Objective: To investigate the role of interleukin-10 (IL-10) in herpetic stromal keratitis (HSK).
Methods: Eighty BALB/c mice were divided into two groups and infected with HSV-1 Mckrae strain by corneal scarification. Murine rIL-10 (20 ng/ml) was inoculated intracorneally 6 h before and again on days 0, 2 and 4 after topical HSV-1 corneal infection. rIL-10 (500 ng) was given intraperitoneally in treated mice simultaneously. The same amount of saline was injected into the control mice. The effects of IL-10 on HSK were evaluated.
Results: In the IL-10-treated animals, the onset of HSK was delayed, corneal stromal opacification and neovascularization were reduced, extensive cellular infiltrates in the cornea were prevented and delayed type hypersensitivity (DTH) was weakened. Examination of pro-inflammatory cytokine levels in the cornea 10 days after the infection revealed that the amounts of IL-2 and IL-6 were lower than those found in the controls. IL-10 did not suppress the viral replication nor did it eliminate the virus from IL-10-treated eyes, as compared with the controls.
Conclusions: IL-10 treatment can suppress DTH responsiveness and the production of certain cytokines by corneal cells. It delays the onset and decreases the severity of HSK.