Complications of proliferative diabetic retinopathy have become the major indications of vitrectomy. The surgery, however, is not basically a causative therapy. The visual function after operation depends on the degree of retinal ischemia and damage induced. The surgery itself has a potential for severe complications. Therefore it is important to better understand the pathology and to master surgical strategy and techniques in order to improve surgical outcomes and reduce the surgical complications.
(Chin J Ocul Fundus Dis,2007,231-233)
Objective
To observe the expression of N-cadherin in streptozotocin (STZ)-induced diabetic Sprague-Dawley (SD) ratsprime;retinae.
Methods
Celiac injection with 65 mg/kg STZ was performed on 20 rats to set up the diabetic model, and celiac injection with the same volume citrate buffer was performed on other 20 SD rats as the control. Vascular permeability was detected by Evans blue method. The expression of N-cadherin in both normal and STZ-induced diabetic ratsprime;retinae and trypsinase-digested retinal microvessels were detected by immunohistochemistry method and Western blotting analysis.
Results
Retinal vascular permeability increased 68%, 91% and 125% 4, 8, and 12 weeks, respectively, after diabetic models was induced (Plt;0.005). In the control group, the expression of N-cadherin was detected in the outer and inner plexiform layer, inner nuclear layer，ganglion cell layer,internal limiting membrane and between retinal endothelial cells and pericytes. However, the expression of N-cadherin significantly decreased in STZ-induced diabetic rats retinae at the 12th week. The results of Western blotting analysis showed that the expression of N-cadherin obviously decreased as the diabetic retinopathy developed.
Conclusion
The decrease of expression of Ncadherin in the retinae of STZ-induced diabetic rats suggests that N-cadherin may participate in the development of diabetic retinopathy at the early stage.
(Chin J Ocul Fundus Dis,2007,23:269-272)
Purpose
To study the refractive state of silicone oil tamponade eyes.
Methods
To calculate the theoretical refractive state of eyes with silicone oil based on clinical visual optics and to perform retinoscopy on 48 silicone oil filled eyes with pars plana vitrectomy (PPV) and 45 ones with PPV plus lens ectomy with retinal reposition, and then study theoretical and experimental differences of diopter in silicone oil filled eyes.
Results
Postoperative diopter of the former increases (+6.26plusmn;1.20)D than preoperative diopter, while that of the latter is (+11.40plusmn;2.22)D.
Conclusion
Hyperopic changes are found in silicone oil tamponade eyes, and the experimental values are lower than the theoretical ones. This may be helpful in predicting the change of diopter of silicone oil tamponade eyes.
(Chin J Ocul Fundus Dis, 2001,17:102-104)
Objective
To investigate the molecular mechanism of apoptosis in cultured human retinal pigment epithelial (RPE) cells.
Methods
The growth media of confluency human RPE cells were replaced with a daunoblastinacontaining one at a dose of 180mu;g/L,and the cells were incubated for 12 hr at 37℃.After incubation with the drug,the medium was withdrawn,fresh medium was added and incubation was carried out for an additional 24 hr.Apoptosis was monitored by light microscopy,enzyme linked immunosorbent assay(ELISA)and terminal deoxynucleotidyl transferase mediated biotin-dUTP nick-end labelling(TUNEL)staining.The expression of bax and bcl-2 were evaluated by immuncoytochemical staining with anti-human bcl-2 and bax antibodies.
Results
After the RPE cells treated with daunoblastina,shrinkage of cytoplasm and nucleus was identified.The ratio of nucleus to cytoplasm was increased.TUNEL staining showed that many cells were positive staining.The amount of apoptotic cells was directly proportional to the drug dose.The integral optical desity values for expression of bax inereased by 22.0%(Plt;0.05), and that of bcl-2 did not change significantly(Pgt;0.05).
Conclusions
During human RPE cell apoptosis induced by daunoblastina,overexpression of bax or low bcl-2/bax ratio were demonstrated.The results suggest that bax and bcl-2 gene expression could play a role in regulation of RPE cell apoptosis.
(Chin J Ocul Fundus Dis, 1999, 15: 153-156)
Purpose
To investigate the expression of intercellular adhesion molecules ICAM-1 and Mac-1，in epiretinal membanes (ERM) of eyes wi th proliferative vitreoretinopathy (PVR)．
Methods
Twenty epiretinal membranes were obtained from eyes undergone vitrectomy for retinal detachment complicated with PVR and observed by immunohistochemical examination．
Results
Expressions of ICMA-1 and Mac-1 were observed in 18 and 15 membranes respectively．Expression of both adhesion molecules in 12 membranes．
Conclusion
The findings indicate that adhesion molecules might be involved in the development of PVR．
(Chin J Ocul Fundus Dis，2000，16：71-138)
Purpose
To study inhibition effects of retinal pigment epithelial (RPE) cells by hyaluronic acid-stimulating activity(HASA)．
Methods
The cultured human RPE cells added with a series of HASA was measured with cell counting,tetrazolium(MTT)colorimetric assay and tritium labelled thymidine deoxyribosｅ(3H-TdR)incorporation assay.Flow cytometry(FCM)analysis was used to examine RPE cells cycles.
Results
HASA at concentrations of 12.5～200 mu;g/ml and within 48 hours inhibited RPE cells proliferation with a dose-dependant and time dependant manners.The maximal inhibition rate of RPE cells by HASF was about 48.0%.FCM revealed that the cells in G1 phase increased 7.2% and cells in S phase decreased 9.7%,compared to controls.
Conclusion
HASA at a certain dose range and period can inhibit RPE cells proliferation.
(Chin J Ocul Fundus Dis,1999,15:72-74)
Purpose
To evaluate the efficacy of vitreous surgery for treatment of fundus damages caused by ocular blunt trauma.
Methods
Clinical records were reviewed retrospectively for a series of consecutive 101 patients (105 eyes) with fundus damages caused by ocular blunt trauma underwent vitreous surgery from October 1992 to March 1998．
Results
Based on clinical examination and findings during surgery,all cases were divided into 4 subgroups:vitreous hemorrhage(VH)in 23 yes,VH with retinochoroidal rupture or optic damage in 25 eyes,traumatic retinal detachment in 46 eyes,and retinal giant tear in 11 eyes.Vision acuity improvement achieved in 77 eyes(73.3%)and of them 69 eyes(65．7%)had 0.02～0．6with 38 eyes(55．0%)better than 0．1.Two eye s with no light perception obtained better than 0.1． Visual acuity remained unchanged in 26 eyes(24.8%)and 2 eyes(1.9%)became worse after operation．The retina reattached in 54 eyes(94.7%).
Conclusion
Severe ocular blunt trauma may cause visual impairment and various fundus damages.Appropriate vitreous surgery can salvage most eyes with those injuries.
(Chin J Ocul Fundus Dis,1999,15:100-102)
Objective
To observe whether apoptosis was involved in cells of aspiration fluid from vitrectomy for proliferative vitreoretinopathy(PVR),and whether there was an association with expression of Fas antigen(Fas )and Fas ligand (FasL).
Methods
Cytocentrifuge slides of 11 fresh vitreous specimenｓ of PVR were prepared to be stained by TUNEL met hod for detection of apoptosis and by immunohistochemical technique for detection of Fas,FasL，and cytokeratin (CK),a cell-type specific antigen.
Results
Fas and FasL were expressed in normal human retina.Fas,FasL,CK，and apoptosis were found in all preparations.TUNEL-positive cells were 20.53% in total cells.70.35%,51.58%，and 82.97% of cells highly expressed Fas,FasL，and CK,respectively.The linear correlation coefficient of Fas and apoptosis was 0.99(Plt;0．001).
Conclusion
Vitrectomy specimens of PVR showed expression of Fas，FasL，and apoptosis.Prominent Fas and FasL expressions may be associated with apoptosis of proliferating retinal pigment epithelial cells in the vitreous of PVR.
(Chin J Ocul Fundus Dis,1999,15:78-80)
Purpose
To investigate bax expression and induction of apoptosis in normal cultured retinal pigment epithelium (RPE) cells ．
Methods
Cultured human RPE cells were transfected by PMDNA3-hbax，which incoded the whole bax gene and may be induced by Zn2+ under the MTII promoter， through lepofectin mediated protocol．The tested RPE cells were divided into three groups of A，PMDNA3-hbax transfected ;B，PMDNA3 (nude vector) transfected and C ，normal RPE cells．After transfection， DNA gel electrophoreses were perform ed ，the tested RPE cell cycles were analyzed with flow cytometry (FCM)．
Results
The gel electrophoretogram showed DNA ladder phenomenon，FCM confirmed the apoptosis of RPE cells PMDNA3-hbaxtransfected ， consisting of significant apoptotic peak sited before the G 1 phase and the apoptotic rate was 36%．
Conclusion
The foreign bax gene can be effectively conducted in to the RPE cell through lepofectinmediated protocol and induced expression ． The foreign bax overexpression may induce the cultured human RPE cell susceptibi lity to apoptosis．
(Chin J Ocul Fundus Dis, 2001,17:132-134)
