视网膜Müller细胞的生理功能及在青光眼病理中的作用

Roles of retinal Müller cells in health and glaucoma

Müller胶质细胞是脊椎动物视网膜主要的一类胶质细胞,在解剖和功能上与视网膜各层神经元的胞体和突起有广泛联系。Müller细胞上表达有主要神经递质的受体、转运体、离子通道,以及和细胞功能活动相关的酶分子,而且,Müller细胞也释放一些活性因子,如D-丝氨酸和谷氨酸等,从而调控神经元的兴奋性。因此,除了传统认为的对神经元支持、营养作用,Müller细胞和神经元之间的信息交换和相互作用在维持视网膜神经元功能中发挥有重要作用。在青光眼等病理过程中,Müller细胞被激活。激活的Müller细胞发生许多生理、生化和形态学改变,并释放多种有害因子[(如一氧化氮(NO)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、氧自由基(ROS)和前列腺素E2(prostaglandin E2,PGE2)等],参与视网膜神经节细胞的损伤。本文综述了视网膜Müller细胞的基本生理特征,以及在青光眼病理过程中Müller细胞的功能变化。

In the vertebrate retina, MOiler cells are principal glial cells which stretch across the whole thickness of the retina and contact with the somata and processes of all retinal neurons, thus forming an anatomical and functional link between glial cells and retinal neurons. Numerous studies have shown that Müller cells express various neurotransmitter receptors, transporters, ion channels and enzymes that are relative to cellular activities. In addition, the cells also release factors, such as D-serine and glutamate etc., to regulate the neuron excitability. Therefore, retinal Müller cells may play more curious roles in addition to supporting the retinal neurons, The information exchange and interaction between Müller cells and neurons may regulate and maintain retinal neuronal functions. In the glaucomatous retina, Müller cells are reactivated （gliosis）. Reactivated Müller cells undergo a variety of changes in cellular physiology, biochemistry and morphological features. Meanwhile, the reactivated Müller cells may produce and release cytotoxic factors, such as nitric oxide （NO）, tumor necrosis factor-α （TNF-α）, reactive oxygen species （ROS） and prostaglandin E2 （PGE2）, thus involving in the induction of retinal ganglion cell apoptosis and death. Here, we reviewed the physiological properties of retinal Miiller cells, and the functional changes of Mtiller cells in the glaucomatous retina.