FIGURE 4.

Defects in meibomian glands of Fatp4^−/−;Tg(IVL-Fatp4) mice. Eyelids (A and B) or meibomian glands within the tarsal plate (C–L) of Fatp4^−/−;Tg(IVL-Fatp4) mice and control littermates were untreated (A and B), digested in collagenase and dispase (C and D), or subjected to Oil Red O staining (E–L). At P12.5, the meibomian glands of the Fatp4^−/−;Tg(IVL-Fatp4) mice were much less fluffy (compare arrowheads in A and B) and displayed larger gland orifices (arrows in B) than controls. These abnormalities (arrowheads and arrows in D) were also observed upon removal of the tarsal plate using collagenase and dispase. Glands in C and D are those from the upper eyelids in A and B, respectively. Meibocytes were properly arranged in vertical clusters at P6.5 (arrowheads in E and F). From P10.5 and onwards, compared with controls (G, I, and K), meibocytes of Fatp4^−/−;Tg(IVL-Fatp4) mice showed less dense lipid droplets (H), became dystrophic (J), and eventually atrophied by 3 months of age (arrowheads in L). Arrows in E and F mark eyelash follicles.