Abstract
Purpose: :
Our previous report demonstrated that air-exposure induced abnormal epidermal differentiation of limbal epithelial cells, however, Pax6 expression maintained after 2 weeks airlift culture of limbal explant. It remains unknown whether conjunctival epithelium present the same characteristic.
Methods: :
Human conjunctival explants were cultured on type I collagen coated inserts under airlift or submerged manner for different duration up to 14 days in supplemented hormonal epithelial medium. Cryo-sections of the explants as well as normal conjunctiva were objected to H&E staining and immunostaining of Pax6, keratin K19, and keratin K10.
Results: :
Under airlift manner, there was dramatic stratification and digital invasion of conjunctival epithelium, which is prominent as early as 2 days culture. In contrast, epithelial stratification did not increase dramatically in submerged culture. K19 staining showed that groups of epithelial cells invaded into sub-conjunctival stroma in airlift culture, which started from day 2, while such invaded cells were much less in submerged culture. K10 expression was negative in both airlift and submerged culture through out the culture duration. Nucleic Pax6 staining of the conjunctival epithelial cells decreased in airlift culture, started from basal layer at day 6 and gradually spread to suprabasal layers at day 10. Majority of the epithelial cells lost nucleic Pax6 expression after 14 days airlift culture. However, most of the epithelial cells maintained Pax6 expression in submerged culture. Interestingly, some invaded epithelial cells retained nucleic Pax6 expression in airlift culture.
Conclusions: :
Airlift culture reduced Pax6 expression, while could not induce abnormal epidermal differentiation of human conjunctival epithelial cells in 2 weeks. Further study may reveal the signaling difference between limbal and conjunctival epithelium which control epithelial proliferation and differentiation.
Keywords: conjunctiva • differentiation • transcription factors