Grp78 alleviates sodium iodate-induced retinal cell injury in vivo and in vitro

Abstract Objective Glucose-regulated protein 78 (Grp78) has been regarded as a main member of the endoplasmic reticulum proteins, Grp78 could protect cells from apoptosis under stress conditions. However, whether Grp78 could protect retinal pigment epithelium (RPE) cells from oxidative injury and then protect retinas from morphological changes and functional abnormalities remain undetermined. Here, we try to explore the effect of Grp78 on retinal cell injury induced by sodium iodate in vivo and in vitro. Methods To investigate whether Grp78 has a protective effect on RPE injury in vitro, human retinal pigment epithelium (ARPE-19) cells were treated with sodium iodate. The cell proliferation, morphology, apoptosis and ROS production assays were detected. In vivo, We established sodium iodate-induced retinal injury model in mice by intravenous injection of sodium iodate into tail vein. After that, we examined the morphology and function of retina in mice by fundus photography, OCT and ERG. Finally, we removed the retina of mice for histological examination. Results Grp78 significantly inhibited sodium iodate-induced reactive oxygen species (ROS), and decreased apoptosis of RPE in vitro. Furthermore, Grp78 significantly decreased the apoptosis of retinal cells in vivo, resulting in the inhibition of morphological changes of retina, and improving the function of retina. The underlying mechanisms included inhibited caspase3 and Nos, and increased expression of Bcl2, thereby protecting RPE from SI-induced ROS and apoptosis. Conclusion Grp78 could reduce the injury of retinal cells induced by sodium iodate in vitro and in vivo. These findings suggested Grp78 may become a new therapeutic target for retinal injury in clinical practice.