Control and HU groups of male and female mice will be studied. The ocular structure and function will be assessed after baseline, and 2 weeks and 4 weeks of HU or control conditions. We will use a systematic approach of in vivo and in vitro studies to assess artery, vein, and lymphatic vessel structure and function.

We will perform in vivo approaches to assess retinal microvascular structure and function using fundus imaging, Doppler ultrasound (central retinal artery flow velocity) and intravital imaging (microvascular permeability) in control and HU mice. Optical coherence tomography (OCT) imaging and histochemical staining of retinal tissue will also be performed for comprehensive evaluation of neural retina structure and function. In addition, neural retina function (a-wave and b-wave, and oscillatory potentials) will be assessed using the electroretinogram (ERG) and intraocular pressure will be measured with a tonometer.

To directly assess vascular function, ophthalmic arteries and ocular lymphatic vessels will be isolated and pressurized for in vitro studies of vascular reactivity. The immunohistochemical, molecular, and biochemical tools will be used to assess the impact of HU on the retinal microvascular tight junction proteins and levels of inflammatory cytokines in the retinal tissue. The outcomes from the vascular studies will be evaluated in relation to SANS symptoms and neural retina structure (OCT)/function (ERG).

RESULTS:
This experiment is currently in progress. Results will be available at the conclusion of the study.