Meclofenamic acid blocks the gap junction communication between the retinal pigment epithelial cells

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used to manage the pain and inflammation. NSAIDs can cause serious side effects, including vision problems. However, the underlying mechanisms are still unclear. Therefore, we aimed to investigate the effect of meclofenamic acid (MFA) on retinal pigment epithelium (RPE).

In our study, we applied image analysis and whole-cell patch clamp recording to directly measure the effect of MFA on the gap junctional coupling between RPE cells.

Analysis of Lucifer yellow (LY) transfer revealed that the gap junction communication existed between RPE cells. Functional experiments using the whole-cell configuration of the patch clamp technique showed that a gap junction conductance also existed between this kind of cells. Importantly, MFA largely inhibited the gap junction conductance and induced the uncoupling of RPE cells. Other NSAIDs, like aspirin and flufenamic acid (FFA), had the same effect.

The gap junction functionally existed in RPE cells, which can be blocked by MFA. These findings may explain, at least partially, the vision problems with certain clinically used NSAIDs.