南方鲇中肾的发生及肾单位的发育

STUDIES ON GENESIS OF MESONEPHROS AND DEVELOPMENT OF NEPHRON IN THE CATFISH,SILURUS MERIDIONALIS CHEN

应用组织学、组织化学技术对南方鲇(Silurus meridionalis Chen)肾的发生及肾单位的发育进行了详细研究。结果表明:中肾的发生始于出膜后24h,其发生、发育过程可分为间充质细胞聚集、中肾小泡出现、肾小管芽形成、肾小体发生、初级肾单位形成、初级肾单位成熟及第二、三级肾单位发生等时期。出膜后19d,前肾解体时,第一代中肾单位才开始行使功能。19d至3月龄幼鱼中肾有大量间充质细胞。中肾肾单位的发育包括分化前期、分化期、发育期、成熟期4个时期。幼鱼PI上皮细胞具有大型PAS阳性颗粒是由于肾单位发育不完善,血管球有较大的通透性所致,也是区别于成鱼肾单位的明显特点。3月龄至2龄个体肾中仍有大量发育中的肾单位。

In order to find out the rides of the meso-nephric genesis and nephron＇ s development of the fishes, the embryos, larvae and juveniles of Silurus meridionalis for experimentation, which were hatched by controlling the temperature, were fixed in Smith＇ s, Boun＇ s, and Carnoy＇ s liquid from March, 2001 to March, 2002. The methods of histology and histo-chemistry were applied to study the development of the kidney in the catfish. The results are indicated as following： The genesis of mesonephros started at 24h after hatching. The process of mesonephric genesis and nephron development includes the mesenchymal cells assembling stage from 24h to 48h after hatching which divided and assembled into mesonephrogenic bridge, the mesonephric vesicle and the renal tubule bud forming stage from 4d to 5d after hatching, the development stage of primary nephron from 6d to 10d after hatching, the primary nephron maturing and the sublevel, the third class nephron forming stage from 16d to 19d after hatching. When the pronephron was disintegration at 19d after hatching, the primary nephron started to work. In the kidney of larvae or juveniles between three months and two years, there are a lot of mesenchymal cells and developing nephrons in various stages ： the prodefferentiation stage, the differentiation stage, the developing stage and the mature stage. The prodifferentiation stage is the forming of mesonephrogenic cellular mass and renal tubule bud. The renal tubule differentiates into proximal segment in the differentiation stage. The renal tubule differentiates into every discriminating segments in the developing stage. The nephron is working in the mature stage. It is obvious variations with adult＇s renal tissue. Especially there are abundant in large PAS-positive granule in epithelia of the primary proximal segment because the nephron is premature and the glomendus is easily permeable. There are a large number of developing nephrons in kidney of the larvae or juveniles between three months and two years.