Effects of Topical Thymoquinone in an Experimental Dry Eye Model

To comparatively evaluate the effects of thymoquinone (TQ), the biologically active main component of volatile oil derived from Nigella sativa seeds, in an experimental dry eye model.

A total of 36 BALB/c mice 10 weeks of age were used in the study. The mice were divided into 6 groups of 6 mice. Two groups were negative and positive controls, and the other 4 groups were treated with balanced salt solution, fluorometholone (FML), TQ, or vehicle (Tween80). After 1 week of treatment, the mice were killed and the eyes removed for histopathologic examination and cytokine analysis. Interleukin (IL)-1α tumor necrosis factor-α, interferon-γ, IL-2, IL-6, IL-10, and lactoferrin levels in the conjunctival tissue were measured by multiplex immunobead assay. The presence of inflammatory cells in ocular tissue samples were investigated by hematoxylin-eosin and periodic acid-Schiff staining. Inflammatory T cells containing CXT receptor in the conjunctiva were determined by flow cytometry.

FLML and TQ groups had less inflammatory cell density and more goblet cells compared to the other groups. High levels of IL-1α and IL-2 were found in the TQ group.

TQ treatment was associated with reduced inflammation in pathological examination, but did not significant lower cytokine levels.