Abstract
Purpose: :
Diabetic patients have an increased prevalence of keratoconjunctivitis (Kaiserman et al. Am. J. Ophthalmol. 2005 139:498). NOD mice are used as a model of diabetes yet no one has examined the fluid production of their exorbital lacrimal glands. This study examined fluid flow in situ and cell volume changes in response to carbarchol stimulation in NOD mice. Similar studies were done on Swiss Webster (SW) mice which served as age and sex matched controls.
Methods: :
The duct of glands from male and female NOD and SW mice aged either 2 or 6 months of age was placed in a calibrated microcapillary tube and the exposed gland was perfused with 10 µM carbachol. The rate of fluid secretion was monitored by video microscopy. Cells were isolated from NOD and SW mouse glands and were plated on matigel for 24 hours. Their volume was measured in response to local application of 100 µM carbachol.
Results: :
Both male and female NOD mice had lower stimulated flow rates than the equivalent SW controls. Male NOD glands showed less (approx 50%) flow in 6 month old animals compared to 2 month animals while the smaller (14 mg) female glands had less flow than even older males but showed no decrease with age. Older female SW glands (16 mg) produced the largest flow rates showing that gland weight was not the determining factor. The pattern of secretion–induced shrinkage of isolated acinar cells paralleled the tear flow results: NOD cells shrank significantly less than age– and gender–matched controls.
Conclusions: :
Both male and female NOD mice have impaired tear secretion compared to SW mice, which suggests that the NOD mouse may be model of lacrimal dysfunction in diabetes.
Keywords: lacrimal gland • diabetes • cornea: tears/tear film/dry eye