Spontaneous Ocular Surface Inflammation and Goblet Cell Disappearance in IκBζ Gene-Disrupted Mice

The ocular surface epithelium is part of the mucosal defense system. Because transcription factor NF-kappa B in mucosal epithelial cells plays a central role in regulating the genes that govern the onset of mucosal inflammatory responses, we examined the role of a regulator of NF-kappa B, I kappa B zeta, in murine ocular surface inflammation.The eyes of I kappa B zeta(-/-) mice were analyzed biomicroscopically and histologically. I kappa B zeta expression in normal mouse cornea and conjunctiva was examined by RT-PCR. The results were compared with those obtained in other tissues by real-time PCR. I kappa B zeta mRNA on the ocular surface and in other mucosal tissues was localized by in situ hybridization.I kappa B zeta(-/-) mice manifested chronic inflammation, specifically in the ocular surface, but not in other tissues. In normal mice, I kappa B zeta was expressed in a variety of mucosal tissues. The I kappa B zeta transcript was predominantly distributed in the epithelia of these tissues. As inflammatory symptoms progressed on the ocular surface of I kappa B zeta(-/-) mice, inflammatory cells, mainly CD45R/B220(+) and CD4(+) cells, intensely infiltrated the submucosa of the conjunctival epithelia. This infiltration was accompanied by an almost complete loss of goblet cells in the conjunctival epithelia.The authors postulate that I kappa B zeta in the ocular surface epithelia negatively regulates the pathologic progression of ocular surface inflammation.