Quantitative assessment of the blood-retinal barrier leakage in rat diabetic retinopathy by dynamic contrast enhanced-MRI

Abstract

Objective To quantitatively assess the damage of blood-retinal barrier (BRB) in rats with diabetic retinopathy using dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI). Methods Forty 3-week-old Sprague-Dawley (SD) rats were randomly divided into experiment and control group. The rats in experiment group underwent intraperitoneal injection of streptozotoein. The rats with blood glucose over 16.65 mmol/L and +++ of urine glucose were considered as diabetes and were further divided into four subgroups according to the course of diabetes mellitus (2, 4, 6, and 8 months). The rats in control group underwent intraperitoneal injection with the same volume of buffer and were divided into four subgroups (with 5 rats in each subgroup) according to the coordinate age of rats in experimental group. All of the eyeballs were scanned by DCE-MRI and enucleation was performed after intraperitoneal injection with pentobarbitone. The data were analyzed by SPSS 12. 0 statistical software. Results All the rats in experiment group became diabetic models. There was no obvious BRB permeability in control group and in 2- and 4-months experiment group. The average BRB permeability rate in 6- and 8-month experiment groups were (0. 1399±0. 0065) and (0. 1816±0. 2756) mm~3/min respectively (Z= -2. 121, P<0. 05). Retinal edema and cellular disorganization appeared at 4-months and became more severe when diabetes course extended. Conclusions DCE-MRI can measure the BRB permeability rate accurately and assess the extent of BRB damage quantitatively in rats with diabetic retinopathy. Key words: Diabetic retinopathy/Phisiopathology; Magnetic resonance imaging/methods; Blood-retinal barrier/physiology; Diabetes mellitus, experimental