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)
Objective To investigate the effect of hypericin on the activity of protein kinase C (PKC) in cultured human retinal pigment epithelium (RPE) cells in vitro.Methods RPE cells were cultured in standard medium with 10% serum concentrations containing 0.5 to 5.0 μmol/L hypericin with or without preincubation of phorbol 12-myristate 13-acetate (PMA). The activities of cytosolic PKC (c-PKC) and membranous PKC (m-PKC) were assayed by PKC kit. Results The original activities of c-PKC and m-PKC of RPE cells were (35.34±4.10) pmol·min-1·mg-1and (62.52±8.80) pmol·min-1·mg-1.The activity of c-PKC in RPE cells with PMA preincubation decreased rapidly in 5 minutes, with a subsequent slow decrease after 20 minutes and a decrease to 18% of the activity of c-PKC in RPE cells without PMA preinubation after 60 minutes. While the activity of m-PKC in RPE cells with PMA preincubation increased gradually after 5 minutes and reduced after reached the peak at 40 minutes, and then returned to baseline after 60 minutes, eventually decreased below 30% of the control group. When RPE cells were cultured with PMA for 48 hours, the activities of c-PKC and m-PKC were hardly detectable, while RPE cells were cultured with both PMA and hypericin, hypericin could counteract most of down-regulation by PMA. Conclusion Hypericin may inhibit the translocation of PKC in RPE cells,change the activity of PKC, promote the apoptosis of RPE cells likely,and then prevent proliferative vitreoretinopathy. (Chin J Ocul Fundus Dis，2003，19：55-58)
Objective To observe the expression of proinflammatory factors messenger RNA(mRNA) in periretinal membrane of proliferative vitreoretinopathy. Methods Fourteen specimens of periretinal membrane were collected during vitrectomy, and they were made into paraffin sections.The presence of mRNA coding for IL-1,IL-6,IL-8 and TNF alpha was observed by in situ hybridization(ISH) with biotin labeled oligonuclotide probes respectively.The eyeball after corneal grafting was made as normal control. Results No expression of proinflammatory factors mRNA was found in normal human retina.Positive staining was present in 5 specimens.In these specimens, IL-1βmRNA was found in 3 specimens and TNFαmRNA was found in 3 specimens,there is 1 specimen expressed IL-8 mRNA and 3 specimens expressed IL-6 mRNA.In these positive specimens, one contained cells expressing mRNA for IL-1βbeta and IL-6, and one exhibited cells expressing mRNA for IL-1β、IL-8 and TNFα,two membranes possessed positive cells for IL-6 and TNFαmRNA, one membrane contained IL-1βmRNA positive cells only. Conclusion These findings suggest that these cytokines may be locally produced by cells infiltrating epiretinal membranes. The expression of IL-1β, IL-6, IL-8 and TNFαmRNA within retinal membranes provides further evidence of a pathogenic role of these cytokines in proliferative vitreoretinopathy. (Chin J Ocul Fundus Dis, 2002, 18: 286-288)
Objective To evaluate the visual results,surgical tec hnique and safety of secondary intraocular lens (IOL) implantation in aphakic eyes following vitrectomy and lensectomy for complicated ocular trauma or retinal detachment． Methods The clinical records of 3 2 cases (32 eyes),received these surgeries during November 1996 and December 1999,were reviewed retrospectively.During the secondary operation，intraocular infu sion through the pars plana was performend and the type of IOL was chosen based on the integrity of lens capsule. Results The study included 30 eyes suffering from trauma (foreign bodies in 15 eyes,penetrating injury with traumatic endophthalmitis and with vitreous hemorrhage in 6 eyes respectively, blunt trauma with lens dislocation in 3 eyes),and 2 eyes with primary retinal detachment.Those eyes all received vitrectomy,lensectomy,and/or remova l of foreign bodies and corneal suture.The interval of two operations ranged from 1 to 16 months with an average of 6.8plusmn;3.7 months.Posterior chamber IOL was implanted in the ciliary sulcus in 25 eyes with a whole or 2/3 of lens capsule,trans scleral suture fixation of IOL in 5 eyes,anterior chamber IOL and IOL with artificialiris in one eye respectively.Silicone oil was removed in 5 eyes duri ng the secondary operation.Post-operative visual improvement was achieved in 29 eyes.Main complications were corneal edema and low intraocular pressure after operation. Conclusion Intraocular infusion and proper IOL implantation during the secondary operation following vitrectomy can provide selected aphakic eyes with better visual recovery. (Chin J Ocul Fundus Dis, 2001,17:96-98)
Objective To investigate the therapeutic effects of vitre ctomy for primary retinal detachment due to macular hole in high myopic eyes. Methods Consecutive patients with primary retinal detachment due to macular hole who went to our hospital from March 1996 to March 2004 were retrospectively analyzed. The condition of the patients must accord with the previous refractive error of ge;6.00 D or the axial length of ge;26 mm without peripheral retinal hole; and with primary retinal detachment due to macular hole which had undergone vitrectomy. Results In 83 patients (85 eyes) including 63 females and 20 males with an average age of 54.1 years, preoperative visual acuity was light perception to counting finger in 49 eyes, 0.01-0.1 in 33, and 0.12-0.2 in 3 eyes; the extent of retinal detachment was only in the macular area in 15 eyes, in 1-2 quadrants in 11 eyes, and in 3-4 quadrants in 59 eyes; extraction of the lens or phako fragmentation was simultaneously performed during the operation in 62 eyes (72.9%), macular epiretinal membrane was removed in 37 eyes, and C3F8 or silicone oil was injected intravitreously in 29 (34.1%) and 56 (65.9%) eyes, respectively; the retina was reattached postop eratively in 77 eyes (90.6%) and failed to reattach in 8; visual acuity improved in 47 eyes (55.3%), remained unchanged in 25 (29.4%), and decreased in 13 (15.3%) after operation. Conclusions Primary retinal detachment due to macular hole often occurs in elder female patients with high myopic eyes.Simultaneous vitrectomy procedures including removal of posterior vitreous cortex, macular epiretinal membrane, cataractous lens and internal tamponade may usu ally beneficial to improve or preserve. The visual acuity improves or remains still in most of the affected eyes after the surgery. （Chin J Ocul Fundus Dis, 2006, 22: 287-290)
Objective To investigate the effect of dissociation of the human retinal pigment epithelium (RPE) cells by ficoll hypaque gradient centrifugation.Methods The primary human RPE cells and subcultured human RPE cells were dissociated with ficoll gradient centrifugation solution (d=1.077 g/ml)and the same divid ed cells as the control were dissociated with routine normal culture medium cent rifugation. The Trypan blue (0.4%) rejection staining was used, and the mouse anti-human monoclonal anti-body and fluorescein isothiocyanate (FITC) labeled rabbit anti-mouse IgG were utilized for indirect immunoreactivity for the test of human cytokeratin (CK) in active RPE cells cytoplasm. Flow cytometry assay was used to analyzed the percentages of CK positive staining RPE cells. simultaneously, the cells configuration, growth condition, the rate of clone formation, and the purifying result were observed under the fluorescent and confocal microscope.Results The survival rate and positive rate of CK of RPE cells in experimental group were higher than those in the control（P＜0.001）, but the number of the cells was reduced. The cells in the experimental group were integrated round with smooth border, symmetrical staining, homogeneous configuration and higher rate of clone formation （P＜0.001）. Conclusions RPE cells disas sociated with ficoll gradient centrifugation have the better dissociation effects. (Chin J Ocul Fundus Dis，2003，19：333-404)
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)