Reduction of experimental ocular axial elongation by neuregulin-1 antibody

Since the mechanisms underlying myopic axial elongation have remained unclear, we examined the effect of neuregulin-1 (NRG-1), an epidermal growth factor family member, on myopic axial elongation. The guinea pigs aged two to three weeks were subjected to bilateral negative lens-induced axial elongation and received weekly intravitreal injections into their right eyes of NRG-1 antibody (doses: 5 μg, = 8; 10 μg, = 8, 20 μg, = 9) or of NRG-1 (doses: 0.05 μg, = 8; 0.01 μg, = 9; 0.2 μg, = 8), underwent only bilateral negative lens-induced axial elongation (myopia control group, = 10), or underwent no intervention (control group, = 10). The contralateral eyes received corresponding intravitreal phosphate-buffered solution injections. One week after the last injection, the guinea pigs were sacrificed, the eyeballs were removed, the thicknesses of the retina and sclera were histologically examined, the expression of NRG-1 and downstream signal transduction pathway members (ERK1/2 and PI3K/AKT) and the mRNA expression of NRG-1 in the retina was assessed. The inter-eye difference in axial length at study end increased (