The occurrence of high intraocular pressure (IOP) after vitrectomy for diabetic retinopathy (DR) is related to many factors, including the type and stage of DR, macular detachment, surgical methods, and the type of ocular tamponade. Early high IOP occurred mainly due to laser photocoagulation, inflammatory response, improper ocular tamponade, residual viscoelastic agents and ciliary body dysfunction. In addition to the above reasons, early-middle stage high IOP is also related to tamponade gas expansion peak, encircling scleral buckle and hyphema. The major reason for middle-stage high IOP is hyphema and silicon oil in anterior chamber. The reasons for late-stage high IOP are glaucoma, silicone oil emulsification, long-term use of glucocorticoid, and iris incision closure. Most high IOP can be controlled by proper treatment such as stopping use of glucocorticoid, anti-glaucoma eye drops and surgeries. But there are still a small number of patients with unexplained refractory high IOP, the mechanism need to be further explored.
Objective To observe the therapeutic effect of pars plana vitrectomy (PPV) on myopic traction maculopathy (MTM).Methods The clinical data of 31 eyes of 29 patients with MTM diagnosed by timedomain optical coherence tomography (TDOCT) and slitlamp ophthalmoscopy were retrospectively analyzed. The cases were divided into 2 groups according to the stage of MTM: 12 eyes of 10 patients at the early stage of MTM were in group 1; 19 eyes of patients at the most Advanced stage of MTM were in group 2. All of these eyes had undergone PPV with 10％15％ inert gas filling. The patients were followed postoperatively for 6 to 12 months with the average of 8 months, and the best corrected visual acuity, reattachment of macular and retina was examined. Results The improvement rate of visual acuity after surgery for 6 months was 100% in group 1, and 63.2% in group 2 had (12/19); the visual acuity in group 1 was apparently better than that in group 2 (Z=-5477, P=0000). The macular hole disappeared without exposure of the pigment epithelium in all eyes of Group 1, but only 3 eyes in Group 2. For Group 2 patients, 3 eyes had reattached retina with macular holes, and 3 eyes had detached retina with macular holes. The recovery of macular configuration in Group 1 was obviously better than that in Group 2 (Z=-4318, P=0000). Conclusion The surgical intervention of MTM before the formation of macular hole and retinal detachment may prevent the formation of macular holes.
Objective To explore the effects of Zhaoke defibrase and anti alpha;vbeta;3mAb (23C6) on the adhesion and immigration of bovine retinal vascular endothelial cells. Methods The culture dishes coated with vitronectin (Vn) and collagen，assays of adhesion and immigration were performed 60 minutes after different concentration of Zhaoke defibrase and anti-alpha;vbeta;3 mAb was added to the bovine retinal vascular endothelial cells. The apoptosis of bovine retinal vascular endothelial cells induced by Zhaoke defibrase and anti-alpha;vbeta;3 mAb was detected by electron microscopy. Results Both Zhaoke defibrase and anti-alpha;vbeta;3 mAb inhibited the adhesion and immigration of bovine retinal vascular endothelial cells in a dose-dependent manner. The inhibited concentration (IC50) of Zhaoke defibrase was less than 0.05 mu;mol/L, while (IC50) of anti-alpha;vbeta;3 mAb was more than 2.5 mu;mol/L. 81.8% endothelial cells adhering to Vn were inhibited by 0.1 mu;mol/L Zhaoke defibrase, while 76.3% by endothelial cells adhering to Vn were inhibited by 10 mu;mol/L anti-alpha;vbeta;3 mAb. Typical apoptosis cells were found in bovine retinal vascular endothelial cells after affected by Zhaoke defibrase and anti-alpha;vbeta;3 mAb. Conclusion Both Zhaoke defibrase and anti- alpha;vbeta;3mAb can significantly inhibit the adhesion and immigration of bovine retinal vascular endothelial cells to extracellular matrix， and the mechanism may lie in inducing the apoptosis of endothelial cells. (Chin J Ocul Fundus Dis, 2005,21:118-121)
Objective To investigate the effect of hypoxia on the exp ression and function of integrin receptor αvβ3 of bovine retinal vascular endotheliocytes. Methods Bovine retinal vascular endotheliocy tes in the culture dishes coated by vitronectin was put into the normal and hypoxemic condition, respectively. Enzyme linked immunosorbent assay and cell adhesion analysis were used to detect the expression and function of integrin receptor αvβ3 in bovine retinal vascular endotheliocytes, respectively. Results Under the condition of hypoxia, the expression of αvβ3 increased gradually, and reached the peak at the 48th hour. The expression of αvβ3 at the 60th and 72nd hour in hypoxia group was higher than that in the normal group. Bovine retinal vascular endotheliocytes absorbed more Vn of extra-cellular matrixes (ECM) after cultured under hypoxemic condition for 24 hours.Conclusion Hypoxia may up-regulate the expression of αvβ3, which promote the adsorbability of endotheliocytes.(Chin J Ocul Fundus Dis，2004，20：360-363)
Objective To investigate the effect of advanced glycation end products (AGEs) on the catalase activity and the levels of malondialdehyde in cultured bovine retinal capillary pericytes (BRPs), and to investigate the relationship between oxidative stress and diabetic retinopathy. Methods Cultured BRPs were exposed to AGEs (0, 8, 32, 125, 500, 2 000 μg/ml) for four days. Activity and the levels of catalase and malondialdehyde in cultured BRPs were examined by spectrophotometry. Results AGEs decreased the catalase activity, whereas increased the levels of malondialdehyde of cultured BRPs in a dose-dependent manner (r=-0.714, r=0.748, P＜0.01).There were significant differences between BRPs cultured in 32 μg/ml AGEs and in control group (P＜0.01), while no significant differences between BRPs cultured in non-glycated bovine serum albumin and absence of bovine serum albumin were found. Conclusion Oxidative stress may be one of the reasons why the pericyte disappears in diabetic retinopathy. (Chin J Ocul Fundus Dis, 2002, 18: 143-145)
Objective To study the effect of hypoxia on proliferation of cultured bovine retinal pigment epithelium (RPE) cells and expression of the antiapoptotic protein bcl-2. Methods The bovine RPE cells were cultured under normal and hypoxic chamber respectively. After 24 hours, the proliferation of RPE cells was evaluated by［3-(4,5-dimethylthiazole-2yl)-2,5-diphenyl tetrazolium bromide, MTT］test. At the same time, anti-bcl-2 protein antibody was examined by immuno-histochemistry method. Results The A value in the hypoxia group was higher than that in the normal group after 24 hours (P＜0.05 )in MTT-test. Positive staining for anti-bcl-2 protein antibody was seen in 72.6% cells in hypoxia group and 38.64% in normal group. The positive staining was more obvious near the nucleus, and fine granules scattered in cytoplasm of some cells. Conclusion Hypoxia can stimulate the proliferation of RPE cells and expression of antiapoptotic protein bcl-2. The results indicate that bcl-2 may play an important role in mediating the proliferation activity of RPE cells. (Chin J Ocul Fundus Dis, 2002, 18: 293-295)