Mast cell activation is involved in stress-induced epithelial barrier dysfunction in the esophagus.

OBJECTIVE: We aimed to investigate the role of mast cell in stress-induced barrier dysfunction in the esophagus and its possible pathway involved using mast cell-deficient (Ws/Ws) rats. METHODS: Ws/Ws rats and normal (+/+) rats were submitted to chronic restraint stress (CRS) 2 h/day for 7 days. Tissues were obtained from distal esophagus. Mast cells were counted under Alcian blue-safranin O stain. Activation of mast cells was assessed using transmission electron microscope. Esophageal epithelial barrier dysfunction was evaluated by measuring intercellular spaces (ICS) and by quantifying tight junction (TJ) proteins. The localization and expression of mast cell-derived tryptase and proteinase activated receptor 2 (PAR-2) were assessed. RESULTS: A higher number of mast cells and higher proportion of activated mast cells were observed in CRS +/+ rats compared with non-stress controls. Increased ICS and decreased expression of some TJ proteins were observed in the CRS +/+ rats but not in the CRS Ws/Ws rats. Tryptase and its receptor PAR-2 were found elevated concomitantly by nearly 100% in CRS +/+ rats, but not in CRS Ws/Ws rats. CONCLUSIONS: Mast cells play an important role in stress-induced epithelial barrier dysfunction in esophagus. The mechanism may involve the activation of PAR-2 by mast cell-derived tryptase, causing proinflammatory responses and the subsequent disruption of the epithelial TJ proteins and a disturbed cytoskeleton function, resulting in dilated intercellular spaces.

[Reconstitution of mast cell population in gastrointestinal tract by bone marrow transplantation in mast cell deficient rats].

OBJECTIVE: To explore whether bone marrow transplantation (BMT) can restore gastrointestinal mast cells in mast cell deficient (Ws/Ws) rats and understand the features of these reconstituted mast cells. METHODS: Thirty-six Ws/Ws rats were subjected to Co(60) radiation at 6 gradient doses (6.0, 7.0, 8.0, 9.0, 10.0 and 11.0 Gy, n = 6) to confirm the appropriate dosage. And another 6 rats served as non-radiated controls. Sixteen Ws/Ws rats were exposed to a 7.5 Gy radiation and sacrificed at Day 1, 5, 8 and 12 (n = 4) to obtain hemogram and myelogram. And 4 non-radiated Ws/Ws rats served as control. Ws/Ws rats received an intravenous injection of bone marrow cells harvested from healthy congenic Brown Norway (BN) rats after a dosage of 7.5 Gy radiation. Y-chromosome fluorescence in situ hybridization (Y-FISH) was used to identify the survival and differentiation of bone marrow cells of male BN rats in female BMT-Ws/Ws rats (n = 4). Another set of 24 male BMT-Ws/Ws rats were sacrificed Weeks 5, 8, 13 and 23 post-BMT (n = 6). Tissues from esophagus, stomach, ileum and colon were harvested to perform mast cell quantification by Alcian blue staining. And mast cell derived proteinases (tryptase and chymase) were quantified by Western blotting. RESULTS: Y-FISH showed bone marrow cells from male BN rats survived in female BMT-Ws/Ws rats and mast cells were restored in gastrointestinal tract. Compared with control, the highest level of mast cell number (103 ± 6) vs (35 ± 4)/mm(2) for esophagus, (271 ± 23) vs (124 ± 13)/mm(2) for stomach, (200.1 ± 13.3) vs (103.2 ± 6.6)/mm(2), all P < 0.05) and mast cell proteinases (1.3 ± 0.3 vs 0.6 ± 0.2 for esophagus, 3.6 ± 0.8 vs 1.9 ± 0.4 for ileum, both P < 0.05) in BMT-Ws/Ws rats were observed at Week 8 post-BMT. The number of mast cell and proteinases decreased at Week 13 post-BMT. CONCLUSIONS: BMT may restore mast cells in Ws/Ws rats. The best time period for using BMT-Ws/Ws rats in the study of mast cell function is between Weeks 8-13 post-BMT.

Essential role of mast cells in the visceral hyperalgesia induced by T. spiralis infection and stress in rats.

Mast cells (MCs) deficient rats (Ws/Ws) were used to investigate the roles of MCs in visceral hyperalgesia. Ws/Ws and wild control (+/+) rats were exposed to T. spiralis or submitted to acute cold restraint stress (ACRS). Levels of proteinase-activated receptor 2 (PAR2) and nerve growth factor (NGF) were determined by immunoblots and RT-PCR analysis, and the putative signal pathways including phosphorylated extracellular-regulated kinase (pERK1/2) and transient receptor potential vanilloid receptor 1 (TRPV1) were further identified. Visceral hyperalgesia triggered by ACRS was observed only in +/+ rats. The increased expression of PAR2 and NGF was observed only in +/+ rats induced by T. spiralis and ACRS. The activation of pERK1/2 induced by ACRS occurred only in +/+ rats. However, a significant increase of TRPV1 induced by T. spiralis and ACRS was observed only in +/+ rats. The activation of PAR2 and NGF via both TRPV1 and pERK1/2 signal pathway is dependent on MCs in ACRS-induced visceral hyperalgesia rats.

2,2'-[4-Acetyl-1,3-phenyl-enebis(-oxy)]diacetic acid.

In the title compound, C12H12O7, the dihedral angles between the benzene ring and the mean planes of the 3-carb-oxy-meth-oxy, 1-carb-oxy-meth-oxy and acetyl substituents are 8.67 (7), 7.81 (6) and 10.3 (18)°, respectively. In the crystal, mol-ecules are linked by typical carb-oxy-lic acid O-H⋯O hydrogen bonds, forming a zigzag chain. C-H⋯O inter-actions also occur.

Vesicular glutamate transporter-3 contributes to visceral hyperalgesia induced by Trichinella spiralis infection in rats.

BACKGROUND: According to a recent study, vesicular glutamate transporter-3 (VGLUT3) contributes to injury-induced mechanical hyperalgesia in mice. AIMS: The aims of the study were to investigate whether VGLUT3 is involved in visceral pain, and whether transient intestinal infection or acute cold restraint stress (ACRS) affects VGLUT3 expression levels in rats. METHODS: Changes in VGLUT3 and c-Fos proteins were evaluated in rats which received noxious colorectal distension (CRD) stimulation. Transient intestinal infection was effected by oral administration of Trichinella spiralis (T. spiralis) larvae in Brown Norway rats. On the 100th day post-infection (PI), half of the PI-rats and non infected controls were subjected to an ACRS procedure. The visceromotor response to CRD was measured using the abdominal withdrawal reflex (AWR) score. Immunofluorescence and western blot analysis were used to estimate the expression of VGLUT3 in both peripheral and central neurons. RESULTS: Noxious stimulation induced a significant increase in the expression of VGLUT3 in the L6S1 spinal dorsal horn. Compared with the control group, the pain threshold was significantly decreased in the ACRS, PI, and PI + ACRS groups. VGLUT3 expression in the L6S1 dorsal root ganglion (DRG) and spinal neurons were significantly increased in PI and PI + ACRS groups as compared with the control group. CONCLUSIONS: VGLUT3 is involved in conduction of visceral pain sensation and in visceral hyperalgesia induced by Trichinella spiralis infection in rats.

(E)-1-(2,4-Dihy-droxy-phen-yl)-3-(4-hydroxy-phen-yl)prop-2-en-1-one monohydrate.

In the title compound, C(15)H(12)O(4)·H(2)O, the two benzene rings are not coplanar, making a dihedral angle of 7.24 (16)°. An intra-molecular hy-droxy-carbonyl O-H⋯O hydrogen bond occurs. In the crystal, four inter-molecular O-H⋯O hydrogen bonds involving the hy-droxy residues, the carbonyl group and the water mol-ecule lead to the formation of a three-dimensional network. The supra-molecular structure is further stabilized by weak C-H⋯O inter-actions.