Ultrastructural morphology of goblet cells of the conjunctiva of dogs

Abstract

Objective: To describe the morphology of goblet cells of the eyelid conjunctiva in dogs using transmission and scanning electron microscopy. Animal studied: Ten dogs, both male and female of different breeds, with no ocular changes were examined (20 eyes). Procedures: Ten samples of conjunctiva were collected and processed for scanning and transmission electron microscopy (SEM and TEM), while another 10 samples were stained with Schiff's periodic stain (SPA) and alcian blue, pH 2.5, and analyzed using light microscopy. Results: Scanning electron microscopy revealed several points of mucus extrusion in the free apical portion of the goblet cells as well as a wide distribution of lymphoid follicles and macrophages intermingling with the microvilli of palpebral epithelium cells. TEM revealed normal goblet cells that were predominantly oval with wide cytoplasm of different diameters, and large vesicles with heterogeneous granules and free edges, suggesting the release of mucus content onto the conjunctival surface.Cytoplasmic organelles, such as the Golgi apparatus, endoplasmic reticulum, and a high number of mitochondria were also observed. All the samples were positive for SPA and alcian blue staining. Conclusion: This is the first study to evaluate the goblet cells of the eyelid conjunctiva in healthy dogs using electron microscopy techniques. These results are useful for comparing the palpebral conjunctiva of dogs without ocular changes to palpebral conjunctiva of dogs and other species with ocular changes. K E Y W O R D Sdogs, electron microscopy, goblet cells, keratoconjunctivitis sicca, ocular surface How to cite this article: Araújo RLS, Corrêa JR, Galera PD. Ultrastructural morphology of goblet cells of the conjunctiva of dogs. Vet Ophthalmol.

Morphological and ultrastructural study of the palpebral conjunctiva of healthy domestic cats

“…The secretory vesicles identified in the cell cytoplasm were globular and bulged, with homogeneous content (Figure 3C), in which granules were not identified, unlike the description of this cell type in dogs. 9 The high concentration of mitochondria and segments of the endoplasmic reticulum in the cellular cytoplasm (Figure 3D) matches the energy demand of secretory cell types. 13 It is noteworthy that the comparison of the cell contours between the studies must consider the arrangement of the tissue at the time of the cut.…”

“…The morphological description of goblet cells by electron microscopy has been reported in humans, 8 dogs, 9 and laboratory animals 4,10,11 . Like other species, a high concentration of goblet cells was observed in the lower nasal fornix region, as described in cats, 6 dogs, 9 rats, 10 and humans 12 …”

“…As visualized by SEM, the evaluation by TEM showed the grouping of goblet cells in the epithelium of the palpebral conjunctiva of cats (Figure 3), which predominantly presented with a more rounded contour. The secretory vesicles identified in the cell cytoplasm were globular and bulged, with homogeneous content (Figure 3C), in which granules were not identified, unlike the description of this cell type in dogs 9 . The high concentration of mitochondria and segments of the endoplasmic reticulum in the cellular cytoplasm (Figure 3D) matches the energy demand of secretory cell types 13 .…”

“…[1][2][3]7 Unlike other sebaceous glands, meibomian glands do not have direct contact with hair follicles and are lined by stratified epithelium, similar to the skin epidermis, except for the absence of a granular layer. 1,2 The morphological description of goblet cells by electron microscopy has been reported in humans, 8 dogs, 9 and laboratory animals. 4,10,11 Like other species, a high concentration of goblet cells was observed in the lower nasal fornix region, as described in cats, 6 dogs, 9 rats, 10 and humans.…”

“…Therefore, loss of goblet cells can result in ocular surface diseases. 5,6 Araújo et al 9 examined canine conjunctival tissue using SEM and described a homogeneous surface formed by fair put hexagonal cells and the presence of microvilli in the apical portion of the epithelial cells, interspersed with several points of mucus extrusion, released in small fusiform vesicles by the free edges of goblet cells.…”