Immunochemical analysis of laminin in duct-ligated submandibular glands of rats

Immunochemical methods have been used to study the expression of laminin during experimental atrophy of the submandibular gland of rats caused by ductal ligation. In normal submandibular glands, laminin immunoreactivity appeared as continuous linear staining around acini and ducts. In the ligated glands, it exhibited an irregular pattern and intensity. Staining was usually stronger around small ducts and acini, which were most prominent in glands ligated for 30 days. Immunoblot analysis showed that the laminin of the rat submandibular gland contains bands that correspond to the EHS α1, β1 and γ1 chains, and that the composition of the laminin chains does not change during the atrophy.     

Histologic assessment of the submandibular glands in autoimmune-disease-prone mice

Submandibular glands were examined from three autoimmune-disease-prone strains of mice (NZB/W, MRL/l and MRL/n) and controls (C57BL/6J). Focal lymphocytic adenitis was more prevalent and more severe in autoimmune-disease-prone strains than controls and in females than males. Lymphocytic foci were more frequent in older age groups, but female MRL/1 mice exhibited high levels of focal lymphocytic adenitis irrespective of age. Salivary parenchyma was generally well preserved. In the strain-age groups with the highest focal lymphocytic scores proportional acinar volumes were significantly less than in controls. However, the proportion of acinar tissue showed no consistent relation to the severity of focal lymphocytic adenitis across all strains and age groups of either sex. Sexual dimorphism in granular duct prominence was weakened in NZB/W and MRL/l strains compared to controls.     

Immunohistochemical and electronmicroscopic studies of obstructive lesions in submandibular glands

Obstructive sialoadenitis was examined by immunohistochemical techniques for keratin (MoAb KL1, PKK1 and K8.12) and actin. Electronmicroscopy (EMS) was used to identify ultrastructural changes in myoepithelial cells and ductal basal cells. With immunohistochemistry, actin staining was used as a marker of myoepithelium, MoAbs KL1 and PKK1 for ductal luminal cells, and MoAb K8.12 for ductal basal cells. Histologic features of the lesion usually showed degenerative changes of acinar and duct cells with cell infiltration and fibrous replacement. Immunohistochemical findings indicated that actin staining in the changed myoepithelial cells was irregularly positive or negative, and also keratin staining in luminal and ductal basal cells was reduced or disappeared. Ultra-structural features of the changed myoepithelial cells indicated that these cells appeared less altered than adjacent acinar and ductal cells and showed increased amounts of lipid droplets and lipofuscin granules, and also wrinkled processes filled the prominent myofilament material.     

Age-dependent changes in insulin-like immunoreactivity in rat submandibular salivary glands

In recent years, a growing interest had arisen in hormonal factors in salivary glands. We have investigated the changes in the content of an insulin-like immunoreactive (ILI) compound in the submandibular salivary glands of Sprague Dawley rats during physiological aging, in the range 15 days -27 months. The amount of ILI in the submandibular glands of young adult rats was found to be doubled in the post-natal period until the age of puberty and was maintained in senescence. No significant correlation was found between age-dependent variations in ILI levels of submandibular salivary glands and circulating insulin concentrations, further supporting previous indications that ILI is being synthesized in situ. It is possible that ILI could exert paracrine effects within the glands, as regards the development of other glandular structures during the first months of life, as well as the preservation of glandular function in senescent animals as well.     

Acute irradiation effects on morphology and function of rat submandibular glands

In this study the morphologic and functional changes were compared after irradiation (single dose, 15 Gy) of rat submandibular salivary glands. Before and 1-10 days after local irradiation of the gland region, samples of submandibular saliva were collected after stimulation by pilocarpine. At the same time-points and also 3 h postirradiation submandibular glands were carefully extirpated and prepared for histocytologic examination (LM, TEM). Maximal increase of the lag phase and decrease of the flow rate were observed 3 days after irradiation, while [K+] and [Na+] increased and decreased, respectively, from days 1 and 3 after irradiation. Morphologic changes were observed from the third hour after irradiation, were maximal 3 days after irradiation and had partially recovered by day 10. Three hours and 1 day after irradiation degranulation of convoluted granulated tubes (CGT) was observed. Three days after irradiation the most striking morphologic changes in serous and mucous cells were distension of the cisternae of the RER, degeneration of mitochondria and vacuolization of the cytoplasm. Fibril-like condensations of electron dense material in the mucous granules were observed 3 h, 1 and 6 days after irradiation. Regranulation of CGT cells was observed from day 6. From this study it is concluded that changes in salivary gland function can be observed before major morphologic changes occur. Functional changes persist after the morphologic changes seem to have virtually returned to normal.     

大鼠颌下腺上皮间紧密连接蛋白表达特点

目的：观察大鼠颌下腺上皮间紧密连接蛋白表达特点。方法：分离大鼠颌下腺,冰冻切片,免疫荧光染色检测 ZO-1、Occludin、Claudin-3和 Claudin-4等紧密连接蛋白的表达。结果：Claudin-3表达于涎腺腺泡上皮及导管上皮,与 Occludin 及 ZO-1共表达提示位于紧密连接处。Claudin-4只表达于导管,腺泡中不表达。结论：Claudin 在鼠颌下腺中表达具组织特异性。     

Gene transfer mediated by different viral vectors following direct cannulation of mouse submandibular salivary glands

The salivary gland has been suggested as an accessible organ for gene transfer to express recombinant proteins locally in the saliva, as well as for secretion to the blood circulation. The aim of this study was to evaluate the efficiency of gene transfer to salivary glands using different viral vectors: adenovirus, vaccinia, herpes simplex type 1 (HSV), and two retroviral vectors (murine leukemia virus (MuLV) and lentivirus). We show, by in situ staining and beta-galactosidase reporter activity assay, that the adenoviral and vaccinia vectors were able to deliver the reporter gene efficiently to acinar and duct cells. The HSV vector was less efficient and infected only the acinar cells. The lentiviral vector infected acinar and duct cells, but at a relatively low efficiency. The MuLV vector did not infect the salivary gland unless cell proliferation was induced. Host immune responses to viral infection, inflammation, apoptosis and lymphocyte infiltration, in the transduced glands, were assessed. The DNA viral vectors induced local lymphocyte infiltration and apoptosis. In contrast, the retroviral vectors did not induce an immune response. Our results describe the outcome of salivary gland infection with each of the five different viral vectors and indicate their advantages and limitations for transferring genes to the salivary glands.     

不对称牵引对成年SD大鼠髁突软骨中胶原类型影响的研究

目的 观察不对称牵引作用下,成年SD大鼠髁突软骨中胶原类型的变化。方法 选用10周龄雄性SD大鼠220只(随机分为轻力组104只、重力组104只、对照组12只),实验组动物使用关节外固定加力装置,分别施加0.39N和1.18N(轻力组和重力组),加力第28天拆除加力装置。在加力后3、7、14、28d以及停止牵引后3、7、14、28d分别取得标本,进行苦味素-天狼星红染色,用偏振光显微镜进行观察。结果 不同类型胶原的主要分布位置和排列形态不同,Ⅰ、Ⅱ、Ⅲ型胶原出现的部位和数量随着加力的大小和不同的实验阶段出现变化。Ⅲ型胶原较多出现在受力较大、负荷出现时间较长的部位。结论 成年个体的髁突软骨在外力刺激下,仍然出现胶原合成和类型的变化,重力组的胶原类型更替在经历了较长的时间后仍然持续进行。?     

Focal lymphocytic infiltration in aging human palatal salivary glands: a comparative study with labial salivary glands

Investigation of age-related prevalence of various types of focal lymphocytic infiltration (FLI) and degrees of histomorphologic changes was conducted on 120 biopsies of palatal and labial salivary glands (PSG and LSG, respectively) obtained from autopsy subjects free of salivary gland tumors/diseases. Biopsies were divided into young (<30 years, n=30), adult (30-60 years, n=45) and old (>60 years, n=45) age groups. A modified Chisholm & Mason grading system was used to record grades of FLI and a modified Greenspan et al. system was used to evaluate the severity of histomorphologic changes. The prevalence of FLI in PSG increased significantly from 10% in the young group to 46.6% in the old group (P=0.0012). No significant changes were found with aging in LSG. FLI was significantly more prevalent in the adult and old age groups in PSG as compared with LSG (P=0.015 and P=0.003, respectively). Both glands demonstrated significant histomorphologic changes among age groups (p<0.0001); however, these changes were significantly less common in the old age group in PSG as compared to LSG (P=0.003). In cases showing severe histomorphologic changes, FLI was not present. Therefore, FLI should not be considered as part of the deteriorating histomorphologic changes that are usually encountered in salivary glands with aging. The immunologic profile of these infiltrates should be further clarified to understand their role, both in physiologic and pathologic conditions.     

化痰软坚中药对大鼠离体灌流颌下腺唾液分泌作用的研究

目的中草药能通过增加唾液的分泌而缓解口腔干燥症状。本试验研究临床常用化痰软坚类促唾液分泌功能。方法成年wistar大鼠,用苯巴比妥钠麻醉后,外科分离颌下腺,转移至37℃恒温浴槽。使用蠕动泵(Cole-Palmer)进行灌流,氨甲酰胆碱(CCh)对照灌流,用缓冲液洗脱后,单独用含中药的缓冲液灌流,和中药与CCh联合灌流,通过对分泌速率的统计学分析,观察中药对颌下腺唾液分泌的影响。结果化痰软坚类中药,单独灌流,几乎不能或仅能少量促进唾液分泌,而灌流同时加入CCh,能明显促进唾液的分泌,唾液分泌曲线呈快速升高后有一轻微的下降过程。结论化痰软坚类中药对离体唾液腺具有促分泌作用。中药促唾液分泌实验研究将会为中药治疗口干症状及相关疾病的临床应用提供依据。     

Expression of aquaporin 5 during murine palatine glands development: a light and electron microscopic immunocytochemical study

Although aquaporin 5 (AQP5) seems to play a role in cytodifferentiation and cell proliferation during the development of salivary glands, its distribution during minor salivary glands development has been scarcely reported. This study examined the temporal-spatial distribution of AQP5 in the developing rat palatine glands using light and electron microscopy. At embryonic (E) age E18, AQP5 labeling was observed on the cell membranes of some terminal bulb cells. After lumenization at E20, AQP5 labeled the apical membrane in acini where a lumen existed, in addition to displaying positive diffuse cytoplasmic and cell membrane staining. At the electron microscopic level, AQP5 labeled the supranuclear cytoplasm and the luminal microvilli along the apical membrane. At birth, AQP5 was also localized to the lateral membranes associated ultrastructurally with the microvilli of intercellular canaliculi. After postnatal (PN) day PN7, mucous acini and serous demilunes showed reactivity. AQP5 reached peak reactivity around PN13 with a similar staining pattern in all acini, but had reduced dramatically by PN21. Thereafter, AQP5 reactivity was mainly associated with serous cells in adults. In conclusion, the transitory expression of AQP5 during palatine glands development may reflect changing physiological functions of the secretory cells and/or AQP5 throughout the maturation of the glands.     

Variation in the response to ductal obstruction of feline submandibular and sublingual salivary glands and the importance of the innervation

A variable response following ductal ligation of feline salivary glands corresponds to the human condition but contrasts with a predictable atrophy in obstructed salivary glands of rodents popularly used as a model for human salivary problems. The present investigation is concerned with a possible reason for the variable response, namely the preservation of the innervation. Ducts of feline submandibular and sublingual salivary glands were ligated with or without the inclusion of the chorda tympani. Inclusion led to a delayed initial response followed by progressive atrophy until the parenchyma was extremely atrophic, whereas avoidance of the chorda led to the variable response in which variable numbers of acini of a similar form to normal persisted. The results establish the atrophic effect of inclusion of the chorda tympani in ductal ligation and indicate the caution that should be exercised in the extrapolation of the rodent model to the human condition.     

Expression of two drug-metabolizing cytochrome P450-enzymes in human salivary glands

Objective:  The oral cavity is constantly lubricated by saliva and even small amounts of xenobiotics and / or their metabolites in the saliva may affect the oral mucosa. Our aim was therefore to clarify if xenobiotic metabolizing enzymes CYP1A2 and CYP3A4 are expressed in salivary glands.
Methods:  Formalin-fixed paraffin-embedded specimens from parotid (10), submandibular (7) and labial (10) salivary glands were examined immunohistochemically and by in situ hybridization for expression of CYP1A2 and CYP3A4 protein and mRNA.
Results:  CYP1A2 and CYP3A4 protein and mRNA were detected in ductal and seromucous / serous acinar cells in all gland types although to a varying degree and intensity. Mucous acinar cells were positive to a lesser extent.
Conclusion:  The results indicate a xenobiotic metabolizing capability of salivary glands. This may have implications for development of oral mucosal disease as a result of mucosal exposure to metabolites originating from internal sources (blood) as well as from saliva.     

Effect of moderate protein-deficiency on ultrastructure in parotid and submandibular acinar cells in the adult rat

Abstract— Powdered diets, of three different levels of protein, were given to groups of adult male rats for 21 days. Two diets with reduced protein content, 5% or 10% casein, were given to experimental rats. A diet with an adequate protein content, 20% casein, was given to controls. A reference group of rats was fed a standard pellet diet for the same period. At the end of the experimental period, the parotid and the submandibular glands were removed and subjected to electron microscopy. The zymogen granules of acinar cells in the parotid glands from the rats receiving the 5% protein diet had lost their normal opaqueness and turned electron lucid whereas parotid glands from the rats fed the 20%, the 10%, and the standard pellet diet exhibited normal acinar cells. The ultrastructure of submandibular acinar cells was not affected in any dietary group.     

Local variations in turnover of periodontal collagen fibers in rats

Henneman S, Reijers RR, Maltha JC, Von den Hoff JW. Local variations in turnover of periodontal collagen fibers in rats. J Periodont Res 2012; 47: 383–388. © 2011 John Wiley & Sons A/S Background and Objective: The exact cause of orthodontic relapse is still unclear, although it is often suggested to be caused by periodontal collagen fibers. We hypothesize that long‐lived collagen fibers in the periodontium cause relapse. The aim was to determine the half‐life of periodontal collagen fibers around rat molars. Material and Methods: Thirty weanling rats were repeatedly injected with ³H‐proline, and autoradiography of histological sections was performed at 1, 4, 8, 15, 22, 29, 36, 57, 78 and 113 d after labeling. Grain densities determined in specific areas of the periodontium were used to calculate collagen half‐life. Results: The half‐life (t_½) was found to decrease from the supra‐alveolar region to the apical periodontal ligament region. It was longer in the supra‐alveolar region (1.39 ± 0.14 wk) compared with the deeper regions (p < 0.05). The t_½ of the upper periodontal ligament region (0.78 ± 0.20 wk) was longer than that of the inter‐radicular periodontal ligament region (0.42 ± 0.07 wk, p < 0.05). The t_½ of the apical periodontal ligament region was 0.61 ± 0.15 wk. Conclusion: The data indicate that long‐lived collagen fibers do not exist in the soft tissues of the periodontium, and are probably not responsible for relapse. The differences in collagen half‐life might be caused by local variations in compressive strain induced by normal function.     

Expression of cytoskeletal proteins in developing human minor salivary glands

The presence of an epithelium at different stages of proliferation and differentiation raises interesting questions concerning the histogenesis, cell turnover and differentiation of normal salivary glands. In order to expand knowledge of these aspects, we investigated the expression of cytokeratins (CKs) 7,8,10,13,14,16,18 and 19, vimentin (VIM), and smooth muscle actin (SMA) in developing human minor salivary glands using monoclonal antibodies. Labial, buccal, palatine, and lingual salivary glands and those from the floor of the mouth were obtained from human fetuses (forensic postmortem) ranging in age from gestational weeks 10 to 29. Serial sections, 3 microm thick, were immunostained using a strepto-avidin-biotin technique. Reactivity for all antibodies was negative in the salivary gland epithelium during the developmental stages of bud formation, cord growth, and branching of cord. During canalization and cytodifferentiation, the glandular epithelial cells showed a positive reaction to some CKs and SMA. Cytokeratins 7, 8, 18, and 19 showed strong labeling in luminal duct cells that exhibited some degree of morphological differentiation. Myoepithelial cellc were recognized by antibodies to SMA. Cytoskeletal protein expression changes according to the cell type, degree of differentiation, and stage of morphological development of the glandular structure. These changes occur independently of the localization of the gland.     

Chemistry of the sulfate groups in a sulfated glycoprotein from rabbit submandibular gland

abstract – A ³⁵S-labeled sulfated glycoprotein was isolated from rabbit submandibular glands. Acid stability studies on the ³⁵sulfate groupings present in the intact glycoprotein gave a half-life of 45 min. Partial acid hydrolysis of the ³⁵S-labeled glycoprotein in 0.1 M HCl for 90 min at 100°C liberated a radioactive fraction which was free from peptide and fractionated in the monosaccharide range of a Sephadex G-15 column. Examination of this fraction by paper chromatography revealed the presence of a major component having the characteristics of N-acetylglucosaminc 6-0-sulfate and a minor component having the properties of N-acetylgalactosaminc 6-0-sulfate. The presence of ester sulfate groups in the intact glycoprotein was confirmed by infrared spectroscopy.     

Amyloid deposits in labial salivary glands identified by electron microscopy

Abnormal proteinaceous deposits identified by light microscopy as amyloid in labial salivary gland biopsies were studied by transmission electron microscopy in order to establish (heir ultrastructural characteristics. Results showed fine fibrils approximately 10 nm in diameter located in close relation to the basal lamina of the secretory end-pieces and ducts as well as in the interstitial connective tissue stroma of labial salivary glands: these are the typical features of amyloid. Thus, the present study confirms the light microscopy diagnosis of amyloid deposits in labial salivary gland biopsies, supporting the use of lip biopsy as a readily accessible method for the diagnosis of secondary amyloidosis.