Abstract
Purpose: :
To induce necrotizing scleritis in rabbit using Mitomycin C and investigate the mechanism and histological change of necrotizing scleritis by comparing with normal rabbit sclera.
Methods: :
We removed conjunctiva and Tennon’s capsule in 5mm round shape at each 2mm apart from the superior rectus muscle and superior limbus of 9 rabbit eyes. And after giving mechanical damage with blade, 0.02% Mitomycin C soaked sponge was contacted over the damaged sclera. We investigated formation of necrotizing scleritis with slit-lamp biomicroscope and external photographs. H&E, collagen I immunohistochemistry, Elastin, Alcian blue, Massin trichrome staining was used to investigate the inflammation, cellular component and the extraceulluar matrix change of necrotized sclera. Also, gene expression difference between normal sclera and necrotized sclera was compared in RT-PCR.
Results: :
After the surgery, sclera was hyperemic and vessel engorgement around limbal area was found in necrotizing scleritis rabbit eye. But in the necrotized scleral tissue where directly damaged, showed relatively avascular and was less hyperemic than surrounding sclera. There was no epithelial healing over the damaged sclera area until 3month after the surgery. Many inflammatory cells were infiltrated in sclera stroma and around the vessels showing vasculitis with granulomatous inflammation. Collagen, elastin firbers and proteoglycans were decreased and keratinization of sclera stroma was found. In RT-PCR analysis, VEGFR1, TGF-β and K12 were more expressed in necrotizing sclera, and vimentin, CD29, CD34 were less expressed than normal rabbit sclera. Also, inflammatory markers including TNF-α, CD3, CD4, IL-1β, and IL-2 were more expressed, but anti-inflammatory marker IL-10 was less expressed.
Conclusions: :
Induced inflammatory reactions from mechanical damage and suppression of vascularization using Mitomycin C, authors were able to induce necrotizing scleritis in rabbit. This necrotizing scleritis rabbit model may provide useful informations in researching and treatment development in necrotizing scleritis.
Keywords: sclera • wound healing