The corneal endothelium in an endotoxin‐induced uveitis model: Correlation between in vivo confocal microscopy and immunohistochemistry

Abstract Purpose To analyze the involvement of the corneal endothelium in uveitis in order to better understand the formation mechanisms and the keratic precipitate composition. In vivo confocal microscopy images were correlated with ex vivo immunostaining of corneal endothelium from rat eyes with endotoxin‐induced uveitis (EIU). Methods EIU was induced in Lewis rats by lipopolysaccharide (LPS) injection. Slit‐lamp examination and in vivo confocal microscopy were performed 6, 24, 48, 72 and 96 h after the LPS injection. Immunohistochemistry on corneal endothelium, using antibodies to ICAM‐1, phalloidin, CD68 (anti‐macrophage), MA967 (anti‐granulocyte), alpha beta‐TCR (anti‐lymphocyte) was performed on flat‐mount corneas and was analyzed using a 3D laser confocal microscope. Results In vivo confocal microscopy showed numerous hyper‐reflective round dots on the corneal endothelium, in the anterior chamber and in the anterior stroma corresponding to inflammatory cells until 96 h, peaking at 24 h. On immunostaining, corneal endothelial cells in rats with EIU overexpressed ICAM‐1. Compared to controls, CD68, MA 967 and alpha beta‐TCR expression was observed in corneas in rats with EIU. Conclusion The correlation between in vivo confocal microscopy and ex vivo immunostaining helped to better understand in vivo confocal microscopy images. The two new techniques applied here were very effective and complementary in evaluating the corneal endothelium involvement in EIU. Based on these findings, in vivo confocal microscopy in clinical practice could be very helpful to better analyze keratic precipitates and corneal modifications in patients with uveitis.