Purpose To investigate apoptosis in vitrectomy specimens of proliferative vitreoretinopathy. Methods Vitrectomy specimens from 60 cases of different classes of proliferative vitreore tinopathy were studied by TdT-mediated dUTP nick end labelling(TUNEL)method. Results The characteristic change of apoptosis was observed in all vitrectomy specimens.The amount of apoptotic non-pigmentary cell is gradually decreasing along with the development of proliferative vitreoretinopathy,and apoptotic pigmentary cells are observed. Conclusion There are different kinds of apoptosis cell in vitrectomy specimens of proliferative vitreoretinopathy.It is suggested that apoptosis might be one of the important mechanisms of regulating the degree in proliferative vitreoretinopathy. (Chin J Ocul Fundus Dis,1999,15:81-83)
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 observe the protective effects of Na2SeO3 on the damage of retinal neuron induced by microwave. Methods Cultured fluids of retinal neuron were divided into 4 groups,including 1 group of control, according to the concentration of Na2SeO3 in cultured fluid and then exposed to 30 mW/cm2 microwave for 1 hour.The targets of lipid peroxidation and the concentration of selenium in cells were measured.Apoptosis detection was taken by TUNEL detection kit. Results The activity of SOD and GSH-Px rised,meanwhile the content of MDA and the amount of apoptosis cells decreased in 1times;107 mol/L group compared with the group without Na2SeO3.The other groups was superior in antioxdant capacity to 1times;107 mol/L group. Conclusion Na2SeO3 might be possessed of the effect of protecting the damage of retinal neuron induced by microwave. (Chin J Ocul Fundus Dis,2000,16:97-99)
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)
Retinal neuronal cells are crucial in the formation of vision. Injury or death of these cells may lead to irreversible damage to visual function due to their low regenerative capacity. The P2X7 receptor is a trimeric adenosine triphosphate (ATP)-gated cation channel. Recent studies have shown that P2X7 receptor plays a role in retinal neuronal death. In a series of animal models, when exposed to conditions of hypoxia or ischemia, elevated ocular pressure, trauma and exogenous agonists, P2X7 receptor activated by extracellular ATP can cause death of retinal neuronal cells such as retinal ganglion cells and photoreceptor cells through direct or indirect pathways. Blocking the expression and function of P2X7 receptor by its specific antagonist and gene knocking-out, the loss of retinal neuronal cells is significantly attenuated. P2X7 receptor may become a potential novel neuroprotective target for diseases related to the loss of retinal neurons.
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)
Objective To investigate the correlation of ascorbic acid distribution and retinal susceptibility to iron toxicity of the retina.Methods Autoclaved iron particles of 5 mg and 15 mg were implanted into the vitreous cavities of 32 Spragu-Dawley (SD) rats and 9 rabbits, respectively. The retinal sections of rats and rabbits were examined after hemotoxylin-eosin (HE) staining. Apoptos is of rabbits′retinal neurons was investigated by TdT-mediated dUTP-biotin nick-end labeling (TUNEL). Chinoy′s method was used to observe the distribution of as corbic acid in the retinae of the 2 kinds of animals.Results In rats, histological and structural densification was observed only in the photoreceptor cells after implantation of the iron particles. In rabbits, however, histological and structural destruction as well as TUNEL-positive nuclei were observed in all neuronal layers of the retina 3 days after the implantation of the iron particles. Silver granules reduced by ascorbic acid from silver nitrate were observed only in the outer nuclear layer in normal rats retinae, while they were observed evenly throu ghout all layers of rabbits′retinae. Conclusions The suscept ibility of retina to iron toxicity is correlated to the distribution of ascorbic acid in retina. (Chin J Ocul Fundus Dis，2003，19：269-332)
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 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 observe the effect of visible light on apoptosis of cultured human retinal pigment epithelium (RPE) cells. Methods Being the light source,500lx,(2 000±500)lx and (3 400±200)lx cold white light were used. The duration of exposure was 0,6,12 and 24 hours respectively. Apoptosis was detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labelling, Annexin V-flunorescein isothiocyanate/Propidium iodium labelling and flow cytometry. Results Apoptosis and necrosis were found in cultured human RPE cells which were exposed to visible light.(1)A significant increase in apoptotic and necrotic percentages was consistent with a higher light intensity.(2)Apoptosis was the main response to shorter (6 h and 12 h) exposure duration,while necrosis was more pronounced correlated to the prolongation of post-exposure culture (P＜0.05),and the longer the post-exposure period was, the more apoptotic necrosis were seen.Thirty-six hours after exposure the necrotic percentages were more pronounced (P＜0.01). Conclusions Visible light (＞500 lx) increases the proportion of apoptosis and necrosis of human RPE cells in vitro.The extent is related to exposure intensity and duration. It demonstrates that the lower intensity and the shorter duration of exposure to light are, the more pronounced apoptotic percentages are observed,otherwise necrosis. (Chin J Ocul Fundus Dis, 2002, 18: 227-230)