The role of corneal lymphangiogenesis in a murine bacterial keratitis model.

Abstract

Purpose : We previously reported that lymphatic vessel formation in a murine bacterial keratitis model using Pseudomonas aeruginosa was significantly reduced by macrophage depletion (ARVO 2016). In this study, we evaluated the role of corneal lymphangiogenesis by evaluating clinical score and corneal edema.

Methods : A mouse bacterial keratitis model was established using Pseudomonas aeruginosa strain PAO-1 in C57BL/6 mice. After the corneal epithelium was scratched, strain PAO-1 (1×10⁵ CFU/2.5 ml) was inoculated in the control group. In addition to establishing bacterial keratitis model, macrophages were depleted in the macrophage depleted group. Alteration of lymphangiogenesis by macrophage depletion was also evaluated by intraperitoneal injection of clodronate-containing liposomes on days 4, 8, and 12 post-inoculation. Lymphangiogenesis and macrophage infiltration were evaluated by immunostaining using whole-mount cornea on day 14 post-inoculation. Anti-LYVE-1 antibody, anti-CD11b antibody and anti-F4/80 antibody were used for immunostaining. Corneal infection was graded by a previously reported method and central corneal thickness as a measure of corneal edema was evaluated by anterior segment optical coherence tomography (CASIA SS-1000; Tomey, Nagoya, Japan).

Results : Lymphangiogenesis was significantly reduced by macrophage depletion on day 14 post-inoculation. There is no significant difference the control group and the macrophage depleted group on day 7 post-inoculation. However, clinical infection score and corneal edema significantly increased in the macrophage depleted group on day 14 post-inoculation.

Conclusions : These results suggest that the process of lymphangiogenesis in bacterial infection of the cornea presumably suppresses keratitis in the late stage of infection.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.