Helicobacter Pylori Infection And Gastric Mitochondrial Dna Microsatellite Instability And Integration In The Nuclear Relationship,

It has been confirmed that H.pylori infection is an important pathogenic factor for chronic gastritis and peptic ulcer,recently, more studies showed that it was also associated with the occurrence of gastric cancer,and H.pylori infection was classified by WHO as Class I pathogen for gastric cancer in 1994.The occurrence of gastric cancer is a long multistep process,and it deals with the mutation and accumulation of many oncogenes.Some researches also showed that extra-chromosome fractions could be involved in the cacinogenesis of cells.Mitochondrion is a special organelle with mtDNA itself.Compared with nDNA,mtDNA can be damaged more frequently by many factors such as Oxygen Free Radicals, mutagens, and so on.More recently researches have discovered that mtDNA might take part in the apoptosis and transformation of cells;Mutation of mtDNA is consistent with tumorigenic phenotype; Instability and mutation of mtDNA and integration of mtDNA or its fragments into nDNA might be involved in the occurrence and development of tumor. The relationship between H.pylori infection and mtDNA microsatellite instability has not been studied, up to now, to our knowledge. In this study,32 chronic superficial gastritis(CSG)~. 20 chronic atrophic gastritis(CAG)~ 15 intestinal metaplasia(IM) 10 dysplasia(Dys)~ 30 gastric cancer(GC) and their adjacent tissues to cancer(AGC) were collected, modified Giemsa staining,H.pylori immunohistocbemistry and PCR were VI used to detect H.pylori.The results are as follows:the rates of H.pylori and CagA4 H.pylori infection in CAG~ IM% Dys and AGC were marked higher than that in CSG(p<0.05); H.pylori infection in GC was similar to that in CSG(p>0.05),but significant difference of CagA~ H.pylori infection was found between GC and CSG(p<0.05). To evaluate the relationship between H.pylori infection and severity of gastritis as well as the activity of IL-S in gastric mucosa, in this study,ELISA was used to detect IL-S in gastric mucosa from 20 endoscopically normal contro1~ 32 CSG.. 20 CAG~ 20 gastric ulcer(GU)and 40 duodenal ulcer(DU): H.pylori was detected using the same method mentioned above;Severity of gastritis was grading using the Sydney standard.The results are as follows: H.pylori infection rates and IL-S levels increased with severity of gastritis IL-8 level in H.pylori infection group was significantly higher than that in non-H.pylori infection group(Ip<0 .05). To explore the effect of H.pylori infection on mitochonrdial DNA microsatellite instability&ntMSI) of gastric mucosal cells, total DNA of gastric mucosa from 15 IM~ 10 Dys.. 30 GC and their paired normal tissues were purified using classical hydroxybenzene/chloroform method; Entire mtDNA was amplified by Long Distance PCR,these PCR products were digested by restriction endonucleases; 2 microsatellite sequences in D-loop and 6 in coding region were amplified by PCR using Long Distance PCR products as templates.PCR-SSCP was used to detect mtMSI.The results are as follows:The length of long distance PCR products was about 16.Skb,and the restriction patterns were consistent with human mtDNA Cambridge standard, and these patterns also indicated no large-scale deletion, rearrangement or mutation occurred in gastric cancer and its precancerous lesions.The mtMSI was detected in 11 of 30(36.7%) gastric Lancers, 4 of 15(26.7%) of intestinal...