Lemiaa Eissa; Rasha B. Yaseen; Abdelrahman M. A. Elseory; Thnaian A. Al-Thnaian & Mortada M. O. Elhassan

The infundibulum of the uterine tube provides a highly specialized microenvironment essential for oocyte capture, fertilization, and early embryonic development. In the dromedary camel (Camelus dromedarius), adaptation of this segment to environmental stress is mediated by coordinated structural and cytoskeletal modifications. However, the cellular basis of these adaptations remains insufficiently understood. This study investigated the histological organization, cytoskeletal protein distribution, and ultrastructural characteristics of the infundibulum. Tissue samples from nine adult non-pregnant camels were examined using routine histology, periodic acid–Schiff (PAS) histochemistry, immunohistochemistry for vimentin, desmin, and smooth muscle actin (SMA), and transmission electron microscopy. Histological results showed extensive hierarchical folding of the mucosa, lined by a simple columnar epithelium. This epithelium was composed of ciliated and secretory cells. Strong PAS reactivity in secretory cells was identified. Immunohistochemically, vimentin immunoreactivity was predominantly localized to non-ciliated epithelial cells and the vascular endothelium, supporting a role in epithelial stability and stromal organization. Desmin and SMA were strongly expressed in the tunica muscularis, with extensions into the cores of primary mucosal folds. Ultrastructurally, the secretory cells showed abundant rough endoplasmic reticulum, a prominent Golgi complex, and electron-dense granules. Ciliated cells contained numerous mitochondria, consistent with sustained ciliary activity. Apical cytoplasmic blebbing in secretory cells suggested an apocrine-like mode of secretion. In conclusion, the infundibulum of the camel oviduct shows coordinated changes in its lining cells and structural proteins, resulting in the integration of secretion, mechanical strength, and contractile areas. These structural features are likely important for successful reproduction under challenging environmental conditions.

KEY WORDS: Camelus dromedarius; Infundibulum of uterine tube; Cytoskeletal remodeling; Epithelial specialization; Immunohistochemistry; Transmission electron microscopy.

EISSA, L.; YASEEN, R. B.; ELSEORY, A. M. A.; AL-THNAIAN, T. A. & ELHASSAN, M. M. O. Histological and cytoskeletal specialization of the infundibulum of the camel uterine tube: structural adaptations for reproductive function. Int. J. Morphol., 44(4):1337- 1349, 2026.