Endocannabinoids mediate hyposalivation induced by inflammogens in the submandibular glands and hypothalamus

Objective: The aim of this study was to investigate the factors that could participate on salivary glands hypofunction during inflammation and the participation of endocannabinoids in hyposalivation induced by the presence of inflammogens in the submandibular gland (SMG) or in the brain. Design: Salivary secretion was assessed in the presence of inflammogens and/or the cannabinoid receptor antagonist AM251 in the SMG or in the brain of rats. At the end of the experiments, some systemic and glandular inflammatory markers were measured and histopathological analysis was performed. Results: The inhibitory effect observed 1 h after lipopolysaccharide (LPS, 50 μg/50 μl) injection into the SMG (ig) was completely prevented by the injection of AM251 (5 μg/50 μl) by the same route (P < 0.05). The LPS (ig)-induced increase in PGE2 content was not altered by AM251 (ig), while the glandular production of TNFa induced by the endotoxin (P < 0.001) was partially blocked by it. Also, LPS injection produced no significant changes in the wet weight of the SMG neither damage to lipid membranes of its cells, nor significant microscopic changes in them, after hispopathological analysis, compared to controls. Finally, TNFα (100 ng/5 μl) injected intracerebro-ventricularly (icv) inhibited methacholine-induced salivary secretion evaluated 30 min after (P < 0.01), but the previous injection of AM251 (500 ng/5 μl, icv) prevented completely that effect. Conclusion: We conclude that endocannabinoids mediate the hyposialia induced by inflammogens in the SMG and in the brain. The hypofunction would be due to changes on signalling pathway produced by inflammatory compounds since anatomical changes were not observed. © 2013 Elsevier Ltd. All rights reserved.Fil: Prestifilippo, Juan Pablo. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Fisiología; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Ciencias Biológicas. Cátedra de Fisiopatología; ArgentinaFil: Medina, Vanina Araceli. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Fisicomatemática. Cátedra de Física; ArgentinaFil: Mohn, Claudia Ester. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Fisiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Rodriguez, P. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - La Plata. Unidad de Administración Territorial; Argentina. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Elverdin, Juan Carlos. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Fisiología; ArgentinaFil: Fernández Solari, Jose Javier. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Fisiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin

Endocannabinoids in TNF-α and Ethanol Actions

During marijuana and alcohol consumption as well as during inflammation the reproductive axis is inhibited, mainly through the inhibition of luteinizing hormone-releasing hormone release. In male rats, this inhibitory effect is mediated, at least in part, by the activation of hypothalamic cannabinoid type 1 receptors (CB1). During inflammation, this activation of the endocannabinoid system seems to be mediated by an increase in TNF-α production followed by anandamide augmentations, similarly the effect of intragastric administration of ethanol (3 g/kg) seems to be due to an increase in anandamide. On the other hand, a number of different actions mediated by the endocannabinoid system in various organs and tissues have been described. Both cannabinoid receptors, CB1 and CB2, are localized in the submandibular gland where they mediate the inhibitory effect of intrasubmandibular injections of the endocannabinoid anandamide (6 × 10–5M) on salivary secretion. Lipopolysaccharide (5 mg/kg/3 h) injected intraperitoneally and ethanol (3 g/kg/1 h) injected intragastrically inhibited the salivary secretion induced by the sialogogue metacholine; this inhibitory effect was blocked by CB1 and/or CB2 receptor antagonists. Similar to the hypothalamus, these effects seem to be mediated by increased anandamide. In summary, similar mechanisms mediate the inhibitory actions of endocannabinoids and cannabinoids in both hypothalamus and submandibular gland during drug consumption and inflammation.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich

Protection of radiation-induced damage to the hematopoietic system, small intestine and salivary glands in rats by JNJ7777120 compound, a histamine H4 ligand.

Based on previous data on the histamine radioprotective effect on highly radiosensitive tissues, in the present work we aimed at investigating the radioprotective potential of the H4R ligand, JNJ7777120, on ionizing radiation-induced injury and genotoxic damage in small intestine, salivary glands and hematopoietic tissue. For that purpose, rats were divided into 4 groups. JNJ7777120 and JNJ7777120-irradiated groups received a daily subcutaneous JNJ7777120 injection (10 mg/kg) starting 24 h before irradiation. Irradiated groups received a single dose of 5 Gy on whole-body using Cesium-137 source and were sacrificed 3 or 30 days after irradiation. Tissues were removed, fixed, stained with hematoxylin and eosin or PAS staining and histological characteristics were evaluated. Proliferative and apoptotic markers were studied by immunohistochemistry, while micronucleus assay was performed to evaluate DNA damage. Submandibular gland (SMG) function was evaluated by methacholine-induced salivation. Results indicate that JNJ7777120 treatment diminished mucosal atrophy and preserved villi and the number of crypts after radiation exposure (240±8 vs. 165±10, P<0.01). This effect was associated to a reduced apoptosis and DNA damage in intestinal crypts. JNJ7777120 reduced radiation-induced aplasia, preserving medullar components and reducing formation of micronucleus and also it accelerated bone marrow repopulation. Furthermore, it reduced micronucleus frequency in peripheral blood (27±8 vs. 149±22, in 1,000 erythrocytes, P<0.01). JNJ7777120 completely reversed radiation-induced reduced salivation, conserving glandular mass with normal histological appearance and reducing apoptosis and atrophy of SMG. JNJ7777120 exhibits radioprotective effects against radiation-induced cytotoxic and genotoxic damages in small intestine, SMG and hematopoietic tissues and, thus, could be of clinical value for patients undergoing radiotherapy

Effect of JNJ7777120 on the radiobiological parameters of two human breast cancer cell lines.

<p>(A) MDA-MB-231 and (B) MCF-7 cells were cultured in presence or absence of 10 µM JNJ7777120 and clonogenic survival was determined. (C) Radiobiological parameters (SF 2Gy, Dose 0.01, Dose 0.10) were obtained from the survival curves adjusted to the linear quadratic model [SF=e^-(αD+βD2)]. Values are means ± SEM.</p

Effect of JNJ7777120 on radiation-induced morphological, proliferative and apoptotic alterations in the rat SMG.

<p>(A) SMG histopathology. (a,e) Normal histological appearance of untreated and (b,f) JNJ7777120-treated SMG (c, g). SMG of irradiated rats displaying damage in the epithelial architecture of the granular convoluted ducts, mild edema (red arrow), partial loss of eosinophilic secretor granular material and vacuoles (arrow head). (d,h) SMG of JNJ7777120-treated and irradiated animals showing preserved structure organization of secretor granules, with normal appearance of granular convoluted ducts with eosinophilic secretion. (a–d) H&E staining. (e–h) PAS staining. (i) Occasional TUNEL-positive cells in glandular duct cells in untreated and (j) JNJ777120-treated rats. (k) Massive presence of TUNEL-positive cells in ductal and acinar cells of glands of irradiated rats. (l) Significant reduction of TUNEL-positive cells in glands of treated and irradiated rats. (m,n) Similar PCNA immunoreactivity in SMG from untreated and JNJ7777120-treated rats. (o) Almost total absence of PCNA immunoreactivity in irradiated gland. (p) Partial preservation of PCNA-positive cells in treated and irradiated glands. Arrows indicate positive cells. Pictures were taken at 630x-fold magnification. Scale bar= 20 µm. (B) Average number of apoptotic cells and PCNA-positive cells are shown. Error bars represent the means ± SEM. **P<0.01, ***P<0.001 vs. Untreated; ^# P<0.05, ^{# # #} P<0.001 vs. Untreated-5Gy.</p

Effect of JNJ7777120 on radiation-induced damage on salivary function.

<p>(A) Mean salivary secretion in irradiated and non-irradiated, untreated and JNJ7777120-treated rats. Error bars represent the means ± SEM (**P<0.01, ***P<0.001, vs. Untreated, ###P<0.001 vs. Untreated-5Gy). (B) ¶SMG’s percentage of body weight (SMG weights were divided by total body weight in grams and multiplied by 100). Data represent the means ± SEM (*P<0.05 vs. Untreated; #P<0.05 vs. Untreated-5Gy). Inset: JNJ7777120 compound significantly preserves SMG mass. (C) H₄R immunoreactivity. H₄R was detected in some (a) acini and also (b) excretory ducts. (D) AQP5 immunoreactivity. AQP5 was detected almost exclusively in acini in (a) untreated, (b) JNJ777120-treated and (d) treated and irradiated rats. (c) Reduce AQP5 immunoreactivity and altered distribution in SMG of irradiated rats. Pictures were taken at 630x-fold magnification. Scale bar= 20 µm.</p

Evidence of the radioprotective effect of JNJ7777120 on rat hematopoietic tissue 3 days after irradiation.

<p>(A) H&E stained representative bone marrow sections of (a) untreated-5Gy and (b) JNJ7777120-5Gy rats. Pictures were taken at 630x-fold magnification. Scale bar= 20 µm. (B) Micronucleus frequency. ¶ The number of micronuclei (MN) was determined in 1,000 erythrocytes and is expressed as mean ± SEM. < The number of micronuclei (MN) was determined in 1,000 bone marrow cells and is expressed as mean ± SEM (*P<0.05, **P<0.01, ***P<0.001 vs. Untreated; #P<0.05, # # #P<0.001 vs. Untreated-5Gy). (C) H&E stained representative spleen sections of (a) untreated-5Gy and (b) JNJ7777120-5Gy rats. Pictures were taken at 630x-fold magnification. Scale bar= 20 µm. (D) § Spleen’s percentage of body weight (spleen weights were divided by total body weight in grams and multiplied by 100). Data represent the means ± SEM (*P<0.05 vs. Untreated).</p

Effect of JNJ7777120 on bone marrow repopulation 30 days after whole body irradiation.

<p>(A) Bone marrow histopathology. (a,e) Normal trophism of untreated, and (b,f) JNJ7777120-treated bone marrow. (c,g) Bone marrow of irradiated rats showing a reduced number of components and an important adipose replacement (red arrow head). (d,h) Bone marrow of treated and irradiated animals demonstrating significant preservation of bone marrow components and minor adipose replacement. (a–d) H&E staining. (e–h) PCNA immunoreactivity. Arrows indicate PCNA-positive cells. 630x-fold magnification. Scale bar= 20 µm. (B) Histopathological characteristics of rat bone marrow. Error bars represent the means ± SEM (*P<0.05, **P<0.001 vs. Untreated; ^# P<0.05 vs. Untreated-5Gy).</p