Immunohistochemical Study on the Distribution of Carbonic Anhydrase Isozymes in Rat Small Intestine / 대한해부학회지

Carbonic anhydrase catalizes the reversible hydration of carbonic dioxide and participate in various biological processes. There are several isozymes and differ in their kinetic properties, tissue distribution and subcellular localization. The expression of carbonic anhydrase isozymes in digestive tract vary according to animal species and region of the tract. The distribution of carbonic anhydrase (CA) isozymes I, II, IV and IX was investigated in various portions of the rat small intestine using Western blotting analysis and immunohistochemical staining. Western blotting analysis of rat small intestine revealed that CAI was found to be abundantly expressed throughout the small intestine. Expression of CAII in duodenum was much higher than that in jejunum and ileum. Expression of CAIV and IX was found to be weak throughout the small intestine. Immunohistochemical reaction revealed no staining of CAI in all parts of small intestine except blood vessels. CAII was detected at the supranuclear cytoplasm of surface epithelium, but not in intestinal gland. Staining intensity was most strong in the proximal duodenum. CAIV was detected at the apical surface of epithelial cells of villi, and showed most strong staining intensity in the terminal ileum. CAIX was detected at the surfcae epithelium, cells of intestinal gland and Brunner's gland, and the positive reaction was confined to the supranuclear cytoplasm. CAIX differed from CAII in tissue distribution, but subcellular localization of CAIX and II were the same. These results indicate that the surface epithelium of small intestine express CAII, IV and IX, intestinal gland and Brunner's gland express CAIX, and suggest that CAIX may somewhat contribute the control of acid-base balance in the small intestine.

Expression of Matrix Metalloproteinase-2 and Tissue Inhibitor of Metalloproteinase-2 in Radiation Exposed Small Intestinal Mucosa of the Rat / 대한방사선종양학회지

PURPOSE: The matrix metalloproteinases (MMPs) are a family of enzymes whose main function is the degradation of the extracellular matrix. Several studies have revealed that MMPs and TIMPs are related to the wound healing process and in photoaging caused by ultraviolet irradiation. However, the expressions of MMP and TIMP after irradiation have not, to the best of our knowledge, been studied. This study investigates the expressions of MMP-2 and TIMP-2 in rat intestinal mucosa following irradiation. Material and Methods:The entire abdomen of Sprague-Dawley rats was irradiated using a single dose method. The rats were sacrificed on day 1, 2, 3, 5, 7 and 14 following irradiation. Histopathological observations were made using hematoxilin & eosin staining. The expressions of MMP-2 and TIMP-2 were examined using immunohistochemistry, immunoblotting and ELISA. RESULTS: Radiation induced damage, associated with atrophic villi, and infiltration of inflammatory cells was observed from the first postirradiation day, and severe tissue damage was observed on the second and the third postirradiation days. An increase in mitosis and the number of regenerating crypts, as evidence of regeneration, were most noticeable on the fifth postirradiation day. From the immunohistochemistry, the MMP-2 expression was observed from the first postirradiation day, but was most conspicuous on the third and the fifth postirradiation days. The TIMP-2 expression was most conspicuous on the fifth postirradiation day. From the immunoblotting, the MMP-2 expression was strongly positive on the third postirradiation day, and that of TIMP-2 showed a strong positive response on the fifth postirradiation day. In ELISA tests, the expressions of MMP-2 and TIMP-2 were increased in the postirradiation groups compared to those of the normal controls, and showed a maximum increase on the fifth postirradiation day. These results were statistically significant. CONCLUSION: The expressions of MMP-2 and TIMP-2 were increased in the intestinal mucosa of the rats following irradiation, and these results correlated with the histopathological findings, such as tissue damage and regeneration. Therefore, this study suggests that MMP-2 and TIMP-2 play roles in the mechanisms of radiation-induced damage and regeneration of intestinal mucosa of rats.