目的：观察亚硒酸钠在大鼠实验性胃癌发生过程中对垂体远侧部ACTH细胞、GH细胞和TSH细胞的免疫组织化学影响。方法：用断乳雄性Wistar大鼠62只,分正常对照组、N-甲基-N'-硝基-N-亚硝基胍( N-methyl-N'-nitro-N-nitrosoguanidine,MNNG)实验对照组、MNNG低硒组和MNNG高硒组。43周时取大鼠垂体和胃组织。用免疫组织化学ABC法显示垂体ACTH细胞、GH细胞和TSH细胞,结果进行图像分析。结果：MNNG实验对照组和加硒组均有数只大鼠胃浆膜面出现肿块,且光镜下显示为肠上皮化生,其中加硒组的肠化生率明显高于实验对照组(P<0.05)。图像分析结果显示,MNNG实验组、低硒组、高硒组大鼠垂体远侧部ACTH阳性细胞的平均光密度(MOD)分别为0.0623±0.02024、0.0680±0.08948和0.0574±0.01949；GH阳性细胞MOD分别为0.0380±0.01311、0.0415±0.01559和0.0293±0.01323；TSH阳性细胞数MOD分别为0.0943±0.18606、0.1272±0.05389和0.1044±0.04166。结论：在实验性大鼠胃癌形成过程中,低剂量亚硒酸钠组的大鼠腺垂体远侧部ACTH、GH和TSH阳性细胞反应增强；而高剂量亚硒酸钠的作用则完全相反。%Objective:To observe effect of sodium selenite on ACTH, GH and TSH cells in pars distalis of pituitary during the carcinogenesis of gastric cancer in rat. Methods:62 weaning male Wistar rats were divided into 4 groups: normal control group; N-methyl-N'-nitro-N-nitrosoguanidine( MNNG) experimental control group;MNNG low-selenium group;MNNG high-selenium group. At the 43rd weeks, the four groups of rat pituitary and gastric tissue were collected. Changes of ACTH, GH and TSH positive cells were detected using immunohistochemical ABC methods. The results were processed by image analysis. Results:Tumor mass appeared in gastric serosa and were shown intestinal metaplasia in gastric mucosa by light microscope in MNNG experiment control group and se-lenium group. And the intestinal metaplasia in selenium group was remarkably higher than that in experiment control group (P<0. 05). ACTH, GH and TSH positive cells were labeled using immunohistochemical method. The mean optical densities (MOD) of ACTH pos-itive cells in MNNG experiment control group, MNNG low-selenium group, and MNNG high-selenium group were 0. 0623±0. 02024, 0. 0680±0. 08948, and 0. 0574±0. 01949 respectively;the MOD of GH positive cells were 0. 0380±0. 01311, 0. 0415±0. 01559 and 0. 0293±0. 01323 respectively;and the MOD of TSH positive cells were 0. 0943±0. 18606, 0. 1272±0. 05389 and 0. 1044±0. 04166 respectively. Conclusions:During the carcinogenesis of gastric cancer in experimental animal models, the reactivity of ACTH, GH, TSH positive cells located in pars distalis of pituitary increase after the treatment of sodium selenite in a low dosage;however, a high dosage of sodium selenite exerts opposite effects.
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