Alleviating early demyelination in ischaemia/reperfusion by inhibiting sphingosine‐1‐phosphate receptor 2 could protect visual function from impairment

Abstract

Retinal ischaemia/reperfusion (I/R) injury is a common cause of retinal ganglion cell (RGC) apoptosis and axonal degeneration, resulting in irreversible visual impairment. However, there are no available neuroprotective and neurorestorative therapies for retinal I/R injury, and more effective therapeutic approaches are needed. The role of the myelin sheath of the optic nerve after retinal I/R remains unknown. Here, we report that demyelination of the optic nerve is an early pathological feature of retinal I/R and identify sphingosine‐1‐phosphate receptor 2 (S1PR2) as a therapeutic target for alleviating demyelination in a model of retinal I/R caused by rapid changes in intraocular pressure. Targeting the myelin sheath via S1PR2 protected RGCs and visual function. In our experiment, we observed early damage to the myelin sheath and persistent demyelination accompanied by S1PR2 overexpression after injury. Blockade of S1PR2 by the pharmacological inhibitor JTE‐013 reversed demyelination, increased the number of oligodendrocytes, and inhibited microglial activation, contributing to the survival of RGCs and alleviating axonal damage. Finally, we evaluated the postoperative recovery of visual function by recording visual evoked potentials and assessing the quantitative optomotor response. In conclusion, this study is the first to reveal that alleviating demyelination by inhibiting S1PR2 overexpression may be a therapeutic strategy for retinal I/R‐related visual impairment.

Modulating amacrine cell–derived dopamine signaling promotes optic nerve regeneration and preserves visual function

“…FVEP was measured following the international standard steps that have been described in our previous study ( 87 ). Briefly, after anesthesia, the recording electrode was inserted between the two ears of the mouse and reached the occipital skull subcutaneously, whereas the reference and ground electrodes were placed subcutaneously in the forehead and tail, respectively.…”

“…The spatial frequency of eyes was measured using the OMR test (Optodrum, Striatech, Germany) to evaluate the visual acuity of mice as described in our previous studies ( 87 ). Briefly, living mice were placed on a round platform located at the center of four monitors arranged in a quadrangle.…”