The expression of mucin genes was evaluated in rat intestinal cell lines in order to establish an in vitro model for investigating the regulation of intestinal mucin expression in this species. Two rat intestinal cancer cell lines (DHE, LGA) and three nontumoral rat intestinal cell lines (IEC6, IEC17, IEC18) were screened. The mRNA expression of rMuc1, rMuc2, rMuc3, rMuc4, and rMuc5AC mucin genes was studied by semiquantitative RT-PCR, real-time RT-PCR and Northern-blot analysis. Results were correlated with immunohistochemical expression of rat gastric and intestinal mucin proteins, and secretion of glycoconjugates was examined by enzyme-linked lectin assay. We showed that mRNA of rMucl and rMuc2 were constitutively expressed in all IEC cell populations but periodic acid Schiff staining of these cells did not reveal the presence of glycoproteins. DHE cells expressed rMuc1-5AC mRNA and LGA expressed the same mucins but the level of rMuc4 was much lower. Mucin mRNA expression also differed in relation with the length of cultivation. Immunocytochemical studies revealed the presence of gastric and intestinal mucins in the two tumoral cell lines. Functional experiments showed that bethanechol, A23187 and PMA stimulated release of glycoconjugates in DHE but not in LGA cells. Treatment of DHE cells with dexamethasone (10(-7) mol/l) enhanced rMuc2 mRNA but decreased rMuc1 and rMuc5AC mRNA. Real-time RT-PCR showed that the expression of rMuc1 and rMuc5AC genes was reduced by more than tenfold after 24 h. The increased expression of rMuc2 gene was confirmed by Northern blot analysis. In conclusion, DHE cells provide a valuable cellular model for research on rat mucin secretion and expression.

中文翻译：

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DHE细胞系作为研究大鼠胃肠粘蛋白表达的模型：地塞米松的作用。

在大鼠肠细胞系中评估粘蛋白基因的表达，以建立用于研究该物种中肠粘蛋白表达的调控的体外模型。筛选了两种大鼠肠道癌细胞系（DHE，LGA）和三种非肿瘤大鼠肠道细胞系（IEC6，IEC17，IEC18）。通过半定量RT-PCR，实时RT-PCR和Northern印迹分析研究rMuc1，rMuc2，rMuc3，rMuc4和rMuc5AC粘蛋白基因的mRNA表达。结果与大鼠胃和肠粘蛋白蛋白的免疫组化表达相关，并通过酶联凝集素测定检查糖结合物的分泌。我们显示rMuc1和rMuc2的mRNA在所有IEC细胞群体中组成性表达，但这些细胞的高碘酸席夫染色未显示糖蛋白的存在。DHE细胞表达rMuc1-5AC mRNA，LGA表达相同的粘蛋白，但rMuc4的水平要低得多。粘蛋白mRNA表达也与培养时间有关。免疫细胞化学研究表明，两种肿瘤细胞系中都存在胃粘膜和肠粘蛋白。功能实验表明，苯乙二酚，A23187和PMA刺激DHE而非LGA细胞中糖缀合物的释放。用地塞米松（10（-7）mol / l）处理DHE细胞可增强rMuc2 mRNA，但降低rMuc1和rMuc5AC mRNA。实时RT-PCR显示，rMuc1和rMuc5AC基因的表达在24小时后降低了十倍以上。rMuc2基因表达的增加通过Northern印迹分析证实。总之，DHE细胞为研究大鼠粘蛋白的分泌和表达提供了有价值的细胞模型。