Ted persistent fluorescein staining at 96 hours (Figure 3 B4) and penetration of LC-biotin into the stroma (Figure 3 C2) compared to the WT where there was no longer any staining by 72 hours (Fig, 3 A3) and most of the eyes were impermeable to LC-biotin (Figure 3 C1). Analysis of the LC-biotin staining showed penetration of the molecule into the stroma in 100 (7/7) of Notch1-/- mice compared to only 28.6 (2/7) WT Title Loaded From File littermates at 96 hours post wounding (P = 0.021) (Figure 3 C3). The barrier in Notch1-/mice was found to recover by 144 hours after wounding, indicating that 10457188 it is ultimately able to reform the barrier however with a significant delay (data not shown). Previously, it was reported that atrophy of the meibomain glands and secondary eyelid margin keratinization is an important contributing factor to 16574785 the corneal pathology in Notch1-/- mice [14]. Meibomain glands are holocrine glands located in the upper and lower eyelid that are analogous to sebaceous glands. They produce an oily secretion that contributes to the stability of the ocular surface tear film [36]. The importance of eyelid trauma to the corneal disease was shown in an experiment by Vaulclair et al. where suturing the eyelids closed prevented the development of the keratinized corneal plaques [14]. In order to determine whether the delayed barrier recovery is related to the eyelid pathology, we proceeded to examine the meibomian glands in the same wounded mice. Oil red O staining of the eyelid tissue confirmed that the meibomian glands (N= 5) still produced oil at 1 week after 4-OHT treatment (Figure 3 D1 2). These findings suggest that the delay in barrier recovery is most likely due to an intrinsic Title Loaded From File defect in the corneal epithelium and is not directly due to the eyelid pathology. It should be noted that examination of the eyelid histology at later time points (2-3 weeks after 4OHT) did demonstrate cystic changes and loss of the meibomian glands as reported before (data not shown) [14].production in conditional Notch1-/- mice, especially given that keratin 14 is also expressed in the lacrimal gland. We measured the aqueous tear production using phenol red thread test in conditional Notch1 knockout and WT mice both of which had previously been treated with 4-OHT. The mean aqueous tear production at baseline (immediately after 4-OHT treatment) was similar in Notch1-/- (3.09 ?1.05 mm) and WT (3.31?0.9 mm) mice (P = 0.62). At 2 weeks post treatment, when the cornea was beginning to show barrier impairment, the aqueous tear production in Notch1-/- eyes was found to be significantly higher than WT (7.4 ?2.3 mm versus 3.6 ?1.4, P = 0.001). At 4 weeks after 4-OHT treatment, the mean aqueous tear production had increased even further to 10.5 ?1.8 mm for Notch1-/- compared to 2.7 ?0.9 mm in WTs (P <0.001) (Figure 4A). Thus, the aqueous tear production was not only intact, but also seemed to be enhanced in the Notch1-/- mice. Pathologic examination of the lacrimal gland did not reveal any difference between WT and Notch1 knockouts (data not shown).Goblet cells are intact in the conditional Notch1-/- miceThe production of soluble mucins by the conjunctival goblet cells also contributes to the tear film and plays a central role in maintaining the mucosal phenotype on the ocular surface. Since keratin 14 is also expressed in the conjunctiva, we proceeded to examine the presence of goblet cells in Notch1-/mice. Histologically, goblet cells were present in the conjunctival fornix in.Ted persistent fluorescein staining at 96 hours (Figure 3 B4) and penetration of LC-biotin into the stroma (Figure 3 C2) compared to the WT where there was no longer any staining by 72 hours (Fig, 3 A3) and most of the eyes were impermeable to LC-biotin (Figure 3 C1). Analysis of the LC-biotin staining showed penetration of the molecule into the stroma in 100 (7/7) of Notch1-/- mice compared to only 28.6 (2/7) WT littermates at 96 hours post wounding (P = 0.021) (Figure 3 C3). The barrier in Notch1-/mice was found to recover by 144 hours after wounding, indicating that 10457188 it is ultimately able to reform the barrier however with a significant delay (data not shown). Previously, it was reported that atrophy of the meibomain glands and secondary eyelid margin keratinization is an important contributing factor to 16574785 the corneal pathology in Notch1-/- mice [14]. Meibomain glands are holocrine glands located in the upper and lower eyelid that are analogous to sebaceous glands. They produce an oily secretion that contributes to the stability of the ocular surface tear film [36]. The importance of eyelid trauma to the corneal disease was shown in an experiment by Vaulclair et al. where suturing the eyelids closed prevented the development of the keratinized corneal plaques [14]. In order to determine whether the delayed barrier recovery is related to the eyelid pathology, we proceeded to examine the meibomian glands in the same wounded mice. Oil red O staining of the eyelid tissue confirmed that the meibomian glands (N= 5) still produced oil at 1 week after 4-OHT treatment (Figure 3 D1 2). These findings suggest that the delay in barrier recovery is most likely due to an intrinsic defect in the corneal epithelium and is not directly due to the eyelid pathology. It should be noted that examination of the eyelid histology at later time points (2-3 weeks after 4OHT) did demonstrate cystic changes and loss of the meibomian glands as reported before (data not shown) [14].production in conditional Notch1-/- mice, especially given that keratin 14 is also expressed in the lacrimal gland. We measured the aqueous tear production using phenol red thread test in conditional Notch1 knockout and WT mice both of which had previously been treated with 4-OHT. The mean aqueous tear production at baseline (immediately after 4-OHT treatment) was similar in Notch1-/- (3.09 ?1.05 mm) and WT (3.31?0.9 mm) mice (P = 0.62). At 2 weeks post treatment, when the cornea was beginning to show barrier impairment, the aqueous tear production in Notch1-/- eyes was found to be significantly higher than WT (7.4 ?2.3 mm versus 3.6 ?1.4, P = 0.001). At 4 weeks after 4-OHT treatment, the mean aqueous tear production had increased even further to 10.5 ?1.8 mm for Notch1-/- compared to 2.7 ?0.9 mm in WTs (P <0.001) (Figure 4A). Thus, the aqueous tear production was not only intact, but also seemed to be enhanced in the Notch1-/- mice. Pathologic examination of the lacrimal gland did not reveal any difference between WT and Notch1 knockouts (data not shown).Goblet cells are intact in the conditional Notch1-/- miceThe production of soluble mucins by the conjunctival goblet cells also contributes to the tear film and plays a central role in maintaining the mucosal phenotype on the ocular surface. Since keratin 14 is also expressed in the conjunctiva, we proceeded to examine the presence of goblet cells in Notch1-/mice. Histologically, goblet cells were present in the conjunctival fornix in.
