Histology, histochemistry and fine structure of the Harderian gland, lacrimal gland and superficial gland of the third eyelid of the European bison, Bison bonasus bonasus (Artiodactyla: Bovidae)

ABSTRACT

The macroscopic anatomy and the microscopic and ultrastructural features of the Harderian gland (HG), lacrimal gland (LG) and superficial gland of the third eyelid (SGTE) of the adult European bison are described. In addition, morphometric studies were conducted and were followed by statistical analysis of the results. Tissue sections were stained with hematoxylin and eosin, methyl green-pyronin Y, periodic acid-Schiff, Alcian blue pH 2.5, aldehyde fuchsin and Hale's dialysed iron. Analysis of the staining showed that the HG has a multilobular tubuloalveolar structure with mixed secretion. The LG and the SGTE have a multilobar tubuloacinar structure with serous secretion in the LG and mucoserous in the SGTE. The TEM study demonstrates that the secretory cells of the HG, LG and SGTE have similar ultrastructural appearance, with two types of secretory vesicles in the cytoplasm of all studied glands. The histochemical staining methods and the TEM study revealed the secretory activity in the HG, LG and SGTE ducts. The structural studies can be important for establishing relations between morphological structure and functions of these glands. It can have clinical implications especially when taking into consideration the protective mechanisms of the eye.(AU)