Monteiro Sandra Mariza, Oliveira Elsa, Fontaínhas-Fernandes António, Sousa Mário
Department of Biology and Environment, UTAD-University of Trás-os-Montes and Alto Douro, 5001-801 Vila Real, Portugal.
J Morphol. 2010 May;271(5):621-33. doi: 10.1002/jmor.10821.
We have studied the gill epithelium of Oreochromis niloticus using transmission electron microscopy with the particular interested relationship between cell morphology and osmotic, immunoregulatory, or other non-regulatory functions of the gill. Pavement cells covered the filament epithelium and lamellae of gills, with filament pavement cells showing distinct features from lamellar pavement cells. The superficial layer of the filament epithelium was formed by osmoregulatory elements, the columnar mitochondria-rich, mucous and support cells, as well as by their precursors. Light mitochondria-rich cells were located next to lamellae. They exhibited an apical crypt with microvilli and horizontal small dense rod-like vesicles, sealed by tight junctions to pavement cells. Dark mitochondria-rich cells had long dense rod-like vesicles and a small apical opening sealed by tight junctions to pavement cells. The deep layer of the filament epithelium was formed by a network of undifferentiated cells, containing neuroepithelial and myoepithelial cells, macrophage and eosinophil-like cells and their precursors, as well as precursors of mucous cells. The lateral-basal surface was coated by myoepithelial cells and a basal lamina. The lamellar blood lacunae was lined by pillar cells and surrounded by a basal lamina and pericytes. The data presented here support the existence of two distinct types of pavement cells, mitochondria-rich cells, and mitochondria-rich cells precursors, a structural role for support cells, a common origin for pavement cells and support cells, a paracrine function for neuroepithelial cells in the superficial layer, and the control of the lamellar capillary base by endocrine and contractile cells. Data further suggest that the filament superficial layer is involved in gill osmoregulation, that may interact, through pale mitochondria-rich cells, with the deep layer and lamellae, whereas the deep layer, through immune and neuroendocrine systems, acts in the regeneration and defense of the tissue.
我们利用透射电子显微镜研究了尼罗罗非鱼的鳃上皮，特别关注细胞形态与鳃的渗透、免疫调节或其他非调节功能之间的关系。扁平细胞覆盖鳃丝上皮和鳃小片，鳃丝扁平细胞与鳃小片扁平细胞呈现出不同的特征。鳃丝上皮的表层由渗透调节元件、柱状富含线粒体的细胞、黏液细胞和支持细胞及其前体细胞组成。浅色富含线粒体的细胞位于鳃小片旁边。它们具有顶端隐窝，带有微绒毛和水平排列的小致密棒状小泡，通过紧密连接与扁平细胞密封相连。深色富含线粒体的细胞具有长的致密棒状小泡和一个小的顶端开口，通过紧密连接与扁平细胞密封相连。鳃丝上皮的深层由未分化细胞网络组成，包含神经上皮细胞、肌上皮细胞、巨噬细胞和嗜酸性粒细胞样细胞及其前体细胞，以及黏液细胞的前体细胞。外侧基表面由肌上皮细胞和基膜覆盖。鳃小片血腔由柱状细胞衬里，周围有基膜和周细胞。此处呈现的数据支持存在两种不同类型的扁平细胞、富含线粒体的细胞及其前体细胞，支持细胞具有结构作用，扁平细胞和支持细胞有共同起源，表层神经上皮细胞具有旁分泌功能，以及内分泌和收缩细胞对鳃小片毛细血管基部的控制。数据进一步表明，鳃丝表层参与鳃的渗透调节，可能通过浅色富含线粒体的细胞与深层和鳃小片相互作用，而深层通过免疫和神经内分泌系统在组织的再生和防御中发挥作用。
