Objective To observe the relationship between the size of idiopathic macular hole (IMH) and the healing types of postoperative photoreceptor layer after vitrectomy. Methods This prospective uncontrolled study included 33 eyes of 31 consecutive patients who underwent vitrectomy for IMH. There were 9 males (9 eyes) and 22 females (22 eyes), with the mean age of (58.16±9.10) years. The mean duration of symptoms was (4.97±5.97) months. The best corrected visual acuity (BCVA) and optical coherence tomography (OCT) were measured for all patients. BCVA was measured with international standard visual acuity chart and then converted to logarithm of the minimum angle of resolution (logMAR). The mean logMAR BCVA was 1.07± 0.38. The mean intraocular pressure was (14.05±0.54) mmHg (1 mmHg=0.133 kPa). The minimum size of the macular hole (MIN), the base diameter of the macular hole (BASE), the average width of the macular hole (AWMH) and the average height of the macular hole (AHMH) were (465.19±232.84), (943.63±389.26), (704.72±292.64), (443.84±72.47) μm, respectively. According to the MIN value, the hole size were divided into small, medium and large group which had 9 eyes, 15 eyes, 9 eyes, respectively. According to the postoperative OCT characteristics, the healing types of the photoreceptor layer were divided into 0 - Ⅳ types. All patients underwent pars plana vitrectomy (25G or 27G standard three-incision) with internal limiting membrane peeling with tamponade agents. The mean follow-up was (326.42±157.17) days. The first postoperative OCT characteristics were defined as the early period. The therapy results were evaluated according to the last follow-up time point. BCVA and intraocular pressure before and after operation were compared by paired t test. The postoperative BCVA were compared with preoperative BCVA, MIN, AWMH, AHMH and follow-up using Pearson correlation analysis. Results At the last follow-up, the LogMAR BCVA was 1.52 - 1.40 in 3 eyes, 1.30 - 0.52 in 22 eyes and 0.40 - −0.07 in 8 eyes. Compared with preoperative that, the difference was statistically significant (t=−6.023, P＜0.001). The photoreceptor healing was type 0 in 10 eyes (30.3%), type Ⅰ in 4 eyes (12.1%), typeⅡ in 10 eyes (30.3%), type Ⅲ in 9 eyes (27.3%) at the early postoperative period. The photoreceptor healing was type 0 in 5 eyes (15.2%), type Ⅰ in 5 eyes (15.2%), type Ⅲ in 12 eyes (36.4 %), type Ⅳ in 11 eyes (33.3%) at the last follow-up. The preoperative size of IMH was negatively correlated to the photoreceptor healing types at early postoperative period (r=−0.590, P＜0.01) and the last follow-up (r=−0.768, P＜0.01), respectively. The correlation analysis showed that the postoperative BCVA associated with the preoperative BCVA, the stage of the macular hole, the size of the macular hole, MIN, BASE, AWMH, AHMH, the healing types of photoreceptor layer of the early and the last follow-up after surgery (r=0.500, 0.370, 0.470, 0.435, 0.533、0.505, 0.462, −0.442, −0.656, P＜0.05). There was no correlation between age, visual decreasing times and follow-up times (r=0.285, 0.234, −0.310, P＞0.05). Conclusion The preoperative sizes of IMH were associated with the postoperative healing types of photoreceptor layer.
Objective To observe the effects of Crumbs (Crb) proteins on different types of zebrafish photoreceptors. Methods The retinal cell population dynamics of adult wild-type zebrafish and Tg (RH2-2:Crb2b-sf-EX/RH2-2:GFP)pt108b transgenic zebrafish (called pt108b zebrafish for short) were evaluated by monitoring the densities of three categories of retinal photoreceptors (rod cells, UV cone cells and RGB cone cells) in different retinal regions, which were visualized by Feulgen nuclear staining histology technique. Results The wild-type zebrafish retinal photoreceptor cell densities are generally higher in the central region than the peripheral regions. Compared with wild-type zebrafish, pt108b zebrafish had much less RGB cone cells at the top of outer nuclear layer, and no RGB cone cells at the central and intermediate regions of retina. While pt108b zebrafish had normal density of UV cone cells at the top of rods and the bottom of outer limiting membrane, they had much higher density of rods. Conclusions Crb proteins may affect the zebrafish retinal cell densities of different photoreceptor types.
ObjectiveTo evaluate the photoreceptor-protective effects of Cdk5 inhibitor Roscovitine on retinal degeneration in Royal College of Surgeons (RCS) rat. MethodsThe RCS rats were divided into three groups according to postnatal days: the early (17 days), medium (25 days) and late intervention group (35 days). Cdk5 inhibitor Roscovitine were used in the right eyes by intravitreal injection as experimental eyes and Roscovitine solvent dimethylsulfoxide were used in the left as control at postnatal 17, 25, 35 days. Hematoxylin-eosin (HE) staining was used to observe the thickness of outer nuclear layer. The expression of Cdk5 P25 and cleave-caspase 3 in the retina was evaluated by immunohistochemistry. The protein expression of cleave-caspase 3 in the retina was determined by Western blot. The apoptosis of retinal cells was examined by terminal-deoxynucleotidyl transferase mediated nick end labeling. ResultsHE staining showed that thickness of outer nuclear layer in the early and medium intervention groups were significantly thicker than that in the control group (P < 0.05), particularly in the early intervention group. And there was no significant change in the late intervention group (P > 0.05). The expression level of Cdk5, p25, cleave-caspase 3 in the outer nuclear layer in three intervention groups were lower than that in the control group (P < 0.05), especially in the early intervention group. ConclusionCdk5 inhibitor Roscovitine can delay the retinitis pigmentosa process in RCS rats by early, medium interventional therapy and may have a certain degree of photoreceptor-protective effects.
Objective To observe the changes of electrophysio logical results in rabbits with normal and injured photoreceptor due to subretinal implantation of chip. Methods Photoreceptor damage was induced by injection with NaIO3 solution in 22 out of 30 rabbits. A chip with the diameter of 3 mm made by the array composed of 90 microelectrodes photodiode and conjoint electrode was implanted into subretinal space or choroid of the right eyes of 22 rabbits with photoreceptor and 4 normal rabbits, and the left eyes were the control. The examinations of local flash-visual evoked potential (F-VEP), local flash-electroretinogram (F-ERG), full-field F-ERG and full-filed F-VEP were measured respectively.Another 4 rabbits underwent biocular extirpation for path ological examination . Results In 22 rabbits with photo-receptor damage, the amplitude of the main wave of local ERG was obviously higher in 11 eyes with chips than that in the control ones, and was also higher in 2 eyes with chips of the 4 mormal rabbits than that in the control eyes. No wave was found in an eye with retinal hole on the surface of the chip. The repeataility of main amplitude of local-VEP and full-field F-VEP is not satisfactory; no significant changes were observed between chip-implanted eyes and the control eyes examined by full-filed F-ERG. Conclusion The implanted chip may stimulate local retina and induce electrical activities after stimulated by light. (Chin J Ocul Fundus DIs, 2006, 22: 324-327)
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)
Objective To study on the ultrastructural characteristic of segments of photoreceptors from neonatal retinas for supporting donor retina choice of retinal transplantation． Methods Photoreceptors from neonatal calf and adult calf were analysed by scanning electron microscopy and transmission electron microscopy． Results Segments of photoreceptors from neonatal calf appeared the mushroom pattern, in which, distal end of outer segment which was ball-shaped formed the head with mushrooms appearance, and the inner segments along with some of outer segments formed the body with mushrooms appearance． Within the outer segment, plasma membranes of adjacent evaginations form a disk subsequently． The a rray of most disks were vertical to the entire length of segments, but some were parallel and slope to．Owing to the incomplete formation, some rim of disk near distal end of outer segment revealed step-shaped appearance． The distal end of outer segment displays some processes consisted of membranous discs, much vesicular material and mitochondria, much rough endoplasmic reticulum (RER) and numerous polyso mes．Segments of photoreceptor connected with outer nuclear layer via the external limiting membrane． Conclusion The typical morphol ogical structures of outer segments suggest the immature and b gowth ability of photoreceptors of the retina of neonatal calf, and therefore the competence for donor material of retinal transplantation． (Chin J Ocul Fundus Dis, 2001,227-229)
Objective To investigate the apoptosis of photoreceptor cells in experimental model of retinal detachment in mice. Methods Thirty-six adult C57Bl/6J mice were divided into 2 groups: retinal detachment model was set up in the left eyes of 18 mice by subretinal injection with 1.4% sodium hyaluronate in the experimental group, while the left eyes of other 18 mice underwent scleral puncture only as the control. The retinal sections were stained with histochemical and immunofluorescent staining and examined by confocal microscopy 1,3,7 and 28 days after injection. eye enucleated, and retinal sections studied by histochemistry, immunofluorescence labeling, and confocal microscopy. Rods, cones, and apoptotic cells were labeled by antibodies of anti-rod and anti-cone cells, and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL), respectively. Photoreceptor cell apoptosis and cell loss were assessed quantitatively by counting both surviving and apoptotic rod and cone cells. Results TUNEL-positive cells were only found in the outer nuclear layer (ONL) of the detached portion of the retina, which were detected at the 1st day after the detachment. The apoptosis of the cells reached the peak at the 3rd day and decreased sharply after 7 days. Photoreceptor cell loss of both rod and cone cells followed a similar time course after retinal detachment. Conclusion Apoptosis is a major pathological degeneration of photoreceptor cell death after retinal detachment. (Chin J Ocul Fundus Dis, 2006, 22: 124-127)
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 the effects of SARS-CoV-2 infection on the morphology, proliferation, apoptosis, cell cycle, and immune response function of mouse retinal photoreceptor cells (661w cells). MethodsA cell experiment. Logarithmic growth phase 661w cells were cultured in vitro and transfected with angiotensin-converting enzyme 2 (ACE2) overexpressing lentivirus to construct ACE2 overexpressing 661w cells that could be infected with SARS-CoV-2 pseudovirus (hereafter referred to as ‘pseudovirus’). The 661w cells were divided into three groups: the normal group (untreated), the siACE2 group (overexpressing ACE2 and not infected with the pseudovirus) and the infected group (overexpressing ACE2 and infected with the pseudovirus), in which the infected group was 5 TU/ml pseudovirus group, 15 TU/ml pseudovirus group, 30 TU/ml pseudovirus group and 50 TU/ml pseudovirus group, and the cells were infected with the pseudovirus for 12, 24, 48 and 72 h, respectively. The infected group was infected with 5 TU/ml pseudovirus group, 15 TU/ml pseudovirus group, 30 TU/ml pseudovirus group and 50 TU/ml pseudovirus group, respectively, for 12, 24, 48 and 72 h. Fluorescence microscopy was used to observe the transfection efficiency of ACE2; protein immunoblotting (Western blot) was used to detect the relative expression level of ACE2 in the cells; light microscope was used to observe the morphology of the cells in the normal and the infected groups; cell proliferation was detected by Cell Counting Kit-8 (CCK8) assay; flow cytometry was used to detect the cell cycle; Western blot and real-time quantitative polymerase chain reaction (qPCR) were used to detect the relative expression of interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), B lymphocytoma-2 (Bcl-2), Bcl-2-associated X-protein (Bax) proteins and mRNA in the cells of siACE2 group, infected group (30 TU/ml pseudovirus group); qPCR was used to detect the relative expression of nuclear factor (NF)- κB1 and NF-κB2, as well as NF- kB enhancer (P65) and precursor protein (P100) in cells of the siACE2 group and the infected group (30 TU/ml pseudovirus group). One-way ANOVA was used for comparison between multiple groups; t-test was used for comparison between two groups. Results Compared with the siACE2 group, the cells in the infected group showed different degrees of crumpling, and with the increase of the concentration and time of pseudovirus induction, the crumpling of the cells worsened, and the number of cells decreased. Compared with the normal group, the cells in the infected group showed a gradual decrease in cell viability with the prolongation of pseudovirus induction time, and the difference was no statistically significant (F=0.840, 0.412, 1.498, 1.138; P＞0.05), and the apoptotic index of the cells induced in the 30 and 50 TU/ml pseudovirus group was significantly elevated, and the difference was statistically significant (F=2.523, 6.716, 3.477, 3.421; P＜0.05). At 72 h of pseudovirus induction, compared with the siACE2 group, the G1 phase cells in the 30 TU/ml pseudovirus group were significantly increased, and the difference was statistically significant (t=3.812, P＜0.05); the relative expression of IL-6, TNF-α, Bax protein and mRNA in the cells was up-regulated (t=7.601, 6.039, 3.088, 5.193, 6.427, 7.667; P＜0.05), the relative expression of Bcl-2 protein and mRNA was down-regulated (t=3.614, 6.777; P＜0.05), and the relative expression of NF-κB1, NF-κB2, P65, and P100 mRNA was significantly up-regulated with statistically significant differences (t=3.550, 3.074, 3.307, 4.218; P＜0.05). ConclusionSARS-CoV-2 infection may inhibit photoreceptor cell proliferation, promote apoptosis and cycle blockade by activating the NF-κB signalling pathway.