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Purpose: We evaluated the potential of leukotriene B4 receptor antagonist (LTB4 RA) as an anti-inflammatory agent on experimental autoimmune uveoretinitis (EAU)., Materials and Methods: LTB4 RA was administered to Lewis rats twice a day on days 0-10, 0-5, and 6-10 after immunization. Rats treated on days 0-10 after immunization were subdivided into three groups according to the dosage of LTB4 RA. The eyes were examined histopathologically, and the expression of CD 45 RC in CD 4+T cells was analyzed., Results: The inflammatory changes in the eyes of EAU were decreased in all groups treated with LTB4 RA in a dose-dependent manner. The treatment with LTB4 RA on days 0-10 after immunization achieved much higher uveitis suppression. The infiltration into eye tissues by neutrophils and lymphocytes was decreased by treatment with LTB4 RA. In treated groups, the CD 45 RChigh subset decreased in the induction phase of EAU as compared with the untreated group., Conclusion: The suppressive mechanisms of LTB4 RA on EAU may be dependent on suppression of the activation of neutrophils and CD 4+T cells.

One human body is composed of 6 x 10(13) cells, and eyes are also composed of many cells of different functions. The cellular functions and intercellular interaction are regulated by many regulators including cytokines and growth factors to maintain the homeostasis. The transforming growth factor-beta (TGF-beta) superfamily, a large family of multifunctional factors, regulates various cellular functions, including cellular proliferation, migration, differentiation, apoptosis and extracellular matrix production. The TGF-beta superfamily contains about 30 multifunctional factors, and is divided into several families according to the sequence homology. The TGF-beta family, the activin family, and bone morphogenic proteins belong to the TGF-beta superfamily. TGF-beta superfamily members transduce signals through type I and type II serine/threonine type transmembrane receptors. The signals are transduced from receptors through nuclei by Smad family members, which are phosphorylated by the activated type I receptors and translocate from cytoplasm into nuclei. TGF-beta family members and the TGF-beta superfamily receptor family are expressed in ocular tissues including the cornea, ciliary epithelium, lens epithelium, retina, and blood vessels. This observation suggests the importance of the TGF-beta superfamily in eyes. Smad family members (Smad 1, Smad 2, Smad 3 and Smad 4) are expressed in the cultured retinal pigmant epithelial cell line (D407), in which TGF-beta and activin A stimulate the translocation of Smad 2, but not Smad 1 into nuclei, whereas bone morphogenetic protein (BMP) stimulates that of Smad 1, but not Smad 2. TGF-beta superfamily members play important roles in the pathogenesis of retinal neovascularization and in the wound healing process of corneal tissue. TGF-beta inhibits the endothelial functions, but, stimulates angiogenesis in vivo. TGF-beta is involved in the formation of abnormal connective tissue in corneal wound healing. In these processes, many cytokines and growth factors are involved, interacting with each other and forming networks. It is mandatory to clarify the networks to investigate molecular pathogenesis and new therapeutic agents.

We evaluated cell replication in wound healing following experimental filtration surgery. Cell replication was measured via immunohistochemistry for proliferating cell nuclear antigen, which is a marker of cell proliferation. Trabeculectomy was performed on albino rabbit eyes, with the filtering site harvested on postoperative days 1, 4, 7, and 14. Samples were fixed with 10% buffered formalin and prepared for paraffin section, and proliferating cell nuclear antigen was detected in filtering site tissue using the labeled streptavidin-biotin method. The number of immunoreactive cells increased at days 4 to 7 and was markedly decreased at day 14; the filtering site was obstructed at days 7 to 14. These findings may have clinical implications for the administration of antiproliferative agents after filtration surgery. Evaluation of cell replication following filtration surgery by detecting proliferating cell nuclear antigen is a simpler technique than autoradiography.

The authors developed radioimmunoassay (RIA) for proliferating cell nuclear antigen (PCNA/cyclin), which a protein synthesizes in phase with DNA, as a marker for cell replication. We used it to detect the amounts of PCNA and estimated rates of cell replication in ocular tissues (cornea, lens epithelium, retina-plus-choroid and optic nerve) and in non-ocular tissues (skin, skeletal muscle, brain, thymus, small intestine and liver) in rats. Antisera were raised in rabbits to oligopeptide fragment of human PCNA (hPCNA): the C-terminal fragment [Tyr254]-hPCNA (254-261). For RIA the synthetic peptides were used as standards and radioiodinated [125I-Tyr254]-hPCNA (254-261) as radioligands. The IC50 was 30-40 f mole/tube with a sensitivity 0.5-1.0 f mole/tube for this assay. Tissue extracts in 1 M acetic acid were digested with trypsin to release fragment (255-261) from whole PCNA and were assayed by this method. The highest amounts of immunoreactive PCNA were found in lens epithelium and skin, while the lowest amounts were found in optic nerve and muscle. The cornea showed a higher value than retina-plus-choroid or optic nerve. A high cell replication in the lens epithelium was revealed.