Abstract
Purpose :
Our study aimed to further characterize and validate the lacrimal gland excision as an aqueous dry eye model and compare male and female animals with respect to corneal epithelium damage, apoptosis, and cell proliferation.
Methods :
Male and female C57BL/6J mice were obtained from Jackson Labs. Under isoflurane anesthesia, a unilateral lacrimal gland excision (LGE) was performed, removing either the exorbital lacrimal gland (single LGE) or both the exorbital and intraorbital lacrimal glands (double LGE). For sham surgeries, incisions were made and glands were partially exposed. Excised tissue was stained by haematoxylin and eosin (H&E) and tearing was evaluated with phenol red thread. Fluorescein was applied to the cornea and staining was scored to quantify the severity of corneal damage. At 7, 14, and 28 days post surgery, corneas were excised, cryosectioned and then evaluated for apoptosis by terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL) assay and corneal proliferation was evaluated by Ki-67 staining.
Results :
The cytoarchitecture of H&E stained exorbital and intraorbital lacrimal gland tissue was consistent with published reports. Tearing levels were significantly reduced following LGE across the 4-weeks when compared to sham treatment, with the lowest levels recorded after double LGE. As determined by fluorescein staining, double and single LGE produced damage to the corneal epithelium with graded severity. Furthermore, in female mice, both single and double LGE produced more severe damage to the cornea when compared to male mice. Both single and double LGE increased TUNEL and Ki-67 staining in the cornea when compared to sham treatment, indicating an increase in both apoptosis and cell proliferation.
Conclusions :
These results indicate a sex specific difference in response to aqueous tear deficiency produced by LGE, with female animals displaying greater epithelial damage. The greater susceptibility of female animals to the detrimental effects of LGE are consistent with epidemiological reports indicating a greater prevelance of dry eye in women. LGE could be useful in determining the mechanisms involved in producing these sex differences.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.