Study on blood-ocular barrier between the anterior and posterior chamber after peripheral iridectomy by contrast-enhanced magnetic resonance in rabbit / 中华实验眼科杂志

ABSTRACT

Background Whether ocular anterior and posterior chamber exist a blood-aqueous barrier is in controversy.Conventional method can not offer a good evidence because it is unable to detect the aqueous component in the posterior chamber.Objective This study was to investigate the distribution of Gadolinium-diethylene triamine pentaacetic acids(Gd-DTPA)after peripheral iridectomy with magnetic resonance imaging(MRI)in rabbit.Methods Monocular peripheral iridectomy was performed on the right eyes in 8 clean New Zealand white rabbits and the fellow eyes were as controls.0.2 ml/kg(0.5 mol/L)Gd-DTPA,a tracer of MRI,was injected into ear vein in vivo to scan the eyes with MRI for the observation of the permeability and distribution.The signal enhanced ratio of interest region associated with time were analyzed.Results The signal in ciliary body of both eyes showed an immediately sharp enhancement within 10 minutes following the injection of Gd-DTPA with a peak intensity at 30-40 minutes,and then the intensity was gradually weaken over time.The signal was stronger in the operative eyes than that in the fellow eyes.The signal in the posterior chamber was gradually increased after operation,however,that in posterior chamber of the control eyes was lower.The interest regions of Gd-DTPA were ciliary,anterior chamber and posterior chamber,and the enhanced signal intensities were consisted in the posterior chamber after operation.However,the increase of the signal was not seen in the posterior chamber in the control eyes.Conclusions The pathway of plasma protein entering into the anterior chamber is very different from that of aqueous secretion.There exists a barrier between the anterior and posterior chamber which might be an integral part of the blood-ocular barrier.