An Association between Corneal Inflammation and Corneal Lymphangiogenesis after Keratoplasty

Weihua Li， Wencong Wang， Shiqi Ling

1 State Key Laboratory of Ophthalmology，．Zhongshan Ophthalmic Centre，．Sun Yat-sen University， Guangzhou 510060， China，

2 Department of Ophthalmology， The Third Affiliated Hospital， Sun Yat-sen University， Guangzhou 510630，China

Introduction

Materials and methods

Animals

Orthotopic corneal transplantation

Immunohistochemistry

Histopathological examination

Immunofluorescence of whole-mount rat corneas

Inflammatory index （IF）

Statistical analysis

Results

The development of corneal lymphangiogenesis after keratoplasty

Figure 1 Whole-mount immunofluorescence of a rat cornea after keratoplasty．Lymphatic and blood vessels were present only in the normal rat limbus（A）．Some new blood and lymphatic vessels appear in the cornea 3 days after keratoplasty （B）， then extend forward gradually 7 days after keratoplasty （C）， corneal lymphangiogenesis and hemangiogenesis both peak 14 days after keratoplasty （D）．（Green arrows： lymphatic vessels； red arrows： blood vessels．Magnification ×100）

Figure 2 Immunohistochemistry of the rat cornea after keratoplasty．NF-κB （A） or LYVE-1 （C） proteins were not present in the normal rat corneal stoma， but the expression of NF-κB in the stroma was dramatically increased 2 weeks after keratoplasty （B），and some LYVE-1-positive lymphatic vessels merged into larger vessels at the same time （D）．（Magnification ×200）

The development of corneal inflammation after keratoplasty

The relationship between corneal lymphangiogenesis and corneal inflammation after keratoplasty

Figure 3 Observation under a slit lamp microscope and histopathological examination after corneal transplantation．The normal rat cornea was transparent with no invading inflammatory cells in the stroma （A）．On day 3 after the transplantation， corneal inflammation was so intense it obscured the pupil．The corneal hypothallus was obviously thickened， with a large number of infiltrating inflammatory cells （B）．Corneal edema and inflammation decreased gradually； the grafts became transparent and the pupils could be visualized．Few inflammatory cells invaded into the stroma 7 days after the transplantation （C）．Inflammatory cells and blood vessels increased dramatically after 7 days．A great many inflammatory cells appeared in the stroma together with many new blood vessels， giving a hairbrush-like appearance from the limbus to the central region， filling the whole cornea， suggesting that corneal inflammation peaked at that time point（D）．（Footnote 1： photograph of burned rat cornea； Footnote 2： Histopathological examination； Magnification：（A1，B1，C1，D1 ） ×25； （A2，B2，C2，D2 ） ×200）

Figure 4 The relationship between LVC and IF after keratoplasty．A significantly positive correlation was evident between LVC and IF after the transplantation （r＝0．41 P＜0．05 ） （A）．However， the changes in corneal lymphangiogenesis and corneal inflammation did not occur in parallel（B）．

Discussion

Acknowledgments