Nrf2-HO1 signaling pathway-mediated axial elongation in lens-induced myopia in Guinea pigs through regulation of tight junctions in retinal pigment epithelial cells.

The study aimed to explore the potential involvement of Nrf2-HO1 (nuclear factor erythroid 2-related factor 2 heme oxygenase-1) in the process of myopic axial elongation, which influenced the disruption of tight junctions in retinal pigment epithelium (RPE) cells. Guinea pigs aged 2-3 weeks underwent bilateral lens-induced myopization (LIM) and received weekly intraperitoneal injections of the heme oxygenase-1 (HO-1) activators Hemin (25 mg/kg and 50 mg/kg, respectively), or Quercetin (25 mg/kg and 50 mg/kg, respectively). The study additionally included normal control groups with or without LIM and with vehicle injections. Ocular biometry, optical coherence tomography, and high-throughput sequencing were performed. Eyes with LIM showed a significantly increased expression of the Nrf2-HO1 signal pathway. Eyes with Hemin injections demonstrated axial elongation in a Hemin-dose dependent manner. Eyes with LIM and Quercetin injections showed in a dose-dependent manner and inhibition of the Nrf2 overexpression and an attenuation of axial elongation, a disruption of RPE cell tight junctions, and retinal and choroidal thinning. Immunofluorescence revealed the RPE cell as the main location of the HO-1 activation. Transmission electron microscope showed that Hemin was associated with a disruption of RPE tight junctions with axial elongation. The overexpression of Nrf2-HO1 signal pathway may be involved in LIM development and RPE tight junction disruption. The potential anti-myopic therapeutic value of Quercetin may be further explored.