Excessive Supplement of <scp>l</scp>-Arginine Induces Myopia via Orchestrating the MEK-ERK-NO Signaling Pathway

Myopia can impact an individual's quality of life and induce multiple complications. In this study, we randomly divided guinea pigs into the normal control (NC) group, the lens-induced myopia (LIM) group, the normal control plus l-arginine injection (l-Arg) group, and the normal control plus saline injection (NaCl) group. The animals in each group received the relevant treatments. The results showed that myopia was deeper in the LIM and l-Arg groups compared with the NC and NaCl groups. Our experimental results suggest that the excessive supplement of l-Arg will induce myopia onset and a MEK-ERK cascade that stimulates the downstream nNOS-MMP2 and NRF2-KEAP1 signaling pathways, which is accompanied by inflammatory responses, fibrosis changes, and oxidative stress. After receiving excessive arginine supplements, the experimental individuals showed myopic shifts and a similar pathological state as the LIM group. In conclusion, the supplement of excessive arginine may be a danger factor for myopia onset.