Gut region-specific TNFR expression:TNFR2 is more affected than TNFR1 in duodenal myenteric ganglia of diabetic rats

BACKGROUND Cytokines are essential in autoimmune inflammatory processes that accompany type 1 diabetes.Tumor necrosis factor alpha plays a key role among others in modulating enteric neuroinflammation,however,it has a dual role in cell degeneration or survival depending on different TNFRs.In general,TNFR1 is believed to trigger apoptosis,while TNFR2 promotes cell regeneration.The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy,however,the expression and alterations of different TNFRs in the gastrointestinal tract has not been reported.AIM To investigate the TNFR1 and TNFR2 expression in myenteric ganglia and their environment in different intestinal segments of diabetic rats.METHODS Ten weeks after the onset of hyperglycemia,gut segments were taken from the duodenum,ileum and colon of streptozotocin-induced(60 mg/body weight kg i.p.)diabetic(n=17),insulin-treated diabetic(n=15)and sex-and age-matched control(n=15)rats.Myenteric plexus whole-mount preparations were prepared from different gut regions for TNFR1/HuCD or TNFR2/HuCD double-labeling fluorescent immunohistochemistry.TNFR1 and TNFR2 expression was evaluated by post-embedding immunogold electron microscopy on ultrathin sections of myenteric ganglia.TNFRs levels were measured by enzyme-linked immunosorbent assay in muscle/myenteric plexus-containing(MUSCLE-MP)tissue homogenates from different gut segments and experimental conditions.RESULTS A distinct region-dependent TNFRs expression was detected in controls.The density of TNFR1-labeling gold particles was lowest,while TNFR2 density was highest in duodenal ganglia and a decreased TNFRs expression from proximal to distal segments was observed in MUSCLE-MP homogenates.In diabetics,the TNFR2 density was only significantly altered in the duodenum with decrease in the ganglia(0.32±0.02 vs 0.45±0.04,P<0.05),while no significant changes in TNFR1 density was observed.In diabetic MUSCLE-MP homogenates,both TNFRs levels significantly decreased in the duodenum(TNFR1:4.06±0.65 vs 20.32±3.1,P<0.001;TNFR2:11.72±0.39 vs 15.91±1.04,P<0.01),which markedly influenced the TNFR2/TNFR1 proportion in both the ganglia and their muscular environment.Insulin treatment had controversial effects on TNFR expression.CONCLUSION Our findings show diabetes-related region-dependent changes in TNFR expression and suggest that TNFR2 is more affected than TNFR1 in myenteric ganglia in the duodenum of type 1 diabetic rats.

Distribution of nitric oxide synthase in stomach myenteric plexus of rats

AIM: To study the distribution of nitric oxide synthase (NOS) in rat stomach myenteric plexus. METHODS: The distribution of NOS in gastric wall was studied in quantity and location by the NADPH-diaphorase (NDP) histochemical staining method and whole mount preparation technique. RESULTS: NOS was distributed in whole stomach wall, most of them were located in myenteric plexus, and distributed in submucosal plexus.The shape of NOS positive neurons was basically similar, most of them being round and oval in shape. But their density, size and staining intensity varied greatly in the different parts of stomach. The density was 62+/-38 cells mm(2) (antrum), 43+/-32 cells/mm(2) (body), and 32+/-28 cells mm(2) (fundus), respectively. The size and staining intensity of NOS positive neurons in the fundus were basically the same, the neurons being large and dark stained, while they were obviously different in antrum. In the body of the stomach, the NOS positive neurons were in an intermediate state from fundus to antrum. There were some beadlike structures which were strung together by NOS positive varicosities in nerve fibers, some were closely adherent to the outer walls of blood vessels. CONCLUSION: Nitric oxide might be involved in the modulation of motility, secretion and blood circulation of the stomach, and the significant difference of NOS positive neurons in different parts of stomach myenteric plexus may be related to the physiologic function of stomach.

Expression of c-fos in gastric myenteric plexus and spinal cord of rats with cervical spondylosis

AIM: To determine the expression of c-fos in gastric myenteric plexus and spinal cord of rats with cervical spondylosis and its clinical significance. METHODS: A cervical spondylosis model was established in rats by destroying the stability of cervical posterior column,and the cord segments C4-6 and gastric antrum were collected 3, 4 and 5 mo after the operation. Rats with sham operation were used as controls. c-fos neuronal counter-staining was performed with an immunohistochemistry method. Every third sections from C4-6 segments were drawn. The 10 most labeled c-fos-immunoreactive (Fos-IR) neurons were counted, and the average number was used for statistical analysis. The mean of Fos-IR neurons in myenteric plexus was calculated after counting Fos-IR neurons in 25 ganglia from each antral preparation, and expressed as a mean count per myenteric ganglion.RESULTS: There were a few c-fos-positive neurons in the cervical cord and antrum in the control group. There was an increased c-fos expression in model group 3, 4 and 5 mo after operation, whereas there was no significant increase in c-fos expression in the control group at 3, 4 and 5 mo.More importantly, there was a significant difference in c-fos expression between rats followed up for 3 mo and those for 5 mo in the model group (11.20±2.26 vs 27.68±4.36,P＜0.05, for the cervical cord; and 11.3±2.3 vs 29.3±4.6,P＜0.05, for the gastric antrum). There was no significant difference between rats followed up for 3 mo and those for 4 mo and between rats followed up for 4 mo and those for 5 mo in the model group.CONCLUSION: c-fos expression in gastric myenteric plexus was dramatically associated with that in the spinal cord in rats with cervical spondylosis, suggesting that the gastrointestinal function may be affected by cervical spondylosis. If this hypothesis is confirmed by further studies, functional gastrointestinal diseases such as functional dyspepsia and irritable bowel syndrome could be explained by neurogastroenterology.

Effects of electroacupuncture at Zusanli (ST 36) on neurons in the colonic myenteric plexus in rats with irritable bowel syndrome with constipation

We studied the effects of electroacupuncture at Zusanli （ST 36） on neurons in the colonic myenteric plexus and on defecation in rats with irritable bowel syndrome with constipation （IBS-C）. We also used intragastric administration of pinaverium bromide as a positive control treatment to reveal the pathway mediating the onset of IBS-C. Both electroacupuncture and pinaverium bromide greatly improved defecation in rats with IBS-C. Immunohistochemical staining of the enteric nervous system neuronal marker protein gene product 9.5 in the colonic myenteric plexus showed that electroacupuncture by itself, or in combination with pinaverium bromide, increased the number of neurons and the staining intensity of protein gene product 9.5 in the colonic myenteric plexus. We conclude that visceral hypersensitivity is likely to be a primary cause of constipation in IBS-C rats.

Myenteric neurons and intestinal mucosa of diabetic rats after ascorbic acid supplementation

AIM: To investigate the effect of ascorbic acid (AA) dietary supplementation on myenteric neurons and epithelial cell proliferation of the jejunum of adult rats with chronic diabetes mellitus. METHODS: Thirty rats at 90 d of age were divided into three groups: Non-diabetic, diabetic and diabetic treated with AA (DA) (1 g/L). After 120 d of treatment with AA the animals were killed. The myenteric neurons were stained for myosin-V and analyzed quantitatively in an area of 11.2 mm2/animal. We further measured the cellular area of 500 neurons per group. We also determined the metaphasic index (MI) of the jejunum mucosa layer of about 2500 cells in the intestinal crypts, as well as the dimensions of 30 villi and 30 crypts/animal. The data area was analyzed using the Olympus BX40 microscope. RESULTS: There was an increase of 14% in the neuronal density (792.6 ± 46.52 vs 680.6 ± 30.27) and 4.4% in the cellular area (303.4 ± 5.19 vs 291.1 ± 6.0) respectively of the diabetic group treated with AA when compared to control diabetic animals. There were no signifi cant differences in MI parameters, villi height or crypt depths among the groups.CONCLUSION: Supplementation with AA in the diabetic animal promoted moderate neuroprotection. There was no observation of alteration of the cellular proliferation of the jejunum mucosa layer of rats with chronic diabetes mellitus with or without supplementation with AA.

Expression of the P2X_2 receptor in different classes of ileum myenteric neurons in the female obese ob/ob mouse

AIM:To examine whether the ob/ob mouse model of obesity is accompanied by enteric nervous system ab-normalities such as altered motility METHODS:The study examined the distribution of the P2X 2 receptor (P2X 2 R) in myenteric neurons of female ob/ob mice. Specifically, we used immunohistochemistry to analyze the co-expression of the P2X 2 R with neuronal nitric oxide synthase (nNOS), choline acetyltrans-ferase (ChAT), and calretinin (CalR) in neurons of the small intestine myenteric plexus in ob/ob and control female mice In these sections, we used scanning confocal microscopy to analyze the co-localization of these markers as well as the neuronal density (cm 2 ) and area profile (μm2) of P2X 2 R-positive neurons In addition, enteric neurons were labeled using the nicotinamide adenine dinucleotide (NA H) diaphorase method and analyzed with light microscopy as an alternate means by which to analyze neuronal density and areaRESULTS:In the present study, we observed a 29 6% increase in the body weight of the ob/ob animals (OG) compared to the control group (CG) In addition, the average small intestine area was increased by approxi-mately 29 6% in the OG compared to the CG Immu-noreactivity (IR) for the P2X 2 R, nNOS, ChAT and CalR was detectable in the myenteric plexus, as well as in the smooth muscle, in both groups This IR appeared to be mainly cytoplasmic and was also associated with the cell membrane of the myenteric plexus neurons, where it outlined the neuronal cell bodies and their processes P2X 2 R-IR was observed to co-localize 100% with that for nNOS, ChAT and CalR in neurons of both groups In the ob/ob group, however, we observed that the neuronal density (neuron/cm 2 ) of P2X 2 R-IR cells was in-creased by 62% compared to CG, while that of NOS-IR and ChAT-IR neurons was reduced by 49% and 57%, respectively, compared to control mice The neuronal density of CalR-IR neurons was not different between the groups Morphometric studies further demonstrated that the cell body profile area (μm2) of nNOS-IR, ChAT-IR and CalR-IR neurons was increased by 34%, 20% and 55%, respectively, in the OG compared to controls Staining for NA H diaphorase activity is widely used to detect alterations in the enteric nervous system; however, our qualitative examination of NA H-diaphorase positive neurons in the myenteric ganglia revealed an overall similarity between the two groups CONCLUSION:We demonstrate increases in P2X2R expression and alterations in nNOS, ChAT and CalR IR in ileal myenteric neurons of female ob/ob mice compared to wild-type controls.

Effects of combined pre- and post-natal protein deprivation on the myenteric plexus of the esophagus of weanling rats:A histochemical,quantitative and ultrastructural study

AIM: To evaluate the effects of protein deprivation on the myenteric plexus of the esophagus of weanling rats. METHODS: Pregnant female Wistar rats were divided into 2 groups: nourished (N),receiving normal diet,and undernourished (D),receiving a protein-deprived diet,which continued after birth. At twenty-one days of age,13 esophagi from each group were submitted to light microscopy and morphometrical analysis employing the NADH diaphorase,NADPH diaphorase and acetylcholinesterase techniques. Three other esophagi from each group were evaluated with transmission electron microscopy (TEM). RESULTS: In both the NADH- and the NADPH-reactive mounts,the neurons of the N mounts were more intensely stained,while in the D esophagi only the larger neurons were reactive. Many myenteric neurons of N were intensely reactive for AChE activity but only a few neurons of D exhibited these aspects. Ultrastructural analysis revealed that the granular reticulum of N showed large numbers of ribosomes aligned on the outer surface of its regularly arranged membrane while the ribosomes of D were disposed in clusters. The chromatin was more homogeneously scattered inside the neuron nucleus of N as well as the granular component of the nucleolus was evidently more developed in this group. Statistically significant differences between N and D groups were detected in the total estimated number of neurons stained by the NADPH technique. CONCLUSION: The morphological and quantitative data shows that feeding with protein-deprived diet in 21-d old rats induces a delay in the development of the myenteric neurons of the esophagus.

P2X7 receptor antagonist recovers ileum myenteric neurons after experimental ulcerative colitis

BACKGROUND The P2X7 receptor is expressed by enteric neurons and enteric glial cells.Studies have demonstrated that administration of a P2X7 receptor antagonist,brilliant blue G(BBG),prevents neuronal loss.AIM To report the effects of BBG in ileum enteric neurons immunoreactive(ir)following experimental ulcerative colitis in Rattus norvegicus albinus.METHODS 2,4,6-trinitrobenzene sulfonic acid(TNBS group,n=5)was injected into the distal colon.BBG(50 mg/kg,BBG group,n=5)or vehicle(sham group,n=5)was given subcutaneously 1 h after TNBS.The animals were euthanized after 24 h,and the ileum was removed.Immunohistochemistry was performed on the myenteric plexus to evaluate immunoreactivity for P2X7 receptor,neuronal nitric oxide synthase(nNOS),choline acetyltransferase(ChAT),HuC/D and glial fibrillary acidic protein.RESULTS The numbers of nNOS-,ChAT-,HuC/D-ir neurons and glial fibrillary acidic protein-ir glial cells were decreased in the TNBS group and recovered in the BBG group.The neuronal profile area(μm^2)demonstrated that nNOS-ir neurons decreased in the TNBS group and recovered in the BBG group.There were no differences in the profile areas of ChAT-and HuC/D-ir neurons.CONCLUSION Our data conclude that ileum myenteric neurons and glial cells were affected by ulcerative colitis and that treatment with BBG had a neuroprotective effect.Thus,these results demonstrate that the P2X7 receptor may be an important target in therapeutic strategies.

Effects of perinatal protein deprivation and recovery on esophageal myenteric plexus

AIM:To evaluate effects of preand postnatal protein deprivation and postnatal recovery on the myenteric plexus of the rat esophagus. METHODS: Three groups of young Wistar rats (aged 42 d) were studied: normalfed (N42), proteindeprived (D42), and proteinrecovered (R42). The myenteric neurons of their esophagi were evaluated by histochemical reactions for nicotinamide adenine dinucleotide (NADH), nitrergic neurons (NADPH)diaphorase and acetylcholinesterase (AChE), immunohistochemical reaction for vasoactive intestinal polypeptide (VIP), and ultrastructural analysis by transmission electron microscopy.RESULTS: The cytoplasms of large and medium neurons from the N42 and R42 groups were intensely reactive for NADH. Only a few large neurons from the D42 group exhibited this aspect. NADPH detected in the D42 group exhibited low reactivity. The AChE reactivity was diffuse in neurons from the D42 and R42 groups. The density of large and small varicosities detected by immunohistochemical staining of VIP was low in ganglia from the D42 group. In many neurons from the D42 group, the double membrane of the nuclear envelope and the perinuclear cisterna were not detectable. NADH and NADPH histochemistry revealed no group differences in the prof ile of nerve cell perikarya (ranging from 200 to 400 μm2).CONCLUSION: Protein deprivation causes a delay in neuronal maturation but postnatal recovery can almost completely restore the normal morphology of myenteric neurons.

Effect of motilin and erythromycin on intracellular Ca2+ mobilization in rat myenteric neurons in culture

Objective: To investigate the effects of motilin and erythromycin on intracellular Ca2+ mobi-lization in cultured myenteric neurons of rats. Methods: The cultured myenteric neurons were identified with immunofluorescence staining technique. Motilin-induced and erythromycin-induced intracellular Ca2+ mobilization was studied in primary cultures of myenteric neurons using the ratiometric Ca2+ indicator Furo3/AM, with a laser confocal microscope. Results: The effects of motilin and erythromycin on intracellular Ca2+ mobilization were as follows: (1)In Hank's solution, 10 -8, 10-7, 10-6 mol/L motilin could elevate intracellular Ca2+ concentration ([Ca2+]i)in a dose-dependent manner. (2) In Hank's solution, 10μg/ ml erythromycin also could induce the elevation of [Ca2+]i. (3) After pretreatment with antibody against the motilin receptor in Hank's solution, the Ca2+ response to erythromycin was almost restricted. Conclusion: It is suggested that motilin could increase [Ca2+]i in myenteric neurons in a dose-dependent manner, and erythromycin may also have this effectivenesss by binding to the motilin receptor.

Gut region-dependent alterations of nitrergic myenteric neurons after chronic alcohol consumption

Chronic alcohol abuse damages nearly every organ in the body. The harmful effects of ethanol on thebrain, the liver and the pancreas are well documented. Although chronic alcohol consumption causes serious impairments also in the gastrointestinal tract like altered motility, mucosal damage, impaired absorption of nu-trients and inflammation, the effects of chronically consumed ethanol on the enteric nervous system are less detailed. While the nitrergic myenteric neurons play an essential role in the regulation of gastrointestinal peristalsis, it was hypothesised, that these neurons are the first targets of consumed ethanol or its metabolites generated in the different gastrointestinal segments. To reinforce this hypothesis the effects of ethanol on the gastrointestinal tract was investigated in different rodent models with quantitative immunohistochemistry, in vivo and in vitro motility measurements, western blot analysis, evaluation of nitric oxide synthase enzyme activity and bio-imaging of nitric oxide synthesis. These results suggest that chronic alcohol consumption did not result significant neural loss, but primarily impaired the nitrergic pathways in gut region-dependent way leading to disturbed gastrointestinal motility. The gut segment-specific differences in the effects of chronic alcohol consumption highlight the significance the ethanol-induced neuronal microenvironment involving oxidative stress and intestinal microbiota.

Morphological effects of autoclaved diet on the myenteric neurons of rats

AIM:To evaluate the effect of autoclaved diet on the jejunum neurons of the myenteric plexus of rats during their growth.METHODS:The experimental groups were made up of rats going through weaning whose mothers received either an autoclaved or a non-autoclaved diet during gestation and lactation,and rats that were fed the same diet as their mothers during the post-weaning period.In order to measure the neurons'body profile and to quantify the number of neurons per area,preparations were stained by the nicotinamide adenine dinucleotide-diaphorase method.RESULTS:No significant changes were observed in rats'body weight or in the number of neurons regardless of the diet used(P>0.05) .There was a decrease in the jejunum-ileum length in rats treated with an autoclaved diet(P<0.05) .An increase in the neuronal cross-sectional area was seen in rats that had received the autoclaved diet,an effect that was significant for animals undergoing weaning.In addition,all observed factors showed significant differences when related to the age of the animals.CONCLUSION:The autoclaved diet did not alter the quantity of neurons,but increased their cell body area,suggesting changes similar to those observed in protein deficiency.

DISTRIBUTION OF NOS-B1 IN THE MYENTERIC PLEXUS OFRABBIT SMALL BOWELS

The distribution or NOS-BI In the myenterlc plexus or the rabbit small ho'vels was studied by using NOS--BI lmm unohlstoc hemlstry with cool emount stal nl ug method. The resul is Indicatedthat the NOS--BI-like lmmunoreactlvity was observed in all specimens or myenterlc plexus. These positive nerve fibers rorlned a regular, ladder-like meSkwork in the myenterlc plexus. The positive product deposited in the cytoplasm, and the majority of NOS-BI neurons had ckaracterlstlcs similar to theDoglel type 1. Thes. cells had many short and long Process. This study provided the morphologicalsupport for the bypotbesls that NO Is pro'duced by neurons and serves as a neurotransmitter in therabbit small bowels.

Quantitative changes of nitrergic neurons during postnatal development of chicken myenteric plexus

Objective: Information regarding the development of the enteric nervous system(ENS) is important for understanding the functional abnormalities of the gut.Because fertilized chicken eggs provide easy access to embryos,chicken models have been widely used to study embryonic development of myenteric plexus;however,no study has been focused on the postnatal period.The aim of this study was to perform a qualitative and quantitative analysis of the nitrergic neurons in the myenteric plexus of developing chickens in the postnatal period.Methods: Whole-mount preparations of the myenteric plexus were made in 7-d,15-d,and 40-d old(adult) chickens of either sex(n=15).The myenteric plexus was studied after nicotinamide adenine dinucleotide phosphate diaphorase(NADPH-d) histochemistry using light microscopy,digital photography,and Image-Pro Plus 6.0 software.The numbers of positively stained neurons and ganglia were counted in the duodenum,jejunum,ileum,caecum,and colon in the different age groups.Data were expressed as mean±standard deviation(SD),and statistical analysis was performed using a one-way analysis of variance(ANOVA) test.Results: The positively stained neurons showed various morphologies and staining intensities,and formed bead-shaped and U-shaped arrangements in the myenteric plexus.The densities of neurons and ganglia increased with age.However,the number of positive neurons per ganglion increased.The number of NADPH-d-positive neurons was highest in the colon,followed by the ileum,the jejunum,the duodenum,and the caeca in all age groups.Conclusions: Developmental changes in the myenteric plexus of chickens continue in the postnatal period,indicating that the maturation process of the gastrointestinal function is gradual.In addition,no significant difference is happening among different intestinal segments during postnatal development,suggesting that the function of different intestinal segments had been determined after birth.

Neuroprotective action of Ginkgo biloba on the enteric nervous system of diabetic rats

AIM: To investigate the effect of Ginkgo biloba extract on the enteric neurons in the small intestine of diabetic rats. METHODS: Fifteen Wistar rats were divided into three groups: control group (C), diabetic group (D) and diabetic-treated (DT) daily with EGb 761 extract (50 mg/kg body weight) for 120 d. The enteric neurons were identified by the myosin-V immunohistochemical technique. The neuronal density and the cell body area were also analyzed. RESULTS: There was a significant decrease in the neuronal population (myenteric plexus P = 0.0351; submucous plexus P = 0.0217) in both plexuses of the jejunum in group D when compared to group C. With regard to the ileum, there was a significant decrease (P = 0.0117) only in the myenteric plexus. The DT group showed preservation of the neuronal population in the jejunum submucous plexus and in the myenteric plexus in the ileum. The cell body area in group D increased significantly (P = 0.0001) in the myenteric plexus of both segments studied as well as in the ileum submucosal plexus, when compared to C. The treatment reduced (P = 0.0001) the cell body area of the submucosal neurons of both segments and the jejunum myenteric neurons. CONCLUSION: The purified Ginkgo biloba extract has a neuroprotective effect on the jejunum submucous plexus and the myenteric plexus of the ileum of diabetic rats.

Immunomodulation of enteric neural function in irritable bowel syndrome

Irritable bowel syndrome(IBS) is a common functional gastrointestinal disorder which is characterised by symptoms such as bloating, altered bowel habit and visceral pain. It's generally accepted that miscommunication between the brain and gut underlies the changes in motility, absorpto-secretory functionand pain sensitivity associated with IBS. However, partly due to the lack of disease-defining biomarkers, understanding the aetiology of this complex and multifactorial disease remains elusive. Anecdotally, IBS patients have noted that periods of stress can result in symptom flares and many patients exhibit comorbid stress-related mood disorders such as anxiety and depression. However, in addition to psychosocial stressors, infection-related stress has also been linked with the initiation, persistence and severity of symptom flares. Indeed, prior gastrointestinal infection is one of the strongest predictors of developing IBS. Despite a lack of overt morphological inflammation, the importance of immune factors in the pathophysiology of IBS is gaining acceptance. Subtle changes in the numbers of mucosal immune cell infiltrates and elevated levels of circulating pro-inflammatory cytokines have been reproducibly demonstrated in IBS populations. Moreover, these immune mediators directly affect neural signalling. An exciting new area of research is the role of luminal microbiota in the modulation of neuro-immune signalling, resulting in local changes in gastrointestinal function and alterations in central neural functioning. Progress in this area has begun to unravel some of the complexities of neuroimmune and neuroendocrine interactions and how these molecular exchanges contribute to GI

Distribution of the P2X2 receptor and chemical coding in ileal enteric neurons of obese male mice(ob/ob)

AIM:To investigate the colocalization,density and profile of neuronal areas of enteric neurons in the ileum of male obese mice.METHODS:The small intestinal samples of male mice in an obese group(OG)(C57BL/6J ob/ob)and a control group(CG)(+/+)were used.The tissues were analyzed using a double immunostaining technique for immunoreactivity(ir)of the P2X2 receptor,nitric oxide synthase(NOS),choline acetyl transferase(ChAT)and calretinin(Calr).Also,we investigated the density and profile of neuronal areas of the NOS-,ChAT-and Calrir neurons in the myenteric plexus.Myenteric neurons were labeled using an NADH-diaphorase histochemical staining method.RESULTS:The analysis demonstrated that the P2X2receptor was expressed in the cytoplasm and in the nuclear and cytoplasmic membranes only in the CG.Neuronal density values(neuron/cm2)decreased 31%(CG:6579±837;OG:4556±407)and 16.5%(CG:7796±528;OG:6513±610)in the NOS-ir and calretininir neurons in the OG,respectively(P<0.05).Density of ChAT-ir(CG:6200±310;OG:8125±749)neurons significantly increased 31%in the OG(P<0.05).Neuron size studies demonstrated that NOS,ChAT,and Calr-ir neurons did not differ significantly between the CG and OG groups.The examination of NADH-diaphorase-positive myenteric neurons revealed an overall similarity between the OG and CG.CONCLUSION:Obesity may exert its effects by promoting a decrease in P2X2 receptor expression and modifications in the density of the NOS-ir,ChAT-ir and CalR-ir myenteric neurons.

Deficiency of platelet-derived growth factor receptor-α-positive cells in Hirschsprung's disease colon

AIM: To investigate whether the expression of platelet-derived growth factor receptor-α-positive (PDGFRα+)-cells is altered in Hirschsprung’s disease (HD).METHODS: HD tissue specimens (n = 10) were collected at the time of pull-through surgery, while colonic control samples were obtained at the time of colostomy closure in patients with imperforate anus (n = 10). Immunolabelling of PDGFRα+-cells was visualized using confocal microscopy to assess the distribution of these cells, while Western blot analysis was undertaken to quantify PDGFRα protein expression.RESULTS: Confocal microscopy revealed PDGFRα+-cells within the mucosa, myenteric plexus and smooth muscle in normal controls, with a marked reduction in PDGFRα+-cells in the HD specimens. Western blotting revealed high levels of PDGFRα protein expression in normal controls, while there was a striking decrease in PDGFRα protein expression in the HD colon.CONCLUSION: These findings suggest that the altered distribution of PDGFRα+-cells in both the aganglionic and ganglionic HD bowel may contribute to the motility dysfunction in HD.

Alleviated mucosal and neuronal damage in a rat model of Crohn's disease

AIM:To establish a rat model suitable to investigate the repetitive relapsing inflammations(RRI)characteristic to Crohn’s disease.METHODS:Colitis was induced by 2,4,6-trinitrobenzenesulfonic acid(TNBS).RRI were mimicked by repeating administrations of TNBS.Tissue samples were taken from control,once,twice and three times treated rats from the inflamed and adjacent non-inflamed colonic segments at different timepoints during the acute intestinal inflammation.The means of the ulcerated area were measured to evaluate the macroscopic mu-cosal damage.The density of myenteric neurons was determined on whole mounts by Hu C/Hu D immunohistochemistry.Heme oxygenase-1(HO-1)expression was evaluated by molecular biological techniques.RESULTS:TNBS-treated rats displayed severe colitis,but the mortality was negligible,and an increase of body weight was characteristic throughout the experimental period.The widespread loss of myenteric neurons,and marked but transient HO-1 up-regulation were demonstrated after the first TNBS administration.After repeated doses the length of the recovery time and extent of the ulcerous colonic segments were markedly decreased,and the neuronal loss was on a smaller scale and was limited to the inflamed area.HO-1 m RNA level was notably greater than after a single dose and overexpression was sustained throughout the timepoints examined.Nevertheless,the HO-1protein up-regulation after the second TNBS treatment proved to be transient.Following the third treatment HO-1 protein expression could not be detected.CONCLUSION:Experimentally provoked RRI may exert a protective preconditioning effect against the mucosal and neuronal damage.The persistent up-regulation of HO-1 m RNA expression may correlate with this.