Changes in protein secretion by rat submandibular salivary glands after enlargement caused by repeated amputation of the lower incisor teeth.

The lower incisors of male rats were repeatedly amputated at 3- or 4-day intervals for about 1 month. Four days after the last amputation, submandibular saliva was collected from the anaesthetized rats by intra-oral cannulation, using methoxamine (6 mg/kg), an α-adrenomimetic drug, as an acute secretory stimulus. The rats showed enlarged submandibular and sublingual glands and the protein concentration was significantly less in submandibular saliva than in controls. The types of protein secreted by the rat submandibular gland in response to methoxamine normally differ from those secreted in response to isoprenaline. In the enlarged glands, methoxamine stimulation caused the secretion of proteins similar, by polyacrylamide gel electrophoresis, to those normally secreted in response to isoprenaline, suggesting that repeated lower incisor amputation had caused the glands to lose their normal responsiveness to α-adrenergic agonists. An abnormal protein was also secreted, identical electrophoretically and immunologically with one secreted by the enlarged submandibular glands of rats exposed to chronic isoprenaline administration.     

Morphological and biochemical changes in the rat parotid gland after compensatory and isoproterenol-induced enlargement

Enlargement of parotid glands can be induced in rats by treatment with isoproterenol (ISP) or by removal of the submandibular and sublingual glands. In this study, morphological changes in the enlarged parotid glands and qualitative changes in secreted proteins were examined in rats that had been treated with ISP for 10 days or that had been partially sialoadenectomized by removal of the submandibular/sublingual glands 2 weeks prior to killing. After ISP treatment or salivary gland ablation, secretory cells were enlarged and contained enlarged secretory granules that stained differently from granules in normal glands. Isoproterenol treatment induced the greatest enlargement of cells and granules. Even though gland structure was altered in both experimental groups, electrophoresis of saliva showed that submandibular/sublingual gland ablation did not lead to significant qualitative changes in secreted proteins, while ISP treatment induced major changes in the pattern of secreted protein. The results suggest that compensatory enlargement of the parotid glands and changes after ISP treatment are induced by stimulation of different regulatory pathways.     

The effects of upper incisor separation on the submandibular and sublingual glands of rats

The effects of upper incisor separation on the submandibular and sublingual glands of rats were examined biochemically, immunohistologically, and radio-immunologically during 28 days of treatment. Lateral separation of the upper incisors by application of force from an orthodontic appliance caused significant enlargement of the sublingual and submandibular glands of rats by three and seven days, respectively, after the beginning of the orthodontic treatment. This enlargement was followed by a significant increase of both RNA and DNA content, with some evidence of hyperplasia and hypertrophy. The enlargement was also associated with a significant increase of substance P at early stages after treatment, suggesting the involvement of the sensory nerves. These changes were largely inhibited by phenoxybenzamine, an alpha-adrenergic blocker, but not by atropine or morphine. Wet weights and RNA contents of the sublingual glands were markedly reduced by atropine. In comparison with control animals, the enlarged submandibular glands of rats subjected to orthodontic treatment secreted additional proteins identical with those secreted by glands enlarged by chronic administration of isoproterenol. In addition, chemical sympathectomy with 6-hydroxydopamine and phenoxybenzamine stimulated the synthesis of these abnormal proteins, but atropine and morphine did not. In contrast, protease activities in the convoluted granular tubule cells in the submandibular glands were increasingly reduced after treatment, as seen in rats subjected to chronic treatment with isoproterenol. However, the submandibular and sublingual glands completely recovered after removal of the orthodontic appliance.     

The effects of epinephrine, norepinephrine, and phenylephrine on the types of proteins secreted by rat salivary glands

The types of proteins secreted by rat submandibular glands in response to secretory stimulation with epinephrine, norepinephrine, or phenylephrine were dose-dependent. At relatively high doses the proteins secreted were characteristic of alpha-adrenergic stimulation, whereas at low doses they were characteristic of beta-adrenergic stimulation.     

Tuberculous parotitis

Tuberculosis, though rare, should be considered in the differential diagnosis of a diffuse swelling of the parotid with enlarged cervical glands, particularly in young, feverish adults.     

Structural and functional injury in minipig salivary glands following fractionated exposure to 70 Gy of ionizing radiation: an animal model for human radiation-induced salivary gland injury

This study explored the feasibility of developing an animal model for radiation-induced salivary gland injury with a radiation protocol identical to current clinical practice. Three male Hanford minipigs were subjected to fractionated daily irradiation with a total dose of 70 Gy; structural and functional measures were compared with those of a control group of minipigs. We found that irradiated submandibular and parotid glands were one-third to one-half the gross size of control glands. Whereas no pathologic changes were noted in control glands, irradiated glands consistently demonstrated significant parenchymal loss with extensive acinar atrophy and interstitial fibrosis, enlarged nuclei in remaining acinar cells, and ductal dilatation and proliferation. Stimulated salivary flow was reduced by 81% in irradiated animals compared with preirradiation flow (P <.001); salivary flow in the control group increased by 30% during the same period (P <.001). The observed radiation-induced structural and functional salivary gland changes are comparable in every respect to those observed following irradiation of human salivary glands.     

Changes in protein secretion by rat submandibular glands in response to isoproterenol, alpha-methylnoradrenaline, and clonidine during post-natal development

We studied developmental changes in salivary volumes and proteins secreted by the submandibular glands of male rats at weekly intervals from two to ten weeks of age in response to the beta 1-, alpha 1-, and alpha 2-adrenoceptor agonists, isoproterenol (IPR), alpha-methylnoradrenaline (alpha-mNA), and clonidine (Clonid). The types of proteins in saliva samples were determined and compared by isoelectric-focusing electrophoresis with the Phast system in both the gradient pH -3.5-to-5 and pH-3.5-to-9 gels by means of silver staining. Salivary volume and protein concentration in saliva samples elicited by IPR and alpha-mNA were positively related to the weight of the submandibular glands up to six or seven weeks of age, whereas in saliva elicited by Clonid, no relation was found in the protein concentration [corrected]. The isoelectric-focusing electrophoretic patterns of proteins secreted by the glands in response to three stimuli were different from each other during post-natal development. Within one stimulation, differences were also observed at two and three weeks of age for Clonid, and from seven weeks of age for the three stimuli, respectively. The alpha-type proteins, but not the beta-type proteins, were very similar to those in extracts from glands of rats at seven weeks of age. Almost all of the alpha-type proteins, but not the beta-type proteins, reacted with antibodies to two proteases. We conclude that functional maturation precedes morphological maturation in the submandibular glands of rats.     

Volume and composition of pilocarpine- and isoproterenol-stimulated submandibular saliva of early postnatal rats

Submandibular saliva was collected from early postnatal rats by cannulation of the main excretory duct of individual glands after i.p. injections of pilocarpine (10 mg/kg body weight) or isoproterenol (10 mg/kg body weight). With this method of saliva collection, a secretory response to pilocarpine was observed at two wk of age. The average weight of 40 glands was 35.6 +/- 1.6 mg, and the average volume of saliva secreted in 60 min was 32 +/- 2.2 microliters. By three wk of age, the gland had approximately doubled in size (average weight of 39 glands = 61.9 +/- 3.1 mg), and the average total volume of saliva secreted in 60 min was more than three times larger (120.4 +/- 10.5 microliters) than that secreted by two-week-old rats. The relationship between electrolyte (Na+, K+, Ca++) and protein concentrations and rate of flow was similar to that observed in pilocarpine-stimulated adult saliva, and did not differ appreciably in the saliva of two- and three-week-old animals. A measurable secretory response to isoproterenol was observed at three wk of age when saliva was collected by duct cannulation. The average total volume of saliva secreted in 60 min was 48 +/- 3.1 microliters, and salivary Na+ and K+ concentrations, and their relationship to flow rate, were similar to those of isoproterenol-stimulated adult saliva. Saliva Ca++ and protein concentrations were also generally similar to those of isoproterenol-stimulated adult saliva. Total protein output (in 60 min) was 2 1/2 times greater in three-week-old rats with isoproterenol stimulation (compared to pilocarpine stimulation), but was significantly smaller than that of isoproterenol-stimulated adult glands. It is concluded that the submandibular gland of early postnatal rats is capable of secreting saliva in vivo following cholinergic and beta-adrenergic stimulation, and that this ability corresponds with the appearance of the corresponding autonomic receptors, but precedes cytodifferentiation. Ductal transport of electrolytes is well-developed at this stage of postnatal development, but fluid and protein output is smaller than in adult glands and requires full morphological maturation of acinar cells.     

Cheilitis glandularis: a case affecting the upper lip

Cheilitis glandularis is a rare disorder characterized by enlarged mucous glands, usually in the lower lip, and possibly predisposing to squamous cell carcinoma. A case affecting the upper lip is presented, which appears to be the first report of the disorder in that site.     

Characterization of cells in salivary gland lesions by immunohistochemical identification of carcinoembryonic antigens

Immunohistochemical demonstration of carcinoembryonic antigen (CEA) was reported in normal salivary glands and in pathologic lesions. Staining patterns of CEA and nonspecific cross-reacting antigen-absorbed CEA (NCAa-CEA) were compared. Normal salivary glands disclosed positive staining by CEA on border and luminal sides of acinar cells and occasionally in components secreted into ductal spaces with both antigens used. Chronic obstructive lesions displayed an intense CEA staining in ductlike structures and in material secreted into their lumina in the two antigens used. Pleomorphic adenoma exhibited varying intensities of CEA in neoplastic epithelial cells of ductal structures. In contrast, they showed a slight staining reaction to NCAa-CEA. Squamous-cell carcinomas showed a strong CEA reaction, whereas they showed no reaction or a trace reaction to NCAa-CEA. Positive staining to CEA in squamous neoplastic lesions was related to nonspecific reacting antigens.     

Demodex infestation of oral mucosal sebaceous glands

An unusual case of oral infestation with the hair mite Demodex is presented. The parasites were observed in enlarged ectopic sebaceous glands following biopsy. From a review of the literature, it would appear that oral involvement has not been reported previously.     

Developmental changes in the volumes, protein, and some electrolyte concentrations of male and female rat submandibular saliva secreted in response to methoxamine and pilocarpine

Saliva secreted in response to methoxamine and pilocarpine was collected from the cannulated ducts of the submandibular glands of male and female rats at weekly intervals from two to 10 weeks of age. It was analyzed for volume and for concentrations of protein, potassium, calcium, and inorganic phosphate. Following the collection of saliva, the submandibular glands were removed and weighted. The wet weights of the glands increased substantially up to seven weeks of age and then reached almost plateau values in both sexes. The salivary volumes secreted in response to both agents in both sexes were positively correlated with the gland weights, except that after five to six weeks of age there was no correlation between gland weight and methoxamine-stimulated salivary volume. The concentrations of protein, potassium, and inorganic phosphate were inversely related to the flow rates only at relatively low rates of flow. The concentration of calcium was positively correlated with the protein concentration and was independent of the nature of the stimulus and of sex differences during postnatal development.     

Studies on saliva in ODU plaque-susceptible rats having experimental gingivitis

Saliva was collected from the submandibular, parotid, and sublingual glands at to compare the amount of saliva between ODU plaque-susceptible (Sus) and plaque-resistant (Res) rats. The amount of saliva secreted was less in the Sus rats than in the Res rats. This difference was mainly due to a decrease in salivation from the submandibular glands, which resulted from the decrease in the weight of these glands. This reduction in salivation may be associated with the rapid rate of plaque formation seen around the mandibular teeth of these animals and the development of periodontal diseases.     

Bulimia nervosa. Its effect on salivary chemistry

Erosion of the dental hard tissues and enlarged parotid and submandibular saliva glands are commonly associated with bulimia nervosa. In 15 patients and controls, no significant difference was detected in the concentrations of potassium, chloride, calcium, urea nitrogen or albumin. There was also no evidence of olfactory dysfunction.     

Relative secretory contributions of the three major salivary glands of the rat in response to substance P and super-sensitivity

In vivo salivation in the rat in response to a range of intravenous doses of substance P was studied. The ducts of the parotid, submandibular and sublingual glands were cannulated. The secretory threshold dose of substance P, in microgram/kg, was 0.05-0.1 in the submandibular glands, 0.2 in the parotid glands and 0.2-0.5 in the sublingual glands. The maximal secretory response in all three types of glands was obtained at a dose level of 5-10 micrograms/kg. The total amount of saliva secreted at this dose level from the three pairs of glands was calculated to about 300 mg; the submandibular glands were responsible for 65 per cent, the parotid glands for 32 per cent and the sublingual glands for 3 per cent. Parasympathetic decentralization but not sympathetic denervation caused the sublingual glands to develop a super-sensitivity to substance P. The secretory effect of substance P was not exerted via cholinergic, alpha-adrenergic or beta-adrenergic receptors.     

Immunoelectron microscopical localization of immunoglobulins, secretory component and J chain in the human minor salivary glands

Localization of IgA, secretory component (SC) and J chain was investigated immunocytochemically in minor salivary glands of the lip and palate to define the mechanism involved in the transport of immunoglobulin A (sIgA) into the saliva from the minor salivary glands. SC synthesis was detected in mucous acinar cells and ductal epithelial cells. Free SC is secreted into the saliva through secretory granules in the mucous acinar cells. Dimeric IgA containing J chain is translocated through these cells as sIgA by a SC-mediated transport mechanism involving cytoplasmic vesicles.     

Transplantation of vascularized submandibular gland in dogs.

PURPOSE: Presently, treatments for xerostomia only target symptoms, as an active therapy method has not been established. Herein, we discuss the possibility of using a submandibular gland allograft technique for the disease. MATERIALS AND METHODS: Using a vascularized submandibular gland transplantation method, we extracted portions of the submandibular gland, including the duct and chorda tympani branches, from beagle dogs and placed them into the submental region of age- and weight-matched dogs. We then measured the amount of saliva secretion and examined the grafted glands histologically. RESULTS: Sufficient quantities of saliva were secreted from the grafted glands with pilocarpine treatment. Histologic findings showed that the acinar cells in the grafted and untreated contralateral glands had some atrophy, as compared with the normal glands; however, periodic acid Schiff staining showed that they produced saliva. CONCLUSIONS: Transplantation of vascularized submandibular glands into dogs was successful and may become a novel treatment strategy for patients with xerostomia.     

健康人腮腺α-淀粉酶、溶菌酶的增龄性改变

目的 观察不同年龄组正常腮腺α－淀粉酶、溶菌酶的分布、含量及增龄性变化的规律。方法 将５１例腮腺标本分为４个年龄组，用免疫组化的方法标记α－淀粉酶、溶菌酶，观察记录不同年龄组α－淀粉酶、溶菌酶的染色强度。结果 ４个年龄组之间α－淀粉酶、溶菌酶染色阳性率差异有显著性，随着年龄增长，其染色阳性率呈逐渐减低的趋势。结论 ＨＥ切片上染色、形态相似的浆液性腺泡之间，实际在功能上存在着很大的不同。α－淀粉酶、溶菌酶增龄性变化的特点与定量组织学研究结果相符合。     

Immunoelectron microscopical localization of immunoglobulins, secretory component and J chain in the human minor salivary glands

Localization of IgA, secretory component (SC) and J chain was investigated immunocytochemically in minor salivary glands of the lip and palate to define the mechanism involved in the transport of immunoglobulin A (slgA) into the saliva from the minor salivary glands. SC synthesis was detected in mucous acinar cells and ductal epithelial cells. Free SC is secreted into the saliva through secretory granules in the mucous acinar cells. Dimeric IgA containing J chain is translocated through these cells as slgA by a SC-medialed transport mechanism involving cytoplasmic vesicles.     

Convenient and reproducible in vivo gene transfer to mouse parotid glands

Oral Diseases (2010) 17 , 77–82 Objectives: Published studies of gene transfer to mouse salivary glands have not employed the parotid glands. Parotid glands are the likely target tissue for most clinical applications of salivary gene transfer. The purpose of the present study was to develop a convenient and reproducible method of retroductal gene transfer to mouse parotid glands. Methods: The volume for vector delivery was assessed by infusion of Toluidine Blue into Stensen’s ducts of Balb/c mice after direct intraoral cannulation. Recombinant, serotype 5 adenoviral vectors, encoding either firefly luciferase or human erythropoietin (hEpo), were constructed and then administered to parotid glands (10⁷ vector particles/gland). Transgene expression in vivo was measured by enzyme activity (luciferase) or an enzyme‐linked immunosorbent assay (hEpo). Vector biodistribution was measured by real‐time quantitative (Q) PCR. Results: The chosen volume for mouse parotid vector delivery was 20 μL. Little vector was detected outside of the targeted glands, with both QPCR and luciferase assays. Transgene expression was readily detected in glands (luciferase, hEpo), and serum and saliva (hEpo). Most secreted hEpo was detected in saliva. Conclusion: These studies show that mouse parotid glands can be conveniently and reproducibly targeted for gene transfer, and should be useful for pre‐clinical studies with many murine disease models.