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AIM: To establish an experimental model of high intraocular pressure in mice by laser photocoagulation and to prepare for future research. METHODS: Experimental model of high intraocular pressure was induced unilaterally in 44 C57BL/6 mice. The fellow eye served as a control. TONO-PEN AVIA Tonomter was used to measure intraocular pressure (IOP) to guarantee IOP value at 1, 2, 4, 8wk. Slit-lamp biomicroscopy was performed throughout the period and the structural changes were assessed histologically. And then, their eyes were enucleated, postfixed, cryoprotected, and embedded in optimal cutting temperature medium. After hematoxylin and eosin stain ( HE stain ) , cryosections of the retina were observed under light microscope. TdT-mediated biotin-dUTP nick end labeling ( TUNEL ) was performed on the retinal sections to determine apoptosis rate. RESULTS: IOP of laser-treated eyes was significantly higher than that of control eyes from 1-8wk (P CONCLUSION: The laser photocoagulation of limbus causes chronic elevation of IOP and this method may be a promising experimental model for the investigation of biological mechanisms of glaucomatous retinal ganglion cell damage.
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Neovascular glaucoma ( NVG ) is a kind of intractable eye disease with complex etiology, strong destruction and poor effect on treatment. Extensive retinal ischemia and hypoxia is the main etiology, and the key of treatment is early diagnosis, active prevention and taking effective measures to prevent the production of vascular endothelial growth factor. According to the related literature over recent years, the authors will discuss pros and cons for medical, surgical and combined treatment in this review.
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Background Glaucoma is common blinding eye diseases characterized by chronic loss of retinal ganglion cells(RGCs).Currently glaucoma pathogenesis is not completely understood,heat shock protein 27 ( HSP27 )may be associated with the pathogenesis of glaucomatous optic neuropathy. Objective Through the establishment of a rat model of high intraocular pressure,detection of the expression of HSP27 antibody in serum and RGCs apoptosis to investigate the role of HSP27 in RGCs apoptosis. Methods Fifty-one clean Wistar rats were divided into high intraocular pressure group (34 rats)and sham operation group( 17 rats)using a random number table.An animal model of high intraocular pressure was established in the right eye by the application of bipolar underwater electrocoagulation on vein of sclera surface in the experimental group,and rats with conjunctiva incision only without electric coagulation were served as sham operation (control).The intraocular pressure of rats of the both groups including experimental and control rats was measured 1,2,4,6,8 weeks after operation and then the rats were sacrificed.1 ml serum was collected from these rats to determine the concentration of HSP27 antibody.The retinas of the rats were isolated and homogenated for the extraction and analysis of the retinal protein by Western blot.Apoptosis of RGCs were assayed by TUNEL.The use of the experimental animals followed the Regulations for the Administration of Affair Concerning Experimental Animals by Kunming Medical Collegc. Results Intraocular pressure was elevated significantly after modeling and remained a high value during the expcrimental duration,showing a significant difference among the different groups ( F =318.502,P＜0.01 ).However,no significant change in intraocular pressure before and after operation in the sham-operation group ( F =2.076,P ＞ 0.05 ).The serum concentration of HSP27 antibody was increased significantly overtime from 1,2,4,6 to 8 weeks after the surgery applied,with a significant difference among various time points( F =154.221,P＜0.01 ),but no obvious difference was seen in the shamoperation group( F =0.422,P＞0.05 ).Importantly,Apoptosis rate of RGCs in the experimental eyes was significant higher as the time prolong after intraocular elevated(x2=856.12,P＜0.05 ).The positive rate of RGCs apoptosis in the rats with high intraocular pressure group was elevated significantly compared to the rats in the sham operation group(P＜0.05). Conclusions High intraocular pressure induces the expressions of HSP27 in retina and the accumulation of HSP27 antibody in rats serum;the elevated HSP27 is associated with the increased cell death in RGCs.
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Background The visual system of animal have to optimally adjust in various environmental conditions in order to obtain stable and effective visual funetion.However,the color vision system of animals which encounter uncertainty of spectral signals should be plastic.Whether the densities of various cones and expression of opsins change with long-time spectral deprivation is unclear.Objective This study was to investigate the changes of cone density as well as the expression of corresponding opsin and mRNA following the long-term illumination of monochromatic light.Methods Thirty 3-day-old guinea pigs were randomized into 3 groups and exposed tO the 530 nm green light,400 nm purple light and white light for consecutive 8 weeks respectively.The flat-mounted retinal sample was prepared and divided into dorsal zone,ventral zone and mixed zone anatomically according to the distribution of difierent light-sensitive cone.The changes in density of cone cells sensitivited to different colored light were detected by single-1abel or double-label immunocytochemistry.The levels of opsin and its mRNA were determined using Western-blot and real-time PCR respectively.Results The density of green-sensitivity cones was significantly different in the dorsal zone of retina among green light group,purple light group and white light group (F=234.28,P<0.01).Compared with white light group,the density of green-sensitive cones in dorsal retina of green light group was obviously higher but that of purple light group wag evidently lower(q=389.68,P<0.01；q=67.11,P<0.01).No significant difference was found in the density of purple-sensitive cones in the ventral zone of retina among green light group,purple light group and white light group(F=3.14,P>0.05).The density of coexpression of the mixed cone cells was increased in green light group(q=157.55,P<0.01)but decreased in purple light roup (q=254.85,P<0.01)in comparison with white light group.The expression levels of green-opsin and green-opsin mRNA in green light group was significantly elevated(q=184.45,P<0.01；q=4.71,P<0.05),but those of purple light group were evidently declined(q=5.87,P<0.05；q=346.66,P<0.01)in comparison with white light group.There was no statistically significant differences were found in the expression of purple-opsin and its mRNA among all the groups(F=1.24,P>0.05；F=3.27,P>0.05).Conclusion After the exposure of long-time monochromatic light illumination,monochromatic cones density and its opsin in guinea pig occur the corresponding alteration to gain good spatial vision as a compensatory reaction.These outcomes imply that there is some plasticity during the development of color vision.The increase of green-sensitive cones might be from the differentiation of coexpression cones in transition region.
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· AIM: To investigate whether heat shock protein 27 (HSP27) is induced in retinal ganglion cells (RGCs) in experimental rat glaucoma and whether the induction of HSP27 by intraocular pressure (IOP) elevation can increase serum autoantibody to HSP27 in the model.IOP elevation、Sham and normal groups by SPSS12.0. IOP was raised by electrocoagulating at least 3 episcleral veins and limbal veins on the right eye of each rat in IOP elevation group and its contralateral eye was used as controls. Immunohistochemical staining for HSP27 was performed in RGCs and retinal nerve fiber layer (RNFL) and serum immunoreactivity against HSP27 was detected by means of enzyme-linked immunosorbent assay (ELISA) in three groups.RNFL of the eyes with IOP elevation, while it was expressed weakly in untreated control eyes. Compared with sham and normal groups, serum autoantibody to HSP27 was slightly high at 1wk (P ＞0.05) and significantly increased at 2, 3, 4 and 8wk (P＜0.05) in IOP elevation group.enhanced expression of the endogenous HSP27 might play an important role in glaucomatous optic neuropathy.
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AIM: To study the experimental method of inducing the chronic intraocular hypertension in rat eyes.METHODS: Twenty Wistar rats were randomly divided into ocular hypertension and Sham control groups. Intraocular pressure (IOP) was raised by electrocoagulating at least 3 episcleral and limbal veins on the right eye of each rat in ocular hypertension group and its contralateral eye was used as control. At 1, 2, 3, 4 and 8wk after the electrocoagulation of the veins, IOP were measured. RESULTS: The treatment of electrocoagulation caused a significant IOP increase of the right eyes over the baseline, over the contralateral eyes, and over the sham control eyes (repeated measures ANOVA, P＜0.001). At 1wk,IOP was (30.12± 5.L8 ) mmHg (1kPa=7.5mmHg), and maintained the high IOP up to 8wk.CONCLUSION: The chronic intraocular hypertension model could be successfully created by electrocoagulating three or more episcleral and limbal veins.
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In the course of follow-up analyses of visual field test,it should take more than two visual field tests that had similar results as baseline test,and some factors should be taken into account,such as accordant testing conditions,reliable indeces,test errors and fluctuation effects,and so on.The indeces of Mean Deviation(MD)and Pattern Standard Deviation(PSD)could reflect the whole change trend of follow-up visual field test,while sensitivity value of every point and their pattern deviations could help to analyse tiny changes of visual field tests.Those statistic softwares provided by automatic perimetry should be used adequately.Through the follow-up analyses of visual field test,glaucoma doctors could adjust therapy schemes in time in order to obtain objective intraocular pressure and stabilize visual field and glaucoma.
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Objective To evaluate the relationship between damages of visual field and retinal nerve fibre layer(RNFL)thickness in primary open angle glaucoma(POAG)with high myopia.Design Retrospective,case-controlled study.Participants POAG group with high myopia(21 eyes of 17 cases),POAG group with non-high myopia(17 eyes of 16 cases),high myopia group without POAG(25 eyes of 20 cases)and normal control group(19 eyes of 17 cases).Methods The static central visual fields were tested with Humphrey 750 automated perimetry and thickness of RNFL was measured with optical coherent tomography(OCT).Main Outcome Measures Mean deviation(MD),pattern standard deviation(PSD)and mean sensitivity at upper,lower,nasal and temporal quadrants in total deviation probability plots.Thickness of RNFL at upper,lower,nasal and temporal quadrants.Results There were more obvious general depression of sensitivity in total deviation probability plots of the early POAG with high myopia than those of POAG without high myopia,and the early visual field defects of glaucoma in pattern deviation probability plots of this group.MD of POAG with high myopia was more than those of others(P＜0.05).The differences of MD,PSD and mean sensitivity between POAG with high myopia and others were significant(P＜0.05).Mean sensitivities in each quadrant of POAG without high myopia were similar to those of high myopia(P＞0.05).The thickness of RNFL of POAG with high myopia was thinner than those of others and the thickness of RNFL of normality was thicker than that of others.The correlationship between mean sensitivity and the thickness of RNFL in each quadrant was significant(P＜0.05).Conclusion Pattern deviation probability plots is an important favor for judgement of the visual field changes in POAG with high myopia.The relationship between RNFL thickness with OCT and visual field damage may provide clinically relevant information in diagnosis of POAG with high myopia