Objective To demonstrate if apoptosis is one of the mechanisms of siderotic retinopathy. Methods Autoclaved iron particles were implanted in the vitreous cavities of 32 eyes of SD rats.Glass chips were implanted in 10 control eyes.The experimental eyes were enucleated at various time intervals from days 1 to 15.Retinal degeneration was examined using the TdT-mediated,dUTP-biotin nickend labeling(TUNEL)method.Electrophoresis on agarose gel was used to detect internucleosomal DNA fragmentation.Results TUNEL-positive nuclei were observed only in the outer nuclear layer beginning on day 2.The nuclei spread throughout the outer nuclear layer by the end of day 3.No TUNEL-positive nuclei were observed in other layers throughout the experimental perios.Analysis of DNA,extracted from the retinas by electrophoresis on agarose gel,revealed a typical ladder pattern of internucleosoma DNA cleavage in the experimental eyes.ConclusionApoptosis of photoreceptors occurs at the early phase of iron-induced retinopathy in the rats.
Objective To investigate the effects of genistein with different concentration on proliferation and apoptosis of cultured human retinal pigment epithelial (RPE) cells in vitro. Methods The effect of genistein with the concentration of 5，10，25，50，75，and 100 mg·L-1on the proliferation of cultured RPE was examined by tetrazolium salt (MTT) assay and AgNORs staining. The cell apoptosis was detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick-end labeling (TUNEL) methods, in the mean time, the morphologic changes of cell apoptosis were observed by light microscopy and transmission electronic microscopy, the results of which were compared with the normal RPE cells. Results Genistein with the concentration of 25, 50, 75, and 100 mg·L-1had a dose-dependent and time-dependent antiproliferative effects on RPE cells with the inhibitory rate of 12.0%-64.6% (P＜0.05). The results of AgNORs staining showed that the number of AgNORs in the nucleolus decreased when treated by genistein. In TUNEL staining, the median of percent of apoptotic RPE cells was 7.6%, 9.8%, 13.7% when treated with 50 mg·L-1genistein, 10.3%, 16.4%, 23.4% when treated with 75 mg·L-1genistein, and 15.4%, 21.2%, 35.8% when treated with 100 m g·L-1genistein respectively for 24, 48, and 72 hours. After the treatme nt with 50 mg·L-1genistein for 48 hours, the apoptosis in the nucleolus of RPE cells was found. Conclusions Genistein with different concentrations has a dose-dependent and time-dependent antiproliferative effect on RPE cells. Genistein can induce the apoptosis of RPE cells when it reaches a certain extent of concentration. (Chin J Ocul Fundus Dis，2004，20：241-244)
Objective To investigate the mechanism of the toxic effect of N methyl N-nitrosourea (MNU) on photoreceptor cell apoptosis of rat’s retina. Methods Thirty 50-day-old female Sprague-Dawley ( SD ) rats were intraperitoneally injected with MNU (60 mg/kg) and were put to death by dislocation of cervical vertebra 12, 24, 48, and 72 hours and 7 days after the injection, respectively. The photoreceptor cell apoptosis was detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and transmission electron microscope. The expression of proliferating cell nuclear antigen (PCNA), vimentin and glial fibrillary acidic protein (GFAP) was detected at different time after injection by immunohistochemical methods. Results The apoptotic index of the retina in the posterior pole was (33. 6±2. 3), (46. 5±5. 7), (20. 1±5. 3), (8. 2±3. 6) and (2. 5±1. 3~//oo at the 12th,24th, 48 th, and 72nd hour and on the 7th day, respectively, after injection. Karyopyknosis was found in most photoreeeptor cells 24 hours after injection. The expression of PCNA was found in internal granularlayer and between internal granular layer and choroid 24 hours after injection, reached the peak after 72 hours, and reduced obviously after 7 days. The positive expression of GFAP and vimentin was found in internal and external granular layer 24 hours after injection, reached the peak after 72 hours, and reducedobviously after 7 days.Conclusion MNU may selectively lead the photoreceptor cell apoptosis and proliferation of Mvller cells. (Chin J Ocul Fundus Dis，2004，20：33-36)
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)
Objective To observe the effect of exogenous basic fibrob last growth factor (bFGF) on apoptosis of cultured human retinal pigment epithelial (RPE) cells exposed to visible light,and determine the role of bFGF, fibroblast growth factor receptor 1 (FGFR1),bcl-2 and caspase-3. Methods 2000±500) lx cold white light was used. Exogenous bFGF was utilized during culture. Annexin annexin V-fluoresce in isothiocyanate/propidium iodium (V-FITC/PI) labeling,flow cytometry, Immunocytochemical staining, enzyme associated absorb examing and reverse transcriptional polymerase chain reaction (RT-PCR) were used to determine the apoptosis, the expression levels of bFGF, FGFR1, bcl-2, as well as the activity of caspase-3. Results No protective effect of bFGF was observed under the concentration 5 ng/ml.A significant inhibition of apoptosis was found in 10 ng/ml and 20 ng/ml groups （P＜0.05）. The upregulation of bcl-2 was observed in bFGF (10 ng/ml, 20 ng/ml) protreated groups（P＜0.01）.Compared to no light exposure group,all light exposure groups (including bFGF pro-treated) had higher endogenous bFGF and FGFR1 levels （P ＜0.05）, and the increase was concentration dependent.The bFGF and FGFR1 levels were higher in exogenous bFGF applied (gt;5 ng/ml) groups than light exposure groups（P＜0.05）. The caspase-3 activity was significantly inhibited in bFGF (10 ng/ml) pro-treated groups. Conclusions Human RPE cells exposed to visible light were rescued by application of exogenous bFGF in vitro.The probable protective mechanism of bFGF partly is directly binding to FGFR1 or potentiating endogenous bFGF autocrine loop,to upregulate bcl-2 and to inhibit caspase-3 activation. (Chin J Ocul Fundus Dis，2003，19：24-28)
Pyroptosis is a newly discovered form of cell death. Through the activation of inflammasome complexes, pyroptosis induces the production of interleukin (IL) -1β and IL-18, and the osmotic swelling of cells, thus induces cellular rupture and death. It plays a role in the pathological process of a variety of human diseases. The death of retinal cells including photoreceptor cells and retinal pigment epithelium (RPE) cells is the main reason leading to visual dysfunction in the pathogenesis in ocular fundus diseases. Researches have demonstrated that pyroptosis is closely related to the onset and progression of various retinal diseases. In age-related macular degeneration, pyroptosis directly causes apoptosis of RPE cells and upregulation of pro-inflammatory factors, enhancing toxic effect of lipofuscin. For retinitis pigmentosa, pyroptosis is the leading manner of death of secondary cone photoreceptor cells. In cytomegalovirus retinitis, pyroptosis is the main responding way to infection. This review presented the molecular mechanism of pyroptosis and its role in age-related macular degeneration, retinitis pigmentosa and cytomegalovirus retinitis and other retinal diseases.
Objective
To investigate the damage to the retinal cells and apoptosis of retinal cells of rats after ischemia-reperfusion insult.
Methods
The retinal ischemia-reperfusion model was developed by increasing intraocular pressure to 109725 mm Hg in rat eyes. Morphological changes of the rat eyes were observed by means of routine histopathology with HE staining. Apoptosis of the retina was assayed by both DNA fragmentation gel-electrophoresis and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labelling (TUNEL).
Results
Compared with the normal control, no histopathological changes were revealed in the rat retinas 30 min after the ischemia and then reperfued for 24 h or 48 h. Retinal ganglion cell layer (RGL) and inner plaxiform layer (IPL) of the retina were observed, however, to become significantly thinner 60 min after the ischemia and then reperfued for 24 h or 48 h. Together with the pathological changes DNA ladder pattern was detected in the same group of the rats. Further, immunochemical stain of the eye demonstrated that TUNEL positive cells were localized in RGL and IPL of the retina.
Conclusion
Ischemia-reperfusion insult of the eye may remarkably damage the retina of the rat eye. The damage to the retinal cells is mainly localized within RGL and IPL and apoptosis is the important mechanism of the retinal disorder.
(Chin J Ocul Fundus Dis, 2002, 18: 296-298)
Objective
To further investigate pathologic mechanism of retinal phototrauma.
Methods
Twenty Wistar rats were divided into control and experimental groups.Their eyes were extracted in 12，24 and 36 hours after light exposure.HE stained retina samples were examined and TDT-mediated dUTP nick end labelling(TUNEL)method was employed to distinguish apoptotic cells.
Results
After 12-hour light exposure,slight vesiculation was observed in the rod outer segment of the retinas.After 24-hour light exposure,the outer nuclear layer showed predominant fractured and condensed nuclei and fragmented DNA.After 36-hour light exposure,the rod outer and inner segments were lysed and most of the nuclei in the outer nuclear layer were disappeared.
Conclusions
Apoptosis of photoreceptor cell is one of the important mechanisms which cause experimental retinal photoinjury of rats.
(Chin J Ocul Fundus Dis, 1999, 15: 167-169)
Objective
To investigate the interference effect of nerve growth factor (NGF) on apoptosis of retinal cells in experimental retinal detac hment (RD).
Methods
Twenty seven Sprague-Dawely rats were selected, and the left and right eyes were in the experimental control group and NGF group, respectively. After the RD model was set up by subretinal injection with sodium hyaluronate, 5mu;l NGF（1mu;g/mu;l）was injected into the vitreous body of the right eyes which were in the NGF group; 5mu;l PBS was injected into vitreous body of left eyes which were in the experimental control group. The injection was performed once every 4 days till the end of the observation period. The eye balls of the 27 rats were extrafted 1.5, 3, 6, 12 hours, 1 day, 2, 4, 8 , 16, and 32 days after the RD model was established. Another 2 rats were selected as the normal control, which underwent none of the injections but eyeball extraction at the end of the observation period. TUNEL and transmission electron microscopy were used to detect the apoptosis of the retinal cells. Cell counts and statis tical analysis were used to assess results.
Results
Typical apoptosis cells were observed in the early time of RD. Apoptosis was found in each retinal layers, especially in inner and outer nuclear layers. The number of apoptosis cells increased as the time of RD was prolonged（Plt;0.01）. It was also found that apoptosis cells in NGF group were less than that in the experimenta l control group（Plt;0.01）.
Conclusion
Intravitreous injection exogenous NGF may inhibit the apoptosis of retinal cells in experimental RD.
(Chin J Ocul Fundus Dis, 2006, 22: 333-335)
