Abstract
Purpose :
Medical society considers that, in human, carotid stenosis of 80% and up might be the cause of clinical symptoms such as transient ischemic atack When carotid stenosis exists, but no symptoms are expressed , the condition is called :Asymptomatic Carotid Stenosis.
Our hypothesis is that carotid stenosis of lesser degree such as 30% to 50% may damage gradualy the brain along life time course and be a risk factor of brain disease later in life ?!
Methods :
We used SD, albino, adult ,male rats. We had 30 rats devided in three groups of 10 rats..The first group was the control , with no carotid stenosis.The sceond group passed unilateral carotid occlusion and the third group passed bilateral carotid stenosis. The carotid stenosis was created under deep anesthezia according to the ARVO rules for Animal Care. We used a 7\0 silk surgical suture to create the stenosis. In order to create equal occlusion we used injection needle of different size such as 30G,27G aligned along the carotid artery. We evaluated the amount of lumen that remained using Doppler examination of each rat.
The morphology of the brain was evaluated using MRI : Two different MRI protocol were used T2 weighed and DTI. MRI scanning was performed using a 7T MRI scanner (Bruker) with a 30 cm bore and a gradient strength of up t0 400 mT/m. The MRI protocols included coronal T2 weighted images (T2W) and Diffusion tensor imaging.
DTI analysis was performed with in -house software, implemented on MATLAB,and FA and MD maps were produced.
Behavioral tests : Moris water maze (WNz) and Open Field test. The WNZ test is used to asses spatial learning memory and is considered a hipocampal task. The test cosists in a pool with water : 1.5 m diameter and 0.6 m depth. A platform is located below the water surface invisible for the rat.
Open field test evaluate general locomotor activity.
Results :
MRI evaluation revealed brain damage in all bilateral carotid stenosis rats and in three unilateral No damage in control rats. The damage was located in the dorsal part of the brain
Behavior tasks reveled latency in learning and shortened memory in both groups of bilateral and unilateral carotid stenosis groups.
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Conclusions :
Long term mild carotid stenosis created morphologic brain damage and functional impairment
When regarding this results we suspect that retina might be involved ,so vision.We started now hystology evaluation of the eyes.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.