Abstract
Purpose :
Ischemia-reperfusion injury (IRI) plays an important role in various retinal diseases. MicroRNA (miR)-133 has been found to regulate myocardial IRI, yet its role in retinal IRI remains unknown. Our goal is to understand the role of miR-133 in retinal IRI using animal and cell models.
Methods :
We established IRI models through induction of high intraocular pressure in SD rats (animal) and oxygen and glucose deprivation (OGD) in rat Muller cell (rMC-1) culture. The expression levels of miR-133 in both models were measured by quantitative PCR (qPCR). The sequential changes of miR-133 levels and the degree of apoptosis were detected at 4 different time points after IRI (4, 8, 24 hours and 7 days) in the animal model using immunohistochemistry staining and TUNEL assay. The expression of ischemia-related and apoptosis-related molecules were detected by western blot and qPCR. Transfection of miR-133 mimic and inhibitors were used to modulate the level of miR-133 in cell culture.
Results :
The increased level of HIF-1α, cleaved caspase-3, and high Bax/Bcl-2 ratio in our models confirmed the induction of IRI and subsequent apoptosis. Upregulated miR-133 expression after IRI was demonstrated in both models. We found similar patterns of temporal change in the miR-133 levels and the severities of apoptosis in the animal model (Fig 1). In the OGD model, the miR-133 significantly increased after transfection with miR-133 mimic, along with decreased HIF-1α expression. In contrast, transfection with miR-133 inhibitor resulted in decreased miR-133 level under OGD and an upregulated expression of HIF-1α.
Conclusions :
Our data from animal and cell models demonstrated increased miR-133 expression after retinal IRI and showed correlation between miR-133 and apoptosis. Additional studies are required to explore the detailed molecular pathway and to confirm the potential role of miR-133 in regulating retinal IRI.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.