Characterization of glycoconjugates in the secretory epithelium of the equine ampulla ductus deferentis

The present work was undertaken to determine the glycoconjugates secreted by the epithelium of the equine ampulla ductus deferentis, using conventional (PAS, AB pH 2.5, AB pH 1.0) and lectin histochemical procedures in conjunction with enzymatic digestion and chemical treatment. The presence of abundant apical cytoplasmic blebs suggests that the equine ampulla secretes its products mainly in an apocrine manner. Glandular cells secrete neutral and acidic sialylated glycoconjugates as revealed by conventional histochemical procedures. Lectin histochemistry helped us to discover the following histological positive sites: the mucosal cells, the glandular epithelial cells, the apical cytoplasmic blebs and the basal cells. The ampullary secretions contained both glycoproteic material (revealed by Con-A-, LCA-, GSA-II-, WGA-, RCA-I- positivity) and sialomucins (evidenced by the reactivity of GSA-II, SBA, PNA and RCA-I after sialidase digestion) having different functional roles. The mucosal cells reacted with Con-A, LCA, and also with sialidase/GSA-II-, SBA-, PNA-, and RCA-I sequences, contributing to the chemical heterogeneity of ampullary secretions. DBA lectin was a specific marker for basal cells. The results obtained were compared with our previous findings regarding the differences in the lectin binding pattern of the plasma-membrane of equine sperm collected from epididymal cauda and the ampulla ductis deferentis. Our results support other studies that indicate that ampullary secretions are involved in altering the plasma-membrane glycoconjugates of spermatozoa, contributing to their maturation.