| To study the roles of MMP-7 and Lysozyme in the pathogenesis of ulcerative colitis (UC), the healthy Balb/c mice were used as the object of study in this experiment. 7% DSS solution were drunk by the experimental mice freely, and the model of acute UC would be built after 7 days. The IL-6 levels of serum, large intestinal fluid and small intestinal fluid in the mice will be tested by ELISA after treatment 1d, 3d, 5d and 7d respectively. At the same time, the duodenum, jejunum, ileum and colon of the mice will be take and store, and then the MMP-7 mRNA will be detected by RT-PCR, the protein of MMP-7 and Lysozyme will be detected by immunohistochemistry. According to the dynamic expression pattern of MMP-7 and Lysozyme, the roles of them in the pathogenesis of UC will be investigated in this study. The main results are as follows:1. After drinking 7% DSS solution 7 days, the body weight of mice declined dramatically, while the DAI score increased gradually. Compared with the control mice, significant changes of acute UC have been observed in the colon of the experimental mice, explained that the acute UC model has been replicated successfully. The IL-6 levels of serum, large intestinal fluid and small intestinal fluid in the mice have been tested by ELISA, and the results showed that the overall trend of IL-6 content in the serum is to increase at first and then decreased, reaching the highest level at 3d, also with the significant difference (P<0.05); the overall trend of IL-6 content in the large intestinal fluid is similar with that of the serum, increased firstly and then decreased, reaching the highest level at 5d, also with the significant difference (P<0.05) compared to that of 0d, 7d; but the overall of IL-6 content in the small intestinal fluid is to reduce at first, reaching the lowest level at 3d, and then increased, reaching the highest level at 5d, and then decreased again. The overall numbers have little changes, and have no statistical significance;2. The results of RT-PCR showed that the expression levels of MMP-7 mRNA presented dynamic change in the different periods of acute UC model, and also had significant differences. The conditions of small intestinal tissues are as follow: the expression level of MMP-7 mRNA in the ileum is higher than that of duodenum and jejunum in all the stages of inflammation, and with the development of the inflammation, the overall trend of MMP-7 mRNA level in all the small intestinal is upward, reaching the highest at 7d, and at this time with the significant difference (P<0.01) compared to that of 0d, 3d in the duodenum, with the significant difference (P<0.01) compared to that of 0d, 1d, 3d and 5d in the jejunum, with the significant difference (P<0.05) compared to that of 5d in the ileum; the expression level of MMP-7 mRNA reached the highest at 3d, with the significant difference (P<0.01) compared to that of 0d, 1d, 5d and 7d, and reached the lowest level at 7d;3. The results of immnohistochemistry showed that most of the MMP-7 protein expressed in the shedding of epithelium cells, inflammatory cells in the enteric cavity of colon, connective tissue hyperplasia, inflammatory cells infiltrating into the submucosa; in addition, the MMP-7 protein also can be found in the Paneth cells of small intestinal, and presented dynamic change in all the intestinal tissues in the different periods of acute UC model with significant differences, of which the expression of MMP-7 protein in the duodenum reached highest at 3d, with the significant difference (P<0.01) compared to that of 5d, which is the lowest one, with the significant difference (P<0.01) compared to that of 0d, 1d, 3d and 7d; the expression of MMP-7 protein in the jejunum reached highest at 1d, with no significant difference (P>0.05) compared to that of 0d, 3d, 5d and 7d; the expression of MMP-7 protein in the ileum reached highest at 0d, with the significant difference (P<0.01) compared to that of 3d, 5d and 7d, and with the significant difference (P<0.05) compared to that of 1d; the expression of MMP-7 protein in the colon reached highest at 3d,with the significant difference (P<0.01) compared to that of 5d;4. The results of immnohistochemistry showed that most of the Lysozyme protein expressed in the shedding of epithelium cells, inflammatory cells in the enteric cavity of colon, connective tissue hyperplasia, inflammatory cells infiltrating into the submucosa; in addition, the Lysozyme protein also can be found in the Paneth cells of small intestinal, and presented dynamic change in all the intestinal tissues in the different periods of acute UC model with significant differences. With the development of inflammation, the expression level of Lysozyme protein of small intestinal tissues existed upward trend in the early inflammatory, of which the expression of Lysozyme protein in the duodenum and jejunum were always higher than that of control ones; and the expression of Lysozyme protein in the colon was always higher than that of control. The expression of Lysozyme protein in the duodenum reached highest at 5d, with the significant difference (P<0.01) compared to that of 0d, 1d; the expression of Lysozyme protein in the jejunum reached highest at 7d, with significant difference (P<0.01) compared to that of 0d, 3d, and with significant difference (P<0.05) compared to that of 1d; the expression of Lysozyme protein in the ileum reached highest at 1d, with the significant difference (P<0.01) compared to that of 0d, 3d and 7d; the expression of Lysozyme protein in the colon reached highest at 1d,with the significant difference (P<0.01) compared to that of 0d, 7d.All of these results indicated that, the acute UC model has been replicated successfully in this experiment. It is also found that both of the MMP-7 and Lysozyme have been detected in the normal and UC intestinal tissues of mice, especially in the Paneth cells of small intestinal and colon tissues. The expression level of MMP-7 and Lysozyme presented dynamic change and had significant differences, which showed that both MMP-7 and Lysozyme have close relationship with the Paneth cells and the development of UC disease, and also play an important role in the pathogenesis of UC, providing a theoretical basis for the further illumination of the nosogenesis of UC, also providing a experimental basis for the clinical treatment of UC. |
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