【摘要】 目的检测γ-氨基丁酸(gamma-aminobutyric acid,GABA)和谷氨酸脱羧酶(glutamic acid decarboxylase,GAD)在大鼠降结肠上皮的表达及分布特征,并探讨GABA与上皮细胞分化增殖的关系。方法用免疫荧光及激光共聚焦显微扫描技术,检测GABA、GAD65及GAD67在大鼠降结肠上皮中的表达,并以麦芽凝聚素组织化学染色与免疫荧光结合的双重染色显示GABA和GAD65表达细胞的分布特征。同时,用RT-PCR方法检测GAD mRNA的表达。此外,用3H-胸腺嘧啶放射自显影及增殖细胞核抗原(PCNA)免疫组化方法显示降结肠上皮的增殖带。结果RT-PCR显示降结肠粘膜中GAD65及GAD67mRNA均为阳性。GABA及GAD65免疫反应阳性细胞主要分布在降结肠的腔面和隐窝的上1/3上皮细胞的胞浆,而GAD67阳性细胞仅分布腔面,此外,GABA及GAD65阳性染色也见于黏膜固有层。双重染色显示杯状细胞中GABA及GAD65均为阴性3。H-胸腺嘧啶及PCNA标记阳性细胞主要在隐窝的中下段。结论GABA及GAD65分布在大鼠降结肠上皮的成熟带及功能带,GABA系统可能参与上皮细胞的分化与增殖的调节。更多还原

【Abstract】 Objective To detect the expression of gamma-aminobutyric acid(GABA) and glutamic acid decarboxylases(GADs) in the epithelial growth zones of rat descending colon,and to investigate its relation to cell differentiation and proliferation.Methods The expressions of GABA and GADs in the epithelial cells of rat descending colon was investigated by immunofluorescent staining and confocal laser scanning techniques,and the goblet cells were further revealed by wheat-germ agglutinin(WGA) histochemistry.GAD65 and GAD67 mRNAs were also detected by reverse transcription-polymerase chain reaction and in situ hybridization.Furthermore,evaluation of cell kinetics in colonic epithelia was conducted by -thymidine autoradiography as well as PCNA immunohistochemistry.Results Immunoreactive GABA and GAD65 were distributed in the upper third of the crypts and at the luminal surface in the rat descending colon.Strong staining for GABA and GAD65 was localized mainly in the cytoplasm of epithelial cells near the neck of the crypts and along the luminal surface.Immunoreactivity of GAD67,however,was localized only on the luminal surface.In addition,GABA and GAD65 were detected at lamina propria in colonic mucosa.No staining for GABA or GADs was found in goblet cells.GAD65 and GAD67 mRNAs were both identified in homogenates of rat descending colon.Meanwhile,-thymidine labeled nuclei and PCNA immunoreactive positive cells were found in the lower two-thirds of the crypts.Conclusion The expression of GABA and GADs in the maturation and function zones suggests that GABA might be involved in the differentiation and proliferation of the colonic epithelial cells.更多还原