Increased proliferation and apoptosis of colonic epithelial cells in dextran sulfate sodium-induced @entity1960 in XXXX .

@entity10740 @entity32 @entity1 @entity2310 @entity13419 @entity23975 @entity31 @entity1960 @entity14 @entity35 @entity1049
We have evaluated morphologic alterations and epithelial cell apoptosis and proliferation of colonic mucosa in the acute and chronic phases of @entity13419 -induced @entity1960 . @entity1960 was induced in @entity35 by 7 days of 4% @entity13419 oral administration followed by 7 days of tap water for one, two, and three cycles. Control @entity35 receved tap water only. Morphological changes in colonic mucosa were evaluated and scored by light and scanning electron microscopy. Apoptosis was studied by TUNEL assay and cell proliferation by Ki-67 immunoreaction. The expression of both proapoptotic (Fas, @entity23975 , @entity2310 , @entity10740 ) and antiapoptotic (Bc12) cellular proteins was determined by immunohistochemistry. Morphologic assessment showed the most severe @entity1049 and @entity32 in the distal colon with a trend to increasing severity from the first to the third @entity13419 cycle. In @entity13419 @entity35 , the epithelial apoptotic index increased 20-fold after the first cycle and 120-fold after the second and third cycles compared with the controls; in the same way, the expression index of proapoptotic proteins (Fas, @entity23975 , @entity2310 , @entity10740 ) dramatically increased. The proliferative index increased about 40 to 60-fold compared to controls, with no difference among the three @entity13419 cycles. In conclusion, @entity13419 -induced @entity1960 in @entity35 , which has many structural and ultrastructural features similar to those seen in @entity1 @entity31 , is a suitable model for studying increased epithelial apoptosis and proliferation. Further studies employing this model will permitt two hypotheses to be tested. (1) Increased apoptosis may lead to a breakdown of the epithelial barrier function and facilitate the mucosal invasion of intraluminal microorganisms and/or antigens. (2) Abnormal and persistent epithelial hyperproliferation could be causally related to the development of @entity14 in the setting of chronic @entity32 .
