金鱼精巢支持细胞间连接和血睾屏障

CELL JUNCTIONS BETWEEN SERTOLI CELLS AND THE BLOOD-TESTIS BARRIER IN GOLDFISH TESTIS

本文主要采用冷冻断裂-蚀刻方法,同时结合超薄切片和镧标记实验,研究金鱼精巢内的支持细胞间连接特点及血-睾屏障的形成。结果发现:1)金鱼精巢内支持细胞间连接呈紧密连接、桥粒和间隙连接同时存在的形式。2)各种连接的数量、面积、分布密度会随着小囊内生精细胞的发育而改变。3)紧密连接在精子发生过程的各个阶段都存在,但在形态上表现为Ⅰ型和Ⅱ型两种。4)血-睾屏障是在粗线期精母细胞期后形成,它是Ⅰ型紧密连接发育为Ⅱ型紧密连接的结果。

Freeze-fracture and etching technique combined with thin sectioning and lanthanum impregnation has been used for the study of Sertoli cell junctions and the blood-testis barrier formation in goldfish testis with lobular organization. Some observations and results are first given in this paper.The results of experiments can be summarized as the following: 1). Sertoli cell junctions are compound junctions of tight junctions, desmosomes and gap junctions. Tight junctions usually appear as parallel or network like ridges on the P face and fine grooves on the E face at the freeze-etching replicas. Desmosomes and gap junctions often are locatcd between or nearby the ridges of tight junctions. In addition, endoplasmic reticulum cristae near thc junction area can also be observed. 2). The number, area and density of each individual junction vary with the development and differentiation stages of germinal cells in the cyst. 3). Tight junctions can be observed at any stage during germinal cell differentiation through the period of sper matogenesis and spermiogenesis. However, they appear morphologically different as type Ⅰ and type Ⅱ. 4). Lanthanum can partially penetrate into the intercellular spaces of spermatogonium and early primary spermatocyte, but can't penetrate after the stage of later primary spermatoeyte. 5). The blood-testis barrier formation starts at the stage of pachytene spcrmatocytes. The formation of the blood-testis barrier is the result of the development of the tight junction from type Ⅰ to type Ⅱ.