Differences in the composition of inflammatory cell infiltrate in lens-induced uveitis under therapy with allopurinol or steroids.

PURPOSE The aim of this study was to compare the qualitative changes in the composition of inflammatory cell infiltrate in lens-induced uveitis (LIU) under treatment with allopurinol (Allo), methylprednisolone (Pred) or the two drugs combined (Allo/Pred). METHODS Twenty male Wistar rats were sensitized with lens proteins for eight weeks. Intravenous (IV) therapy was started after anterior capsule disruption in one eye of each animal. Five rats were randomly assigned to each of the four groups: controls, Allo (50 mg/kg bw), Pred (7.5 mg/kg bw) and Allo/Pred (50 mg/7.5 mg per kg bw). Eyes were enucleated 24 hours later and fixed in paraformaldehyde/glutaraldehyde. Sections at three levels were stained with Giemsa and examined using a 0 to 4+ score for each type of inflammatory cell. Granulocytes were seen as neutrophils and eosinophils. Neutrophils were divided into polymorphs and "others", and graded with lymphocytes. RESULTS In all therapy groups there was a significant reduction of polymorphs (p<0.05) in comparison to the control group. There was also a significant reduction in lymphocytes (p<0.05) in the Pred and Allo/Pred groups as compared to the control group and the Allo group. CONCLUSIONS Single-dose IV allopurinol significantly reduced the overall number of polymorphonuclear leucocytes in LIU. Unlike methylprednisolone, allopurinol did not have any significant impact on lymphocytes.