Müller cells upregulate the expression of SAP97 in light-injured rat retina.

SAP97 is thought to play key roles in synapse assembly and synaptic plasticity. This study was carried out to determine whether it is involved in the Müller cell response to blue light injury. In light-injured rats, obvious intracellular edema in the outer retina was observed by transmission electron microscopy. The immunostaining of SAP97 was upregulated and concentrated in the Müller cell processes after photic injury, which was similar to the changes of AQP4 and the inwardly rectifying potassium channel, Kir4.1. Western blots showed that SAP97 and AQP4 protein levels were both increased on the third day after light exposure when compared with the control group (P<0.05). The upregulation of SAP97 coincides with the redistribution of AQP4 and Kir4.1 in blue light-injured rat retina.