Paul-Flechsig-Institut für Hirnforschung, Universität Leipzig, Jahnallee 59, 04109 Leipzig, Germany.
Invest Ophthalmol Vis Sci. 2011 May 18;52(6):3360-7. doi: 10.1167/iovs.10-6901.
Transient retinal ischemia-reperfusion is associated with neuronal degeneration and activation of Müller glial cells. Reactive gliosis may impede the homeostatic functions of Müller cells. A viable animal model for human ischemic events should display similarities in eye size and retinal blood supply. Therefore, pigs were used in this investigation of physiological alterations in Müller cells after ischemia-reperfusion.
Transient retinal ischemia was induced in young adult pigs by high intraocular pressure in one eye for 1 hour. After 3 days of reperfusion, the retinal tissue and isolated Müller cells were used for osmotic swelling recordings, whole-cell patch-clamp experiments, Ca(2+) microfluorimetry, and immunohistochemistry.
Müller cells in retinal slices from postischemic eyes but not control cells displayed a significant swelling of the somata when osmotic stress was applied by hypotonic extracellular solution. The amplitude of K(+) inward currents was significantly reduced (∼60% of the control value). This decrease was accompanied by a depolarization of the cell membrane. The number of Müller cell end feet displaying a Ca(2+) increase after application of adenosine 5'-triphosphate was increased in the ischemic retina. Moreover, reactive Müller cell gliosis was characterized by an (increased) expression of vimentin, glial fibrillary acidic protein, the phosphorylated mitogen-activated protein kinases extracellular signal-related kinase (ERK) 1 and 2, and the transcription factor c-fos.
The alterations of reactive Müller cells after transient ischemia of the pig eye were similar to those found in rat and rabbit models, demonstrating that the porcine retina is a suitable model for the investigation of ischemic injury.
短暂性视网膜缺血再灌注与神经元变性和 Müller 胶质细胞激活有关。反应性神经胶质增生可能会阻碍 Müller 细胞的稳态功能。具有与人缺血事件相似特征的可行动物模型应该在眼睛大小和视网膜血液供应方面具有相似性。因此，本研究采用猪作为模型，探讨缺血再灌注后 Müller 细胞的生理变化。
通过对一只眼施加高眼压使年轻成年猪发生短暂性视网膜缺血 1 小时。再灌注 3 天后，使用视网膜组织和分离的 Müller 细胞进行渗透肿胀记录、全细胞膜片钳实验、Ca(2+) 微荧光测定和免疫组织化学。
与对照细胞相比，来自缺血眼的视网膜切片中的 Müller 细胞在施加低渗细胞外液渗透压应激时，细胞体明显肿胀。K(+)内向电流的振幅显著降低（约为对照值的 60%）。这种降低伴随着细胞膜的去极化。应用三磷酸腺苷后，显示 Ca(2+) 增加的 Müller 细胞终足数量在缺血视网膜中增加。此外，反应性 Müller 胶质细胞增生的特征是波形蛋白、神经胶质酸性蛋白、磷酸化丝裂原激活蛋白激酶细胞外信号调节激酶（ERK）1 和 2 和转录因子 c-fos 的表达增加。
猪眼短暂缺血后反应性 Müller 细胞的改变与在大鼠和兔模型中发现的改变相似，表明猪视网膜是研究缺血损伤的合适模型。
