双峰驼肾重吸收机能的细胞学证据

MORPHOLOGIC FEATURES OF RENAL CELL RELATED TO REABSORPTION IN TWO-HUMPED CAMEL

电镜下观察了 18峰双峰驼 (Camelusbactrianus)肾脏细胞的超微结构 ,探究驼肾重吸收机能的形态学证据。结果显示 ,驼肾近曲小管的刷状缘高而密集 ,上皮细胞胞质顶端具有丰富的管泡结构 ,侧基底指状突起和基底质膜内褶多而明显 ,板状嵴线粒体发达。远曲小管和远直小管游离面微绒毛短而稀少 ,胞质线粒体排列密集 ,质膜内褶更为发达。集合小管上皮包括多量的亮细胞和少量的暗细胞两种类型 ,亮细胞结构简单 ,线粒体稀少 ,暗细胞线粒体密集 ,由皮质至髓质 ,暗细胞数量呈递减趋势 ,但内髓仍见暗细胞分布。皮质间质极少 ,毛细血管丰富 ,管壁内皮菲薄有孔。髓质直小血管亦为有孔内皮。上述结构特征表明 ,双峰驼具有很强的重吸收能力 ,与其节水耐干渴特性相适应。

Ultrastructure of tubuli renales cells and interstitial tissue capillaries in 18 two humped camels ( Camelus bactrianus ) was investigated with transmission electron microscope in order to find the morphologic features related to renal reabsorption. The results revealed that invaginations extended into the cytoplasm between the bases of the microvilli,that expanded and gave rise to many pinocytotic vesicles in the epithelium of proximal convoluted tubule(PCT) with a well developed brush border. Mitchondria accumulated and the basal infoldings were obvious in the epithelium of PCT. There were more mitchondria and basal infoldings in cells of the distal convoluted tubule(DCT) although microvilli were shorter and fewer than those in PCT. Tight junctions occurred obviously between apices of adjacent epithelial cells of the PCT and DCT. Epithelial cells of collecting tubules included more light cells and less dark ones, the former with a few of mitchondria while the latter with more. Dark cells were seen in inner zone of medulla although their number decreased gradually from cortex to medulla. Interstitial connective tissue was scarce and capillaries were abundant in the cortex. The endothelium of capillary in cortex and vasa recta in medulla was apparently fenestrated capillary. It is showed that the kidney of two humped camels possesed a strong reabsorption ability, which corresponded with their tolerance of water shortage.