| Objectives:1.To study the difference in the expression level of the positive rate of bacterial biofilm in the left colon and right colon,and the difference in the expression of the positive rate of the bacterial biofilm in the normal tissue of the right and left colons.2.To study the difference in the expression of butyric acid and LL-37 in the tissue specimens of biofilm positive and biofilm negative tissues,and to explore the correlation between the expression of butyric acid and LL-37 by statistical method.3.To study the differences in the expression of butyric acid and LL-37 in the normal tissue specimens of bio film positive and biofilm negative tissues were studied,and the correlation between the expression of butyric acid and LL-37 was investigated by statistical methods.4.Through the experimental research of this subject,the important role of bacterial biofilm mediated butyric acid and LL-37 down regulation in the pathogenesis of colon cancer was investigated,and it was suggested that the bacterial biofilm may be to escape the immune killing effect of the organism by downregulating the expression level of LL-37 in the intestinal epithelial cells,and to understand the characteristics of the intestinal bacterial biofilm.It provides new research ideas for its carcinogenic mechanism.Methods:1.A total of 20 cases of right colon and 20 cases of left colon cancer surgery were used to detect the tumor tissue and the corresponding biofilm of left normal tissue by FISH,and the biofilm positive was defined as the mucus layer.The amount of bacterial invasion>109/ml and the biofilm surface of intestinal epithelial thickness(the linear distance)≥200 μm.2.Immunohistochemical method was used to detect the distribution of LL-37 in the above 40 cases of biofilm positive and biofilm negative carcinoma,and the expression level of LL-37 mRNA in all the cancer specimens was detected by qRT-PCR technique and the expression of butyric acid and LL-37 in all the cancer specimens was detected by ELISA method,and the correlation among biofilm,butyric acid and LL-37 were discussed.3.In the same way,the distribution of LL-37 in the normal tissue specimens of 40 cases of biofilm positive and biofilm negative was detected by immunohistochemistry,and the expression level of LL-37 mRNA in all normal specimens was detected by qRT-PCR technique and the expression level of butyric acid and LL-37 in all normal specimens was detected by ELISA method,and the biology was further explored.The correlation among biofilm,butyric acid and LL-37 were discussed.Results 1.The positive rate of the biofilm in the right colon cancer tissue and the corresponding normal tissue was significantly higher than those of the left colon cancer tissue and the corresponding normal tissue.The positive level of biofilm in tumor tissue was consistent with that of the corresponding normal tissue.The corresponding normal tissue of the biofilm positive tumor tissue was also positive.The corresponding normal tissue of the biofilm negative tumor tissue was also negative.2.The expression level of LL-37 mRNA and protein in the carcinoma tissue with positive biofilm were significantly lower than that of the negative biofilm tissue(P<0.05),and the expression level of butyric acid in the biofilm positive carcinoma tissue was significantly lower than that of the biofilm negative carcinoma tissue,and the difference was statistically significant(P<0.05).3.The expression level of LL-37 mRNA and protein in normal tissue with positive biofilm were significantly lower than that of normal tissue with negative biofilm(P<0.05);the expression level of normal tissue butyric acid in biofilm positive was significantly lower than that of biofilm negative normal tissue,and the difference was significant(P<0.05).Conclusions 1.The results showed that the positive rate of tumor biofilm at the right colon was very high,the positive rate of tumor biofilm located at left colon was very low.This suggests that the intestinal flora located at the left colon may be carcinogenic in a non--dependent manner of biofilm,and the development of the tumor at the right colon may be closely related to the formation of biofilm.2.The expression level of LL-37 and butyric acid in the positive specimens of tumor tissues were higher than that in the negative ones.Compared with the bacteriophankton,the ability of the bacteria to produce butyric acid may decrease obviously after the biofilm formation,and the decrease of the expression of LL-3 7 in the biofilm positive specimens may be caused by the down-regulation of butyric acid level.3.Similarly,the expression levels of LL-37 and butyric acid in normal tissue with positive biofilms were also higher than those in normal tissues with negative biofilm.The positive level of biofilm in cancer tissue was consistent with the corresponding normal tissue.4.Bacterial biofilm may furtherz reduce the expression of LL-37 by inhibiting butyric acid production.On the one hand,the decrease of the expression level of LL-37 is beneficial to the formation of bacterial biofilm and to escape the immune defense of the body;On the other hand,the low level of butyric acid and LL-37 weaken the apoptosis of the tumor cells and eventually lead to the occurrence of colorectal cancer. |
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