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KMID : 1101220030350020200
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2003 Volume.35 No. 2 p.200 ~ p.207
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Alterations in Radiation-Induced Apoptosis and Cell Proliferation in the Rat Gastroduodenum
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Min Byung-Woon
Hwang Koo-Yeon
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Abstract
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Radiation-induced apoptosis has been extensively studied in the small intestine where has higher cell proliferation and lower frequency of cancer. There has been no report about radiation-induced apoptosis in the stomach despite high incidence of cancer. The aim of the present study was to evaluate the alterations of radiation-induced apoptosis and cell proliferation in rat stomach. Sprague-Dawley rats were exposed to a single dose of 2 Gy gammy rays and sacrificed at 1, 2, 4, 8, 12, 24 and 48 hours after irradiation. Apoptotic cells and bodies were observed by light and electron microscopy and in situ end labeling (ISEL). Immunohistochemical staining for proliferating cell nuclear antigen (PCNA) was performed simultaneously to evaluate the cell proliferation. Apoptotic index (AI) was defined as the mean number of ISEL-positive cells per fifty longitudinally sectioned gastric glands or duodenal crypt-villi. PCNA index (PI) was also measured by same method of AI. The distribution of ISEL- or PCNA-positive cells was expressed in tripartition on the stomach and quintile on the duodenum from the base of the mucosa. Morphological features of apoptosis were observed with light and electron microscope. The control levels of AI for the stomach and duodenum were 0.12 and 0.26, respectively. After irradiation, an increase of AI from the control levels was observed; AI for the stomach and duodenum reached a peak at 2 hour (0.26) and 4 hour time points (2.05) respectively. Thereafter, AI of both values were declined and returned to the control levels at up to 48 hours time point. The peak position of radiation-induced apoptosis was middle third in the proximal stomach, lower third in the distal stomach, and crypt (1/5-2/5) in the duodenum, respectively. The control levels of PI for the stomach and duodenum were 3.71 and 16.87, respectively. After irradiation, the time course of PI in the gastroduodenum were correlated well with AI. The distribution of PCNA- positive cells was coincident with ISEL-positive position.
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KEYWORD
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Apoptosis, ISEL, PCNA, Apoptotic index
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