A pilot study on purification of human plasminogen from cord blood plasma and inducing posterior vitreous detachment / 中华实验眼科杂志

ABSTRACT

Background Many studies and clinical trials of pharmacologic vitreolysis are already under way to try to improve vitreo-retinal surgery and to liquefy and detach the vitreous from the retina ultimately, including chondroitinase,hyaluronidase,dispase and plasmin. However, there has not been any report on purification of human plasminogen from cord blood plasma and inducing posterior vitreous detachment of the animal eye at present.Objective This study was designed to isolate and purify the production of human plasminogen (Plg) from cord blood plasma with ethanol precipitation and evaluate the efficacy of Plg in inducing posterior vitreous detachment (PVD).Methods Human Plg was Separated and purified from cord blood plasma by ethanol precipitation method. The protein band corresponding to Plg with molecular mass of 92 000 was revealed in SDS-PAGE and confirmed by MALDI-TOF and Mascot database. Anion-exchange chromatography and plasminogen activity assay kit were used to obtain purified Plg with biological activity. Twenty-five fresh pig eyes were enucleated and assigned to 5 groups and 5 eyes for each group. The normal eyes were used as control group. Balanced salt solution(BSS)of 0.1 ml was intravitreally group and standard substance group. All of the eyes were then incubatedfor 60 minutes under the 37 ℃. Retinal histopathology and ultrastructure were examined under the light microscopy, scanning electron microscopy ( SEM ) and transmission electron microscopy (TEM). Results The Plg with potential fibrinolytic activity was successfully extracted and purified from cord blood plasma by ethanol precipitation method. No posterior vitreous detachment (PVD) was seen in normal control group, BSS group and r-SK group following the intravitreal injection under the sem. However,PVD was demonstrated in r-SK+ Plg group and standard substance group under the SEM. The inner limiting membrane ( ILM ) and the retina were well preserved in all of the experimental eyes. No retinal morphology and ultrastructural abnormality were found under the light and SEM and TEM. Conclusion Ethanol precipitation is a feasible way to isolate and purify Plg from human cord blood plasma. Extracted Plg shows potential fibrinolytic intravitreal injection of Plg.