Striated Duct Research Articles

Evaluation of the stability of immediate placed dental maxillary implant in fresh extracted socket versus delayed placed implant

Introduction: Botulinum toxin A (BoNTA) has been used for treating hyperfunction of various glands such as sweat, lacrimal, and salivary glands. However, the long-term histological sequences are largely unknown. Objectives: The present study is to evaluate the histological and ultrastructural effects of BoNTA on submandibular salivary gland (SSG). Methods: Sixty male albino rats received 0.1 ml of either saline (control group) or BoNTA (BoNTA group) injection in the right SSGs. The rats were terminated at 2, 4 and 12 weeks after the injection. The harvested SSGs were embedded and sectioned at 4-5 µm and stained with H&E for histological study. Ultrathin sections (60-90nm) were cut from1 mm3 pieces harvested from the center of SSGs, and mounted on copper grids for ultrastructural study using transmission electron microscope (TEM). Results: All control SSGs showed normal acinar cells with rounded nuclei and regular striated ducts (SD) with characteristic basal striations. By TEM, acinar cells exhibited rounded nuclei, mitochondria, and secretory granules at cytoplasm. Numerous mitochondria presented in SD. Compared with these features, 2-week BoNTA-injected SSGs showed loss of basal striations. Examination by TEM revealed irregular nuclei of acinar cells and SD, and swollen mitochondria. In 4-week SSGs, some acini and ducts lost their spherical fashion and in some areas, these structures disappeared. Ruptured mitochondria were observed in acini and SD by TEM. However, all 12-week BoNTA-injected SSGs seemed to have similar structures to those of control SSGs. By using scoring system for semi-quantifying the histological structural changes of BoNTA-injected SSGs, 2- and 4-week BoNTA-injected SSGs showed significantly higher scores as compared with their control counterparts. However, no significant score difference was found between 12-week BoNTA-injected and control SSGs. Conclusions: Although application of BoNTA results in significant changes in histological structures and ultrastructures of SSGs, these detrimental effects seems to be transient, and the major recovery occurs after 3 months. Thus, BoNTA can be used for treating SSG hyperfunction.

Effects of Botulinum Toxin A (Botox) on cellular organs of Submandibular Salivary Gland in Rats (Ultrastructural study)

Introduction: Botulinum toxin A (BoNTA) has been used for treating hyperfunction of various glands such as sweat, lacrimal, and salivary glands. However, the long-term histological sequences are largely unknown. Objectives: The present study is to evaluate the histological and ultrastructural effects of BoNTA on submandibular salivary gland (SSG). Methods: Sixty male albino rats received 0.1 ml of either saline (control group) or BoNTA (BoNTA group) injection in the right SSGs. The rats were terminated at 2, 4 and 12 weeks after the injection. The harvested SSGs were embedded and sectioned at 4-5 µm and stained with H&E for histological study. Ultrathin sections (60-90nm) were cut from1 mm3 pieces harvested from the center of SSGs, and mounted on copper grids for ultrastructural study using transmission electron microscope (TEM). Results: All control SSGs showed normal acinar cells with rounded nuclei and regular striated ducts (SD) with characteristic basal striations. By TEM, acinar cells exhibited rounded nuclei, mitochondria, and secretory granules at cytoplasm. Numerous mitochondria presented in SD. Compared with these features, 2-week BoNTA-injected SSGs showed loss of basal striations. Examination by TEM revealed irregular nuclei of acinar cells and SD, and swollen mitochondria. In 4-week SSGs, some acini and ducts lost their spherical fashion and in some areas, these structures disappeared. Ruptured mitochondria were observed in acini and SD by TEM. However, all 12-week BoNTA-injected SSGs seemed to have similar structures to those of control SSGs. By using scoring system for semi-quantifying the histological structural changes of BoNTA-injected SSGs, 2- and 4-week BoNTA-injected SSGs showed significantly higher scores as compared with their control counterparts. However, no significant score difference was found between 12-week BoNTA-injected and control SSGs. Conclusions: Although application of BoNTA results in significant changes in histological structures and ultrastructures of SSGs, these detrimental effects seems to be transient, and the major recovery occurs after 3 months. Thus, BoNTA can be used for treating SSG hyperfunction.

Evaluation of the effects of Botulinum Neuro Toxin A (BoNTA) on Submandibular Salivary Gland in Rats by histological examination and semi-quantitative scoring method

Introduction: Botulinum toxin A (BoNTA) has been used for treating hyperfunction of various glands such as sweat, lacrimal, and salivary glands. However, the long-term histological sequences are largely unknown. Objectives: The present study is to evaluate the histological and ultrastructural effects of BoNTA on submandibular salivary gland (SSG). Methods: Sixty male albino rats received 0.1 ml of either saline (control group) or BoNTA (BoNTA group) injection in the right SSGs. The rats were terminated at 2, 4 and 12 weeks after the injection. The harvested SSGs were embedded and sectioned at 4-5µm and stained with H&E for histological study. Results: All control SSGs showed normal acinar cells with rounded nuclei and regular striated ducts (SD) with characteristic basal striations. Compared with these features, 2-week BoNTA-injected SSGs showed loss of spherical fashion and basal striations in serous acini and SD respectively, and the cell boundaries were not clear. In 4-week SSGs, some acini and ducts lost their spherical fashion and, in some areas, these structures disappeared. However, all 12-week BoNTA-injected SSGs seemed to have similar structures to those of control SSGs. By using scoring system for semi-quantifying the histological structural changes of BoNTA-injected SSGs, 2- and 4-week BoNTA-injected SSGs showed significantly higher scores as compared with their control counterparts. However, no significant score differences were found between 12-week BoNTA-injected and control SSGs. Conclusions: Although application of BoNTA results in significant changes in histological structures of SSGs, these detrimental effects seems to be transient, and the major recovery occurs after 3 months. Thus, BoNTA can be used for treating SSG hyperfunction.

Expression and localization of phosphodiesterase 2A in the submandibular gland of mice

ObjectivesPhosphodiesterases comprise a superfamily of enzymes that hydrolyze and inactivate cyclic AMP (cAMP) and/or cyclic GMP (cGMP), thereby regulating cellular signaling mechanisms. We herein investigated the production of phosphodiesterase 2A (PDE2A) in the mouse submandibular gland. DesignThe expression and localization of the mRNA and protein of PDE2A were examined in the submandibular gland of male and female mice using the reverse transcription-polymerase chain reaction, in situ hybridization, Western blotting, and immunohistochemistry. ResultsAmong the different species of phosphodiesterases examined in the mouse submandibular gland, PDE2A, which hydrolyzes cAMP and cGMP, exhibited a marked sexual difference; it was more abundantly expressed in females. The mRNA and protein signals for PDE2A were intense in all acinar and duct portions, including the striated duct, in females, whereas in males, these signals were markedly weaker in the granular convoluted duct, the counterpart of the female striated duct, than in acini and other duct portions. Furthermore, the signals for protein kinases A and G1, which are intracellular effectors of cAMP and cGMP, respectively, were markedly weaker in the male granular convoluted duct. ConclusionsThese results suggest that cyclic nucleotide-dependent signaling mechanisms function poorly in granular convoluted duct cells in the mouse submandibular gland.

Effects of Botulinum Toxin A on Histology and Ultrastructure of Submandibular Salivary Gland in Rats

Introduction: Botulinum toxin A (BoNTA) has been used for treating hyperfunction of various glands such as sweat, lacrimal, and salivary glands. However, the long-term histological sequences are largely unknown. Objectives: The present study is to evaluate the histological and ultrastructural effects of BoNTA on submandibular salivary gland (SSG). Methods: Eighteen 6-week-old male albino rats received 0.1 ml of either saline (sham group, n=9) or BoNTA (BoNTA group, n=9) injection in the right SSGs. Of 9 rats in each group, 3 were terminated at 2, 4 and 12 weeks after the injection. The harvested SSGs were embedded and sectioned at 6µm, and stained with H&E for histological study. Ultrathin sections (60-90nm) were cut from1 mm3 pieces harvested from the center of SSGs, and mounted on copper grids for ultrastructural study using transmission electron microscope (TEM). Results: All sham SSGs showed normal acinar cells with rounded nuclei and regular striated ducts (SD) with characteristic basal striations. By TEM, acinar cells exhibited rounded nuclei, mitochondria, and secretory granules at cytoplasm. Numerous mitochondria presented in SD. Compared with these features, 2-week BoNTA-injected SSGs showed loss of spherical fashion and basal striations in serous acini and SD respectively, and the cell boundaries were not clear. TEM further revealed irregular nuclei of acinar cells and SD, and swollen mitochondria. In 4-week SSGs, some acini and ducts lost their spherical fashion and in some areas, these structures disappeared. Ruptured mitochondria were observed in acini and SD by TEM. However, all 12-week BoNTA-injected SSGs seemed to have similar structures to those of sham SSGs. By using scoring system for semi-quantifying the histological structural changes of BoNTA-injected SSGs, 2- and 4-week BoNTA-injected SSGs showed significantly higher scores as compared with their sham counterparts. However, no significant score difference was found between 12-week BoNTA-injected and sham SSGs. Conclusions: Although application of BoNTA results in significant changes in histological structures and ultrastructures of SSGs, these detrimental effects seems to be transient, and the major recovery occurs in 3 months. Thus, BoNTA can be used for treating SSG hyperfunction.

Pituitary adenylate cyclase-activating polypeptide enhances saliva secretion via direct binding to PACAP receptors of major salivary glands in mice.

Xerostomia, or dry mouth, is a common syndrome that is generally treated with artificial saliva; however, no other effective methods have yet been established. Saliva secretion is mainly under the control of the autonomic nervous system. Pituitary adenylate cyclase-activating polypeptide (PACAP) is recognized as a multifunctional neuropeptide in various organs. In this study, we examined the effect of PACAP on saliva secretion, and detected the distribution of the PACAP type 1 receptor (PAC1R) in major salivary glands, including the parotid, submandibular, and sublingual glands, in 9-week-old male C57BL/6 mice. Intranasal administration of PACAP 38 increased the amount of saliva secreted, which was not inhibited by atropine pretreatment. Immunohistochemical analysis showed that PAC1R was distributed in the three major salivary glands. In the parotid and sublingual glands, PAC1R was detected in striated duct cells, whereas in the submandibular gland, a strong PAC1R immunoreaction was detected in tall columnar epithelial cells in the granular ducts (i.e., pillar cells), as well as in some striated duct cells. PACAP significantly increased the concentration of epidermal growth factor in saliva. These results suggest that PACAP directly regulates saliva secretion by controlling the absorption activity in the ducts, and that pillar cells regulate the function of granular epithelial cells in the granular duct, such as the secretion of growth factors into the saliva. Collectively, these results suggest the possibility of PACAP as a new effective treatment of xerostomia. Anat Rec, 299:1293-1299, 2016. © 2016 Wiley Periodicals, Inc.

Immunohistochemical localization of keratin 5 in the submandibular gland in adult and postnatal developing mice.

Keratin 5 (K5) is a marker of basal progenitor cells in the epithelia of a number of organs. During prenatal development of the submandibular gland (SMG) in mice, K5(+) progenitor cells in the developing epithelia play important roles in its organogenesis. Although K5(+) cells are also present in the adult mouse SMG and may function in tissue regeneration, their histological localization has not yet investigated in detail. In the present study, we examined the immunohistochemical localization of K5 in the SMG in adult and postnatal developing mice. At birth, K5 immunoreactivity was detected in the entire duct system, in which it was localized in the basal cells of a double-layered epithelium, but was not detected in the terminal tubule or myoepithelial cells. At postnatal weeks 1-3, with the development of intercalated ducts (ID), striated ducts (SD), and excretory ducts (ED), K5-immunoreactive basal cells were gradually restricted to the ED and the proximal double-layered portions of the ID connecting to the SD. At the same time, K5 immunoreactivity appeared in myoepithelial cells, in which its positive ratio gradually increased. In adults, K5 immunoreactivity was localized to most myoepithelial cells, most basal cells in the ED, and a small number of ID cells at the boundary between the ID and SD in the female SMG or between the ID and granular convoluted tubules in the male SMG. These results suggest that K5 is a marker of differentiated myoepithelial cells and duct progenitor cells in the mouse SMG.

Effects of Diabetes on Post-Menopausal Rat Submandibular Glands: A Histopathological and Stereological Examination.

The menopause in elderly women is a physiological process where ovarian and uterine cycles end. Diabetes means higher blood glucose level that is a metabolic disease and has an increased incidence. The aim of the study was to examine the single or combined effects of menopause and diabetes that causes pathophysiological processes on submandibular gland on ovariectomy and diabetes induced rat models. Sprague Dawley twelve weeks old female (n=24) rats were divided randomly into four groups; Healthy control group (n=6), diabetic group (DM, n=6), ovariectomized group (OVX, n=6), post ovariectomy diabetes induced group (DM+OVX, n=6) individually. Histopathological, histochemical and stereological analyses were done in these groups. Significant neutrophil cell infiltrations and myoepithelial cell proliferations, granular duct and seromucous acini damages and changes in the content of especially seromucous acini secretion in DM and/or OVX groups and distinctive interstitial and striated duct damages in post ovariectomy diabetes induced group were detected. Alterations ingranular ducts hypertrophic and in seromucous acini atrophic were determined in DM and/or OVX groups. The results revealed the pathophysiological processes that lead to morphological and functional alterations on the cellular level in submandibular glands. The molecular mechanisms related with pathogenesis of diabetes and menopause need further investigation.

Dopamine, vesicular transporters, and dopamine receptor expression in rat major salivary glands.

The localization of dopamine stores and the expression and localization of dopamine (DAT) and vesicular monoamine transporters (VMAT) type-1 and -2 and of dopamine D1-like and D2-like receptor subtypes were investigated in rat submandibular, sublingual, and parotid salivary glands by HPLC with electrochemical detection, as well as immunochemical and immunohistochemical techniques. Male Wistar rats of 2 mo of age were used. The highest dopamine levels were measured in the parotid gland, followed by the submandibular and sublingual glands. Western blot analysis revealed DAT, VMAT-1, VMAT-2, and dopamine receptors immunoreactivity in membrane preparations obtained from the three glands investigated. Immunostaining for dopamine and transporters was developed within striated ducts. Salivary glands processed for dopamine receptors immunohistochemistry developed an immunoreaction primarily in striated and excretory ducts. In the submandibular gland, acinar cells displayed strong immunoreactivity for the D2 receptor, while cells of the convoluted granular tubules were negative for both D1-like and D2-like receptors. Parotid glands acinar cells displayed the highest immunoreactivity for both D1 and D2 receptors compared with other salivary glands. The above localization of dopamine and dopaminergic markers investigated did not correspond closely with neuron-specific enolase (NSE) localization. This indicates that at least in part, catecholamine stores and dopaminergic markers are independent from glandular innervation. These findings suggest that rat major salivary glands express a dopaminergic system probably involved in salivary secretion. The stronger immunoreactivity for dopamine transporters and receptors in striated duct cells suggests that the dopaminergic system could regulate not only quality, but also volume and ionic concentration of saliva.

Localization of cystic fibrosis transmembrane conductance regulator signaling complexes in human salivary gland striated duct cells.

The cystic fibrosis transmembrane conductance regulator (CFTR) is a cyclic AMP-dependent protein kinase (PKA)-regulated Cl(-) channel, crucial for epithelial cell regulation of salt and water transport. Previous studies showed that ezrin, an actin binding and A-kinase anchoring protein (AKAP), facilitates association of PKA with CFTR. We used immunohistochemistry and immunogold transmission electron microscopy to localize CFTR, ezrin, and PKA type II regulatory (RII) and catalytic (C) subunits in striated duct cells of human parotid and submandibular glands. Immunohistochemistry localized the four proteins mainly to the apical membrane and the apical cytoplasm of striated duct cells. In acinar cells, ezrin localized to the luminal membrane, and PKA RII subunits were present in secretory granules, as previously described. Immunogold labeling showed that CFTR and PKA RII and C subunits were localized to the luminal membrane and associated with apical granules and vesicles of striated duct cells. Ezrin was present along the luminal membrane, on microvilli and along the junctional complexes between cells. Double labeling showed specific protein associations with apical granules and vesicles and along the luminal membrane. Ezrin, CFTR, and PKA RII and C subunits are co-localized in striated duct cells, suggesting the presence of signaling complexes that serve to regulate CFTR activity.

Redistribution of Gαs in mouse salivary glands following β-adrenergic stimulation

ObjectiveSignalling via β-adrenergic receptors activates heterotrimeric G-proteins, which dissociate into α and βγ subunits. In salivary glands, the α subunit of Gs stimulates adenylate cyclase, increasing cyclic AMP levels and promoting exocytosis. The goals of this study were to determine Gαs localization in salivary glands and whether it undergoes redistribution upon activation. MethodsMouse parotid and submandibular (SMG) glands were fixed with paraformaldehyde and prepared for immunofluorescence labelling with anti-Gαs. ResultsIn unstimulated parotid and SMG acinar cells, Gαs was localized mainly to basolateral membranes. Some parotid acinar cells also exhibited cytoplasmic fluorescence. Isoproterenol (IPR) stimulation resulted in decreased membrane fluorescence and increased cytoplasmic fluorescence, which appeared relatively uniform by 30min. Beginning about 2h after IPR, cytoplasmic fluorescence decreased and membrane fluorescence increased, approaching unstimulated levels in SMG acini by 4h. Some parotid acini exhibited cytoplasmic fluorescence up to 8h after IPR. The IPR-induced redistribution of Gαs was prevented (SMG) or reduced (parotid) by prior injection of propranolol. Striated duct cells of unstimulated mice exhibited general cytoplasmic fluorescence, which was unchanged after IPR. ConclusionsGαs is localized to basolateral membranes of unstimulated salivary acinar cells. Activation of Gαs causes its release from the cell membrane and movement into the cytoplasm. Reassociation of Gαs with the membrane begins about 2h after stimulation in the SMG, but complete reassociation takes several hours in the parotid gland. The presence of Gαs in striated duct cells suggests a role in signal transduction of secretion and/or electrolyte transport processes.

41. A case of salivary gland adenoma with ductal differentiation with morphological resemblance to normal striated ducts

Background WHO classification of salivary gland adenomas includes a morphological spectrum based on cellular and stromal components. Pure ductal adenoma is not a valid entity in the current WHO classification. Clinical data A 73 year old woman underwent a parotidectomy with clinical suspicion of pleomorphic adenoma. On follow up at 32 months, there was no evidence of recurrence or metastasis. Pathological findings Grossly a relatively circumscribed 22 mm tumour was identified. Histologically it was composed of ductal structures lined by columnar cells with eosinophilic cytoplasm and no cytological or architectural features of malignancy. The ducts showed a great resemblance to normal striated ducts. On immunohistochemistry the lesional cells exhibited an epithelial phenotype (positive for AE1/3, CK7, and CEA) and immunostains for myoepithelial markers failed to demonstrate a myoepithelial component. Electron microscopy attributed an epithelial nature to the tumour with ultrastructural features suggestive of intermediate ducts. Discussion This case demonstrated features of a benign neoplasm, although difficult to subtype. Entities including pleomorphic adenoma, oncocytoma, basal cell and canalicular adenoma were considered in the differential diagnosis. On immunomorphological grounds, there was a great resemblance to striated ducts. A series (6 cases) of striated duct adenomas has been previously reported in the literature. The current tumour had an essential histological resemblance to those cases, although EM failed to prove a definite striated duct origin. Conclusion We report a case of salivary gland neoplasm with ductal differentiation intermediate between striated and intercalated ducts. We believe pure ductal salivary gland adenomas are uncommon but do exist and should be considered in the differential diagnosis if appropriate morphological features are identified.

Morphology and gene expression profile of the submandibular gland of androgen-receptor-deficient mice

ObjectivesIn the submandibular gland (SMG) of mice, the granular convoluted tubule (GCT) develops preferentially in males dependent on androgens. To clarify the molecular mechanism of androgen action in SMG, we examined the SMG of mice deficient for the androgen receptor (ARKO). DesignThe morphological features and gene expression in the SMG of control and ARKO mice with or without hormone treatments were analysed by immunohistochemistry, DNA microarray, and RT-PCR. ResultsThe development of GCT and expression of GCT-specific products such as NGF were even lower in ARKO male SMG than in control female SMG. The administration of androgens to ARKO males had no effect on SMG, whereas the administration of thyroid hormone (T4) caused the extensive conversion of striated duct cells to GCT cells with the increase of NGF mRNA. Gene expression profiles in control and ARKO male SMG were analysed by DNA microarrays, and genes with higher or lower expression in ARKO male SMG were determined. They were then classified into groups according to their responsiveness to the administration of dihydotestosterone (DHT) or T4 to ARKO males. RT-PCR revealed that, while no gene was responsive to DHT, expression of many genes was up- or down-regulated by T4. ConclusionsThese results confirmed that GCT cell differentiation induced by androgens is dependent on the classical androgen receptor (AR), whereas that by T4 is independent of AR. Differential reactivity of genes to androgens and thyroid hormone in ARKO mice may shed light on the mechanism of androgen action in the SMG.

Expression and functional regulation of the nuclear receptors AHR, PXR, and CAR, and the transcription factor Nrf2 in rat parotid gland.

Nuclear receptors and transcription factors regulate the functions of many genes involved in cellular physiology and pathology (e.g. tumorigenesis and autoimmune diseases). The present study was performed to define the expression and the regulation of aryl hydrocarbon receptor (AhR), pregnane X receptor (PXR), constitutive androstane receptor (CAR), and nuclear factor E2-related factor 2 (Nrf2) in the rat parotid gland. Constitutive expression, as well as expression after stimulation with specific inducers for AhR [2,3,7,8-tetrachloro-dibenzylo-p-dioxin (TCDD)], Nrf2(oltipraz), PXR (dexamethasone), and CAR (phenobarbital), was evaluated using the quantitative PCR. Cellular localization of the nuclear receptors and the transcription factor was visualized by immunohistochemical staining. The study revealed constitutive expression of AhR as well as Nrf2, and their induction by TCDD andoltipraz, respectively. Immunohistochemical analysis revealed constitutive, predominantly cytoplasmic, expression of the AhR receptor, especially in interlobular striated duct cells, with nuclear shift upon exposure to TCDD. Inducible expression of Nfr2 was found mainly in the cytoplasm of intralobular striated duct cells. Constitutive expression of PXR and CAR was not found. Bearing in mind the involvement of AhR and Nrf2 in the regulation of many genes, it seems that these factors may play also a role in salivary gland physiology and pathology.

Ontogenic analysis of the PACAP receptor, PAC1R, in mouse major salivary glands (916.1)

The control of saliva secretion is mainly under the autonomic nervous control. Pituitary adenylate cyclase‐activating polypeptide (PACAP) is now recognized as the multi‐functional neuropeptide in various organs. Previous our study indicated the localization of PAC1R in adult mouse major salivary glands. In this study, we examined the ontogenic expression of PAC1R in mouse salivary glands. Salivary glands at 0, 3, 5, 7, 14 and 21 days postnatal male C57BL/6 mice were used for the immunohistochemical detection of PAC1R. In parotid gland, the acinus was not clearly formed and PAC1R was not detected until 14 days after birth. At 14 days, PAC1R was detected in the striated duct. In sublingual gland, Acinus and duct were formed at 0 days after birth. PAC1R was constantly expressed in the striated duct from 0 day postnatal stage. In the case of submandibular gland, granular duct was not clearly identified and PAC1R was localized in striated first detected in striated duct until 21 days after birth. After 21 days, PAC1R was clearly detected at pillar cells in granular duct. Some of cells in the duct showed intense immunoreactions of PAC1R. These results indicated that PAC1R was expressed in the striated duct of parotid and sublingual glands and that the localization of PAC1R was changed with the formation of granular duct. The precise study might be necessary to clarify the function of pillar cells by examining the shift of PAC1R‐positive cells in submandubular gland.

Expression and localization of trefoil factor family genes in rat submandibular glands

The trefoil factor (TFF) family, which comprises TFF1, TFF2 and TFF3, plays an essential role in epithelial regeneration within the gastrointestinal tract. All three TFFs are present in human saliva; TFF3 is the predominant trefoil peptide. Little is known about the expression and tissue distribution of TFFs in rats, which are commonly used as a model system for human studies. We investigated the localization of the TFF genes that encode secretory peptides in rat submandibular glands (SMG). All three TFFs were expressed in rat SMG, although their location varied. Substantial amounts of TFF1 were detected only in the cytoplasm of epithelial cells in the SMG granular convoluted tubules (GCT), while TFF2 and TFF3 were widely distributed in the cytoplasm of epithelial cells of intercalated ducts (ID), striated ducts (SD) and interlobular ducts (ILD). The three TFFs also were detected especially in the lumens of the SD and ILD. Semi-quantitative RT-PCR and in situ hybridization experiments confirmed TFF1, TFF2 and TFF3 mRNA expressions in the SMG. Greater expression of TFF peptides and mRNA was observed in male rats than in females. The broad expression of TFFs in rat SMG cells and lumens suggests that TFFs function in this organ by their secretion into the duct lumens. We also found differences in TFF expression profiles between rat and human SMG; therefore, caution should be exercised when using rats as a model for human TFF studies.

MRNA expression and localization of LPS-induced β-defensin isoforms in rat salivary glands.

β-defensins are small, cationic peptides with broad-spectrum antimicrobial activity that are produced by mucosal epithelia. However, little is known about the expression of β-defensins in the major salivary glands. The purpose of this study was to characterize expression of rat β-defensin-1 (RBD-1) and -2 (RBD-2) mRNA within the major salivary glands together with the effect of injection of intraductal lipopolysaccharide (LPS) on that expression. β-defensin mRNA expression was quantitated by RT-PCR in salivary gland tissues and salivary acinar and striated duct cells collected by laser captured microdissection. RBD-1 and -2 were expressed in the parotid gland, the submandibular gland, and the sublingual gland. β-defensins were expressed in both the acinar and striated duct cells of the major salivary glands. Intraductal injection of LPS increased expression of RBD-1 and -2 mRNA, which peaked at 12 hrs. These results suggest that salivary cells (acinar and striated duct cells) have the potential to produce β-defensins.

Modulation of Sodium/Iodide Symporter Expression in the Salivary Gland

Physiologic iodide-uptake, mediated by the sodium/iodide symporter (NIS), in the salivary gland confers its susceptibility to radioactive iodine-induced damage following (131)I treatment of thyroid cancer. Subsequent quality of life for thyroid cancer survivors can be decreased due to recurrent sialoadenitis and persistent xerostomia. NIS expression at the three principal salivary duct components in various pathological conditions was examined to better our understanding of NIS modulation in the salivary gland. NIS expression was evaluated by immunohistochemistry in human salivary gland tissue microarrays constructed of normal, inflamed, and neoplastic salivary tissue cores. Cumulative (123)I radioactivity reflecting the combination of NIS activity with clearance of saliva secretion in submandibular and parotid salivary glands was evaluated by single-photon emission computed tomography/computed tomography imaging 24 hours after (123)I administration in 50 thyroid cancer patients. NIS is highly expressed in the basolateral membranes of the majority of striated ducts, yet weakly expressed in few intercalated and excretory duct cells. The ratio of (123)I accumulation between parotid and submandibular glands is 2.38±0.19. However, the corresponding ratio of (123)I accumulation normalized by volume of interest is 1.19±0.06. The percentage of NIS-positive striated duct cells in submandibular salivary glands was statistically greater than in parotid salivary glands, suggesting a higher clearance rate of saliva secretion in submandibular salivary glands. NIS expression in striated ducts was heterogeneously decreased or absent in sialoadenitis. Most ductal salivary gland tumors did not express NIS. However, Warthin's tumors of striated duct origin exhibited consistent and intense NIS staining, corresponding with radioactive iodine uptake. NIS expression is tightly modulated during the transition of intercalated to striated ducts and striated to excretory ducts in salivary ductal cells. NIS expression in salivary glands is decreased during inflammation and tumor formation. Further investigation may identify molecular targets and/or pharmacologic agents that allow selective inhibition of NIS expression/activity in salivary glands during radioactive iodine treatment.

Histological and immunohistochemical comparison of major salivary glands in young and old mice

Pituitary adenylate cyclase‐activating polypeptide (PACAP) is now recognized as the multi‐functional neuropeptide in various organs. We have examined the effect of PACAP for saliva secretion. In this study, we compared the parenchymal structure and the distribution of PACAP receptor, PAC1R, in three major salivary glands; parotid (PG), submandibular (SMG), sublingual (SLG) glands of young (8 weeks old) and old (8 months old) male C57BL/6 mouse. In PG, PAC1R was localized in the striated duct. In SMG, PAC1R was detected in the tall columnar epithelial cells in granular ducts and some of the cells in the striated ducts. In SLG, PAC1R was localized in the striated duct. No apparent difference of PAC1R was detected between young and old mice glands. In SLG of old mice, granular epithelial cells are detected in the striated duct. Furthermore, massive infiltrations of CD3‐ positive or B220‐positive lymphocytes were detected in old PG and SMG. These results suggested that PACAP regulated the saliva secretion by modulating the activity of striated duct and that lymphoid infiltration in PG and SMG but not in SLM might give the useful information for the etiology of autoimmune disease of salivary gland.

Expression and localization of receptor protein tyrosine phosphatase β and its ligand pleiotrophin in the submandibular gland of mice

ObjectivesThe family of receptor protein tyrosine phosphatase β (RPTPβ) is composed of 4 splice variants and thought to play roles in the neural migration and outgrowth. Several ligands including the growth factor pleiotrophin (PTN) bind to RPTPβ and inhibit its phosphatase activity, thereby activating cellular signalling pathways. We examined the expression and localization of RPTPβ and its ligands in the submandibular gland (SMG) of mice, which is known for a prominent sexual dimorphism in the duct system. DesignThe homogenates and tissue sections of male and female mouse SMG were analysed with RT-PCR, Western blotting, and immunohistochemistry. ResultsThe short receptor type of RPTPβ (RPTPβ-S) was dominantly expressed in the SMG, and the male gland had significantly higher levels of RPTPβ-S expression than the female gland. In the male, RPTPβ-S was localized predominantly in intercalated duct (ID) cells, but was not found in granular convoluted tubule (GCT) cells or acinar cells. In the female, weaker reactivity was demonstrated in both ID and striated duct (SD) cells. Of the known ligands for RPTPβ, PTN was expressed in the SMG, without sexual difference in levels. In the male, PTN was localized in ID cells as well as in cells located in the distal ends of GCT that are in close vicinity to the ID, whereas in the female PTN was colocalized with RPTPβ-S throughout ID and SD cells. ConclusionsThese results indicated that the distribution of RPTPβ-S and its ligand PTN has a close relation to the sexual dimorphism in the duct system of mouse SMG.