Comparative Analysis of Age-Related Changes in Lacrimal Glands and Meibomian Glands of a C57BL/6 Male Mouse Model.

It is not known how biological changes in the lacrimal (LGs) and meibomian (MGs) glands contribute to dry eye disease (DED) in a time-dependent manner. In this study, we investigated time-sequenced changes in the inflammation, oxidative stress, and senescence of stem cells in both glands of an aging-related DED mouse model. Eight-week (8W)-, one-year (1Y)-, and two-year (2Y)-old C57BL/6 male mice were used. MG areas of the upper and lower eyelids were analyzed by transillumination meibography imaging. The number of CD45 ⁺ , 8-OHdG ⁺ , Ki-67 ⁺ , and BrdU ⁺ cells was compared in both glands. Increased corneal staining and decreased tear secretion were observed in aged mice. The MG dropout area increased with aging, and the age-adjusted MG area in lower lids was negatively correlated with the National Eye Institute (NEI) score. Increased CD4 ⁺ interferon (IFN)-γ ⁺ cells in LGs were found in both aged mice. An increase in 8-OHdG ⁺ cells in both glands was evident in 2Y-old mice. Reduced Ki-67 ⁺ cells, but no change in CD45 ⁺ cells, was observed in the MGs of 1Y-old mice. Increased BrdU ⁺ cells were observed in the LGs of aged mice. This suggests that age-dependent DED in C57BL/6 mice is related to inflammation of the LGs, the development of MG atrophy, and oxidative stress in both glands.