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 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
<p><b>OBJECTIVE</b>To quantify the CD4+ CD25+ CD127(low) regulatory T cell (Treg), the expression levels of forkhead/winged helix transcription factor FOXP3 and Notch1 mRNA in aplastic anemia (AA) patients before and after treatment, and explore the significance of Treg in pathogenesis of AA.</p><p><b>METHOD</b>CD4+ CD25+ and CD4+ CD25+ CD127(low) T cells in peripheral blood were examined with FACS in 29 AA patients at active phase, 14 at recovery phase, 11 at unrecovery phase, and 15 normal controls. The levels of FOXP3 mRNA and Notch1 mRNA expression were detected with RT-PCR, and the correlations between Treg, FOXP3 mRNA and Notchl mRNA were analyzed.</p><p><b>RESULTS</b>The percentages of peripheral activated CD4+ CD25+ T cells in AA patients at active phase (4.3 +/- 0.7)% and unrecovery phase (4.2 +/- 0.6)% were significantly higher than those in normal controls (2.4 +/- 0.8)% (P < 0.05). The proportion of these cells in AA patients at recovery phase was reduced to (2.6 +/- 0.7)% (P < 0.05), being no difference from that in control group. The number of CD4+ CD25+ CD127(low) T cells in AA patients at active phase (2.4 +/- 1.2)% and unrecovery phase (2.5 +/- 1.1)% was decreased significantly compared with those in normal controls (7.1 +/- 2.7)% (P < 0.01) and in AA patients at recovery phase (5.3 +/- 1.0)% (P < 0.01), there was no difference between the latter two groups. In active phase AA patients, the levels of FOXP3 mRNA and Notchl mRNA (0.260 +/- 0.011 and 0.018 +/- 0.005, respectively) were lower than that in control group (1.307 +/- 0.011 and 0.308 +/- 0.028, respectively) (P < 0.01 and P < 0.01). After treatment, the levels significantly increased to 1.287 +/- 0.012 and 0.281 +/- 0.013 (P < 0.01 and P < 0.01), but there was no difference with that of normal controls (P > 0.05). CD4+ CD25+ CD2(low) T cells and FOXP3 were positively related with Notchl (P < 0.01) in AA patients.</p><p><b>CONCLUSION</b>The decreased number and suppressive activity of CD4 CD25+ CD127(low) Treg cells in the peripheral blood of AA patients cause over-activation of autoreactive T cells and suppression of haematopoiesis. One of the mechanisms maybe the reduced expression of Notch1 in the target cells.</p>