[Roles of retinal Müller cells in health and glaucoma]

In the vertebrate retina, Müller 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 Müller cells, and the functional changes of Müller cells in the glaucomatous retina.