渗透压改变与星形胶质细胞水通道蛋白9表达的关系

Relationship between changes of osmotic stress and expressions of aquaporin-9 in astrocytes

目的:探讨渗透压对星形胶质细胞水通道蛋白9(AQP9)表达的影响。方法:通过H-E显色观察渗透压改变(对照组、低渗组和高渗组)对细胞形态的影响,台盼蓝染色评价细胞活力的变化,免疫细胞化学、原位杂交研究星形胶质细胞AQP9及其mRNA的表达变化。结果:对照组细胞形态、活力、AQP9及其mRNA的表达在各时间点均无明显变化。低渗培养导致细胞水肿,细胞活性下降,AQP9及其mRNA的表达水平明显高于对照组,并随低渗作用的增强和时间的延长而上调。高渗作用可导致细胞皱缩,细胞活性下降,AQP9及其mRNA表达在12h内持续增加后下降,至24h后仍高于对照组。结论:低渗液作用下AQP9及其mRNA的表达上调,作为一种病理性适应反应参与了胶质细胞水肿的形成。高渗作用早期(约12h内),AQP9的表达上调对高渗型细胞脱水起到重要的代偿作用。

Objective： To investigate the expressions of aquaporin-9 （AQP9） and the morphological changes in cultured rat astrocytes after being exposured to different osmotic stress. Methods： The primary cultured cells were divided into control group, hypotonic groups and hypertonic groups randomly. HE staining was used to observe the cell morphological changes. The viability of cells in hypotonic or hypertonic medium was measured by trypan blue staining. The alterations of AQP9 and its mRNA expression were studied by the methods of in situ hybridization, immunocytochemistry and imaging analysis. Results： There were no significant changes in the cell morphology, cell viability, the expression of AQP9 and its mRNA in the control cells. At the same time point, astrocytes cultured in hypotonic medium showed typical features of cell edema, and the cell viability decreased, especially in the lower osmotic group. The expression of AQP9 and its mRNA in the hypotonic cells were remarkably higher than those in the control cells, and increased with the osmolarity decreasing. The changes of AQP9 expression showed a positive relationship with AQP9 mRNA. Exposed to the hypertonic medium, cells shrinked, and the cell viability decreased in a time dependent manner. The expression of AQP9 and its mRNA were significantly changed compared with the cells in control group before 12 h, and then decreased until 24 h. At 24 h time point it was mild higher than that of control cells. Conclusion： Hypotonic medium may induce cell edema, inhibit viability of astrocytes and up-regulate the expression of AQP9 and its mRNA is a maladaptation reaction. Hypertonic medium may induce cell shrink, inhibit viability of astrocytes and up-regulate the expression of AQP9 and its mRNA before 12 h may play an important role in compensation in the early stage （about within 12 h） of the hypertonic dehydration.