悬吊应激对小鼠肾上腺超微结构的影响

Changes of the ultrastructure of adrenal gland in mice under tail suspension stress

目的：考察慢性悬吊应激对雄性小鼠血清皮质酮水平的影响，并从肾上腺微观结构方面探讨其病理基础。方法：连续悬吊小鼠4周，酶联免疫法测定小鼠血清皮质酮水平，光镜和电镜下观察慢性悬吊应激小鼠肾上腺形态结构的变化。结果：与正常组比较，应激小鼠的体质量增长缓慢，血清皮质酮水平明显升高，脑组织单胺类神经递质水平变化不明显；光镜下可见肾上腺皮质束状带细胞形态模糊，结构紊乱；透射电镜下可见细胞内含有大量体积小，密度大的脂滴，滑面内质网疏松，分布较多，胞核固缩，线粒体形态拉伸，嵴松散并有轻度肿胀。结论：慢性悬吊应激引起肾上腺皮质束状带细胞内脂滴及滑面内质网数量增加，使得血清皮质酮升高，而过量的皮质酮又造成肾上腺细胞结构的损伤。

Objective： To evaluate the effect of chronic tail suspension stress in mice on serum corticosterone concentrations and to explore the pathological changes in term of the ultrastructure of the adrenal gland. Methods： Twenty mice were randomly divided into a normal control group and a stress group, in which the mice were stressed by tail-suspension. Enzyme linked immunosorbent assay （ELISA） was used to measure the serum corticosterone levels. The microstructure of the adrenal gland was observed under an optical microscope using paraffin section with HE staining, while the ultrastructure of zona fasciculata cells was observed under a transmission electron microscope. Results： The serum corticosterone concentrations of the stressed mice were significantly higher than those of the normal controls, with a slow increase in the body weight. In tail suspended mice, the demarcation between the adrenal cortex and medulla was indistinct, with the structure of the zona fasciculata cells entirely being involuted under the optical microscope. Moreover, the numbers of lipid droplet and smooth endoplasmic reticulum were increased. The mitochondria were ellipsoid or elongated in shape with incompact cristae. Conclusion： The increased numbers of lipid droplet and smooth endoplasmic reticulum are induced by chronic tail suspended stress for more cortieosterone secretion, which injures the structure of some cell organelles in turn.