| BACKGROUND AND AIMS Helicobacter pylori infection of the human stomach is the most important risk factor for development of chronic gastric diease and gastric cancer,and HP is known as I Kind of carcinogenic factor. The prevalence of H pylori infection is worldwide ,but only some small number of them cause the dieases and different clinic outcome. The clinical outcome is closely related to HP gene polymorphisms. Most scholars at home and abroad discovered that cagA and vacA are associated with gastroduodenal diease but they are not helpful in predicting the clinical presentation of HP infection. However,resently most scholars at home and abroad discovered oipA gene and its expression product ,another virulence factor of HP, is probably more improtant than cagA in HP pathogenicity. Ninxia is one of high occurrence area of gastric cancer. Forward research of this subject finded the positive rate of oipA gene among different chronic gastric diseases is significantly different, and oipA is closely related to gastric cacer. However, the mechanisms underlying the involvement of HP oipA in the pathogenesis of chronic gastric disease and carcinoma, are poorly defined. Therefore, this project will study the distribution of HP oipA gene among the chronic gastric dieases in Ninxia in order to shed light on the relationship of oipA-chronic gastric dieases and gastric carcinoma, meanwhile to analyze relationship among oipA gene and IL-17,FAK,8-ohDG in chronic gastric dieases colonized by H.pylori strains and to explore its possible mechanism. METHODS Gastric mucosa biopsies were collected from 200 patients suffering from CAG,GU and GC. From each patient, 1 biopsy specimen from the gastric antrum was used for rapid urease test, 2 biopsy specimen from the gastric antrum for polymerase chain reaction (PCR) for detecting oipA,cagA,vacA,and ureA genes, and 2-6 biopsy specimen from lesion parts for Immunohistochemistry (SP)to detect the expression of IL-17,FAK and 8-ohdG.RESULTS 1. HP genetype status in chronic gastric diease: (1) Of the 200 subjects under study, 73.5%(147/200) were positive for H.pylori.(2)In 147 identified HP strains,the positive ratio of gene cagA is 91.8% and of gene vacA is 95.9%.In CAG,GU and GC infected with HP, the positive ratio of gene cagA is 91.3%,91.3%,93%,and of gene vacA is 95.6%,96.5%,95.3%; there are no significant difference about the distribution of HP cagA and vacA in different chronic gastric diesases(P>0.05). (3) The average detection rate of oipA gene was 70%(104/147) in HP;the detection rate of oipA gene was 56.5%(26/46)among CAG, 77.5%(45/58) among GU,and 76%(33/43) among GC. The detection rate of oipA among GU and GC is significantly higher than that among CAG(P=0.022<0.05,P=0.044<0.05). 2. Relationship between oipA gene and the expression of IL-17,8-ohdG,FAK: (1) Relationship between oipA gene and the expression of IL-17: In groups of HP—,HP+oipA—,HP+oipA+,the expressions of IL-17 is gradually increased(P<0.05,table 3).Among CAG, the expressions of IL-17 in HP+oipA+ group is significantly higher ,compared with HP+oipA-group (P<0.05).Among GU and GC, the expressions of IL-17 in HP+oipA- group is significantly higher, compared with HP—group ;and the expressions of IL-17 in HP+oipA+ group is significantly higher than in HP+oipA-group (P<0.05). In oipA+group, the expressions of IL-17 in patients with CAG,GU and GC is gradually increased (χ2 =17.387, P<0.05).(2)Relationship between oipA gene and the expression of FAK: In groups of HP—,HP+oipA—,HP+oipA+ among CAG and GC,the expressions of FAK is gradually increased , there is significant difference (χ2 =6.703,P<0.05;χ2 =4.416,P<0.05). In oipA+group, the expressions of FAK in patients GC is significantly higher ,compared with CAG and GU(P<0.05). (3) Relationship between oipA gene and the expression of 8-OHDG: the expressions of 8-OHDG in patients GC is significantly higher ,compared with CAG and GU(P<0.05). the expressions of 8-OHDG in groups of HP+oipA—and HP+oipA+ is significantly higher ,compared with the group of HP—(P<0.05). There was no significance in the difference in the expression of 8-OHDG between the group of HP+oipA—and HP+oipA+. CONCLUSION (1) The positive rate of oipA gene among gastric caner is higer than among chronic atrophic gastritis. It indicated that oipA gene may be associated with the pathogenesis of gastric cancer. (2) the virulence gene of cagA and vacA are not helpful in predicting the clinical presentation of HP infection. (3) The expression of IL-17 is high levels in gastric cancer, and IL-17 has a important role in the process of inflammation linked to the occurrence and development of gastric cancer. HP oipA can up-regulate the expression of IL-17.(4) The expression of 8-OHDG is high levels in gastric cancer, and oxidative DNA damage has a important role in the occurrence and development of gastric cancer. H.pylori infection had a profound effect on oxidative DNA damage in gastric mucosa. But no significant relationship was detected between oipA gene and oxidative DNA damage. (5) The expression of FAK is high levels in gastric cancer and it is related to gastric cancer. Significant relationship was detected between oipA gene and the high expression of FAK in chronic gastric dieases colonized by H.pylori strains. |
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