余干乌骨鸡胸腺4种内分泌细胞超微结构特点和形态计量学分析

Ultrastructural Characteristics and Morphometric Analysis of Four Types of Endocrine Cells in Thymus of Yugan Black-Bone Fowl

为阐明禽类胸腺内分泌细胞类型,并进一步了解禽类胸腺发挥功能的结构基础,本试验应用石蜡切片、普通光学显微镜和透射电子显微镜技术观察余干乌骨鸡胸腺组织显微和超微结构,并通过形态计量学对相关细胞参数进行测量和分析。结果显示,余干乌骨鸡胸腺分为很多小叶,每个小叶明显的分为外周的皮质和中间的髓质。髓质内含有胸腺小体。胸腺内还有黑色素分布。超微结构显示,胸腺内含有较多的淋巴细胞、上皮网状细胞和黑色素细胞,并有多种形态的内分泌细胞。内分泌细胞胞质内分泌颗粒的形状和电子密度等特征皆存在差异。根据内分泌细胞的形态和胞质内分泌颗粒的特征,胸腺内分泌细胞分为4种类型。Ⅰ型内分泌细胞胞质内分泌颗粒多呈规整的圆形,电子密度高,大小不等,直径介于400~770 nm。Ⅱ型内分泌细胞胞质内分泌颗粒形态差异较大,多呈卵圆形,或两端粗大、中间细长的哑铃型,电子密度高,直径介于265~1320 nm。Ⅲ型内分泌细胞胞质内分泌颗粒呈圆形或卵圆形,中等电子密度,也有颗粒呈电子疏松的囊泡状,直径介于180~340 nm。Ⅳ型内分泌细胞胞质内分泌颗粒呈圆形或卵圆形,颗粒类脂型或黏液型,电子密度低,直径介于510~1280 nm。结果表明,根据细胞形态和分泌颗粒的异质性,余干乌骨鸡胸腺含有4种类型的内分泌细胞。

In order to elucidate the types of endocrine cells in avian thymus and further understand the structural basis of thymic function in poultry,this study employed paraffin sections,light microscopy,and transmission electron microscopy to observe the microstructure and ultrastructure of the thymic tissue in Yugan black-bone fowl,and morphometric measurements and analyses of relevant cell parameters were conducted.The results revealed that the thymus of Yugan black-bone fowl is divided into numerous lobules,each clearly divided into outer cortex and inner medulla.The medulla contained thymic corpuscles,and melanin was distributed in the thymus.Ultrastructural analysis showed the presence of numerous lymphocytes,epithelial reticular cells,melanocytes,and various types of endocrine cells in the thymus.Endocrine cells exhibited differences in the shape and electron density of secretory granules in the cytoplasm.Based on the morphology of endocrine cells and the characteristics of secretory granules,four types of endocrine cells were identified.Type I endocrine cells had cytoplasmic secretory granules that were mostly regular round,with high electron density and varying sizes,diameter ranging from 400 to 770 nm.Type II endocrine cells had widely differing shapes of secretory granules,mostly oval or dumbbell-shaped with enlarged ends and slender middle,high electron density,diameter ranging from 265 to 1320 nm.Type III endocrine cells had round or oval secretory granules with moderate electron density,and some granules had a vacuolar appearance,diameter ranging from 180 to 340 nm.Type IV endocrine cells had round or oval secretory granules,which were lipid-like or mucus-like,with low electron density,diameter ranging from 510 to 1280 nm.These findings indicate that the thymus of Yugan black-bone fowl contains four types of endocrine cells based on cellular morphology and heterogeneity of secretory granules.