LPS-stimulated inflammation and apoptosis in corneal injury models.
OBJECTIVE
To evaluate and compare the proinflammatory and apoptotic effects of lipopolysaccharide (LPS) in three rabbit corneal injury models using a new in vivo confocal microscope (IVCM) and immunohistological techniques.


METHODS
Adult male New Zealand albino rabbits were used in this study. Three corneal models were tested: corneal incision, corneal epithelium scraping, and corneal suture. Ten rabbits were used in each model and these three groups were subdivided into two subgroups: with or without LPS instillation (with saline used as control) for eight days. Rabbit corneas were analyzed in vivo by using the Rostock Cornea Module (RCM) of the Heidelberg Retina Tomograph (HRT)-II. Immunohistology was used to evaluate inflammatory, proliferating, and apoptotic cells in the different injury models following saline or LPS instillations.


RESULTS
Clinically, LPS induced earlier and higher levels of inflammation and corneal neovascularization in eyes subjected to scraping and suturing compared to saline. The RCM/HRT successfully presented high-quality images allowing analysis of all pathological corneal layers. Compared to groups receiving saline, LPS caused earlier and greater surface and stromal inflammatory infiltration as well as neovascularization. Immunohistology was correlated with in vivo findings and confirmed these results by showing greater infiltration of KI 67+ proliferating cells, TUNEL+ apoptotic cells, and TNF-alpha+, TNFR1+, TLR4/MD2+, ICAM-1+, RLA-DR+, CD11b+, and CD11c+ inflammatory cells, in eyes receiving LPS compared to those receiving saline.


CONCLUSIONS
These results indicate that in various models of corneal injury, LPS is a potent proinflammatory stimulus and its exposure has major effects on determinants of inflammation, angiogenesis, and apoptosis.
Department of Ophthalmology III, Quinze-Vingts National Ophthalmology Hospital, APHP, University of Versailles, Paris, France.
Hong
H
Liang
Françoise
F
Brignole-Baudouin
Antoine
A
Labbé
Aude
A
Pauly
Jean-Michel
JM
Warnet
Christophe
C
Baudouin
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002452:Cell Count; D003316:Corneal Diseases / Q000139:chemically induced / Q000473:pathology*; D003319:Corneal Stroma / Q000098:blood supply / Q000187:drug effects; D004195:Disease Models, Animal; D019573:Epithelium, Corneal / Q000187:drug effects / Q000473:pathology; D007249:Inflammation / Q000473:pathology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D018613:Microscopy, Confocal; D009389:Neovascularization, Pathologic; D011817:Rabbits; D012160:Retina / Q000187:drug effects / Q000473:pathology; D012965:Sodium Chloride / Q000494:pharmacology; D012984:Software; D014054:Tomography
D008070:Lipopolysaccharides; D012965:Sodium Chloride