Graham C, Simmons N L
School of Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, UK.
Am J Physiol Regul Integr Comp Physiol. 2005 Jan;288(1):R173-81. doi: 10.1152/ajpregu.00425.2004. Epub 2004 Aug 19.
The functional organization of the bovine rumen epithelium has been examined by electron and light microscopy combined with immunocytochemistry to define a transport model for this epithelium. Expression of connexin 43, an integral component of gap junctions, the tight-junction molecules claudin-1 and zonula occludens 1 (ZO-1), and the catalytic alpha-subunit of Na(+)-K(+)-ATPase was demonstrated by SDS-PAGE and Western blotting. From the lumen surface, four cell layers can be distinguished: the stratum corneum, the stratum granulosum, the stratum spinosum, and the stratum basale. Both claudin-1 and ZO-1 immunostaining showed plasma membrane staining, which was present at the stratum granulosum with decreasing intensity through the stratum spinosum to the stratum basale. The stratum corneum was negative for claudin-1 immunostaining. Transmission electron microscopy confirmed that occluding tight junctions were present at the stratum granulosum. Plasma membrane connexin 43 immunostaining was most intense at the stratum granulosum and decreased in intensity through stratum spinosum and stratum basale. There was intense immunostaining of the stratum basale for Na(+)-K(+)-ATPase, with weak staining of the stratum spinosum. Both the stratum granulosum and the stratum corneum were essentially negative. Stratum basale cells also displayed a high mitochondrial density relative to more apical cell layers. We conclude that epithelial barrier function may be attributed to the stratum granulosum and that cell-cell gap junctions allow diffusion to interconnect the barrier cell layer with the stratum basale where Na(+)-K(+)-ATPase is concentrated.
通过电子显微镜和光学显微镜结合免疫细胞化学技术，对牛瘤胃上皮的功能组织进行了研究，以确定该上皮的转运模型。通过SDS - PAGE和蛋白质免疫印迹法证实了缝隙连接的组成成分连接蛋白43、紧密连接分子闭合蛋白 - 1和闭锁小带蛋白1（ZO - 1）以及Na(+) - K(+) - ATP酶的催化α亚基的表达。从管腔表面可区分出四层细胞：角质层、颗粒层、棘层和基底层。闭合蛋白 - 1和ZO - 1免疫染色均显示细胞膜染色，在颗粒层存在，从棘层到基底层强度逐渐降低。角质层闭合蛋白 - 1免疫染色呈阴性。透射电子显微镜证实颗粒层存在封闭紧密连接。细胞膜连接蛋白43免疫染色在颗粒层最为强烈，从棘层到基底层强度降低。基底层Na(+) - K(+) - ATP酶免疫染色强烈，棘层染色较弱。颗粒层和角质层基本呈阴性。相对于更靠顶端的细胞层，基底层细胞还表现出较高的线粒体密度。我们得出结论，上皮屏障功能可能归因于颗粒层，细胞间缝隙连接允许扩散，使屏障细胞层与Na(+) - K(+) - ATP酶集中的基底层相互连接。
