大鼠生后发育期胰高血糖素细胞超微结构的观察

①目的观察正常Wistar大鼠生后发育期间胰岛胰高血糖素细胞(A细胞)超微结构的变化,探讨其发育规律。②方法正常Wistar大鼠9只,雌雄兼有。分为生后7,19d和成年3组。常规透射电镜技术观察。③结果A细胞以多边形为主,胞核多为圆形。常见有胞质突起伸达附近毛细血管壁及其它胰岛细胞之间。成年大鼠A细胞内细胞器不发达,只有少量粗面内质网、小型高尔基复合体及线粒体、胞质内空泡多见;膜包颗粒较多,或散布于整个胞质中,或呈极性分布于细胞靠近毛细血管的一侧及突起内;分泌颗粒多呈圆形,含有高电子密度圆蕊,周围有窄晕。生后7d,A细胞内粗面内质网、高尔基复合体及线粒体均较成年组发达,并常见呈同心圆排列的板层髓样体;分泌颗粒也较多见;胞核大而圆,核质较大。生后19d,A细胞内细胞器最为发达,常见呈扩张状态的粗面内质网及核周池、扁平囊状的高尔基复合体及长短不一的杆状线粒体;次级溶酶体较多见;分泌颗粒较少,导管上皮细胞间、腺细胞间及间质内有的细胞含有类似于A细胞的分泌颗粒。④结论大鼠生后发育期间胰岛A细胞不断发育,约在生后18d达高峰。

ULTRASTRUCTURAL STUDIES OF A-CELLS OF RAT PANCREATIC ISLETS DURING POSTNATAL DEVELOPMENT

Objective To investigate the ultrastructural changes of the pancreatic islet A-cells of rat during postnatal development. Method Nine wistar rats with both sexes were divided into 3 groups; 7th day after birth, 19th day after birth, and adult rats. The pancreatic islet A-cells were observed under transmission electron microscope. Result The A-cells were mainly polygonal in shape, their nuclei being mostly round, the prominent cytoplastic processes contacting either the capillary walls or other eridocririe cells. The round secretory granules were mostly abundant in the adult group. They were characterized by a dense round core, surrounded by a ring-like halo and a closely fit limiting membrane. The organelles such as rough endoplasmic reticulums, Golgi complexes and mitochondria were rarely seen in the adult group. On the 7th day after birth, the organelles stated above and the myelinoid bodies within the A-cells could be easily seen. Also there was a number of secretory granules found in the A-cells, which suggested a relatively high level of glucagon biosynthesis at that time. On the 9th day after birth, the A-cells pos-sessed a large number of well-developed organelles including Golgi complexes, mitochondria and rough endoplasmic reticulums which mostly were dilated. The secretory granules were relatively few, especiallyin the cells with the dilated rough endoplasmic reticulums. The typical secretory granules of the A-cells could also be found in the cells between the ductile and acinar cells in the exocrine portion. Conclusion The study confirms that the pancreatic islet A-cells of rats possess different ultrastructural features during postnatal development and are highly developed on the 19th day after birth.