Repair Of Gastric Mucosal Injury Research Articles

Effect of Moxibustion on Intestinal Microbiome in Acute Gastric Ulcer Rats.

In Traditional Chinese Medicine (TCM), moxibustion had been used for thousands of years. Many clinical case reports and scientific studies had proved that moxibustion had a good effect in treating acute gastric ulcer (AGU). Some studies had shown that the relative content and species of bacteria in the intestinal would be changed when gastric mucosal injury happened. However, there was little research on the effect of intestinal microbiome with AGU rats that were treating by moxibustion. This study is aimed at analyzing the effect of fecal microbiome in rats with AGU by the 16S rDNA sequencing technology. Male SD rats were established by orally feeding once with 70% ethanol at 4 ml/kg except the control group, then treated by moxibustion in the stomach meridian group (“Liangmen,” “Zusanli”) and the gallbladder meridian group (“Riyue,” “Yanglingquan”) for 5 days. The 16S rDNA sequencing technology analysis of feces combined with histopathological methods and molecular biological detection methods was used to evaluate the therapeutic mechanism of moxibustion on AGU. AGU brought cause changes in the number and species of intestinal bacteria. Moxibustion on stomach meridian group could reduce the area of gastric mucosal injury and regulate the relative content of GAS and EGF. Moreover, moxibustion on the stomach meridian group could increase the relative content and species of beneficial bacteria in the intestine of rats with AGU. The relative abundance of intestinal probiotics was significantly upregulated in Alphaproteobacteria, Actinomycetales, and Bacillales. In addition, moxibustion might promote the repair of gastric mucosal injury by increasing the number and species of beneficial bacteria in the intestine.

Secretome from hypoxia-conditioned adipose-derived mesenchymal stem cells promotes the healing of gastric mucosal injury in a rodent model

Studies have indicated that the definitive engraftment and transdifferentiation potential of stem cells do not seem crucial for its property of tissue repair. Our previous study showed that transplantation of adipose-derived mesenchymal stem cells (ADMSCs) enhanced the healing of sutured gastric perforation. This study aimed to investigate the paracrine role of ADMSCs in the experimental gastric mucosal injury. Normoxia-conditioned medium (Nor CM) and hypoxia (HPO) CM were obtained after culturing ADMSCs in 20% O2 and 5% O2 for 48h. Cell migration, proliferation, viability, and angiogenesis in vitro were significantly enhanced upon incubation with CM, especially the HPO CM. Experiments in vivo using a rodent model of gastric ulcer demonstrated that HPO CM treatment significantly accelerated wound healing by suppressing inflammation and promoting neovascularization and re-epithelization. Meanwhile, the infusion of HPO CM activated the COX2-PGE2 axis both in vitro and in vivo. And the upregulation of COX2 was further dependent on the activation of ErK1/2-MAPK pathway. In addition, vascular endothelial growth factor, tissue inhibitors of metalloproteinases-1, and chemokine (C-C motif) ligand 20 (CCL-20) were analyzed as being highly abundant factors secreted by ADMSCs under hypoxic condition. Notably, the blockade of CCL-20 abrogated the HPO CM-induced COX2 signaling in the primary gastric mucosal epithelial cells, while incubation with recombinant CCL-20 increased the expression of COX2. In conclusion, the secretome from hypoxia-conditioned ADMSCs facilitates the repair of gastric mucosal injury through the enhancement of angiogenesis and re-epithelization, as well as the activation of COX2-PGE2 axis with a paracrine activity involving CCL-20 factor.

Action mechanism of electroacupuncture at stomach meridian acupoints for oxidative damage in rats with gastric ulcer

To observe the effects of electroacupuncture (EA) at stomach meridian acupoints on expression of oxidation damage factors in serum and gastric mucosal cells in rats with gastric ulcer, and to explore the mechanism of EA at stomach meridian acupoints for oxidative damage in rats with gastric ulcer. Forty clean-grade SD rats were randomly divided into a normal group, a model group, a stomach meridian group and a gallbladder meridian group, ten rats in each one. Except the normal group, rats in the remaining groups were applied the restraint-cold stress method to establish the model of gastric ulcer. Rats in the normal group and model group received no treatment; rats in the stomach meridian group were treated with EA at "Liangmen" (ST 21) and "Zusanli" (ST 36); rats in the gallbladder meridian group were treated with EA at "Riyue" (GB 24) and "Yanglingquan" (GB 34). The EA was given for 30 min, once a day for 7 days totally. The change of gastric mucosal morphology was observed by routine light microscope; enzyme linked immunosorbent assay was used to detect the expressions of malondialdehyde (MDA), glutathione peroxidase (GSH-px) and tumor necrosis factor-α (TNF-α), interleukin-2(IL-2), interleukin-6(IL-6) in serum and gastric mucosal cells of rats. After treatment, compared with the model group, the gastric mucosal damage index was decreased in the stomach meridian group and gallbladder meridian group (both P<0.05), the expressions of MDA, TNF-α, IL-2 and IL-6 in serum and gastric mucosal cells were significantly decreased in the stomach meridian group (all P<0.01), but the contents of GSH-Px in serum and gastric mucosal cells were increased significantly (both P<0.01). Compared with the gallbladder meridian group, the gastric mucosal damage index as well as the expressions of MDA,TNF-α, IL-2 and IL-6 in serum and gastric mucosal cells were significantly decreased in the stomach meridian group rats (P<0.05, P<0.01), and the contents of GSH-px in serum and gastric mucosal cells were increased significantly (both P<0.01). EA at stomach meridian acupoints is likely to inhibit the expressions of oxidative damage factors to promote the repair of gastric mucosal injury, which indicates the correlation between meridians and zang-fu.

Effect of moxibustion stimulation at Zusanli (ST36) on repair of gastric mucosal injury in rats after damage to the nucleus of solitary tract

Effect of moxibustion stimulation at Zusanli (ST36) on repair of gastric mucosal injury in rats after damage to the nucleus of solitary tract

Annexin-1 modulates repair of gastric mucosal injury

Annexin-1 is a glucocorticoid-inducible protein that plays an important effector role in the resolution of inflammation and has recently been shown to contribute to the resistance of the stomach to injury. Using an integrated genetic and pharmacological approach, we have tested the hypothesis that annexin-1 contributes to the healing of mucosal injury, given that such injury is accompanied by an inflammatory response, which is often associated with an overexpression of annexin-1 expression. Gastric ulcers were induced in mice through serosal application of acetic acid. Annexin-1 expression during the healing of the ulcers was examined. The effects on gastric ulcer healing of treatment with an annexin-1 mimetic (Ac2-26), an antagonist of the annexin-1 receptor (Boc2), or a glucocorticoid (dexamethasone) were examined. Finally, susceptibility to and healing of indomethacin-induced gastric lesions were compared in wild-type and annexin-1-deficient mice. Expression of annexin-1 was significantly increased in the gastric ulcer margin throughout the healing process. Treatment with an annexin-1 mimetic (Ac2-26) significantly enhanced gastric ulcer healing. In contrast, both dexamethasone and an formyl peptide receptor-like-1 (FPRL-1) antagonist impaired the early phase of ulcer healing. Annexin-1-deficient mice exhibited the same susceptibility as wild-type mice to indomethacin-induced gastric damage, but the healing of that damage was impaired in the former. These data support the hypothesis that annexin-1 contributes significantly to the process of healing of gastric mucosal damage.

Effect and mechanism of moxibustion on acupoints Zusanli (ST 36) and Liangmen (ST 21) in the prevention and treatment of stress ulcer

Objective: To observe the effect of moxibustion on acupoints Zusanli (ST 36) and Liangmen (ST 31) on cell proliferation and cell apoptosis of gastric mucosa in rats with stress ulcer, investigatethe mechanism of moxibustion in promoting the repair of gastric mucosal injury at cellular and molecular levels. Methods: Sixty healthy Sprague-Dawley rats were randomly divided into four groups: the restraint control group, model group, moxibustion on acupoints group and moxibustion on non-acupoints group. Water immersion and restraint stress (WRS) was used to copy the stress ulcer model of rats, radio-immunoassay was used to detect the content of transforming growth factor (TGF-α), and S-P immunohistochemical assay was adopted to determine the HSP70 expression, the proliferating cell nuclear antigen (PCNA) and cell apoptosis index in gastric mucosa. Results: For the WRS-induced gastric ulcer model of rat,the gastric mucosal injury (gastric ulcer index, UI) was increased, the content of TGF-α was decreased, PCNA was also decreased, HSP70 expression and cell apoptosis index were all increased (P＜0.01). Moxibustion on acupoints Zusanli (ST 36) and Liangrnen (ST 31) could decrease UI, increase the content of TGF-α, promote the expression of PCNA and HSP70,decrease cell apoptosis index in gastric mucosa, with significant differences when compared with the model group and control group (P＜0.01). Conclusions: Moxibustion on acupoints Zusanli (ST 36) and Liangmen (ST 31) had protective effect on the gastric mucosa of stress ulcer, its mechanism may be promoting the TGF-α synthesis, stimulating cell proliferation in gastric mucosa and inhibiting cell apoptosis in gastric mucosa, and this process is related to the moxibustion-induced HSP70 expression.

Activation of hepatocyte growth factor in monkey stomach following gastric mucosal injury.

Hepatocyte growth factor (HGF) is involved in the proliferation and migration of various types of epithelial cells. HGF is produced as a single-chain precursor (pro-HGF) and functions after activation by HGF activator (HGFA). In this study, we aimed to examine the activation of pro-HGF to mature HGF and the expressions of HGF-related molecules, such as HGFA and HGFA inhibitor type 1 (HAI-1), in a monkey model of gastric mucosal injury. Gastric mucosal injury was induced in Japanese monkeys by administration of HCl using nasal-gastric tubes. HGF activation was evaluated by Western blotting and enzyme-linked immunosorbent assay (ELISA), and the expression of HGF, HGFA, HAI-1, and c-Met were examined by Northern blotting and immunohistochemistry. Pro-HGF, but not mature HGF, was detected in normal gastric mucosa. When gastric mucosal injuries were induced, the expression of HGF significantly increased, and immunostaining of HGF was detected in fibroblasts in the gastric mucosa. In addition, conversion to mature HGF was observed in the injured gastric tissues, and mature HGF continued to increase for 48 h. HGFA was stably expressed in monkey livers, regardless of HCl administration. HAI-1 expression was detected in normal gastric mucosa, and its levels decreased after the induction of gastric mucosal injury. These results indicate that pro-HGF is stored in normal gastric tissues, and suggest that its conversion to mature HGF, associated with HGFA and HAI-1, is important for the repair of gastric mucosal injury.

HELICOBACTER PYLORI VACUOLATING CYTOTOXIN (VacA) ALTERS CYTOSKELETON-ASSOCIATED PROTEINS AND INTERFERES WITH RE-EPITHELIALIZATION OF WOUNDED GASTRIC EPITHELIAL MONOLAYERS

In previous studies, we demonstrated that Helicobacter pylori vacuolating cytotoxin (VacA) inhibits gastric epithelial cell proliferation and inhibits epidermal growth factor (EGF)-activated signal transduction. Cell proliferation and migration, both essential for mucosal healing are dependent on the cell cytoskeleton. Other investigators demonstrated that VacA induces vacuolation of eukaryotic cells. Since in some cells, control of actin cytoskeleton involves GTP-binding proteins of Rho family, in this study we examined whether VacA affects wound re-epithelialization, cell cytoskeleton-associated proteins Rho, Rac1 in a gastric epithelial (RGM1) cell monolayer wound model, and whether these changes correlate with vacuolation. VacA treatment significantly inhibited wound re-epithelialization, cell proliferation vs control. VacA-induced cell vacuolation strongly correlated with inhibition of wound re-epithelialization. Furthermore, VacA reduced Rac-1 protein expression and distribution, and C3-mediated ADP-ribosylation of Rho. These findings suggest that VacA may interfere with repair of gastric mucosal injury and ulcer re-epithelialization by altering cytoskeleton-dependent cell functions and signaling.

Effects of growth factors on aspirin-induced inhibition of wound repair in a rabbit gastric epithelial cell model.

Aspirin is known to cause adverse effects, including gastric mucosal injury, and to retard gastric wound healing. Growth factors including hepatocyte growth factor (HGF), epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) have been shown to play an important role in the repair of gastric mucosal injury. To employ the cultured gastric epithelial cell model to elucidate the effects of aspirin, as well as several growth factors (HGF, EGF and IGF-I), on gastric wound repair. Isolated rabbit gastric epithelial cells (92% mucous cells) were cultured in F-12 medium and formed a complete monolayer cell sheet in 48 h. A wound with a cell-free area of constant size (2 mm2) was then created and the wound repair process was monitored by measuring wound size every 12 h. Proliferating cells were detected by BrdU staining. Effects of aspirin (8 mM), HGF (10 ng/mL), EGF (10 ng/mL) and IGF-I (30 ng/mL) were assessed. Aspirin significantly retarded wound healing, but simultaneous addition of growth factors significantly accelerated wound repair compared with aspirin alone. Growth factors reversed the aspirin-induced inhibition of cell proliferation. Growth factors, including HGF, EGF and IGF-I, reversed the aspirin-induced inhibition of wound repair through their cytoprotective effects on gastric epithelial cells.

Reduced adrenomedullin expression in gastric mucosa of portal hypertensive rats after ethanol-induced injury.

To determine the expression and localization of adrenomedullin (AM) and its receptor (AM-R) in portal hypertensive (PHT) gastric mucosa after intragastric ethanol administration. The repair of gastric mucosal injury requires reestablishment of the microvascular network. The authors previously demonstrated impaired angiogenesis of PHT gastric mucosa after ethanol-induced injury. Because AM, a potent vasodilatory peptide, is also a novel growth and angiogenic factor, the authors hypothesized that AM is involved in the impaired repair of PHT gastric mucosa and its microvasculature after damage. Either PHT or sham-operated rats received intragastrically 100% ethanol, and the stomachs were excised at 1, 6, and 24 hours later. Expression and localization of AM and AM-R mRNA were examined by competitive reverse transcription-polymerase chain reaction and in situ hybridization. AM protein expression was examined by Western blot analysis. One hour after ethanol administration, AM mRNA expression in PHT gastric mucosa was significantly decreased by 81%, especially in the superficial mucosa, compared with the gastric mucosa in sham-operated rats. The significant decrease lasted for 24 hours. AM protein expression was significantly decreased by 43% compared with the sham-operated gastric mucosa. Although AM-R mRNA expression in both groups was significantly increased 1 hour after ethanol administration and lasted for 24 hours compared with baseline, there were no differences between the two groups. The expression of AM in PHT gastric mucosa after ethanol-induced injury is significantly decreased compared with controls. This finding could explain one mechanism for the impaired angiogenesis after injury of PHT gastric mucosa.

H. pylori vaca cytotoxin interferes with the RHO/RAC-1 signal cascade in wounded gastric epithelial monolayers: A key to inhibition of reepithelialization

Re-epithelialization is an essential process for repair of gastric mucosal injury and ulcer healing. Previous studies have shown that H. pylori vacuolating cytotoxin (VacA) inhibits gastric epithelial cell proliferation and interferes with EGF-activated signal transduction. Several members of the Rho subfamily of GTPbinding proteins, including Rat-1 and Rho, regulate a signal transduction pathway linking growth factor receptors to the formation of actin stress fibers and focal adhesion which are essential for cell migration. The aims of this study were to determine: a) the effect of H. pylori VacA cytotoxin on levels of Rho and Rac-1 proteins, and ADP-ribosylation levels of Rho in gastric epithelial cells and b) the effect of VacA on reepitbelialization in a wounded gastric cells monolayer model. Methods: VacA purified from H. pylori 60190 or a corresponding VacA-negative preparation from 1-1. pylori 60190-vl (an isogenic mutant strain in which VacA gene has been disrupted) were used. Rat gastric epithelial cells (RGM1) were incubated with either medium only (DMEM/F-12 with 5% FBS), medium containing VacA or medium containing the VacA-negative preparation for 24 and 48 hours. Standard excisional wounds (30 ram) were made in gastric epithelial cells monolayers with a razor blade and treated with H. pylori VacA or VacA-negative preparation as above. Studies: A) Rho and Rac-1 proteins levels by Western blot analysis, B) Rho ribosylation levels by ADPribosylation assay using [32p] NAD with C3 exoenzyme. C) Localization of Rac-1 after immunostaining and D) Actin microfilament assembly using a video image system. Results: VacA (but not a VacA-negative prep) significantly inhibited RGM1 cell migration by 25% (p < 0.03), reduced Rac1 expression by 65% (p < 0.04) and reduced C3-mediated ADP-ribosylation of Rho by 21% (p < 0.03). VacA cytotoxin (but not the VacA-negative prep) inhibited assembly of actin stress fibers and reduced Rac-1 expression in migrating epithelial cells. C_onclusions: H. pylori VacA significantly: 1) inhibits re-epithelialization of wounded gastric epithelial monolayers, 2) reduces Rac-1 expression, 3) affects Rho -ribosylation and 4) interferes with actin filament assembly. These data provide molecular mechanisms for H. pylori cytotoxin interference with re-epithelialization.

Role of Epidermal Growth Factor in Protection and Repair of Gastric Mucosal Injury

A role of epidermal growth factor (EGF) in protection and repair of gastric mucosal injury caused by p.o. administration of 0.6 N HCl was investigated in male Wistar rats. Previous to the study on the role of EGF in gastric mucosal protection and repair, changes of gastric mucosal EGF level was determined sequentially by RIA for 180 min after treatment with 0.6 N HCl and intraperitoneal injection of recombinant hEGF. Concentration of incorporated hEGF into the gastric mucosa reached the peak level at 30 min after injection of hEGF. On the other hand, the gastric endogenous EGF level fell remarkably immediately after treatment with 0.6 N HCl. Successively, an association with the mucosal levels of incorporated hEGF and gastric ulcer indices was investigated in the rats in which hEGF was injected intraperitoneally 30 min prior to or at the same time as oral administration of 0.6 N HCl. In conclusion, pretreatment with hEGF protected significantly against gastric mucosal injury with 0.6 N HCl, whereas simultaneous administration of hEGF could not protect against mucosal injury but indicated possible stimulation of the repair process from acute gastric mucosal damage.