Effect Of Intravitreal Injection Of Urokinase On The Concentration Of Intravitreal Evans Blue In Rats

Background and ObjectiveRetinal vascular occlusion and retinal hemorrhage are common clinical ocular fundus retinal diseases which can cause retinal tissue injury and serious damage to vision, or even blindness. Currently, there have no safe and effective clinical methods towords retinal vessels blocking recanalization and rapidly absorbtion of the retinal hemorrhage to restore the vision. It was designed to observe the effects of urokinase(UK) intravitreal injection on the outward permeability of blood-retinal barrier by using intravitreal evans blue(EB) as the indicator,and through UK permeability effect that can go through all layers even as retinal vasculars. To get achievement of thrombus or blood clot dissolved in Retinal vascular occlusion or retinal hemorrhage.Methods40healthy Sprague-Dawley (SD) rats were randomly assigned into experimental group and contgrol group. Only right eyes of the rats were intravitreally injected with UK350U/4μl for the experimental group and0.01M phosphate buffered saline (PBS) for the control group respectively.24hours later, all rats underwent intravitreal injection with1%EB2μl.4hours after the injection, all the vitreous of right eyes were removed and dried. EB was extracted from dried vitreous by formamide. Then, the concentration of EB in formamide was determined by a formamide extraction-ultraviolet spectrophotometry method.ResultsThe vitreous body colors which viewed under surgical microscopy colors are blue and light blue in experimental and control group respectively, showed significant difference. However, there was not obvious difference found within each group.Statistical analysis of of formamide with multiple measurement EB solution absorbance standard curve:y=0.0734x+0.0068, the coefficient of determination: R2=0.9996, statistically significant. Formamide EB concentration of the solution was0.1μg/ml to13.33μg/ml. Content of EB in formamide and its absorbance (A) value was highly linear correlation,The absorbance and concentration of EB in formamide of the experimental group was (0.166±0.061) and (2.166±0.838)mg/L, while the control group’was (0.474±0.052) and (6.362±0.711)mg/L. The concentration of intravitreal EB of the experimental group was (0.243±0.094)g/L, while the control group was (0.714±0.079)g/L, showing a statistically significant difference between them (t=-17.089, P<0.001)ConclusionIntravitreal injection of UK can increase EB transude through blood-retinal barrier from vitreous space, augment the permeability of blood-retinal barrier in rats.