Abstract
Purpose:
Royal jelly (RJ), which is a yogurt-like bee milk secreted by worker bees, plays an important role in honeybee queen development. RJ has multiple biological activities, including hypotensive activities, prevention of obesity and anti-tumor properties, and is used worldwide as a popular health food. In this study, we investigate the effect of RJ on lacrimal function in VDT associated dry eye using rat model.
Methods:
8-weeks-old female Sprague-Dawley rats were used for this study. A series of treatments were performed under continuous exposure to low humidity airflow (25±5%, 2-4m/s). Rats were placed on a swing made of a plastic pipe for 7.5h/d, and for 16.5hours, they were placed in individual cages without swing treatment. This series of treatments was repeated for up to 10 days. During swing procedures, rats received orally either RJ (300mg/kg) or water (vehicle), administered once daily for 10days. Change in tear secretion and corneal surface was measured by cotton thread test and applying a fluorescein solution under a blue-free barrier filter. Lacrimal glands were subject to assessment of mitochondrial function, contents and ROS production and ATP level.
Results:
A significant decreases in tear secretion were observed in vehicle group compared to initial value (p<0.001). In the RJ group, there were little changes in tear secretion compared with initial value. Changes in tear secretion were significantly suppressed in the RJ compared with vehicle (p<0.001) at day11. A significant increases in corneal fluorescein score were observed in vehicle compared initial value (p<0.001). In the RJ, slight increases in corneal fluorescein score were observed, but the differences were not significant compared with initial value. Changes in corneal fluorescein score were significantly suppressed in RJ compared with vehicle (p<0.001) at day10. The mitochondria and ATP contents increased in the RJ compared to vehicle (128.5±9.2%, 144.7±7.6% vs. vehicle ). The ROS production was significantly suppressed in the RJ group compared to vehicle group (65.1±7.4% vs. vehicle , p<0.05).
Conclusions:
These data demonstrate that RJ might attenuate mitochondrial damage with swing treatment and improve lacrimal gland function.
Keywords: 576 lacrimal gland