Rat Salivary Glands Research Articles

The single-strand DNA-binding protein SSB1 is involved in the expression of salivary gland radiation injury repair.

Single-strand DNA-binding protein 1 (SSB1) plays a crucial role in the cellular response to DNA damage. This study aimed to explore the expression and regulation of SSB1 in normal rat salivary gland tissues and tissues following radiation, with a specific emphasis on its involvement in the repair of salivary gland injury. A total of 45 adult SD rats were randomly assigned to one control group or eight experimental groups. In the control group, five rats were euthanized without irradiation, and their parotid gland tissues were collected for analysis. The experimental groups received a dose of 6Gy of radiation targeting the head and neck region; subsequently, five rats from each group were euthanized hly to collect parotid gland tissue samples, resulting in a total of eight experimental groups. The expression levels of SSB1, γ-H2AX, and PARP1 in the parotid gland tissues were assessed via immunohistochemistry, while changes in SSB1 gene expression were quantified via RT-qPCR. No significant morphological differences were observed between the two groups following HE staining. In the immunohistochemistry (IHC) analysis, notable tissue-specific variation in SSB1 expression was identified, with higher levels detected in the ducts than in the acini and connective tissue. The expression of SSB1 gene initially increased post-radiation before subsequently decreasing, ultimately returning to baseline levels, as corroborated by the RT-qPCR results. In contrast, γ-H2AX and PARP1 exhibited minimal expression in the control group; however, their expression peaked at 1h in the experimental group before gradually declining to levels comparable to those of the control group. Radiation induces time-dependent upregulation of SSB1 expression in rat salivary glands, indicating that SSB1 may play a role in radiation-induced repair processes.

Impact of chlorogenic acid on submandibular salivary gland and liver of albino rats exposed to sodium nitrite

AimThe aim of the present study is to show how sodium nitrite alters the histology of submandibular salivary glands and livers of Albino rats, as well as how chlorogenic acid may have therapeutic benefits.MethodsA sample size of thirty male Sprague Dawley Albino rats weighing between 100 and 150 g (5-6 weeks old) was randomly allocated into 3 equal groups. Group I: rats were used as controls and were given phosphate buffer solution, whereas Group II: rats were given an 80 mg/kg sodium nitrites (SN) daily dissolved in distilled water. The rats in Group III were given a daily dose of 80 mg/kg SN dissolved in distilled water and after 6 hours each rat received 50 mg/mL freshly prepared chlorogenic acid (CGA) every other day. For 12 weeks, all treatment modalities will be administered orally, every day. After the experiment, all rats were euthanized. Samples from salivary glands and livers were processed and stained with H&E and interleukin 6 (IL 6). Malondialdehyde (MDA) and superoxide dismutase (SOD) enzymes were detected using an ELISA assay.ResultsGroups III had nearly comparable findings to Group I regarding histological pattern with normal submandibular glands and livers features. Group III salivary gland treated with CGA exhibited higher SOD levels (20.60±4.81 U/g) in comparison to the SN group, and lower MDA levels (111.58±28.28 nmol/mg) in comparison to the SN treated samples. In comparison to the SN group, CGA treatment significantly reduced MDA levels in liver samples (167.56±21.17 nmol/mg) and raised SOD (30.85±6.77 U/g).ConclusionsChlorogenic acid has a protective effect against salivary gland and liver toxicity induced by SN in rats. This was mediated via the anti-inflammatory and antioxidative properties of CGA and the restoration of oxidant/antioxidant balance in rat salivary gland and liver.

The Antioxidative Role of Moringa Oil extract in Modulating Histological and Biochemical Changes in the Salivary Glands of Rats Under Oxidative Stress Induction

The Antioxidative Role of Moringa Oil extract in Modulating Histological and Biochemical Changes in the Salivary Glands of Rats Under Oxidative Stress Induction

Correlation between the expression of the iNOS, caspase-3 and α-SMA genes in the parotid glands of albino rats following the administration of two antihistamines from two different generations.

Several medications, including antihistamines, can alter salivary gland function, causing dry mouth or xerostomia. Antihistamines are commonly used for treating allergic rhinitis. The aim of the present study was to compare and correlate the effects of first-generation vs. second-generation H1-antihistamines on the parotid glands of rats. Twelve adult male albino rats were used; 4 rats served as a control group (group I) and the remaining rats were divided into 2 groups: group II received promethazine hydrochloride; and group III received cetirizine dihydrochloride for 3 weeks. The parotid salivary glands were dissected, and examined histologically and analyzed histomorphometrically for the acinar area percentage. In addition, mRNA gene expression of iNOS, caspase-3 and α-SMA was assessed using quantitative realtime polymerase chain reaction (qRT-PCR). Finally, all the obtained data was statistically analyzed. Histologically, group I showed the typical architecture of the gland. In group II, degenerative changes were noticed, including acinar degeneration and shrinkage with widened connective tissue septa, intracellular vacuolization, and increased inflammatory cell infiltration. In group III, similar histological features were detected as in group II, but to a lesser extent. Histomorphometric results revealed significant differences in the acinar area percentage between various groups. In addition, qRT-PCR results showed a significant increase in iNOS expression in both groups II and III as compared to group I, caspase-3 gene expression was significantly increased in group II, while in group III, it increased non-significantly. Finally, α-SMA gene expression non-significantly decreased in both groups II and III. A significant positive correlation was observed between caspase-3 and iNOS gene expression, while an inverse correlation was noticed between caspase-3 and α-SMA gene expression. The administration of antihistamines resulted in changes in the rat salivary glands, which could be due to the induction of oxidative stress and the resultant apoptotic effect. These changes were suggested to occur mainly through action on muscarinic receptors; yet, action on histamine receptors could not be excluded. However; these effects were less marked with the second-generation antihistamine.

Effect of lipopolysaccharide on the development of oxidativenitrosative stress in salivary glands and soft periodontal tissues of rats under conditions of water avoidance stress

Introduction and aim. Violation in the salivary glands will inevitably cause changes in periodontium, and periodontitis can disrupt the functioning of the salivary glands. The purpose of the work is to evaluate changes in NO-synthase and arginase activities, pro- and antioxidant balance in rat salivary glands and soft periodontal tissues during administration of bacterial lipopolysaccharide (LPS) and water avoidance stress (WAS) modeling. Material and methods. The experiment was performed on 24 rats. The animals were divided into 4 groups: control, WAS, animals injected intraperitoneally with 0.4 μg/kg of bacterial LPS of Salmonella typhi, WAS+LPS. Results. Water avoidance stress led to decrease of inducible NO-synthase (iNOS) activity in salivary glands by 1.63 times, but decreased arginase activity by 1.15 times, superoxide production increased by 1.53 times, catalase activity decreased by 1.2 times, and malonic dialdehyde (MDA) increased by 1.19 times compared to the control. Lipopolysaccharide led to increase of constitutive NO-synthases (cNOS) activity in salivary glands by 1.48 times, but decreased arginase activity by 6.15 times, catalase activity increased by 2.6 times and superoxide dismutase activity decreased by 2.74 times, and MDA increased by 6.84 times compared to the control. Water avoidance stress + LPS in salivary glands led to decrease of cNOS and arginase activity by 1.09 and 1.19 times, respectively, superoxide production increased by 1.88 times, catalase and superoxide dismutase activity decreased by 1.06 times and 1.34 times, respectively, and MDA increased by 2.44 times compared to the control. Water avoidance stress led to increase of iNOS activity in periodontium by 1.44 times and arginase activity decreased by 1.37 times, superoxide production increased 1.32 times, catalase activity and superoxide dismutase activities decreased by 1.27 times and by 1.53 times, respectively, and MDA increased by 1.31 times compared to the control. Lipopolysaccharide led to increase of iNOS activity in the periodontium by 3.88 times, arginase activity decreased by 2.69 times, superoxide production increased 1.64 times, catalase activity increased by 4.32 times, and MDA increased by 4.51 times compared to the control. Water avoidance stress + LPS in periodontium led to increase of iNOS and cNOS activities by 1.95 times and 1.53, respectively, arginase activity decreased by 1.39 times, superoxide production increased 1.66 times, catalase activity increased by 1.11 times, and MDA increased by 1.53 times compared to the control. Conclusion. The combination of LPS and WAS leads to changes in NO production and oxidative stress in salivary glands and the periodontium.

CORRECTION OF PATHOLOGICAL CHANGES IN SALIVARY GLANDS OF ANIMALS WITH PACLITAXEL-INDUCED NEUROPATHY

Background. Paclitaxel is a highly effective chemotherapeutic agent used to treat breast, ovarian, and other cancers. At the same time, paclitaxel causes peripheral neuropathy as a side effect in 45%—70% of patients. Aim. The aim of the study was to investigate the effect of paclitaxel-induced peripheral neuropathy on the development of pathological changes in the salivary glands of animals and to explore the possibility of correction of the identified changes with vitamin B/ATP complex. Materials and Methods. To simulate toxic neuropathy, animals were injected i/p with paclitaxel 2 mg/kg for 4 days. In order to correct the identified changes, rats were injected i/m with vitamin B/ATP complex (1 mg/ kg) for 9 days. In the homogenate of the submandibular salivary glands, α-amylase activity, total proteolytic activity, total antitryptic activity, the content of medium mass molecules, thiobarbituric acid reactive substances (TBARS), oxidatively modified proteins, and catalase activity were determined. Results. A significant increase in the content of oxidatively modified proteins, medium mass molecules, and the content of TBARS and significant decrease in the activity of catalase and amylase were determined in the salivary glands of animals with toxic neuropathy compared to these parameters in intact animals. Administration of vitamin B/ATP complex for 9 days against the background of paclitaxel-induced neuropathy led to normalization of antitryptic activity and amylase activity, a significant decrease in the content of oxidatively modified proteins, medium mass molecules, and TBARS along with a significant increase in catalase activity in the salivary glands of animals compared to the untreated rats with neuropathy. Conclusion. Paclitaxel-induced neuropathy caused the development of pathological changes in the salivary glands of rats, which was evidenced by a carbonyl- oxidative stress and impaired protein synthetic function. The correction with vitamin B/ATP complex restored the protein-synthetic function and the proteinase-inhibitor balance, suppressed the oxidative stress and normalized free radical processes in the salivary glands of rats.

THE INFLUENCE OF QUERCETIN ON THE PRODUCTION OF REACTIVE OXYGEN-NITROGEN FORMS IN THE STRUCTURE OF THE INTERSTITIAL SPACE OF RAT TESTICLES WITH LONG-TERM EFFECT OF TRIPTORELIN

Quercetin is a flavonoid commonly found in fruits, vegetables, and seeds. Flavonoids can help prevent cardiovascular diseases, reduce the risk of degenerative brain processes and cancer. Studies have shown that blocking the synthesis of luteinising hormone can lead to oxidative stress in the liver, heart, and salivary glands of rats. The purpose of this study was to assess alterations in the interstitial space of rat testes, identify sources of nitric oxide production, and measure the intensity of oxidative stress in the testes during long-term experimental central blocking of luteinising hormone synthesis by tryptorelin. The study was conducted on 15 sexually mature male white rats. The animals were divided into two groups. The first group (control) received a subcutaneous injection of 0.9% sodium chloride solution. The second group (experimental) received a subcutaneous injection of tryptorelin at a dose of 0.3 mg/kg of active ingredient for 365 days, with simultaneous addition of quercetin to the diet, which was administered orally through a gastric tube three times a day. Total nitric oxide production was assessed by measuring the activity of total NO synthase (gNOS). The activity of gNOS was determined by the increase in nitrite (NO2-) after incubation in Tris-buffered saline. The nitrite concentration was determined using the Gris-Ilosvay reagent at a wavelength of 540 nm. The activity of the inducible (iNOS) and constitutive (cNOS) isoforms was also determined using a selective iNOS inhibitor, aminoguanidine hydrochloride. The production of superoxide anion radical (O2--) was measured by the increase in the formation of diformazan resulting from the reaction of O2-- with nitroblue tetrazolium after incubation in a buffered solution containing sodium hydroxide. The administration of quercetin mitigates the adverse effects of tryptorelin on the structural and functional components of the connective tissue in the rat testes. This effect is observed on day 365 and is characterised by fibrosis and impaired nitric oxide production by constitutive isoforms of NO synthase.

Distribution of alpha-synuclein in rat salivary glands.

Expression of alpha-synuclein (Syn), a presynaptic neuronal protein, was immunohistochemically examined in intact rat submandibular, sublingual, and lingual glands. The submandibular gland contained abundant periductal Syn-immunoreactive (-ir) nerve fibers. Abundant Syn-ir varicosities were present in acini of the sublingual and serous lingual glands. By confocal laser scanning microscopy, Syn-ir nerve fibers around smooth muscle actin (SMA)-ir cells alone were infrequent; however, those around aquaporin-5 (AQP5)-ir cells alone and both SMA- and AQP5-ir cells were abundant in the sublingual and serous lingual glands. SMA-ir cells were occasionally immunoreactive for toll-like receptor 4, a Syn receptor. Syn-ir nerve fibers contained tyrosine hydroxylase (TH) in the submandibular gland and choline acetyltransferase (ChAT) in all examined salivary glands. In the superior cervical (SCG), submandibular, and intralingual ganglia, sympathetic and parasympathetic neurons co-expressed Syn with TH and ChAT, respectively. SCG neurons innervating the submandibular gland contained mostly Syn. In the thoracic spinal cord, 14.7% of ChAT-ir preganglionic sympathetic neurons co-expressed Syn. In the superior salivatory nucleus, preganglionic parasympathetic neurons projecting to the lingual nerve co-expressed Syn and ChAT. The present findings indicate that released Syn acts on myoepithelial cells. Syn in pre- and post-ganglionic neurons may regulate neurotransmitter release and salivary volume and composition.

Application Site of Transdermal Scopolamine Influences Efficacy and Drug Concentration in Salivary Glands in Rats.

Transdermal scopolamine applied to the postauricular area is used to treat drooling. We investigated the duration of action of scopolamine ointment and the effect of the application site on drug efficacy and concentration in the salivary glands of rats. Scopolamine ointment was applied to the skin over the salivary glands (SSG) and back (SB). Saliva volume was measured after intraperitoneal administration of pilocarpine. Blood and salivary glands were collected after scopolamine ointment application, and scopolamine concentrations in the plasma and salivary glands were measured. Saliva volume after application in the SSG group was significantly lower at all time points than in the non-treated group, and the change in saliva volume in the SSG group was greater than that in the SB group at all time points. This suggests that applying scopolamine ointment to the SSG strongly suppresses salivary secretion. Scopolamine concentration in the salivary glands of the SSG group was significantly higher at 9 h. The change in the efficacy of scopolamine ointment depending on the application site was due to the difference in transfer to the salivary glands. Transdermal administration of scopolamine to the skin over the salivary glands may have high efficiency in treating drooling.

Injectable decellularized extracellular matrix hydrogel promotes salivary gland regeneration via endogenous stem cell recruitment and suppression of fibrogenesis.

Saliva is key to the maintenance of oral homeostasis. However, several forms of salivary gland (SG) disorders, followed by hyposalivation, often result in dental caries, oral infection, and decreased taste, which dramatically affect the quality of patient's life. Functional biomaterials hold great potential for tissue regeneration in damaged or dysfunctional SGs and maintaining the good health of oral cavity. Herein, we prepared an injectable hydrogel derived from decellularized porcine submandibular glands (pDSG-gel), the material and biological properties of the hydrogel were systematically investigated. First, good biocompatibility and bioactivities of the pDSG-gel were validated in 2D and 3D cultures of primary submandibular gland mesenchymal stem cells (SGMSCs). Especially, the pDSG-gel effectively facilitated SGMSCs migration and recruitment through the activation of PI3K/AKT signaling pathway, suggested by transcriptomic analysis and immunoblotting. Furthermore, proteomic analysis of the pDSG revealed that many extracellular matrix components and secreted factors were preserved, which may contribute to stem cell homing. The recruitment of endogenous SG cells was confirmed in vivo, upon in situ injection of the pDSG-gel into the defective SGs in rats. Acinar and ductal-like structures were evident in the injury sites after pDSG-gel treatment, suggesting the reconstruction of functional SG units. Meanwhile, histological characterizations showed that the administration of the pDSG-gel also significantly suppressed fibrogenesis within the injured SG tissues. Taken together, this tissue-specific hydrogel provides a pro-regenerative microenvironment for endogenous SG regeneration and holds great promise as a powerful and bioactive material for future treatments of SG diseases. STATEMENT OF SIGNIFICANCE: Decellularized extracellular matrix (dECM) has been acknowledged as one of the most promising biomaterials that recapitalizes the microenvironment in native tissues. Hydrogel derived from the dECM allows in situ administration for tissue repair. Herein, a tissue-specific dECM hydrogel derived from porcine salivary glands (pDSG-gel) was successfully prepared and developed for functional reconstruction of defective salivary gland (SG) tissues. The pDSG-gel effectively accelerated endogenous SG stem cells migration and their recruitment for acinar- and ductal-like regeneration, which was attributed to the activation of PI3K/AKT signaling pathway. Additionally, the introduction of the pDSG-gel resulted in highly suppressed fibrogenesis in the defective tissues. These outcomes indicated that the pDSG-gel holds great potential in clinical translation toward SG regeneration through cell-free treatments.

The effect of Metformin on salivary glands of rats with streptozocin-induced diabetes

The effect of Metformin on salivary glands of rats with streptozocin-induced diabetes

Alterations in salivary biochemical composition and redox state disruption induced by the anticonvulsant valproic acid in male rat salivary glands

ObjectiveTo investigate the effects of the anticonvulsant valproic acid (VPA) on salivary glands in male rat using biochemical, functional, histomorphometric, and redox state parameters. Materials and methodsTwenty-four male Wistar rats were randomly distributed into three groups (n = 8 per group): Control (0.9% saline solution), VPA100 (100 mg/kg), and VPA400 (400 mg/kg). After 21 consecutive days of treatment with by intragastric gavage. Pilocarpine-induced saliva was collected to determine salivary flow rate, pH, buffering capacity, and biochemical composition. Analyses of histomorphometric parameters and redox balance markers were performed on the parotid and submandibular glands. ResultsSalivary flow rate, pH, buffering capacity, total protein, potassium, sodium, and chloride were similar between groups. However, phosphate and calcium were reduced in VPA400, while amylase was increased in both VPA100 and VPA400. We did not detect significant differences in the areas of acini, ducts, and connective tissue in the salivary glands between the groups. There were no significant changes in the redox status of the submandibular glands. In turn, in the parotid glands we detected reduced total oxidizing capacity and lipid peroxidation, measured as thiobarbituric acid reactive substances (TBARs) and higher uric acid concentration in both the VPA100 and VPA400 groups, and increased superoxide dismutase (SOD) in the VPA400 group. ConclusionChronic treatment with VPA modified the salivary biochemical composition and caused disruption in the redox state of the parotid gland in rats.

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.

Effects of Diabetes and Voluntary Exercise on IgA Concentration and Polymeric Immunoglobulin Receptor Expression in the Submandibular Gland of Rats.

Background and Objectives: Patients with diabetes are more susceptible to upper respiratory tract infections (URTIs) because they are easily infected. Salivary IgA (sali-IgA) levels play a major role in transmitting URTIs. Sali-IgA levels are determined by salivary gland IgA production and polymeric immunoglobulin receptor (poly-IgR) expression. However, it is unknown whether salivary gland IgA production and poly-IgR expression are decreased in patients with diabetes. While exercise is reported to increase or decrease the sali-IgA levels, it is unclear how exercise affects the salivary glands of patients with diabetes. This study aimed to determine the effects of diabetes and voluntary exercise on IgA production and poly-IgR expression in the salivary glands of diabetic rats. Materials and Methods: Ten spontaneously diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats (eight-week-old) were divided into two groups of five rats each: a non-exercise group (OLETF-C) and a voluntary wheel-running group (OLETF-E). Five Long-Evans Tokushima Otsuka (LETO) rats without diabetes were bred under the same conditions as the OLETF-C. Sixteen weeks after the study began, the submandibular glands (SGs) were collected and analyzed for IgA and poly-IgR expression levels. Results: IgA concentrations and poly-IgR expression levels in SGs were lower in OLETF-C and OLETF-E than in LETO (p < 0.05). These values did not differ between the OLETF-C and OLETF-E. Conclusions: Diabetes decreases IgA production and poly-IgR expression in the salivary glands of rats. Moreover, voluntary exercise increases sali-IgA levels but does not increase IgA production and poly-IgR expression in the salivary glands of diabetic rats. Increasing IgA production and poly-IgR expression in the salivary glands, which is reduced in diabetes, might require slightly higher-intensity exercise than voluntary exercise under the supervision of a doctor.

The NF-κB pathway plays a vital role in rat salivary gland atrophy model

ObjectiveThe aim of this study was to explore the histopathological and genetic changes in the submandibular glands after duct ligation and provide important clues to functional regeneration. DesignWe established a rat salivary gland duct ligation model and observed pathological changes in the rat submandibular gland on day 1 and weeks 1, 2, 3, and 4 using hematoxylin and eosin staining, Alcian blue–periodic acid Schiff staining, Masson staining, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL), and immunohistochemical staining. RNA sequencing was performed on normal salivary glands and those from the ligation model after 1 week. Significantly differentially expressed genes were selected, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed. ResultsApoptosis levels and histological and functional KEGG pathway analyses showed that injury to the salivary gland after ligation gradually increased. The TGF-β pathway was activated and promoted fibrosis. RNA sequencing results and further verification of samples at week 1 showed that the NF-κB pathway plays a vital role in salivary gland atrophy. ConclusionsOur results detailed the pathological changes in the submandibular gland after ligation and the important functions of the NF-κB pathway.

Paclitaxel-induced neuropathy induces changes in oral cavity organs of rats

The developmental mechanisms of pathological changes in the oral cavity organs, in particular, periodontal tissues and salivary glands, were elucidated in the model of paclitaxel-induced neuropathy. Experimental studies were performed on 41 white nonlinear rats of both sexes weighing 180–220 g. Toxic neuropathy was modeled by intraperitoneal injection of paclitaxel (Actavis Ltd; series 5GN5122) 2 mg/kg for 4 days (0, 2, 4 and 6). The presence of paclitaxel-induced peripheral neuropathy was confirmed by the Randall-Selitto tensoalgometric test to determine the threshold of pain sensitivity. The total proteolytic activity, total antitryptic activity, and the content of TBA-active products were determined in the homogenate of the rat submandibular and sublingual salivary glands and periodontal soft tissues, content of oxidatively modified proteins, content of average mass molecules and catalase activity; α-amylase activity was also determined in the salivary glands of animals, and the content of free fucose and glycosaminoglycans in periodontal tissues. Paclitaxel-induced neuropathy causes the development of pathological changes in the oral cavity, in particular in periodontal tissues and salivary glands of rats, as evidenced by impaired proteinase-inhibitory potential, intensification of carbonyl oxidative stress, inhibition of protein synthetic function in salivary glands and increased depolymerization of non-collagenous proteins in periodontal soft tissues.

Impact of bone marrow mesenchymal stem cells on the submandibular gland structure of adult male albino rats exposed to cadmium chloride toxicity

ObjectiveThis study was carried out in submandibular salivary glands of rats to demonstrate the changes induced by cadmium intoxication and the possible prophylactic and therapeutic effects of bone marrow mesenchymal stem cells (BMSCs). DesignSixty-five rats were divided into five groups. Rats in Group I were controls while those of Group II received daily dose of 10 mg/kg cadmium for 24 days. Rats in Group III received single prophylactic dose of 1 × 106 BMSCs one week before cadmium administration. Rats of Group IV were concomitantly administered cadmium and BMSCs, while those of Group V received cadmium for 24 days and were then treated with single dose of 1 × 106 BMSCs. Rats of Groups I, II, III, and IV were euthanized at the end of the experiment while those of Group V were euthanized one week later. Salivary gland specimens were processed and stained with H&E and inducible nitric oxide synthase; other specimens were used to demonstrate metallothionein gene expression using RT-PCR, malondialdehyde and catalase enzymes were detected by ELISA. ResultsGroups III and IV had nearly comparable findings to Group I regarding histological pattern with normal gland features. Group III recorded a lower fold of change for metallothionein gene (1.14 ± 0.20), a lower malondialdehyde enzyme (21.67 ± 1.63 nmol/mg), and a higher catalase enzyme (66.33 ± 2.16 mmol/mg). Regarding all variables, significant differences were found between the different groups (P < 0.001). ConclusionBMSCs have prophylactic and therapeutic effects against cadmium-induced cytotoxicity in rat salivary glands.

A novel cell-based transplantation method using a Rho kinase inhibitor and a specific catheter device for the treatment of salivary gland damage after head and neck radiotherapy

Radiotherapy (RT) for head and neck cancer results in irreversible damage to salivary glands (SGs) and decreases saliva production, leading to a dry mouth. To date, there are no satisfactory therapies to solve this problem. We recently established a novel culturing method using a Rho kinase inhibitor (RI), Y-27632, that maintained cellular morphology and function for a prolonged period of time. In the present study, we investigated whether cell-based transplantation using our culturing method ameliorated the dysfunction of irradiated SGs. First, rat SG cells were cultured in a medium with RI. Cells were characterized by morphological findings and mRNA expression analysis. We also assessed features of SG cells in three-dimensional (3-D) culture by scanning electron microscopy and immunohistochemistry (IHC). The RI-containing medium led to higher cell proliferation of rat SG cells with preservation of cell morphology and higher alpha-amylase (AMY) expression in both 2-D and 3-D culture systems. To establish the atrophic-SG models, external RT at a dose of 15 Gy was delivered to the head and neck fields of nude rats. The SG cells derived from GFP-rats were cultured in medium with RI, after which they were transplanted into the submandibular glands of atrophic-SG rats using a catheter placed into Wharton's duct. IHC and salivary flow rate (SFR) analyses were measured 12 weeks after the transplantation. Following transplantation, donor cells (GFP-SG cells) were primarily located in the ductal region of the SG, and AMY expression in SGs and the SFR were increased in the SG cell transplantation group compared with the control. Those data indicated that cell-based therapy using RI-treated SG cells could restore salivary hypofunction of irradiated SGs by direct integration of the donor cells in the duct of SGs. We propose that these data support future clinical plans in which SG cells would be excised from the labial minor SGs of the patients with head and neck cancers prior to RT, cultured during RT, and auto-transplanted into SGs using a catheter into the Wharton's duct. We believe that our culturing and transplantation methods can be applied to SG cells, constituting a therapeutic approach for the treatment of patients with dry mouth after not only RT but also aging and Sjögren's syndrome.

Glyphosate and AMPA in Human Urine of HBM4EU-Aligned Studies: Part B Adults.

Within HBM4EU, human biomonitoring (HBM) studies measuring glyphosate (Gly) and aminomethylphosphonic acid (AMPA) in urine samples from the general adult population were aligned and quality-controlled/assured. Data from four studies (ESB Germany (2015–2020); Swiss HBM4EU study (2020); DIET-HBM Iceland (2019–2020); ESTEBAN France (2014–2016)) were included representing Northern and Western Europe. Overall, median values were below the reported quantification limits (LOQs) (0.05–0.1 µg/L). The 95th percentiles (P95) ranged between 0.24 and 0.37 µg/L urine for Gly and between 0.21 and 0.38 µg/L for AMPA. Lower values were observed in adults compared to children. Indications exist for autonomous sources of AMPA in the environment. As for children, reversed dosimetry calculations based on HBM data in adults did not lead to exceedances of the ADI (proposed acceptable daily intake of EFSA for Gly 0.1 mg/kg bw/day based on histopathological findings in the salivary gland of rats) indicating no human health risks in the studied populations at the moment. However, the controversy on carcinogenicity, potential endocrine effects and the absence of a group ADI for Gly and AMPA induce uncertainty to the risk assessment. Exposure determinant analysis showed few significant associations. More data on specific subgroups, such as those occupationally exposed or living close to agricultural fields or with certain consumption patterns (vegetarian, vegan, organic food, high cereal consumer), are needed to evaluate major exposure sources.

Tuft Cells Are Present in Submandibular Glands Across Species.

Tuft cells are bottle-shaped, microvilli-projecting chemosensory cells located in the lining of a variety of epithelial tissues and, following their identification approximately 60 years ago, have been linked to immune system function in a variety of epithelia. Until recently, Tuft cells had not been convincingly demonstrated to be present in salivary glands with their detection by transmission electron microscopy only shown in a handful of earlier studies using rat salivary glands, and no follow-up work has been conducted to verify their presence in salivary glands of other species. Here, we demonstrate that Tuft cells are present in the submandibular glands of various species (i.e., mouse, pig and human) using transmission electron microscopy and confocal immunofluorescent analysis for the POU class 2 homeobox 3 (POU2F3), which is considered to be a master regulator of Tuft cell identity.