Purchase this article with an account.
Carol B Toris, Shan Fan, Cassandra L Hays, Bruce M Ishimoto; Type of Anesthesia Affects Aqueous Flow and Efficacy of Aqueous Flow Suppressants in the Mouse. Invest. Ophthalmol. Vis. Sci. 2014;55(13):2901.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
A noninvasive fluorophotometric method was used to measure aqueous flow in mice. Effects on aqueous flow of different anesthesia regimens and aqueous flow suppressants were assessed.
Two hours following topical 1% fluorescein application, CD-1 mice were anesthetized with either ketamine/xylazine, 2,2,2-tribromoethanol, ketamine alone or isoflurane. The eye was aligned with the lens of a modified scanning ocular fluorophotometer and the cornea and anterior chamber fluorescein concentrations were measured at 15-minute intervals for 60 to 90 minutes. A subgroup of ten mice received one topical drop of 0.5% timolol, 2% dorzolamide or vehicle in a crossover manner one hour prior to aqueous flow determination. Comparisons were made by ANOVA with Tukey post-hoc tests to determine significance between 3 or more treatment groups. P-values < 0.05 were considered to be statistically significant.
Fluorophotometric aqueous flow with ketamine/xylazine anesthesia was 0.09±0.01 µl/min (mean±SEM, n=24). This was significantly slower than with ketamine alone or 2,2,2-tribromoethanol (p<0.001). Aqueous flow could not be measured when isoflurane was used because of eye tremor. Timolol reduced aqueous flow from 0.20±0.02 µl/min to 0.07±0.01 µl/min (p=0.001) under 2,2,2-tribromoethanol anesthesia and from 0.14±0.01 µl/min to 0.10±0.01 µl/min (p=0.004) under ketamine anesthesia but did not reduce aqueous flow significantly under ketamine/xylazine anesthesia. Dorzolamide reduced aqueous flow from 0.09 ± 0.01 to 0.06 ± 0.01 ul/min (P = 0.04) under ketamine/xylazine anesthesia.
The advantages of the fluorophotometric method to measure aqueous flow are that it is noninvasive and repeat measurements can be performed on an individual mouse. The method does require anesthesia to sedate mice as the method is sensitive to movement. The type of anesthesia can greatly affect aqueous flow and efficacy of aqueous flow suppressants. When designing an experiment to measure IOP and aqueous humor dynamics in mice, the method of sedation needs to be chosen carefully.
This PDF is available to Subscribers Only