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.
ABSTRACT
Background To establish the ideal animal model of retinitis pigmentosa (RP) is very important for onward relevant study.Previous research determined that N-methyl-N-nitrosourea (MNU) can selectively damage photoreceptors via intravenous injection in mammal.However,whether MNU can be used to create an RP model needs to be investigated.Objective This experiment was designed to evaluate the toxic effect of MNU on photoreceptor cells of cats.Methods MNU was injected into 20 2-year-old cats via femoral vein and randomized into 20mg/kg, 25mg/kg, 30mg/kg, 35mg/kg and 40mg/kg MNU groups,and equal amount of normal saline solution was used in the same way in 4 normal cats as the control group.The activity,pupil size and light reflex were observed after injection of MNU.The cats were sacrificed and eyeballs were enucleated for histological examination to evaluate the structural and morphological changes of photoreceptors at 24 hours,72 hours,7 days and 14 days after the administration of MNU.This experimental study complied with the Statement for the Use of Animals in Ophthalmic and Vision Research.Results Dilated pupil and inertia of light reaction were found in experimental cats on the 7th days in the various groups.In 24 hours after MNU injection,the damage of photoreceptors was primarily characterized by pyknosis and disorder.In 72 hours after MNU injection,attenuation of the outer nuclear layer and disruption of cells were seen.Loss of photoreceptors and disappearance of the outer nuclear layer were observed on the 7th and 14th day.The extent of retinal photoreceptor cell damage was dependent on the dose of MNU.Conclusion MNU can selectively induce serious damage of the photoreceptor cells in cats retina in a time- and dose-dependent manner.
ABSTRACT
Background Bevacizumab is primarily aimed at pathologic angiogenesis for off-label uses such as the treatment of ocular neovascular disorders.However,as a new anti-fibrotic and anti-angiogenic agent following trabeculectomy,the safety and efficacy of bevacizumab by multiple-time and high-dose subconjunctival injection are still under study.Objective This study was to assess the safety and efficacy of bevacizumab after multiple-time and high-dose subconjunctival injections.Methods Regular trabeculectomy filtration surgery was performed on both eyes of 18 clean New Zealand White rabbits 0.1ml of bevacizumab(25g/L) was subconjunctivally injected intraoperatively and 3,5,7 days postoperatively in the left eyes of rabbits,and no any intervene in the right eyes were as normal controls.Bleb morphology was examined every 2 days and graded based on Moorefield's criteria and compared between the bevacizumab-treated eyes and normal saline(NS) eyes.The animals were sacrificed at 10,20 and 30 days after surgery respectively.The histopathological changes of the blebs were detected by hematoxylin and eosin stain to evaluate the cellular element around the bleb,and Masson stain was used to assess the degree of fibroblast proliferation.The degree of vascularity of bleb was identified by anti-vWf stain.Approval of this protocol was obtained and permitted from People's Hospital Institutional Animal Care and Use Committee of Peking University.The use of experimental animals complied with the Regulation for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission.Results Compared to the NS-treated eyes,bevacizumab-treated eyes showed the larger and more diffusely elevated blebs with the significant difference(2.48±0.22cm2 versus 1.73±0.27cm2,t=5.194,P＜0.05).The survival time of the filtration bleb in bevacizumab panel was longer in bevacizumab-treated eyes compared to control eyes,showing a significantly difference between them(21.0±1.56 days versus 12.5±1.97 days,t=3.830,P=0.005).Histological and immunohistochemical analysis confirmed that bleb and adjacent conjunctiva vascularity(A value) was significantly less in bevacizumab-treated eyes than that in control eyes at 20 days after surgery with the difference value 14320.7±4134.9(t=12.275,P＜0.05),and fibroblast deposition value was evidently diminished after bevacizumab treatment at 30 days following surgery in comparison with control eyes with the mean difference 0.27±0.03(t=15.980,P＜0.05＝.Conclusion Repeated subconjunctival injection of bevacizumab can effectively prolong the survival time of bleb in a rabbit model of trabeculectomy and limit the degree and area of vascularization in 30 days following surgery.Bevacizumab inhibit fibroblast-meditated tissue formation significantly in the later phase of vascularization after trabeculectomy.
ABSTRACT
This study was purposed to investigate the effect of different heat stress conditions on expression level of heat shock protein gp96 in K562 cell line of chronic myeloid leukemia in order to provide experiment basis for seeking optimal heat stress condition increasing extraction amount of gp96 from K562 cells. The expression changes of gp96 in K562 cell line was detected by immunocytochemistry under 38, 40, 42, 44, 46 and 48 degrees C for 30 minutes in water, by flow cytometry under 40, 44, 48 and 52 degrees C for 30 minutes in water, by Western blot under 40, 44, 48 and 52 degrees C for 30 minutes in water. Immunocytochemistry assay showed that gp96 existed mainly in cytoplasm. The peak of gp96 expression was at 30 minutes after 48 degrees C in water. The result of flow cytometry was consistent to immunocytochemistry detection results under temperatures 40, 44, 48 and 52 degrees C (P < 0.01). Western blot showed that detection result was the same as the immunocytochemistry and flow cytometry detections. In conclusion, the expression of gp96 in K562 cell line reached peak at 30 minutes after 48 degrees C in water. This condition may be an effective preparative condition for extraction of gp96 from K562 cells.