Mousetap, a Novel Technique to Collect Uncontaminated Vitreous or Aqueous and Expand Usefulness of Mouse Models

Vitreous or aqueous humour taps are widely used in patients or large animals with retinal diseases to monitor disease biomarkers, search for novel biomarkers, assess the integrity of the blood-retinal barrier, or perform pharmacokinetic or pharmacodynamics studies. Although there are many useful mouse models of retinal diseases, the small size of mouse eyes has precluded vitreous or aqueous taps. Herein we describe a novel technique, mousetap, which allows collection of vitreous or aqueous humour uncontaminated by blood or tissue surrounding the vitreous cavity. Mousetap was used to obtain vitreous samples from several mouse models of retinal vascular diseases and vitreous albumin measured by ELISA was highly reproducible among mice of the same model. The mean vitreous albumin concentration differed widely among control mice and mice of different models and correlated with fluorescein angiographic assessment of vascular leakage severity. Protein arrays showed increases in levels of several vasoactive proteins in the vitreous from mice with oxygen-induced ischemic retinopathy compared with age-matched controls; almost all of these proteins are increased in the vitreous of patients with the most common human ischemic retinopathy, proliferative diabetic retinopathy. Thus, mousetap facilitates the use of mice for studies previously reserved for large animal models and patients.