The Refined Fundus Fluorescein Angiography Technique In Diabetic Retinopathology Model Of Rat

BackgroundAlthough researchers have tried various approaches to control the value of blood glucose, there is no definite method to prevent all types of diabetic complications; in addition, the diabetic retinopathy (DR) is still considered the most common sight threatening vascular disorder. To date, rats are commonly used in diabetes and related complication researches for many reasons. A lot of experiments have confirmed that the pathological characters of DR in rat models present retinal vascular leakage, peripheral cell shrinkage and acellular capillaries. However, there are some technical problems in observing these pathological features at present. Firstly, it is impossible to see a clear retinal vascular leakage in DR model in albino rats; secondly, it need a lot of time to obtain a proper eye position using traditional technique as Heidelberg HRA-II combining tail vein injection of fluorescein sodium (FS). How to resolve these two questions?PurposeTo observe the effect of fluorescein fundus angiography (FFA) in pigmented diabetic rats using Micron-Ⅲ retinal imaging system combining intraperitoneal injection of FS, furthermore, we compare the figures and preparation time to that of using Heidelberg HRA-Ⅱ combining tail vein injection of FS.MethodsRegarding of the animals loss,15BN rats and15SD rats were induced to diabetic retinopathy models using tail vein injection of Streptozotocin and blood glucose concentrations were determined every week. Only the rats whose blood glucose concentrations maintained from16.7mmol/1to27.8mmol/1were selected into subsequent ocular observation including slit-lamp, ophthalmoscopes, FFA using new technique as Micron-Ⅲ retinal imaging system combining intraperitoneal injection of FS and retinal digest preparation at8weeks. Subsequently, the rats with high quality FFA figures were chose to check using traditional technique as Heidelberg HRA-Ⅱ combining tail vein injection of FS. The time spending on preparation for FFA and the effects of FFA were observed.Results10BN rats and10SD rats accorded with blood glucose condition8weeks late. The blood glucose level was no significant difference between the group of BN diabetic rats and the group of SD diabetic rats.6animals showed cataract in the group of BN diabetic rats, while5animals showed cataract in the group of SD diabetic rats. In this study, of the10BN diabetic rats,10(100.0%) showed evident vascular disorder as background diabetic retinopathy, whereas none of the SD diabetic rats had distinct photos because rapid interference of choroid fluorescent light. All retinal digest preparations in2groups showed typical vascular disorders, The difference was no significant statistically (P>0.05).The retina of BN rats were quickly achieved the preparation site at averaged57.50±8.17s using new technique, otherwise, it needed320.34±38.79s in traditional technique. The difference was significant statistically (P <0.01), and the time was saved averagely260s. Comparing with the retinal images of traditional technique, there were no obvious difference in new technique except the lag of fluorescent developing time. All photos can show clear normal and abnormal retinal vascular morphology of BN rats.ConelusionsThe fundus vascular morphology of pigmented diabetic rats was more distinct than that of albino rats and FFA can find typical changes of background diabetic retinopathy disorder. Micron-Ⅲ combining intraperitoneal injection of FS is an effective and convenient experimental technique that allows high-quality fluorescence imaging of the pigmented rat retina.