Objective：To observe the protective effect of ginkgo bilo ba extrac t (EGb 761), a free radical scavenger, on the photoreceptor cells after lighti nduced retinal damage. Methods：Seventytwo female SpragueDa wley (SD) rats we re randomly divided into 4 groups: normal control group, lightinduced retinal da m age model group, model+physiological saline group, and model+EGb 761 group, with 18 rats in each group. All of the rats except the ones in the control group were exposed to white light at (2740plusmn;120) lx for 6 hours after the dark adap tation for 24 hours to set up the lightinduced retinal damage model. Rats in m o del + physiological saline group and model+EGb 761 group were intraperitoneall y injected daily with physiological saline and 0.35% EGb 761 (100 mg/kg), respec tively 7 days before and 14 days after the light exposure. Apoptosis of photorec eptor cells was detected 4 days after light exposure; 7 and 14 days after light exposure, histopathological examination was performed and the layer number of ou ter nuclear layers (ONL) on the superior and inferior retina was counted. Results：Four days after light exposure, the apoptosis of photorecep tor cells was fou nd on ONL in model, model+ physiological saline and model+EGb 761 group, and w as obviously less in model + EGb 761 group than in model and model+physiologic al saline group. Seven days after light exposure, the layers of ONL on the super ior retina were 3 to 4 in model and model+physiological saline group, and 7 to 8 in model+EGb 761 group; the mean of the layer number of ONL in model+EGb 761 group (6.92plusmn;0.82) was less than that in normal control group (8.40plusmn;0.95) (t=-1.416, P＜0.05), but significantly more than that in model (5.96 plusmn;1.36 ) and model+physiological saline group (5.90plusmn;1.40）（t=1.024, 1.084; P＜0.05). Fourteen days after light exposure, the layers of ONL on the superior retina were 0 to 1 in model and model+physiological saline group, and 3 to 4 i n model+EGb 761 group. The mean of the layer number of ONL in model+EGb 761 group (5.5 2plusmn;1.06) was significantly more than that in model (3.44plusmn;2.15) and model + physiological saline group (3.37plusmn;1.91) (t=2.082, 2.146, P＜0.05). Conclusion：EGb 761 can partially inhibit the apoptosis of pho toreceptor cells, thus exert protective effect on photoreceptor cells.
Objective To investigate the relationship between exposure intensity and illumination time of blue light and replicative senescence of rat retinal pigment epithelial （RPE） cells.Methods Thirtysix 12-14 weeks Wistar rats were kept in the cage with a bluelight bulb ［(450plusmn;10) nm］, and were randomly divided into four groups (no light，nature light，500 lx light and 1000 lx light illumination), each has nine rats. The rats in each group were further divided into three subgroups according to illumination time (one month，two months or three months). Eyeballs were collected after intraperitoneal injection of 10% chloral hydrate. The right eye of each rat was embedded in paraffin and sectioned for hematoxylineosin (HE) staining, while frozen sections of the left eye were stained for the senescence-associated beta;-galactosidase (SA-beta;-Gal). The data were analyzed by SPSS11.5 statistical software.Results The amounts of SA-beta;-Gal positive RPE cells were significantly different between all groups under the same illumination time 17 (P＝0.000）, and between all subgroups of different illumination time with same exposure intensity （P＜0.01）except for the control group (no light). Conclusion Bluelight can induce replicative senescence in rat RPE cells in an intensity and timedependent manner.
ObjectiveTo observe the effects of repeated intravitreal injections of anti-vascular endothelial growth factor (VEGF) drugs on vitreous macular interface (VMI) in patients with exudative age-related macular degeneration (AMD).MethodsRetrospective study. Thirty-four exudative AMD patients who treated with intravitreal anti-VEGF drugs were included in this study. There were 26 males and 8 females. The age ranged from 50 to 80 years, with the average of (62.8±8.35) years. The eyes with at least 6 treatments during the 1-year follow-up were taken as the study eyes, and the eyes with no anti-VEGF drug treatment were the control eyes. Optical coherence tomography (OCT) examination was used to observe the VMI status of both eyes before treatment. Vitreous macular adhesion (VMA), macular epiretinal membrane (MEM), and complete vitreous detachment (C-PVD) were defined as abnormalities in VMI. The VMA was classified as focal (≤1500 μm) and broad (＞1500 μm) depending on the diameter of the vitreous and macular adhesions on the OCT images. Before treatment, there were 12 eyes with abnormal VMI in study eyes, including 8 eyes with broad VMA, 3 eyes with focal VMA, and 1 eye with MEM; 12 eyes with abnormal VMI in control eyes: broad VMA in 7 eyes, focal VMA in 2 eyes, C-PVD in 2 eyes, and MEM in 1 eye. The average follow-up time after treatment was 16.4 months. During the follow-up period, OCT was performed monthly in a follow-up mode. Comparing the changes on VMI between before and after treatment in both eyes of patients, respectively. The chi-square test was used to compare the difference on VMI. Because the number of samples was ＜40, Fisher's exact test was used for the analysis.ResultsAt the final follow-up, 12 eyes with abnormal VMI in the study eyes, including 5 eyes with broad VMA, 2 eyes with focal VMA, 3 eyes with C-PVD, and 2 eyes with MEM. There were 6 eyes altered comparing with baseline. In the control eyes, there were 13 eyes with abnormal VMI, including 5 eyes with broad VMA, 7 eyes with C-PVD, and 1 eye with MEM. A total of 6 eyes changed on VMI comparing with baseline. At the final follow-up, there was no significant difference on VMI changes between the study eyes and its corresponding control eyes (P=0.053). In all eyes, a total of 4 eyes changed from focal VMA to C-PVD at the final follow-up, accounting for 80.0% of the total focal VMA; 3 eyes changed from broad VMA to C-PVD, accounting for 21.4% of the total broad VMA.ConclusionsRepeated anti-VEGF treatment has little effect on VMI. Regardless of anti-VEGF therapy, eyes with focal VMA appears to be more prone to C-PVD than the broad one.
Objective To investigate the effect of micropulse di ode laser treatment on the retina in Brown-Norway rats (BN Rats). Methods 130 eyes of BN rats received irradiance of different powers of micr opulse diode laser with 810nm wavelength through a contact lens. Fundus color photography and fundus fluorescein angiography (FFA) were performed on day 1, 3, 7, 14 and 28 days after treatment. Animals were sacrificed on 1, 3, 7, 14 and 28 days separately for historical study. The expression of heat shock protein-70 (HSP-70) in the retina was observed with immunohistochemistry. Cell apoptosis of retina tissue was examined by TdT mediated dUTP nick end labeling (TUNEL). Results (1) No change was found in no visible reaction laser spots by light microscope. High duty cycles with threshold and suprathreshold en ergies can produce severe damage even to the inner nuclear layer. (2) HSP-70 ex pression was markedly increased in the inner nuclear layer at 1d after micropulse diode laser. This increase in HSP-70 expression peaked at day 3 whereafter a decline near to normal at 2 weeks was detected. (3) Apoptosis was detected mainl y in retinal pigment epithelium, outer nuclear layer, inner nuclear layer and ev en choroid by TUNEL after micropulse diode laser treatment. The TUNEL-positive cells increased with the laser power. Maximum TUNEL-positive cells could be seen at day 3 after treatment. Conclusions The retinal injury has positive relationship with laser energy. The thermal damage is confined to the RPE and spare the neurosensory retina when using threshold power (50mW) with 50% duty-cycle and supra-threshold power with high duty-cycle (100mW，5%～15%). The hyper expression of HSP-70 and apoptosis mechanism may play an important role in the tissue repair process. (Chin J Ocul Fundus Dis,2008,24:122-126)
Objective To observe the expression of vascular endothelial growth factor A (VEGFA) and its receptors sFlt-1, kinase insert domain receptor (KDR) in lightinjured human retinal pigment epithelial (RPE) cells. Methods Cultured human RPE cells (8th - 12th generations) were divided into normal control group and light damage group. The cells of two groups were exposed to the 18 W cold white light (2200±300) Lux for 12 hours to induce light damage responses, but the cells of normal control group were packed by tinfoil with doubledeck high pressure disinfection. The VEGF-A, sFlt-1 and KDR mRNA and protein expressions were detected by reverse transcriptionpolymerase chain reaction (RT-PCR) and Western blot at 0, 6, 12, 24 hours after light damage. Results The VEGF-A mRNA and protein expressions in light damage group were significantly increased at 6 hours, and reached its peak at 12 hours after light damage which obviously higher than that in normal group (t=2.74, 2.93; P＜0.05), and then went down gradually. The sFlt-1 mRNA and protein expressions in light damage group reached its peak at 12 hours after light damage which obviously higher than that in normal group (t=4.32, P＜0.01), but obviously lower than that in normal group at 24 hours after light damage (t=2.41, P＜0.05). The KDR mRNA and protein expressions in light damage group were obviously higher than that in normal group at 24 hours after light damage （t=2.89, P＜0.05）,but there was no changes at 6, 12 hours after light damage (t=1.84, P＞0.05). Conclusions At 6, 12 hours after light damage, the expressions of VEGF-A and sFlt-1 increases significantly and KDR expression is stable in lightinjured RPE cells. At 24 hours after light damage, the expression of VEGF-A and sFlt-1 decreases, but KDR expression increases in light-injured RPE cells.
Objective To observe the short-term intraocular pressure after 25G+ pars plana vitrectomy (PPV) and analyze the possible influencing factors in rhegmatogenous retinal detachment (RRD) and proliferative diabetic retinopathy (PDR) eyes. Methods This is a retrospective case-control study. A total of 160 patients (163 eyes) of RRD and PDR who underwent 25G+ PPV were enrolled in this study. There were 88 males (89 eyes) and 72 females (74 eyes), with the mean age of (50.37±13.24) years. There were 90 patients (92 eyes) with RRD (the RRD group) and 70 patients (74 eyes) with PDR (the PDR group). Best corrected visual acuity (BCVA) and intraocular pressure (IOP) were performed on all the patients. The BCVA was ranged from hand motion to 0.6. The average IOP was (12.61±4.91) mmHg (1 mmHg=0.133 kPa). There were significant differences in crystalline state (χ2=9.285, P=0.009), IOP (χ2=58.45, P=0.000), history of PPV (χ2=4.915, P=0.027) and hypertension (χ2=24.018, P=0.000), but no significant difference in sex (χ2=0.314, P=0.635) and age (χ2=5.682, P=0.056) between the two groups. A non-contact tonometer has been used to measure IOP on postoperative day 1 and 3. The postoperative IOP distribution has been divided into five groups: severe ocular hypotension (≤5 mmHg), mild ocular hypotension (6 - 9 mmHg), normal (10 - 21 mmHg), mild ocular hypertension (22 - 29 mmHg), severe ocular hypertension (≥30 mmHg). Logistic regression analysis has been used to analyze the risk and protective factors. Results On the first day after surgery, there were 21 eyes (12.9%) in mild ocular hypotension, 96 eyes (58.9%) in normal, 22 eyes (13.4%) in mild ocular hypertension and 24 eyes (14.7%) in severe ocular hypertension. On the first day after surgery, there were 18 eyes (11.0%) in mild ocular hypotension, 117 eyes (71.7%) in normal, 23 eyes (14.1%) in mild ocular hypertension and 5 eyes (3.1%) in severe ocular hypertension. There was no significant difference of IOP distribution between the two groups (Z=−1.235, −1.642; P=0.217, 0.101). The results of logistic regression analysis showed that silicone tamponade was a risk factor for ocular hypertension in PDR eyes on the first day after surgery [odds ratio (OR)=15.400, 95% confidence interval (CI) 3.670 - 64.590; P＜0.001], while intraocular lens was the risk factor for ocular hypotension in PDR eyes on third day after surgery (OR=19.000, 95%CI 1.450 - 248.2; P=0.025). As for RRD eyes, the ocular hypotension before surgery was a risk factor for ocular hypertension on the third day after surgery (OR=3.755, 95%CI 1.088 - 12.955; P=0.036). For all eyes, silicone tamponade (OR=0.236, 95%CI 0.070 - 0.797), air tamponade (OR=0.214, 95%CI 0.050 - 0.911) and inert gas tamponade (OR=0.092, 95%CI 0.010 - 0.877) were protective factors for ocular hypotension on the first day after surgery (P=0.020, 0.037, 0.038); silicone tamponade was protective factor for ocular hypotension on the third day after surgery (OR=0.249, 95% CI 0.066 - 0.94, P=0.040); while aphakic eyes was the risk factor for ocular hypotension on third day after surgery (OR=7.765, 95% CI 1.377 - 43.794, P=0.020). The ocular hypotension before surgery was a risk factor for ocular hypertension on the third day after surgery (OR=4.034, 95% CI 1.475 - 11.033, P=0.007). Conclusions The abnormal IOP is common after 25G+ PPV with a rate from 28.3% to 31.1%. Silicone tamponade, air tamponade and inert gases tamponade are protective factors for postoperative ocular hypotension, aphakic eye is risk factor for postoperative ocular hypotension. Ocular hypotension before surgery and silicone oil tamponade are risk factors for postoperative ocular hypertension.
Objective To explore the connection between the melanin content of retinal pigment epithelial (RPE) cells and the function of photoreceptors, and the function of melanin on retinal light damage. Methods Agematched old dopachrome tautomerase knockout (DCT-/-) mice and wildtype mice were collected as the DCT-/- group and wildtype group, with 20 mice in each group. Baseline electroretinograms (ERG) in accordance with the international standards for the clinical electrophysiology were performed on all the mice, and the max ERG was recorded. Two mice were randomly selected in each group and were executed，and the removal eyeballs were as the control. The remaining 18 mice in each group were exposed to cold fluorescent light with the quantity of electricity of 20 W for 36 hours with a circle of 12 hours light12 hours dark12 hours light, which was repeated continuously for three times. The light intensity was (5000plusmn;356) lx. Six days after the light illumination, ERG were performed again and the results were recorded. Cervical dislocation methods were used to executed 2 mice which were chosen randomly in each group, and the eyeballs were removed. The tissue sections were observed under the optical and electron microscope.Results The results of ERG showed that the amplitude of a and b wave was lower in DCT-/- group than that in wildtype group before and after light injury （a wave before light injury: t=-7.13，Plt;0.01；b wave before light injury: t=-4.414，Plt;0.01；a wave after light injury: t=-10.162，Plt;0.01；b waveafter light injury: t=-6.772，Plt;0.01）. The decrease of amplitude of a and b wave was much obvious in DCT-/- group than that in wildtype group （a wave:t=4.975,Plt;0.01；b wave:t=2.908,Plt;0.01）. After the light injury, retinal edema and thinning were found in DCT-/- group which wasobvious than that in wildtype group; the photoreceptor layers and melanin were more seriously affected in DCT-/- group than that in wild-type group.Conclusions After the light illumination, the melanin of RPE cells reduces and the function of photoreceptors decreases, which suggests that melanin may play an protective role in the light injury.
Objective To investigate the causes of visual loss and failure of treatment after intraocular silicone oil removal. Methods Retrospective clinical analysis of the causes of loss of visual acuity of 15 eyes after silicone oil removal in patients with complicated retinal detachment which were successfully treated with vitreous and retinal microsurgery. Results Among the 15 eyes,retina failed to reattach in 11 eyes,secondary glaucoma occurred in 2 eyes and corneal opacity appeared in another two eyes.All of them were resulted in total loss of vision. Conclusion Retinal redetachment was the leading cause of final visual loss in the failing 15 cases(15 eyes) after intraocular silicone oil removal,and secondary glaucoma and corneal decompensation may also be the causes of visual loss. (Chin J Ocul Fundus Dis, 1999, 15: 230-231)
ObjectiveTo observe the changes in physical properties of silicone oil after intraocular tamponade. MethodsThe silicone oil was removed from 99 patients (99 eyes) of primary retinal detachment with 23G vitreous cutter system. The upper silicone oil was collected after put the vitrectomy samples at room temperature for 3 days. According to the time of intraocular tamponade, the silicone oil samples were divide into six groups including group A (1 month, 12 samples), group B (2 months, 15 samples), group C (3 months, 25 samples), group D (6 months, 22 samples), group E (1-2 years, 13 samples) and group F (above 2 years, 12 sample). Fresh unused silicone oil was set as blank control group. Then the emulsion particles, kinematic viscosity, surface tension, density, transmittance and refractive index were measured. ResultsThe difference between group A-F and the control was statistical significant (P<0.05) in emulsion particles (F=89.337), kinematic viscosity (F=10.660), surface tension (F=11.810), density (F=13.497), transmittance of wavelengths (F=455.496, 566.105, 525.102, 767.573, 622.961, 601.539), but not statistical significant at refractive index (F=2.936, P>0.05). The number of silicone oil emulsion particles has no statistical difference between group A and the control (P>0.05), but was significantly different between group B-F (P<0.05). The kinematic viscosity of silicone oil has no statistical difference between group A, B and the control (P>0.05), but was significantly different between group C-F (P<0.05). The surface tension of silicone oil has no statistical difference between group A-D and the control (P>0.05), but is significantly different between group E and F (P<0.05). The density of silicone oil has no statistical difference between group A-D and the control (P>0.05), but was significantly different between group E and F (P<0.05). The transmittance of silicone oil has statistical difference between group A-F and the control(P<0.05). The refractive index of silicone oil has no statistical difference between all the groups and the controls significantly (P>0.05). ConclusionsThe physical properties of silicone oil will change during the intraocular tamponade. The emulsion particles number will increase and the transmittance will decrease after 2 months, the kinematic viscosity of silicone oil will decrease significantly after 3 months, and the density and surface tension will change significantly after 1 year of tamponade.