Delineation of the healthy rabbit tonsil by immunohistochemistry - A short communication.

Situated in the oral cavity, the rabbit palatine tonsils are part of the mucosal immune system and help to defend the body against foreign pathogens. Expressed as two oval protrusions in the wall of the oropharynx, the rabbit palatine tonsils are characterized by excretory ducts and trabeculae. We here compare paraffin embedded and cryosections of the healthy rabbit tonsils. This analysis centers on evaluating the differential outcomes resulting from the application of these fixation methodologies in conjunction with immunohistochemical assays targeting collagen I, collagen III, fibronectin, α-smooth muscle actin (α-SMA), and ki67. Subsequent recommendations are provided based on our findings. Furthermore, we demonstrate the advantage of an antigen retrieval step in immunohistochemical labeling of paraffin sections. Basic classical histological stainings as HE, GT and elastin were also performed. Comparison of different stainings and labelings was furthermore performed in serial sections, showing that adjacent to the excretory ducts, the tonsillar tissue was particularly composed of collagen I and fibronectin, while the vessel walls were predominantly α-SMA positive. Moreover, PAR-2 immunohistochemical staining was performed, where a small fraction of the cells found in the tonsillar connective tissue were PAR-2 positive (probably a subpopulation of mast cells), as well as the lumen of some excretory ducts and trabeculae. Collagen III on the other hand was only weakly expressed in the tonsils. Proliferating ki67 positive cells were rare. This endeavor serves to furnish the scientific community with reference imagery pertinent to researchers opting for the rabbit palatine tonsil model. The diversity of staining techniques employed herein establishes a foundational repository of images, primed for comparative analysis against pathological conditions. Furthermore, these images hold the potential to illustrate inter-species variations. For instance, they can be juxtaposed against murine or rodent tonsils, or even offer insights into the human context.

Identifying stem cells in the main excretory ducts of rat major salivary glands: adventures with commercial antibodies.

We investigated the entire length of the main excretory ducts (MED) of the major sublingual, parotid and submandibular salivary glands of mature laboratory rats for mucous (goblet) and luminal ciliated cells, biomarkers of cell proliferation, apoptosis, and five biomarkers of stem cells. Spleen and testis were used as positive controls. We used formalin fixed, paraffin embedded tissues. No mucous cells or cells with luminal cilia were observed in hematoxylin and eosin, alcian blue or periodic acid-Schiff stained sections. Immunohistochemistry using rabbit anti-rat antibodies produced anomalous reactions with cleaved caspase-3 for apoptosis, Ki-67 for proliferative activity and Sox 2. Following antigen retrieval, no primary antibody and all three negative controls, labeled macrophages appeared in the spleen. TUNEL staining revealed a few cells per section undergoing apoptosis. Reactions deemed valid occurred in MED with cytokeratin-5 and c-Kit and stem cell antigen 1 (Sca-1) mostly in the gland and middle segments. Other ducts, but not acini or myoepithelial cells, also were variably stained with c-Kit and Sca-1.

Regenerative capacity of bone marrow stem cells on aged albino rat's parotid excretory duct.

OBJECTIVE: To appraise structural features of parotid excretory duct during senility and probable effect of bone marrow-mesenchymal stem cells (BM-MSCs). DESIGN: A total of 14 healthy male albino rats were used. Seven adult rats (24-34-week-old) represented the control group (Group I). Seven senile rats (72-80-week-old) were utilized in which the left parotid gland served as "Old" (Group II) and were injected by 0.2 ml phosphate buffered saline; the right side represented "Old treated" (Group III) and got local injection of 1-1.5 million allogeneic BM-MSCs. One month later, glands were dissected and assessed structurally, ultra-structurally and statistically. RESULT: Histologically, Group I showed normal duct histology. In Group II duct lining lost its pseudostratification which was recovered in Group III. PCNA immunolocalization showed moderate reactivity in Group I, negative to mild reaction in Group II, and strong reaction in some of Group III cells. Ultra-structural features of Group I were ordinary in which basal cell had a large flat nucleus, and dark and light cells showed electron-dense cytoplasm and electron-lucent cytoplasm respectively. Tuft cell displayed long microvilli. Mucous droplets filled goblet cell. Group II revealed an apparent reduction in cells size, organelles and absence of tuft cell. In Group III all cell types were detected and they recovered their organelles, cell and nucleus shape. The highest mean area% of PCNA immunoreactivity was in Group I followed by Group III then Group II. CONCLUSIONS: Aging has a deteriorating effect on structure and ultra-structure of parotid gland excretory duct that could be amended by BM-MSCs.

Glandular structures in the major interlobular and extrapancreatic ducts in the guinea pig.

The morphology of the pancreatic duct system did not receive much attention as compared to the microanatomy of the exocrine and endocrine pancreas. The histological peculiarities of the excretory duct system are of major importance especially in laboratory animals like guinea pigs. The paper describes the histological peculiarities of the major interlobular and extrapancreatic ducts in guinea pigs. The pancreatic tissue samples were collected from five guinea pigs. For histological investigation, several pancreatic fragments underwent fixation in 10% buffered formalin and were later processed by the standard paraffin technique. Subsequentially, tissue sections were stained by Goldner's trichrome staining. The mucous substances were assessed by Alcian blue and Periodic acid-Schiff staining methods. The interlobular and main pancreatic ducts in the guinea pig present a simple columnar epithelium surrounded by a thick layer of dense connective tissue. The aforementioned epithelium of the main pancreatic ducts includes principal cells, goblet cells and basal cells. Additionally, the ductal epithelium presents occasional unicellular multiloculated intraepithelial mucous glands and prominent extraepithelial glands. The latter adopts a simple or compound tubular feature. The mucus elaborated by the three glandular types is mostly neutral in goblet cells, predominantly acidic in extraepithelial ductal glands, and a similar amount of acidic and neutral mucin in intraepithelial glands. In conclusion, the epithelium-associated mucous glands in the interlobular and main pancreatic ducts in the guinea pig are restricted not only to goblet cells. A substantial mucous discharge probably with a protecting role against irritative pancreatic juice derives from the main ductal intraepithelial and extraepithelial glands.

Minor Salivary Gland Changes in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma - A Histopathological Study.

INTRODUCTION: The most common etiology for Oral Squamous Cell Carcinoma (OSCC) is tobacco and tobacco related products which cause nuclear damage to the keratinocytes. The chemical carcinogens not only affect the lining of oral epithelium but also affect the lining epithelium of the excretory ducts of the salivary glands. Thus, there is a possibility of epithelial dysplasia of the salivary duct epithelium which may lead to potential malignant transformation. AIM: The study was performed to see the changes in the minor salivary glands and excretory ducts in cases of oral epithelial dysplasia and OSCC. MATERIALS AND METHODS: A total of 278 archival cases of mild, moderate and severe epithelial dysplasia, carcinoma in situ, OSCC including verrucous carcinoma were histopathologically evaluated to observe changes in the excretory ducts and the minor salivary glands. RESULTS: In the study there were 56.5% males and 43.5% females. The age group that was most commonly affected in both the sexes was 50-60 yr old. Buccal mucosa was the most common site of involvement. Ductal changes observed in the excretory duct include simple hyperplasia, metaplastic changes such as mucous, oncocytic & squamous, and infiltration of inflammatory cells and malignant cells. Acinar changes observed were degeneration, squamous metaplasia, myoepithelial cell proliferation and inflammatory cell infiltration. Both the excretory ducts and ducts within the gland showed dysplasia. CONCLUSION: According to observations in our study it is suggested that histopathological interpretation for oral mucosal lesions especially oral epithelial dysplasias and OSCC should also include changes related to salivary gland tissue to provide a better treatment plan and prevent recurrence of the malignant tumours.

The Excretory Systems of Three Ditylenchus spp.

In Ditylenchus dipsaci the morphologically different anterior and posterior regions of the terminal excretory duct are separated by a constriction. Immediately posterior to the constriction is a valve-like structure composed of dense pieces integral with the wall of the duct. The posterior region is sometimes dilated at intervals along its length. The same structures are present in D. myceliophagus and D. destructor, but the dense pieces appear less well developed. A possible mode of action for the excretory system is discussed.