[Changes of tight junction claudin-1,-3,-4 protein expression in the intestinal mucosa in patients with irritable bowel syndrome].

OBJECTIVE: To investigate the changes of intestinal mucosal tight junction proteins claudin-1, -3, -4 in patients with irritable bowel syndrome (IBS), and elucidate its possible role in the bowel evacuation habit changes and formation in these patients. METHODS: Western blotting was employed to determine tight junction protein claudin-1,-3,-4 levels in the intestinal mucosa of patients in the control group, diarrhea-predominant IBS (D-IBS) group and constipation-predominant IBS (C-IBS) group. RESULTS: Compared with the control group, D-IBS patients showed significantly decreased claudin-1 protein levels in both the small intestinal and colonic mucosae (P<0.05), whereas C-IBS patients had significantly elevated claudin-1 protein levels (P<0.05). No significant difference was found in claudin-3 protein expression in the both small intestinal and colonic mucosae between the D-IBS group and the control group (P>0.05), but claudin-3 protein level was shown to increase significantly in C-IBS patients (P<0.05). Claudin-4 protein followed the same pattern of alteration as claudin-1. CONCLUSION: Down-regulated claudin-1 and -4 expressions can be associated with bowel evacuation habit changes and formation in patients with D-IBS, but up-regulated claudin-1, -3 and -4 expressions may relate to such bowel changes in patients with C-IBS.

Effect of change in an inhibitory neurotransmitter of the myenteric plexus on the pathogenetic mechanism of irritable bowel syndrome subgroups in rat models.

OBJECTIVE: In order to investigate the effect of change in an inhibitory neurotransmitter of the myenteric plexus on irritable bowel syndrome (IBS) subgroups, the amounts of nitric oxide (NO) in constipation-predominant (C-IBS) and diarrhea-predominant (D-IBS) IBS models in rats were studied. METHODS: The D-IBS model was created in rats by intracolonic instillation of acetic acid and by restraint stress. The D-IBS control group underwent intracolonic instillation with saline instead. The C-IBS model was created in rats by gastric instillation of 0-4 degrees C cool water daily for 14 days. The C-IBS control group underwent gastric instillation with saline instead. A blank control group was also made. Viscerosomatic sensitivity was assessed with electromyographic (EMG). Abdominal contractions induced by distension of a colonically inserted balloon (0-1.6 mL) was recorded in rats by implanting electrodes in the abdominal external oblique muscle. An India ink gastric instillation experiment was used to detect the bowel movement and fecal pellets formation. Histological analysis of colonic tissue was performed. Nicotinamide dinucleotide phosphate (NADPH)-diaphorase staining was used to detect positive NO neurons in the myenteric plexus. RESULTS: When the balloon was distended by high volume, there were significantly more contractions of abdominal muscle in D-IBS compared with C-IBS and the control groups (P < 0.05). When the balloon was distended by low volume, there were significantly fewer contractions of abdominal muscle in C-IBS compared with D-IBS and the control groups (P < 0.05). The wet weight and water content of the feces expelled by the rats in the C-IBS and the C-IBS control groups were significantly lower than those in the blank control group (P < 0.05). The time before the first black stool in the C-IBS group was significantly longer than that in the blank control group and C-IBS control group (P < 0.05). Histological analysis of the colon showed no colonic inflammation in any group. The number of NO-positive neurons in the C-IBS group was significantly greater than in the D-IBS and control groups (P < 0.01), although there was no significant difference in the number of neurons between the D-IBS and the control groups (P > 0.05). CONCLUSIONS: Enhanced inhibitory neurotransmitter NO in the myenteric plexus of the colon is related to IBS subgroups, visceral sensitivity and motility dysfunction. The results reveal that NO plays a role in the pathogenetic mechanism of IBS subgroups.

A microarray-based gastric carcinoma prewarning system.

AIM: To develop a microarray-based prewarning system consisting of gastric cancer chip, prewarning data and analysis software for early detection of gastric cancer and pre-cancerous lesions. METHODS: Two high-density chips with 8,464 human cDNA sites were used to primarily identify potential genes specific for normal gastric mucosa, pre-cancerous lesion and gastric cancer. The low-density chips, composed of selected genes associated with normal gastric mucosa, precancerous lesion and gastric cancer, were fabricated and used to screen 150 specimens including 60 specimens of gastric cancer, 60 of pre-cancerous tissues and 30 of normal gastric mucosa. CAD software was used to screen out the relevant genes and their critical threshold values of expression levels distinguishing normal mucosa from pre-cancerous lesion and cancer. All data were stored in a computer database to establish a prewarning data library for gastric cancer. Two potential markers brcaa1 and ndr1 were identified by Western blot and immunohistochemistry. RESULTS: A total of 412 genes associated with three stages of gastric cancer development were identified. There were 216 genes displaying higher expression in gastric cancer, 85 genes displaying higher expression in pre-cancerous lesion and 88 genes displaying higher expression in normal gastric mucosa. Also 15 genes associated with metastasis of gastric cancer and 8 genes associated with risk factors were screened out for target genes of diagnosis chip of early gastric cancer. The threshold values of 412 selected genes to distinguish gastric cancer, pre-cancerous lesion from normal gastric mucosa were defined as 6.01+/-2.40, 4.86+/-1.94 and 5.42+/-2.17, respectively. These selected 412 genes and critical threshold values were compiled into an analysis software, which can automatically provide reports by analyzing the results of 412 genes obtained by examining gastric tissues. All data were compiled into a prewarning database for gastric cancer by CGO software. Northern blot and immunohistochemistry analysis confirmed that gene and protein of brcaa1 displayed lower expression in normal gastric mucosa and higher expression in gastric cancer tissues, conversely, ndr1 displayed lower expression in gastric cancer and higher expression in normal gastric mucosa. CONCLUSION: The microarray-based prewarning system for gastric cancer was developed. This system consisted of gastric cancer-associated gene chip, prewarning data and analysis software, which has a high potential for applications in the early detection of gastric cancer. The two potential markers brcaa1 and ndr1 identified may be used to distinguish cancer status fand non-cancer status.

[Experimental study of apoptosis and proliferation of gastric mucosal cells in chronic atrophic gastritis].

OBJECTIVE: To study the relationship between long-term high-salt hot diet and chronic atrophic gastritis (CAG). The expression of apoptosis cells, proliferation cells, bcl-2 and Fas proteins were detected in the gastric mucosa of CAG rates induced by high-salt hot water. METHODS: TUNEL technique and immunohistochemical method were used in the experiment. Flow cytometry method was used to detect the DNA content of apoptosis cells. RESULTS: (1) The detection of apoptosis with TUNEL showed that the apoptosis cells in CAG rates induced by high-salt hot water were high. These cells could be seen in all layers of gastric mucosa, apoptosis index of model rates was higher than that of normal rates (P < 0.05). (2) The result of detecting apoptosis gene and proliferating cell nuclear antigen (PCNA) by immunohistochemical method showed that the expression of bcl-2, Fas and PCNA in the CAG rates induced by high-salt hot water was much higher than that of normal gastric mucosa (P < 0.05). The expression rates of bcl-2, Fas proteins were higher with time going on. After being given high-salt hot water intragastrically for 4, 8, 12 weeks, the bcl-2 protein expression rates were 12.5%, 16.7%, 76.5%, the Fas protein expression rates were 18.7%, 22.2% and 64.7%. (3) Flow cytometry technique showed that there was a second G(0)/G(1) peek, which was apoptosis cells peak, but was not seen in the normal gastric mucosa. CONCLUSIONS: Abnormality of proliferation and apoptosis in gastric mucosa could be induced by high-salt hot water. bcl-2, Fas gene played an important role in this course.

Mechanism of exogenous nucleic acids and their precursors improving the repair of intestinal epithelium after gamma-irradiation in mice.

AIM:To clone expressed genes associated with repair of irradiation-damaged mice intestinal gland cells treated by small intestinal RNA, and to explore the molecular mechanism of exogenous nucleic acids improving repair of intestinal crypt.METHODS:The animal mode of test group and control group was established, forty-five mice being irradiated by gamma ray were treated with small intestinal RNA as test group, forty mice being irradiated by gamma ray were treated with physiological saline as control group,five mice without irradiation were used as normal control, their jejunal specimens were collected respectively at 6h, 12h,24h, 4d and 8d after irradiation. Then by using LD-PCR based on subtractive hybridization, these gene fragments differentially expressed between test group and control group were obtained, and then were cloned into T vectors as well as being sequenced. Obtained sequences were screened against. GeneBank, if being new sequences, they were submitted to GeneBank.RESULTS:Ninety clones were associated with repair of irradiation-damaged intestinal gland cells treated by intestinal RNA. These clones from test group of 6h, 12h, 24h, 4d and 8d were respectively 18, 22, 25, 13, 12. By screening against GeneBank, 18 of which were new sequences, the others were dramatically similar to the known sequences, mainly similar to hsp, Nmi,Dutt1, alkaline phosphatase, homeobox, anti-CEA ScFv antibody, arginine/serine kinase and BMP-4,repA. Eighteen gene fragments were new sequences,their accept numbers in GeneBank were respectively AF240164-AF240181.CONCLUSION:Ninety clones were obtained to be associated with repair of irradiation damaged mice intestinal gland cells treated by small intestinal RNA, which may be related to abnormal expression of genes and matched proteins of hsp, Nmi, Dutt1, Na, K-ATPase,alkalineph-osphatase, glkA, single stranded replicative centromeric gene as well as 18 new sequences.