Nutrient-sensing components of the mouse stomach and the gastric ghrelin cell.

BACKGROUND: The ability of the gut to detect nutrients is critical to the regulation of gut hormone secretion, food intake, and postprandial blood glucose control. Ingested nutrients are detected by specific gut chemosensors. However, knowledge of these chemosensors has primarily been derived from the intestine, while available information on gastric chemosensors is limited. This study aimed to investigate the nutrient-sensing repertoire of the mouse stomach with particular emphasis on ghrelin cells. METHODS: Quantitative RT-PCR was used to determine mRNA levels of nutrient chemosensors (protein: G protein-coupled receptor 93 [GPR93], calcium-sensing receptor [CaSR], metabotropic glutamate receptor type 4 [mGluR4]; fatty acids: CD36, FFAR2&4; sweet/umami taste: T1R3), taste transduction components (TRPM5, GNAT2&3), and ghrelin and ghrelin-processing enzymes (PC1/3, ghrelin O-acyltransferase [GOAT]) in the gastric corpus and antrum of adult male C57BL/6 mice. Immunohistochemistry was performed to assess protein expression of chemosensors (GPR93, T1R3, CD36, and FFAR4) and their co-localization with ghrelin. KEY RESULTS: Most nutrient chemosensors had higher mRNA levels in the antrum compared to the corpus, except for CD36, GNAT2, ghrelin, and GOAT. Similar regional distribution was observed at the protein level. At least 60% of ghrelin-positive cells expressed T1R3 and FFAR4, and over 80% expressed GPR93 and CD36. CONCLUSIONS AND INFERENCES: The cellular mechanisms for the detection of nutrients are expressed in a region-specific manner in the mouse stomach and gastric ghrelin cells. These gastric nutrient chemosensors may play a role modulating gastrointestinal responses, such as the inhibition of ghrelin secretion following food intake.

A cross-sectional study of nausea in functional abdominal pain: relation to mucosal mast cells and psychological functioning.

BACKGROUND: Nausea is a common symptom in youth with chronic abdominal pain. The aims of the current study were to assess: 1) the frequency of nausea in patients with functional dyspepsia (FD) and irritable bowel syndrome (IBS), respectively, as defined by Rome IV criteria; and, 2) relationships between nausea and mucosal inflammation as defined by antral and duodenal eosinophil and mast cell densities. A secondary aim was to assess relationships between nausea and other gastrointestinal symptoms, non-gastrointestinal somatic symptoms, and psychological dysfunction. METHODS: Records from patients with pain associated functional gastrointestinal disorders were retrospectively reviewed for gastrointestinal and somatic symptoms and anxiety, depression, and somatizations scores as assessed by the Behavior Assessment System for Children (BASC-2). In addition, previous gastric and mucosal biopsies were assessed for mast cell and eosinophil densities, respectively. RESULTS: 250 patients, ages 8 to 17 years, were assessed. Nausea was reported by 78% and was equally prevalent in those with FD alone, those with IBS alone, and those with both FD and IBS. Nausea was associated with increased mean (21.4 vs. 17.5) and peak (26.2 vs. 22.9) duodenal mast cell densities as compared those without nausea. Nausea was also associated with a wide variety of individual gastrointestinal symptoms, as well as headaches, fatigue, and dizziness. Lastly, nausea was associated with elevated self-report scores for anxiety (55.2 vs. 50.0), depression (50.2 vs. 46.1), and somatization (70.3 vs. 61.8). CONCLUSIONS: Nausea is common in children and adolescents with pain-associated FGIDs as defined by Rome IV and is not unique to either FD or IBS. Nausea is associated with increased mucosal mast cell density, non-gastrointestinal somatic symptoms, and psychologic dysfunction.

E-cadherin is Required for the Homeostasis of Lgr5+ Gastric Antral Stem Cells.

Lgr5-expressing stem cells contribute to the epithelial turnover of the gastric antrum. However, the mechanism controlling the homeostasis of Lgr5+ antral stem cells is not fully understood. Here, we demonstrate the key role of E-cadherin in the homeostasis of Lgr5+ gastric antral stem cells. The deletion of E-cadherin in these cells results in their apoptosis, thereby leading to a marked decrease in their number. A reduced Lgr5+ stem cell pool caused by the loss of E-cadherin impairs gastric antral epithelial homeostasis in vivo and organoid growth in vitro. Furthermore, p53 contributes to the apoptosis of Lgr5+ stem cells following E-cadherin loss, while the simultaneous deletion of p53 rescues the phenotype in E-cadherin mutants. Our study reveals the critical pro-survival function of E-cadherin in Lgr5+ gastric antral stem cells and the key role of the Lgr5+ stem cell pool in the maintenance of gastric epithelial homeostasis.

Generation of human antral and fundic gastric organoids from pluripotent stem cells.

The human stomach contains two primary domains: the corpus, which contains the fundic epithelium, and the antrum. Each of these domains has distinct cell types and functions, and therefore each presents with unique disease pathologies. Here, we detail two protocols to differentiate human pluripotent stem cells (hPSCs) into human gastric organoids (hGOs) that recapitulate both domains. Both protocols begin with the differentiation of hPSCs into definitive endoderm (DE) using activin A, followed by the generation of free-floating 3D posterior foregut spheroids using FGF4, Wnt pathway agonist CHIR99021 (CHIR), BMP pathway antagonist Noggin, and retinoic acid. Embedding spheroids in Matrigel and continuing 3D growth in epidermal growth factor (EGF)-containing medium for 4 weeks results in antral hGOs (hAGOs). To obtain fundic hGOs (hFGOs), spheroids are additionally treated with CHIR and FGF10. Induced differentiation of acid-secreting parietal cells in hFGOs requires temporal treatment of BMP4 and the MEK inhibitor PD0325901 for 48 h on protocol day 30. In total, it takes ~34 d to generate hGOs from hPSCs. To date, this is the only approach that generates functional human differentiated gastric cells de novo from hPSCs.

Effects of Exogenous Interleukin-9 on the Growth, Proliferation and Activity of Interstitial Cells of Cajal Cultured in vitro.

OBJECTIVES: To evaluate the role of exogenous interleukin-9 (IL-9) in the growth, proliferation and activity of interstitial cells of Cajal (ICCs) cultured in vitro, and to assess its role in maintaining the functions of ICCs. METHODS: ICCs of murine gastric antrum were isolated and cultured in vitro. ICCs were identified with c-Kit and ANO1 immunofluorescent antibodies. Both fluorescence microscope and confocal microscopy were used to observe the effects of IL-9 on the growth, proliferation and activity of ICCs in cultured in vitro. ICCs were loaded with fluorescence probe Fluo-3/AM and the fluorescence of intracellular calcium concentration ([Ca2+]i) was measured by confocal microscopy. The effects of exogenous IL-9 on the sulfated cholecystokinin octapeptide (CCK-8S)-evoked [Ca2+]i elevation were observed by confocal microscopy. RESULTS: Immunofluorescence results confirmed the successful separation and culture of ICCs in vitro. IL-9 in concentrations ranging from 0.02 to 1 µg/ml promoted the growth, proliferation and activity of ICCs in culture, and ICCs grew best with 0.5 mg/ml of IL-9. The presence of IL-9 could significantly increase the CCK-8S-evoked [Ca2+]i oscillation, which is probably caused by facilitating the maintenance of the functions of ICCs under suitable conditions for culture. CONCLUSION: IL-9 could promote the growth, proliferation and activity of ICCs, reinforce the CCK-8S-induced [Ca2+]i increment in ICCs, and facilitate the maintenance of the functions of ICCs under suitable culture condition.

Complex morphology of gastrin-releasing G-cells in the antral region of the mouse stomach.

Gastrin-releasing enteroendocrine cells (G-cells) are usually described as flask-shaped cells with a large base and a small apical pole, integrated in the epithelium lining the basal region of the antral invaginations in the stomach. By means of a transgenic mouse line in which the enhanced version of GFP is endogenously expressed under the control of a gastrin promoter, we have analyzed the spatial distribution and morphological features of G-cells. We found that G-cells were not only located at the basal region of the invagination but to a lesser extent also at the upper region. Visualization of the entire cellular morphology revealed that G-cells show complex morphologies. Basally located G-cells are roundish-shaped cells which project a prominent apical process towards the lumen and extend basal protrusions containing the hormone gastrin that were frequently found in close proximity to blood vessels and occasionally in the vicinity of nerve fibers. Inspection of G-cells in the upper region of antral invaginations disclosed a novel population of G-cells. These cells have a spindle-like contour and long apical and basal processes which extend vertically along the antral invagination, parallel to the lumen. This G-cell population seems to be in contact with a network of nerve fibers. While the functional role of these untypical G-cells is still elusive, the results of this study provide some useful indications to possible roles of these G-cells.

Long-pulse gastric electrical stimulation protects interstitial cells of Cajal in diabetic rats via IGF-1 signaling pathway.

AIM: To investigate the effects of different parameters of gastric electrical stimulation (GES) on interstitial cells of Cajal (ICCs) and changes in the insulin-like growth factor 1 (IGF-1) signal pathway in streptozotocin-induced diabetic rats. METHODS: Male rats were randomized into control, diabetic (DM), diabetic with sham GES (DM + SGES), diabetic with GES1 (5.5 cpm, 100 ms, 4 mA) (DM + GES1), diabetic with GES2 (5.5 cpm, 300 ms, 4 mA) (DM + GES2) and diabetic with GES3 (5.5 cpm, 550 ms, 2 mA) (DM + GES3) groups. The expression levels of c-kit, M-SCF and IGF-1 receptors were evaluated in the gastric antrum using Western blot analysis. The distribution of ICCs was observed using immunolabeling for c-kit, while smooth muscle cells and IGF-1 receptors were identified using α-SMA and IGF-1R antibodies. Serum level of IGF-1 was tested using enzyme-linked immunosorbent assay. RESULTS: Gastric emptying was delayed in the DM group but improved in all GES groups, especially in the GES2 group. The expression levels of c-kit, M-SCF and IGF-1R were decreased in the DM group but increased in all GES groups. More ICCs (c-kit(+)) and smooth muscle cells (α-SMA(+)/IGF-1R(+)) were observed in all GES groups than in the DM group. The average level of IGF-1 in the DM group was markedly decreased, but it was up-regulated in all GES groups, especially in the GES2 group. CONCLUSION: The results suggest that long-pulse GES promotes the regeneration of ICCs. The IGF-1 signaling pathway might be involved in the mechanism underlying this process, which results in improved gastric emptying.

A novel human gastric primary cell culture system for modelling Helicobacter pylori infection in vitro.

BACKGROUND AND AIMS: Helicobacter pylori is the causative agent of gastric diseases and the main risk factor in the development of gastric adenocarcinoma. In vitro studies with this bacterial pathogen largely rely on the use of transformed cell lines as infection model. However, this approach is intrinsically artificial and especially inappropriate when it comes to investigating the mechanisms of cancerogenesis. Moreover, common cell lines are often defective in crucial signalling pathways relevant to infection and cancer. A long-lived primary cell system would be preferable in order to better approximate the human in vivo situation. METHODS: Gastric glands were isolated from healthy human stomach tissue and grown in Matrigel containing media supplemented with various growth factors, developmental regulators and apoptosis inhibitors to generate long-lasting normal epithelial cell cultures. RESULTS: Culture conditions were developed which support the formation and quasi-indefinite growth of three dimensional (3D) spheroids derived from various sites of the human stomach. Spheroids could be differentiated to gastric organoids after withdrawal of Wnt3A and R-spondin1 from the medium. The 3D cultures exhibit typical morphological features of human stomach tissue. Transfer of sheared spheroids into 2D culture led to the formation of dense planar cultures of polarised epithelial cells serving as a suitable in vitro model of H. pylori infection. CONCLUSIONS: A robust and quasi-immortal 3D organoid model has been established, which is considered instrumental for future research aimed to understand the underlying mechanisms of infection, mucosal immunity and cancer of the human stomach.

Notch signaling regulates gastric antral LGR5 stem cell function.

The major signaling pathways regulating gastric stem cells are unknown. Here we report that Notch signaling is essential for homeostasis of LGR5(+) antral stem cells. Pathway inhibition reduced proliferation of gastric stem and progenitor cells, while activation increased proliferation. Notch dysregulation also altered differentiation, with inhibition inducing mucous and endocrine cell differentiation while activation reduced differentiation. Analysis of gastric organoids demonstrated that Notch signaling was intrinsic to the epithelium and regulated growth. Furthermore, in vivo Notch manipulation affected the efficiency of organoid initiation from glands and single Lgr5-GFP stem cells, suggesting regulation of stem cell function. Strikingly, constitutive Notch activation in LGR5(+) stem cells induced tissue expansion via antral gland fission. Lineage tracing using a multi-colored reporter demonstrated that Notch-activated stem cells rapidly generate monoclonal glands, suggesting a competitive advantage over unmanipulated stem cells. Notch activation was associated with increased mTOR signaling, and mTORC1 inhibition normalized NICD-induced increases in proliferation and gland fission. Chronic Notch activation induced undifferentiated, hyper-proliferative polyps, suggesting that aberrant activation of Notch in gastric stem cells may contribute to gastric tumorigenesis.

CCK2R identifies and regulates gastric antral stem cell states and carcinogenesis.

OBJECTIVE: Progastrin is the incompletely cleaved precursor of gastrin that is secreted by G-cells in the gastric antrum. Both gastrin and progastrin bind to the CCK2 receptor (Cckbr or CCK2R) expressed on a subset of gastric epithelial cells. Little is known about how gastrin peptides and CCK2R regulate gastric stem cells and carcinogenesis. Interconversion among progenitors in the intestine is documented, but the mechanisms by which this occurs are poorly defined. DESIGN: We generated CCK2R-CreERT mice and performed inducible lineage tracing experiments. CCK2R+ antral cells and Lgr5+ antral stem cells were cultured in a three-dimensional in vitro system. We crossed progastrin-overexpressing mice with Lgr5-GFP-CreERT mice and examined the role of progastrin and CCK2R in Lgr5+ stem cells during MNU-induced carcinogenesis. RESULTS: Through lineage tracing experiments, we found that CCK2R defines antral stem cells at position +4, which overlapped with an Lgr5(neg or low) cell population but was distinct from typical antral Lgr5(high) stem cells. Treatment with progastrin interconverts Lgr5(neg or low) CCK2R+ cells into Lgr5(high) cells, increases CCK2R+ cell numbers and promotes gland fission and carcinogenesis in response to the chemical carcinogen MNU. Pharmacological inhibition or genetic ablation of CCK2R attenuated progastrin-dependent stem cell expansion and carcinogenesis. CONCLUSIONS: CCK2R labels +4 antral stem cells that can be activated and expanded by progastrin, thus identifying one hormonal trigger for gastric stem cell interconversion and a potential target for gastric cancer chemoprevention and therapy.

Function of ghrelin and ghrelin receptors in the network regulation of gastric motility.

Numerous previous studies have demonstrated that ghrelin promotes gastric motility when administered peripherally. This effect appears to be regulatory but not directly stimulatory, and therefore may involve a number of complex mechanisms. In the periphery, ghrelin may affect gastric motility through intercellular networks among interstitial cells of Cajal, myenteric nerve cells and smooth muscle cells. The aim of the present study was to investigate the effects and possible mechanisms underlying this hypothesis. The effects of ghrelin on the contraction force of gastric antrum smooth muscle strips of rats were studied in the presence or absence of carbachol (CCh), [D­Lys3]­GHRP­6, atropine, tetrodotoxin (TTX) and nimodipine in vitro. The expression of ghrelin receptors (GHS­Rs) on different cell types in gastric muscle layers was observed by means of immunofluorescence. Ghrelin enhanced smooth muscle strip contraction induced by CCh, but when CCh was absent, this effect was eliminated. Atropine and nimodipine eradicated the muscle strip contraction enhanced by ghrelin, while [D­Lys3]­GHRP­6 was only able to partly block this effect and TTX had no effect on muscle strip contraction. It was identified that ghrelin had no effect on the contractive rhythm of the strips. GHS­R1s were located differentially depending on the cell type, including myenteric nerve cells, interstitial cells of Cajal and smooth muscle cells. In conclusion the present study demonstrated that ghrelin may act as an adjuvant to regulate gastric smooth muscle contraction induced by CCh through GHS­R1s, which are expressed on myenteric nerve cells, Cajal cells and smooth muscle cells. Ghrelin may exert its effects by influencing the functional status of different cell types in the gastric muscle layer to subsequently enhance the contractive effect of cholinergic neurotransmitters and enhance gastric motility.

Roles of interleukin-9 in the growth and cholecystokinin-induced intracellular calcium signaling of cultured interstitial cells of Cajal.

Interstitial cells of Cajal (ICC) are pacemaker cells in the gastrointestinal (GI) tract and loss of ICC is associated with many GI motility disorders. Previous studies have shown that ICC have the capacity to regenerate or restore, and several growth factors are critical to their growth, maintenance or regeneration. The present study aimed to investigate the roles of interleukin-9 (IL-9) in the growth, maintenance and pacemaker functions of cultured ICC. Here, we report that IL-9 promotes proliferation of ICC, and culturing ICC with IL-9 enhances cholecystokinin-8-induced Ca²âº transients, which is probably caused by facilitating maintenance of ICC functions under culture condition. We also show co-localizations of cholecystokinin-1 receptor and IL-9 receptor with c-kit by double-immunohistochemical labeling. In conclusion, IL-9 can promote ICC growth and help maintain ICC functions; IL-9 probably performs its functions via IL-9 receptors on ICC.

Cell lineage distribution atlas of the human stomach reveals heterogeneous gland populations in the gastric antrum.

OBJECTIVE: The glands of the stomach body and antral mucosa contain a complex compendium of cell lineages. In lower mammals, the distribution of oxyntic glands and antral glands define the anatomical regions within the stomach. We examined in detail the distribution of the full range of cell lineages within the human stomach. DESIGN: We determined the distribution of gastric gland cell lineages with specific immunocytochemical markers in entire stomach specimens from three non-obese organ donors. RESULTS: The anatomical body and antrum of the human stomach were defined by the presence of ghrelin and gastrin cells, respectively. Concentrations of somatostatin cells were observed in the proximal stomach. Parietal cells were seen in all glands of the body of the stomach as well as in over 50% of antral glands. MIST1 expressing chief cells were predominantly observed in the body although individual glands of the antrum also showed MIST1 expressing chief cells. While classically described antral glands were observed with gastrin cells and deep antral mucous cells without any parietal cells, we also observed a substantial population of mixed type glands containing both parietal cells and G cells throughout the antrum. CONCLUSIONS: Enteroendocrine cells show distinct patterns of localisation in the human stomach. The existence of antral glands with mixed cell lineages indicates that human antral glands may be functionally chimeric with glands assembled from multiple distinct stem cell populations.

Electroacupuncture at ST36 increases contraction of the gastric antrum and improves the SCF/c-kit pathway in diabetic rats.

Electroacupuncture (EA) at ST36 is effective for improving gastric motility. However, the underlying mechanism remains poorly understood. The aim of this study was to investigate the effects of EA on gastric contraction and to determine whether interstitial cells of Cajal (ICCs) are involved. Rats were randomized into control, diabetic (DM), diabetic with sham EA (DM + SEA), diabetic with low frequency EA (DM + LEA) and diabetic with high frequency EA (DM + HEA) groups. EA was performed everyday for four and eight weeks. Contractions in antrum strips were explored using the organ bath technique. Western blotting was employed to determine c-kit and transmembrane stem cell factor (M-SCF) expression in the gastric antrum, and levels of soluble stem cell factor (S-SCF) in serum were determined by enzyme-linked immunosorbent assay (ELISA). The distribution of ICCs was further assessed by immunohistochemistry. The results were as follows: (1) Contractions in the DM group were attenuated at four and eight weeks, but LEA and HEA restored the attenuated contraction. (2) ICCs were significantly decreased at eight weeks without alteration at four weeks in DM group, but were rescued in the LEA and HEA groups. (3) Whereas M-SCF and S-SCF in the DM group were slightly decreased at four weeks and were dramatically reduced at eight weeks, LEA and HEA markedly enhanced SCF at eight weeks. Collectively, the data suggest that in diabetic rats, LEA and HEA at ST36 could facilitate contraction of the gastric antrum, possibly by involving the SCF/c-kit pathway.

[The role of gastric APUD system in progression of chronic Helicobacter gastritis].

The study included 60 patients with chronic Halicobacter gastritis (30 with chronic non-atrophic and 30 with atrophic Halicobacter gastritis (CNAHG and CAHG)). The control group was comprised of 15 practically healthy subjects. The aim of the work was to elucidate the role of Helicobacter infection, disturbances of regeneration, endothelin-1 and melatonin-secreting neuroendocrine cells of gastric antrum in progression of chronic Helicobacter gastritis (CHG). It was shown that CHG is due to H. pylori persistence and that patients with CNAHG undergo grade III microbial contamination while in CAHG patients atrophic changes are accompanied by metaplasia of gastric mucosa (GM) and inflammation of different severity. Patients with CNAHG has an increased number of melatonin-positive gastric cells and enhanced apoptotic activity of GM epitheliocytes. Patients with CAHG experience a reduction of melatonin-positive cells correlated with enhanced apoptotic activity of GM epitheliocytes. The number of endothelin-1 positive cells in patients with CNAHG and CAHG was similar to that in controls. Adequate eradication promoted normalization of the number of gastric endothelin-1 and melatonin-secreting neuroendocrine cells in patients with CHG. The apoptotic index reached the control value within 1 month after eradication in CNAHG patients but remained relatively high in CAHG patients.

Tonic and phasic smooth muscle contraction is not regulated by the PKCα - CPI-17 pathway in swine stomach antrum and fundus.

Regulation of myosin light chain phosphatase (MLCP) via protein kinase C (PKC) and the 17 kDa PKC-potentiated inhibitor of myosin light chain phosphatase (CPI-17) has been reported as a Ca(2+) sensitization signaling pathway in smooth muscle (SM), and thus may be involved in tonic vs. phasic contractions. This study examined the protein expression and spatial-temporal distribution of PKCα and CPI-17 in intact SM tissues. KCl or carbachol (CCh) stimulation of tonic stomach fundus SM generates a sustained contraction while the phasic stomach antrum generates a transient contraction. In addition, the tonic fundus generates greater relative force than phasic antrum with 1 µM phorbol 12, 13-dibutyrate (PDBu) stimulation which is reported to activate the PKCα - CPI-17 pathway. Western blot analyses demonstrated that this contractile difference was not caused by a difference in the protein expression of PKCα or CPI-17 between these two tissues. Immunohistochemical results show that the distribution of PKCα in the longitudinal and circular layers of the fundus and antrum do not differ, being predominantly localized near the SM cell plasma membrane. Stimulation of either tissue with 1 µM PDBu or 1 µM CCh does not alter this peripheral PKCα distribution. There are no differences between these two tissues for the CPI-17 distribution, but unlike the PKCα distribution, CPI-17 appears to be diffusely distributed throughout the cytoplasm under relaxed tissue conditions but shifts to a primarily peripheral distribution at the plasma membrane with stimulation of the tissues with 1 µM PDBu or 1 µM CCh. Results from double labeling show that neither PKCα nor CPI-17 co-localize at the adherens junction (vinculin/talin) at the membrane but they do co-localize with each other and with caveoli (caveolin) at the membrane. This lack of difference suggests that the PKCα - CPI-17 pathway is not responsible for the tonic vs. phasic contractions observed in stomach fundus and antrum.

Differential expression of multidrug resistance protein 5 and phosphodiesterase 5 and regulation of cGMP levels in phasic and tonic smooth muscle.

Previous studies have identified differences in the expression of proteins that regulate myosin light chain phosphorylation and contraction in tonic and phasic smooth muscle. cGMP plays a critical role in smooth muscle relaxation and is important for optimal function of phasic and tonic smooth muscle. The intracellular cGMP levels are regulated by its hydrolysis via phosphodiesterase 5 (PDE5) and efflux via novel multidrug resistance protein 5 (MRP5). In the present study we tested the hypothesis that the differences in the phasic and tonic behavior of smooth muscles may be related to differences in mechanisms that terminate cGMP signaling. Expression of PDE5 and MRP5 was significantly (more than 2-fold) higher in fundus compared with antrum. The NO donor S-nitrosoglutathione (GSNO) caused an increase in PDE5 activity and intra- and extracellular cGMP levels in both fundus and antrum. Stimulation of PDE5 activity and increase in extracellular cGMP were significantly higher in fundus, whereas increase in intracellular cGMP was significantly higher in antrum. GSNO-induced increase in extracellular cGMP was blocked in dispersed cells by the cyclic nucleotide export blocker probenecid and in cultured muscle cells by depletion of ATP or suppression of MRP5 by siRNA, providing evidence that cGMP efflux was mediated by ATP-dependent export via MRP5. Consistent with the higher expression and activity levels of PDE5 and MRP5, GSNO-induced PKG activity and muscle relaxation were significantly lower in muscle cells from fundus compared with antrum. Thus higher expression of PDE5 and MRP5 in muscle cells from fundus correlates with tonic phenotype of muscle.

[Effect of banxia xiexin decoction on gastric antral interstitial cells of Cajal and stem cell factor in diabetic rats].

OBJECTIVE: To observe the effect of Banxia Xiexin Decoction (BXD) on expression of the interstitial cells of Cajal (ICCs) and stem cell factor (SCF) in the antrum of rats with diabetes mellitus (DM). METHODS: Totally sixty healthy male SD rats were randomly divided into the control group, the model group, the BXD group, and the Western medicine group (WM, treated by domperidone), 15 in each group. Diabetic rat models were established by a single intraperitoneal injection of streptozotocin (STZ, 55 mg/kg). Those in the BXD group were perfused with BXD at the daily dose of 5.4 g/kg. An equal volume of distilled water was given by gastrogavage to those in the WM group and the control group for 8 successive weeks. The body weight and blood glucose of all rats were detected, and the gastric residual rates were detected with semisolid nutrient paste by gastrogavage. The expression of positive ICCs and SCF were observed by immunohistochemical method and quantified image analyzer. RESULTS: Compared with the control group,the body weight reduced, blood glucose and gastric residual rates increased, and the mean optical density of positive ICCs and SCF significantly decreased in the model group (P < 0.05). Compared with the model group,symptoms such as polydipsia, polyphagia, polyuria were relieved, spirits improved, the body weight and mean optical densities of positive ICCs and SCF significantly increased (P < 0.05), and gastric residual rates significantly decreased in the BXD group and the WM group (P < 0.05). The blood glucose significantly decreased (P < 0.05) in the BXD group. The mean optical density of positive ICCs was higher in the BXD group than in the WM group (P < 0.05). CONCLUSIONS: BXD could promote the expression of positive ICCs and SCF. It could improve the gastric motility in DM rats by partially inverting abnormal changes of gastric antral ICCs and SCF.