Morphology Of Salivary Glands Research Articles

The long-term effects of multidrug immunosuppressive protocols based on calcineurin inhibitors and conversion to rapamycin on the morphology, apoptosis, and proliferation of rat salivary glands

BackgroundThe effect of multidrug immunosuppressive protocols on the salivary glands is still unknown. This study aimed to determine the influence of immunosuppressive regimens based on calcineurin inhibitors (CNIs) and conversion to rapamycin on the morphology, apoptosis, and proliferation of rat salivary glands.MethodsMale rats received cyclosporin A (CsA), tacrolimus (FK-506), mycophenolate mofetil (MMF), rapamycin (Rapa), and prednisone (Pre) according to three-drug protocols: CMP (CsA, MMF, and Pre), CMP/R (CsA, MMF, and Pre with conversion to Rapa), TMP (FK-506, MMF, and Pre), and TMP/R (FK-506, MMF, and Pre with conversion to Rapa). Morphological and immunohistochemical and quantitative analyses of the salivary glands were performed.ResultsStructural changes in salivary glands were observed in all experimental groups, especially in the submandibular gland. In the salivary glands, the percentages of collagen fibers and TUNEL-, Ki67- and PCNA-positive cells were higher in the experimental groups vs. the control but were lower in the CMP/R and TMP/R groups vs. the CMP and TMP groups, with the exception of collagen fibers in the parotid gland in the TMP/R group vs. the TMP group.ConclusionsLong-term administration of CNIs in triple regimens and after conversion to rapamycin monotherapy, causes morphological changes in the salivary glands of rats. Immunosuppressive treatment based on CNIs is associated with an increase in collagen accumulation. The effects of the conversion of treatment with CNIs to rapamycin in immunosuppressive protocols in rat salivary glands lead to decreased fibrosis, apoptosis, and proliferation. These changes may possibly prevent abnormalities resulting from the application of CNIs.

Morphology and physiology of salivary glands.

This article discusses the issues of classification and morphology, ultrastructural features of their cells, embryogenesis. The importance of saliva for the normal functioning of the oral cavity is described.

Salivary Gland Adaptation to Dietary Inclusion of Hydrolysable Tannins in Boars.

Simple SummaryTannins have traditionally been avoided in animal nutrition due to their anti-nutritive effects. However, recent studies reported hydrolysable tannins as beneficial additives that have antimutagenic, anticarcinogenic, antidiarrheal, and antiulcerogenic effects on animals. In a study testing the inclusion of hydrolysable tannins as a potential nutritive factor to reduce boar taint in entire males, significant enlargement of the parotid glands (parotidomegaly) was observed. In this study, we aimed to determine the morphological and immunohistochemical basis for the observed parotidomegaly. We discovered that enlargement of glandular lobules and acinar area, an increased ratio between the nucleus and cytoplasm of serous cells, and increased excretion of proline-rich proteins (PRPs) were characteristic of the experimental group that received the highest dietary tannin intake. The mandibular salivary gland, on the other hand, did not show significant morphological changes among the experimental groups. This suggests increased functional activity of the parotid salivary glands as the first and most important line of defense against high dietary tannin and its potential negative effects.The ingestion of hydrolysable tannins as a potential nutrient to reduce boar odor in entire males results in the significant enlargement of parotid glands (parotidomegaly). The objective of this study was to characterize the effects of different levels of hydrolysable tannins in the diet of fattening boars (n = 24) on salivary gland morphology and proline-rich protein (PRP) expression at the histological level. Four treatment groups of pigs (n = 6 per group) were fed either a control (T0) or experimental diet, where the T0 diet was supplemented with 1% (T1), 2% (T2), or 3% (T3) of the hydrolysable tannin-rich extract Farmatan®. After slaughter, the parotid and mandibular glands of the experimental pigs were harvested and dissected for staining using Goldner’s Trichrome method, and immunohistochemical studies with antibodies against PRPs. Morphometric analysis was performed on microtome sections of both salivary glands, to measure the acinar area, the lobular area, the area of the secretory ductal cells, and the sizes of glandular cells and their nuclei. Histological assessment revealed that significant parotidomegaly was only present in the T3 group, based on the presence of larger glandular lobules, acinar areas, and their higher nucleus to cytoplasm ratio. The immunohistochemical method, supported by color intensity measurements, indicated significant increases in basic PRPs (PRB2) in the T3 and acidic PRPs (PRH1/2) in the T1 groups. Tannin supplementation did not affect the histo-morphological properties of the mandibular gland. This study confirms that pigs can adapt to a tannin-rich diet by making structural changes in their parotid salivary gland, indicating its higher functional activity.

The complex and often confusing history, histology and histogenesis of mesonephric, STK11 adnexal tumour and mesonephric-like neoplasms of the upper female genital tract (including broad ligament).

Mesonephric lesions in the female genital tract are uncommon, with those arising from the upper tract being much less frequent than those developing in the lower tract (mesonephric hyperplasia and carcinoma). The most common upper tract lesions include rete cyst/cystadenoma and female adnexal tumour of Wolffian origin (FATWO). The integration of morphological, immunohistochemical and molecular studies on FATWOs has enabled recognition of a novel entity, the STK11 adnexal tumour, which is often associated with Peutz-Jeghers syndrome (~50%) and frequently has a salivary gland morphology but an unknown origin. Similarly, 'mesonephric-like' adenocarcinoma, an entity with striking similarities to mesonephric carcinoma but currently favoured to be of Müllerian derivation based on its association with other Müllerian tumours and molecular findings, has also been recently described, and may histologically mimic both FATWOs and STK11 adnexal tumours. In this review, we provide a historical overview of upper female genital tract mesonephric proliferations and discuss mesonephric lesions, STK11 adnexal tumour, mesonephric-like adenocarcinoma, and mimickers, the most common being endometrioid carcinoma.

Effective Oral RNA Interference (RNAi) Administration to Adult Anopheles gambiae Mosquitoes.

RNA interference has been a heavily utilized tool for reverse genetic analysis for two decades. In adult mosquitoes, double-stranded RNA (dsRNA) administration has been accomplished primarily via injection, which requires significant time and is not suitable for field applications. To overcome these limitations, here we present a more efficient method for robust activation of RNAi by oral delivery of dsRNA to adult Anopheles gambiae. Long dsRNAs were produced in Escherichia coli strain HT115 (DE3), and a concentrated suspension of heat-killed dsRNA-containing bacteria in 10% sucrose was offered on cotton balls ad-libitum to adult mosquitoes. Cotton balls were replaced every 2 days for the duration of the treatment. Use of this method to target doublesex (a gene involved in sex differentiation) or fork head (which encodes a salivary gland transcription factor) resulted in reduced target gene expression and/or protein immunofluorescence signal, as measured by quantitative Real-Time PCR (qRT-PCR) or fluorescence confocal microscopy, respectively. Defects in salivary gland morphology were also observed. This highly flexible, user-friendly, low-cost, time-efficient method of dsRNA delivery could be broadly applicable to target genes important for insect vector physiology and beyond.

Effective Oral RNA Interference (RNAi) Administration to Adult <em>Anopheles gambiae</em> Mosquitoes

RNA interference has been a heavily utilized tool for reverse genetic analysis for two decades. In adult mosquitoes, double-stranded RNA (dsRNA) administration has been accomplished primarily via injection, which requires significant time and is not suitable for field applications. To overcome these limitations, here we present a more efficient method for robust activation of RNAi by oral delivery of dsRNA to adult Anopheles gambiae. Long dsRNAs were produced in Escherichia coli strain HT115 (DE3), and a concentrated suspension of heat-killed dsRNA-containing bacteria in 10% sucrose was offered on cotton balls ad-libitum to adult mosquitoes. Cotton balls were replaced every 2 days for the duration of the treatment. Use of this method to target doublesex (a gene involved in sex differentiation) or fork head (which encodes a salivary gland transcription factor) resulted in reduced target gene expression and/or protein immunofluorescence signal, as measured by quantitative Real-Time PCR (qRT-PCR) or fluorescence confocal microscopy, respectively. Defects in salivary gland morphology were also observed. This highly flexible, user-friendly, low-cost, time-efficient method of dsRNA delivery could be broadly applicable to target genes important for insect vector physiology and beyond.

The effect and mechanism of gene Fam20a on the development and function of salivary glands in mice

ObjectiveThe influence of the knockout of gene Fam20a on mice salivary glands was studied in this research, to provide a potential gene therapeutic target for salivary gland dysfunction. DesignThe control group with genotype Fam20af/f and conditional knockout (cKO) group with Fam20af/f;K14-Cre were constructed with Cre-Loxp. The influence of Fam20a on the salivary glands was studied in terms of morphology, functionality and molecular mechanism. ResultsIn terms of morphology, the cross-sectional area ratio of ductal to the total was reduced in the cKO mice, while that of extracellular matrix to the total was increased. At the sub-microscopic level, the knockout of Fam20a led to abnormal sub-microscopic structure of the duct cells. Functionally, saliva flow rate was significantly reduced in cKO mice. The result was consistent with the change of acinar cell marker Aquaporin 5 which was abnormally diffusely expressed in the cytoplasm of acinar cells. Meanwhile, the expression of ductal cell markers Cytokeratin 7 and nerve growth factor β were significantly decreased, suggesting the abnormal development and function of the duct cells. The research on the mechanism reveals that the loss of Fam20a led to the decreased expression and varied localization of bone morphogenetic protein 4 (BMP4), and a significant decrease of the proportion of phosphorylated extracellular signal-regulated protein1/2 (ERK1/2) to total ERK1/2. These changes suggested that the loss of Fam20a attenuated the activity of the BMP/ERK signaling pathway. ConclusionsFam20a affects the morphology and function of salivary glands, probably by attenuating the activity of the BMP/ERK signaling pathway.

Repellent activity of acetylcarvacrol and its effects on salivary gland morphology in unfed Rhipicephalus sanguineus sensu lato ticks (Acari: Ixodidae)

Rhipicephalus sanguineus sensu lato (s.l.), commonly known as brown dog tick, is a widely distributed tick species that is substantially important for human and veterinary medicine. Therefore, it is the target of different control methods. Carvacrol and its semisynthetic derivative, acetylcarvacrol, are promising chemical compounds for alternative tick control. Thus, this study aimed to compare the repellent activities of carvacrol and acetylcarvacrol at different concentrations and drying times. Additionally, morphological alterations found in salivary glands were evaluated through histological techniques after exposure to acetylcarvacrol. The impact of the morphological changes on the development and survival of acini/cells in salivary glands was measured by a semiquantitative analysis. The repellent action of both compounds did not differ when evaluated at different concentrations, although acetylcarvacrol increased its effects as the concentration raised. Regarding the different drying times, acetylcarvacrol maintained its effects after 3 hours of exposure, while the efficacy of carvacrol decreased during this time period. Salivary glands of unfed R. sanguineus s.l. females showed dose-dependent alterations in the size and shape of acini as well as cytoplasmic vacuolization. Loss of the acinar cell limit, rupture of secretory granules and nuclear changes in the cells were also observed in the treated groups. Thus, our results demonstrated the potential of acetylcarvacrol to act as repellent against R. sanguineus s.l. Additionally, the morphological alterations found in salivary glands may interfere with the feeding process of ticks, which contributes to mitigate infestation by this species.

Neurofibromin expression by normal salivary glands

IntroductionNeurofibromin, a protein encoded by the NF1 gene, is mutated in neurofibromatosis 1, one of the most common genetic diseases. Oral manifestations are common and a high prevalence of hyposalivation was recently described in individuals with neurofibromatosis 1. Although neurofibromin is ubiquitously expressed, its expression levels vary depending on the tissue type and developmental stage of the organism. The role of neurofibromin in the development, morphology, and physiology of salivary glands is unknown and a detailed expression of neurofibromin in human normal salivary glands has never been investigated.AimTo investigate the expression levels and distribution of neurofibromin in acinar and ductal cells of major and minor salivary glands of adult individuals without NF1.Material and methodTen samples of morphologically normal major and minor salivary glands (three samples of each gland: parotid, submandibular and minor salivary; and one sample of sublingual gland) from individuals without neurofibromatosis 1 were selected to assess neurofibromin expression through immunohistochemistry. Immunoquantification was performed by a digital method.ResultsNeurofibromin was expressed in the cytoplasm of both serous and mucous acinar cells, as well as in ducts from all the samples of salivary glands. Staining intensity varied from mild to strong depending on the type of salivary gland and region (acini or ducts). Ducts had higher neurofibromin expression than acinar cells (p = 0.003). There was no statistical association between the expression of neurofibromin and the type of the salivary gland, considering acini (p = 0.09) or ducts (p = 0.50) of the four salivary glands (parotid, submandibular, minor salivary, and sublingual gland). Similar results were obtained comparing the acini (p = 0.35) and ducts (p = 0.50) of minor and major salivary glands. Besides, there was no correlation between the expression of neurofibromin and age (p = 0.08), and sex (p = 0.79) of the individuals, considering simultaneously the neurofibromin levels of acini and duct (n = 34).ConclusionNeurofibromin is expressed in the cytoplasm of serous and mucous acinar cells, and ductal cells of salivary glands, suggesting that this protein is important for salivary gland function.

Effect of homeopathy in the function and morphology of salivary parotid glands of irradiated rats

Objective: To evaluate the radioprotective effect of a homeopathic solution in salivary function and parotid glands morphology of irradiated rats. Materials and Methods: The sample consisted of 150 rats randomly divided into 6 groups. The groups were named based on the substance administered: Control- saline solution; Irradiated Control- saline solution and 15 Gy of X radiation; Alcohol-hydroalcoholic solution dynamized at 15 CH; Irradiated Alcohol- hydroalcoholic solution dynamized at 15 CH and 15 Gy of X radiation; Homeopathy- 0.25 ml (1mL/kg) of the irradiated hydroalcoholic solution and dynamized at 15 CH; Irradiated homeopathy- homeopathic solution and 15 Gy of X radiation. Each group was subdivided into 5 different subgroups, based on the time point of euthanasia: 12 hours, 3, 10, 17, and 24 days. The medication was administered for 7 days before and 7 days after the radiation treatment. On the day of euthanasia, salivation was induced with pilocarpine and collected. The animals were then sacrificed and the parotid glands were removed. Results: Salivary function analysis showed that only group irradiated homeopathy euthanized on day 17 had a statistically significant difference when compared to other irradiated groups, presenting a higher salivation flow rate. The only group that showed a statistically significant difference in the number of acini over time was the irradiated alcohol group, which presented a tendency of reduction. Conclusion: The homeopathic solution presented a late radioprotective effect based on salivary function and morphological analysis of the parotid gland.

Human Submandibular Salivary Gland Morphology Associated to Transcription and Growth Factors from Fetus to Aging

Saliva carries out several functions in the digestive system like the protection of the oral cavity and the beginning of carbohydrate digestion. This liquid is mainly produced by the submandibular gland as it is responsible for 60% of total saliva flow. This gland is characterized as acinar tubule composed, and during the fetal period, it develops in five stages, which are molded through high proliferative indices of the components. However, the aging process changes the morphology and function of this gland.Transcription factors such as Nanog and Signal transducer and activator of transcription 3 (Stat‐3) regulate the process of proliferation, ckit and musashi‐1 induce cell proliferation while epidermal growth factor (EGF) is secreted by the submandibular gland and it has combined action to the Stat‐3. Considering the importance of these transcription factors and the role of EGF, the present study evaluated immunohistochemical expression of EGF, Nanog, Ckit, Musashi‐1 and Stat‐3 in submandibular glands of human fetuses between 12 and 18 gestational weeks, in adults (40 to 55 years old) and senile (over 85 years old). It was also evaluated quantitatively the morphological changes in components during development using Image J and statistical softwares. This study was approved by the Research Ethical Committee of UNIFESP, research number 618131.The present study showed significant expression of all the transcription factors in the acinar system as in the ductal system during the stages of development. Also showed differences in the number of components between the adult and senile glands. Considering these results, we reinforce that the morphological changes observed in the submandibular gland is in consonance with the levels of the studied markers and the proliferation pattern during aging.Support or Funding InformationThis study was financed in part by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior ‐ Brasil (CAPES) Finance code 001 and also by FAPESP process number 2015/03967‐5.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Protective effects of curcumin on radioiodine-induced salivary gland dysfunction in mice.

Radioiodine (RI) treatment is widely used in patients with differentiated thyroid cancer. However, RI exposure often induces salivary gland (SG) dysfunction. In this study, we investigated the effect of curcumin on RI-induced SG dysfunction in mice. Mice were assigned to one of four groups (n=6 per group) as follows: normal control, RI only, RI+curcumin, and RI+amifostine group. Salivary flow rate, lag time, and changes in 99m Tc (technetium)-pertechnetate uptake and excretion were measured, and changes in SG morphology and histology were analysed. Salivary epidermal growth factor content, amylase, and superoxide dismutase (SOD) activities were also measured. A terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was performed to assess SG apoptosis, and the expression of apoptosis-related protein was determined by western blotting. The reduced salivary flow rate and prolonged lag time in the RI group was restored by treatment with curcumin or amifostine. In the histological analysis, compared with the RI group, RI+curcumin and RI+amifostine groups had more mucin-rich acini and less periductal fibrosis. Compared with the RI group, RI+curcumin and RI+amifostine groups showed evidence of tissue remodelling, with a greater number of salivary epithelial cells (AQP-5-positive), SG ductal cells (CK18-positive), endothelial cells (CD31-positive), and myoepithelial cells (α-SMA-positive). RI+curcumin and RI+amifostine groups alleviated RI-induced cell death, demonstrating antiapoptotic effect, compared with the RI group. Both SOD activity and the protein expression levels of SOD2 were higher in the RI+curcumin and RI+amifostine groups than in the RI group. Our results demonstrate that curcumin ameliorates RI-induced SG dysfunction in mice.

Peculiarities of Morphology of Large Salivary Glands in Experimental Animals Under Different Conditions of Motor Activity of Their Mothers During Pregnancy

Objective: To evaluate of the microstructure of the salivary glands of experimental animals born from of females rats, who were subjected to different modes of motor activity during the pregnancy: limited and compensated by regular moderate training. Material and Methods: The sample was composed 84 three-month-old descendants of Wistar rats which were divided into three groups: G1 (n = 27): posterity of female rats, who during gestation were in standard conditions; G2 (n = 25): posterity of female rats, who during pregnancy were in hypokinesia conditions; G3 (n = 32): which stayed in conditions of hypokinesia, but had running load in running wheel regularly 5 times a week. Results: In adult descendants of G2, morphological structure of the submandibular salivary glands was characterized by decrease size and number of glandular cells; reduction of their cytoplasm; increase in heterochromatin amount and decrease in the intensity of fuchsinophilia. Microstructure of the submandibular salivary glands of the offspring of G3 indicates positive effect of regular short-term physical activity on the morphofunctional state of the specified glands. An increased number of tissue basophils in their stroma is also in favor of greater functional activity of salivary glands. Conclusion: This study indicates deceleration of the metabolic processes in salivary glands of animals under the influence of hypokinesia of their mothers during pregnancy. It was also confirmed that regular physical activity completely eliminates the negative effect of mothers' hypokinesia on morphology the salivary glands of the descendant.

Role of current strategies for preventing xerostomia in oropharyngeal cancer patients: A literature review

Xerostomia occurring as sequelae of radiation therapy results in oral complications, i.e., acid erosion, dysphagia, dysgeusia, periodontal diseases, taste disturbance, and dental caries. The best strategy should be to prevent damage of any salivary acini during the course of radiotherapy; therefore, we planned to look for all the strategies for its prevention. We searched PubMed, Google Scholar, and Oral and Dentistry database thoroughly and included all the relevant articles published in the past 12 years (2005–2017). We found the following strategies for the prevention of xerostomia during radiation therapy: amifostine, pilocarpine, Vitamin C, and Vitamin E, acupuncture, bethanechol, botulism toxin, histamine, insulin growth factor, submandibular gland transfer, intensity-modulated radiation therapy, radiation stents, stem cell transplantation, intravenous injection of adipose stem cells, lasers, and lidocaine HCL. These preventive methods not only maintain the morphology and function of salivary glands but also reduces the need for saliva-enhancing therapies later.

Drosophila FoxL1 non-autonomously coordinates organ placement during embryonic development

Determining how organs attain precise positioning within an organism is a crucial facet of developmental biology. The Fox family winged-helix transcription factors are known to play key roles in development of multiple organs. Drosophila FoxL1 (aka Fd64A) is dynamically expressed in embryos but its function is completely uncharacterized. FoxL1 is expressed in a single group of body wall - muscles in the 2nd and 3rd thoracic segments, in homologous abdominal muscles at earlier stages, and in the hindgut mesoderm from early through late embryogenesis. We show that FoxL1 expression in T2 and T3 is in VIS5, which is not a single muscle spanning the entire thorax, as previously published, but is, instead, three individual muscles, each spanning a single thoracic segment. We generate mutations in foxL1 and show that, surprisingly, none of the tissues that express FoxL1 are affected by its loss. Instead, loss of foxL1 results in defects in salivary gland positioning and morphology, as well as defects in the migration of hemocytes, germ cells and Malpighian tubules. We also show that FoxL1-dependent expression of secreted Sema2a in T3 VIS5 is required for normal salivary gland positioning. Altogether, these findings suggest that Drosophila FoxL1 functions like its mammalian counterpart in non-autonomously orchestrating the behaviors of surrounding tissues.

Long- and short-term diabetes mellitus type 1 modify young and elder rat salivary glands morphology

ObjectiveIn this study we performed a temporal analysis of the effects of Diabetes Mellitus on morphology and laminin deposition in salivary glands of young (2 months-old) and aging (12 months-old) male Wistar rats, using immunohistochemistry. Materials and methodsThe animals were divided in control and diabetic (Streptozotocin induced) groups and euthanized after short and long-term diabetes induction. ResultsShort-term induction led to vacuolization of parotid acinar cells and increased laminin deposition in both animal ages. In young rats, no difference was observed between short or long-term diabetes regarding laminin deposition, but parotid acinar cells vacuolization was more discrete after long-term diabetes. A slight decrease of submandibular gland convoluted granular ducts was observed in young and elder diabetic animal ages. In diabetic aging rats was observed an increase of laminin content only in the parotid gland. ConclusionsThese results suggest that some Diabetes Mellitus effects on salivary glands are not progressive over time, possibly due to the existence of adaptive mechanisms in response to chronic hyperglycemia. They also show that the duration of the disease was more relevant to the morphological effects than the age, although it is known that aging per se affects salivary gland morphology and function.

Feeding and related morphology of salivary glands of Bradysia odoriphaga (Diptera: Sciaridae)

The amount of Bradysia odoriphaga larval feeding at each developmental stage and the related morphology of salivary glands were investigated in this study. The amount of daily feeding in the third instar was greatest among all the developmental stages while the amount of cumulative feeding in the fourth-instar accounted for 53.56% of the total amount of larval feeding. The daily amount of feeding by B. odoriphaga during the whole larval stage peaked in the 8th and 14th day after hatching. The paired and transparent salivary glands of B. odoriphaga were characterized by two distinct regions: an anterior region and a posterior region. At the fourth-instar and pupal stage, the length of salivary glands decreased significantly compared with that of the third-instar, and the integrity of epithelium cytoplasm in the salivary glands also decreased markedly because of the formation of cytoplasmic vacuoles and degradation of rough endoplasmic reticulum and mitochondria. We concluded that the decrease of daily feeding amount in the last instar was related to the structural change of salivary gland closely. The function of salivary glands in B. odoriphaga was mainly secretion of silk and cocooning-like materials during the last larval instar.

Salivary gland morphology, tissue tropism and the progression of tospovirus infection in Frankliniella occidentalis

Tomato spotted wilt virus (TSWV) is transmitted by thrips in a propagative manner; however, progression of virus infection in the insect is not fully understood. The goal of this work was to study the morphology and infection of thrips salivary glands. The primary salivary glands (PSG) are complex, with three distinct regions that may have unique functions. Analysis of TSWV progression in thrips revealed the presence of viral proteins in the foregut, midgut, ligaments, tubular salivary glands (TSG), and efferent duct and filament structures connecting the TSG and PSG of first and second instar larvae. The primary site of virus infection shifted from the midgut and TSG in the larvae to the PSG in adults, suggesting that tissue tropism changes with insect development. TSG infection was detected in advance of PSG infection. These findings support the hypothesis that the TSG are involved in trafficking of TSWV to the PSG.

Aquaporins in Salivary Glands: From Basic Research to Clinical Applications.

Salivary glands are involved in saliva secretion that ensures proper oral health. Aquaporins are expressed in salivary glands and play a major role in saliva secretion. This review will provide an overview of the salivary gland morphology and physiology of saliva secretion, and focus on the expression, subcellular localization and role of aquaporins under physiological and pathophysiological conditions, as well as clinical applications involving aquaporins. This review is highlighting expression and localization of aquaporins in human, rat and mouse, the most studied species and is pointing out possible difference between major salivary glands, i.e., parotid, submandibular and sublingual glands.

Protective efficacy of intravenous transplantation of adipose-derived stem cells for the prevention of radiation-induced salivary gland damage

ObjectiveHigh-dose radiation therapy in the head and neck area can lead to irreversible damage to salivary glands (SGs) with consequent xerostomia. Adipose-derived stem cells (ADSCs) have been shown to repair or rescue damaged SGs. Thus, we investigated the protective efficacy of ADSCs in the prevention of SG damage induced by high dose radiation. MethodsThird-passage ADSCs (1×106) were transplanted by intravenous infusion into the tail-vein of 8-week-old C57BL/6 mice, immediately after local irritation at a dose of 18Gy. The process was repeated twice a week during a period of six consecutive weeks. Eight weeks after radiation, functional evaluations were conducted by measuring salivary flow rate (SFR). Histological, immunohistochemical and transmission electron microscopic (TEM) examinations were performed to analyze microstructural and ultrastructural changes, microvessel density, amylase production, apoptosis, and proliferation activity. ResultsIntravenously administrated ADSCs could home to irradiated SGs within 24h after infusion, significantly increasing SG weights, improving SFR, and preserving the microscopic morphologies of SGs eight weeks post-radiation. More functional acini, higher amylase production levels, and higher microvessel densities were observed in ADSC-treated SGs than in irradiated SGs. Additionally, enhanced cell proliferation activity and reduced radiation-induced SG apoptosis was observed in the ADSC-treated group when compared with the irradiated group. ConclusionSystemic administration of ADSCs immediately after radiation at a dose of 18Gy can protect both the morphology and function of SGs eight weeks after radiation in mice, and can be used as a protective measure for the prevention of SG damage induced by high-dose radiation.