Porcine submandibular glands as potential salivary gland experimental models: histological, immunohistochemical, and ultrastructural characterization.

Salivary glands play an essential role in oral homeostasis by producing saliva, which protects oral tissues and maintains the oral environment. Despite growing interest in porcine models for translational biomedical research, the immunophenotypic characterization of porcine salivary glands remains limited in the literature, with few studies addressing their cytokeratin and contractile protein expression profiles. This gap constrains the ability to directly compare porcine and human glandular phenotypes and hinders the establishment of the pig as a validated salivary gland experimental model. This study evaluates the histological, immunophenotypic, and ultrastructural features of porcine submandibular glands as potential experimental models. Submandibular glands from 11 pigs aged 3 to 6 months (average weight: 20 kg) were examined histologically using hematoxylin and eosin staining and ultrastructurally by transmission electron microscopy, and phenotypically via immunohistochemistry for key markers such as CK5, CK7, CK19, SMA, calponin, caldesmon and S-100. Porcine submandibular glands exhibit a lobular organization akin to human glands, with mucous acinar cells, intercalated and excretory ducts, and rich vascularization. Immunohistochemistry revealed cytokeratins in epithelial cells and contractile proteins in myoepithelial cells, mirroring human glandular markers. Ultrastructural analysis highlighted robust cellular junctions, myoepithelial support, and intricate nerve fiber networks essential for glandular function. The structural and phenotypic parallels between porcine and human submandibular salivary glands provide a descriptive basis supporting their potential use in comparative salivary gland research.