Abstract
Purpose:
We have previously established a model of anterior scleritis by modifying a collagen-induced autoimmune arthritis model. In the present study, the long-term observation of the clinical and the immunological findings were performed.
Methods:
Male DBA/1J mice (8-week-old) received primary immunization in the back of the neck with 200ug of bovine type II collagen (CII) emulsified using equal volume of complete Freund's adjuvant (CFA, containing 100ug H37Ra Mycobacterium tuberculosis). After 3 weeks, CFA-emulsified CII was injected intradermally around the eye for secondary immunization, then the arthritis and eyes were examined. Eyeballs were excised at 3, 5, 8, 12 and 24 weeks after secondary immunization and analyzed histologically and immunohistologically.
Results:
Clinical findings comprised severe arthritis and dilation of scleral blood vessels from 3 weeks after secondary immunization. Histological findings revealed anterior scleral thickening, with significantly large number of infiltrating cells as compared to untreated mice. The number of infiltrating cells in anterior sclera peaked at 8 weeks and remained for 24 weeks. The inflammation of anterior sclera peaked at a later time point compared with arthritis. Infiltration of CD4+, CD11b+ cells were present in the Tenon's layer, while deposition of plasma cells (CD138), complement (C3), immunoglobulin (Ig)G and IgM were seen in the anterior sclera in contact with the ciliary body and blood and lymphatic growth (CD31 and LYVE-1) expression was increased in the corneal limbus compared to untreated mice, throughout all observation periods.
Conclusions:
T cells, macrophages, plasma cells, complement, immunoglobulins, the outgrowth of blood and lymphatic vessels were persistently found in the sclera of the collagen-induced anterior scleritis model. It is suggested that the involvement of immunocomplex deposition, and blood and lymphatic growth in the sclera is one of immunopathology of this scleritis model.