球腺。梨形双侧尿道球腺位于腹股沟区的腹部外。囊的小梁将实质分为许多管状腺泡状腺小叶。粘膜由单层柱状上皮覆盖，由主分泌细胞、柱状致密细胞和基底细胞组成，在旱季逐渐明显。主细胞含有嗜酸性颗粒，PAS 阳性，而致密细胞对染色没有亲和力。旱季时，尿道球腺的总体重量、腺泡直径和上皮高度均大于雨季。超微结构评估显示，主细胞的细胞质含有发育良好的高尔基复合体、粗面内质网、线粒体和大小和电子密度不同的分泌小泡。在早雨季，分泌小泡数量较多，在晚雨季减少，在旱季高峰期稀少。在雨季观察到的单层柱状上皮在旱季被不定形的复层上皮取代，这与细胞变性和再生有关。总之，E. helvum 具有典型的哺乳动物尿道球腺，具有独特的细胞类型，即功能尚未完全了解的致密细胞。该腺在结构和分泌活动上表现出周期性的季节性变化；在早雨季（繁殖季节）活跃，在旱季（非繁殖季节）表现出最低的活性。在旱季，腺体上皮细胞会进行更新，为下一个繁殖季节做准备。
