Figure 7. Immunohistochemistry analysis of Islet-1 expression in murine retinas. A: Room air–raised mice. B: The murine model of oxygen-induced retinopathy (OIR). C: The murine OIR model with injection of negative control siRNA. D: The murine OIR model injected with siRNA targeting Islet-1. Positive immunostaining for Islet-1 was detected at the inner nuclear and ganglion cell layers in the room air–raised mice. A more apparent immunostaining signal was found in the murine model of OIR. SiRNA against Islet-1 decreased the immunostaining of Islet-1 in the hyperoxia-exposed mouse retina. RGC = retinal ganglion cell; INL = inner nuclear layer; ONL = outer nuclear layer.