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)
Objective
To study the expression and its significance of bcl-2 associated death (bad) gene in human optic nerves from traumatic atrophic eyeballs.
Methods
The optic nerves from 8 normal human donor eyes and 31 traumatic atrophic eyes were studied by immunohistochemistry technique.
Results
Bad protein was positively expressed in the normal optic nerve myelin sheath and residual myelin portions of optic nerve tissues from traumatic atrophic eyes. The expression of bad protein in the residual portions of myelin sheath was stained significantly ber than that in normal optic nerves (P＜0.05)。The pathological durations for ocular atrophy was not co-related with the quantites of expression of bad protein. There was no significant difference between pathogenic causes of ocular atrophies and the quantites of bad expression (P＞0.05).
Conclusion
Bad might possess the function of promoting the optic nerve atrophy processes in traumatic atrophic eyes.
(Chin J Ocul Fundus Dis, 2002, 18: 276-278)
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 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 observe the effect of blue light on apoptosis of cultured human retinal pigment epithelial (RPE) cells in vitro.
Methods
Human RPE cells were exposed to blue light, and the cells were divided into 3 groups: group A, with various intensity of illumination; group B: with same intensity but different time of illumination; group C: with same intensity and time of illumination but different finish time of the culture. The apoptosis of RPE cells was observed by TdT-dUTP terminal nick-end labeling (TUNEL) and annexin V-fluoresein isothiocyanate (FITC)/propidium iodide (PI) flow cytometry, and transmission electron microscopy.
Results
The positive cells stained by TUNEL shrinked and turned round, whose nuclei concentrated and congregated like the crescent or hat. Cracked nuclei and membrane bleb were found. Swollen mitochondrial, disappeared inner limiting membrane of mitochondria, and dilation of the rough endoplasmic reticulum with metabolite were observed by transmission electronmicroscopy. In group A, mild damage of RPE cells was found when the threshold value of the intensity of illumination was less than（500±100）lx, and the apoptosis and necrosis of RPE cells aggravated as the intensity of illumination increased; in group B, as the time of illumination extended, the number of apoptotic RPE cells didn′t increase while the necrosis increased; in group C, 6 and 12 hours after illumination, apoptosis of cells was the main injury, while apoptosis with necrosis was found and necrotic cells increased as the time of illumination was prolonged.
Conclusions
Illumination with blue light may cause damages of human RPE cells in vitro, with the modalities of apoptosis, apoptotic necrosis and necrosis. The extent of injury is dependent on intensity and duration of the illumination.
(Chin J Ocul Fundus Dis, 2005, 21: 384-387)
Objective To investigate the role of anti apoptosis gene bcl-2 in the survival of cultured uveal melanoma UM cells. Methods Antisense oligodeoxynucleotides (AS-ODN) bcl-2 were delivered with cationic lipid to primary cultured UM cells. The inhibitory effect of AS-ODN bcl-2 on proliferation of UM cells was examined by 3,-4,5 Dimethyliazol-2,5 diphenyl tetrazolium bromide (MTT) method. Using DNA ladder to determine if the UM cells had been apoptotic. Bcl-2 expression was detected by RT-PCR and Westernblot technics. Results The effect of AS-ODN bcl-2 in inhibiting the proliferation of cultured UM cells had opposite relation to dosage. It down regulated the mRNA and protein level of bcl-2 gene, and the sense ODN didn′t have this effect. Conclusion AS-ODN bcl-2 can down regulate bcl-2 expression, inhibits UM cells proliferation and induces apoptosis. (Chin J Ocul Fundus Dis, 2002, 18: 38-41)
Objective To investigate the effects of epidermal growth factor (EGF)，fibroblast growth factor(FGF), and bovine serum on proliferation and apoptosis of the cultured fetal human retinal cells.Methods EGF and FGF were added or not to the medium of fetal human retinal cells cultured by bovine serum in vitro. The number of cells, bromodeoxyuridine(BrdU) incorporation and Tdt-mediated dUTP nick end labelling(TUNEL) were detected to determine the proliferation and apoptosis. Immunohistochemical staining of neuron specific enolase(NSE), Thy1.1, glial fibrillary acidic protein(GFAP) and scan electromicroscopy were performed to identify cell components. The expression of transcription factor c-fos, c-jun and apoptosis regulation factor bcl-2 and Bax were examined by immunohistochemical staining to explore the underlying mechanism.Results The increased number of NSE and Thy1.1 positive cells and BrdU incorporation, and decreased apoptotic cells were found in the groups treated with EGF and FGF. Meanwhile, the up-regulation of c-fos, c-jun and bcl-2 were also found. Conclusion EGF and FGF can promote the survival and proliferation of cultured retinal cells by up-regulating the expression of c-fos, c-jun and bcl-2. (Chin J Ocul Fundus Dis，2003，19：113-116)
Drusen is one of the early hallmark changes of AMD. The oxidative stress and inflammatory reaction caused by oxidative phospholipids (OxPLs) in drusen can lead to retinal pigment epithelium (RPE) cell death (apoptosis, pyroptosis, etc.) and the formation of choroidal neovascularization, which is the pathogenesis of AMD. Pyroptosis, also known as inflammatory necrosis, is one of the main forms of OxPLs induced cell death. Proinflammatory factors released by pyroptic cells can in turn aggravate the inflammatory reaction, leading to further damage. In order to prevent AMD, inflammatory response and cell death may be reduced by regulating lipid metabolism, reducing OxPLs endocytosis and increasing cholesterol efflux. In-depth understanding effects of OxPLs, inflammation and RPE pyrosis in the pathogenesis of AMD in elucidate the pathogenesis of AMD and to seek new treatment measures has important clinical significance.
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)
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)
