Objective To investigate the protective effects of estrogen on rabbit retinal damages induced by chronic ocular hypertension.Methods A total of 18 white New Zealand female rabbits were randomly divided into ovariectomized (OV) group and sham OV (SOV) group. Bilateral ovaries were remove in OV group while only the adipose tissue around ovarian were remove in SOV group. Chronic ocular hypertension was induced by anterior chamber injection of carbomer. Retinal cell apoptosis was measured by terminal deoxynucleotidyl transferasemediated dUTP nick end labeling (TUNEL), the expression of bcl-2, bax were detected by immunohistochemistry. The images were captured under microscope and analyzed with computer-image-analysis system. Results Four, six and eight weeks after ocular hypertension modeling, the OV retinas have less retinal ganglion cells, thinner optic nerve fiber layer and inner nuclear layer and more TUNEL positive cells (t=3.285，4.012，3.624；P＜0.01). The OV retinas also have less bcl-2 expression (t=4.256，3.867，3.459；P＜0.01), more bax positive cells (t=3.211，3.625，3.253；P＜0.01). Bcl-2 expression was negatively correlated with TUNEL positive cells indicating bcl-2 can inhibit apoptosis. Bax expression was positively correlated with TUNEL positive cells indicating bax induce apoptosis.ConclusionEstrogen has a neuroprotection role to rabbit retina under chronic ocular hypertension by reducing apoptosis.
Objective:To observe the inhibited effect and its mechani sm of estro gen on lightinduced apoptosis of retinal photoreceptor cells. Methods:Twenty female Sprague-Dawley rats were randomly divided into two groups: ovariectomized (OV) group and OV and estrogen (E2) replacement (OV+E2) group, with 10 rats in each group. All of the rats were exposed to the cyclic illumination under 12 hou r light and 12 hour dark condition with the light intensity of (600plusmn;35.4) lx ( a total of 14 times). All of the right eyes were extracted and the thickness of r etinal outer nuclear layer (ONL) was measured. Terminal deoxynucleotidyl Transfe rasemediated dUTP nick end labeling (TUNEL) method was used to evaluate positi v e apoptosis cells in ONL. The expression of nitric oxide synthase (NOS) in retin al cells was detected by immunohistochemistry with image analysis method. Results:The thickness of ONL in OV group was obviously thinner than that in the OV+ E2 group. The number of positive apoptosis of the cells was (0.0275plusmn;0.0069) c el ls/mu;m2 in OV group and (0.0162plusmn;0.0054) cells/mu;m2 in OV+E2group; the di fferen ce between the two groups was significant (t=4.1370，P=0.0012). The values o f in tegral optical density of NOS positively stained cells in retinal inner nuclear layer was (0.3675plusmn;0.0662) in the OV group and (0.2941plusmn;0.0350) in OV+E2 group ; the difference between the two groups was significant (t=3.4885, P=0.0031). Conclusion:Estrogen can protect retina from light injuries by regu lating NOS synthesis and inhibiting apoptosis of photoreceptor cells.
Objective:To observe the effect of beta;estradiol on gluta mate concentration in rabbitsprime; retinae injured by ischemic reperfusion. Methods:Twenty r abbits ware randomly divided into two groups, the control group and the treatmen t group, with 10 rabbits in each group. Before examined by binocular flash elect roretinography (FERG), retinal ischemic reperfusion (RIR) model was induced in t h e right eyes of all the rabbits by increasing intraocular pressure to 120 mm Hg for 60 minutes; the left eyes were as the control eyes. The rabbits were hypoder mically injected with beta;estradiol (0.1 mg/kg) in treatment group and with phys i ological saline in the control group 2 hours before ischemia. The results of FER G of the right eyes in both of the 2 groups 0, 4, 8, and 24 hours after reperfus ion were record respectively and were compared with the results of FERG before r eperfusion. The retina tissue was collected after the last time of FERG. The con c entration of glutamate was detected by Hitachi L8800 amino acid analyzer. Results:In the right eyes in both of the 2 groups, the result of F ERG showed a beeli ne just after reperfusion. There was no significant difference of awave amplit u de between the 2 groups (t=1.357, 0.798, 0.835; Pgt;0.05); the b wave amplitudes i n experimental group were much higher than those in the control group (t=4.447, 2.188, 3.106; Plt;0.01). The concentration of glutamate in retina was (0.265plusmn;0.014) g/L in the right eyes and (0.207plusmn;0.013) g/L in the left eyes in the control group, and (0.231plusmn;0.007) g/L in the right eyes and (0.203plusmn;0 .014) g/L in the le ft eyes in the treatment group; the difference between the 2 groups was signific ant (F=50.807, P=0.000). There was statistical difference between righ t and left eyes both in the 2 groups and the significant difference of the right eyes betw een the two groups was also found (P=0.000); there was no statistical diffe rence of the left eyes between the 2 groups (P＝0.505). Conclusion:beta;-estradiol may prevent the increase of the concentration of glutamate in retina induced by RIR to protect retinal tissue.
Objective：To investigate the role of 17beta; estradiol on th e expressi on of vascular endothelial growth factor (VEGF) and on the releasing rate of lac tate dehydrogenase (LDH) in cultured anoxiainjured human retinal pigment epit h eliual (RPE) cells. Methods:Established the anoxiainjuried m odel of human RPE c ells with Cobalt Chloride (CoCl2) after RPE cells were pretreated with 17beta;E 2 and tamoxife, 17beta;E2 antagonist. The expression of VEGF mRNA was detecte d by re v erse transcriptionpolymerase chain reaction technique (RTPCR). The cultured RP E cells were divided into four groups: normal control group, anoxiainjured gro u p, 17beta;E2 pretreatment group and 17beta;E2 with tamoxifen pretreatment grou p. The releasing rate of LDH was detected by chromatometry. The expression of VEGF pro tein were detected by cellular immunohistochemistry. Results:T he expression of VEGF and LDH releasing rate were higher in anoxiainjured grou p than that in nor m al control group (P＜0.05), and were lower in 17beta;E2 pretreatment group than th at in anoxiainjured group （P＜0.05）. When the effect of 17beta;E2 was o bstructe d by tamoxifen, the expression of VEGF and LDH releasing rate increased but didn prime;t differ much from which in anoxiainjured group (P＞0.05). Conc lusion:The ex pression of VEGF increases in anoxiainjured human RPE cells. 17beta;E2 can do wnr egulate the expression of VEGF and decrease the releasing rate of LDH, which can be blocked by tamoxifen.
In addition to its role as a sex hormone, estrogen aff ects the struc ture and function of many other systems such as the bone, the cardiovascular and the nervous system. Here, we review the most recent supporting evidence for es trogen as an important player in ocular fundus diseases, focusing particularly o n the effects of estrogen on these diseases and the underlying mechanisms. Base d on this, we also discuss the clinical applicability of estrogen in treating va rious agerelated disorders including agerelated macular degeneration and ret in al neurodegeneration. Our growing understanding of estrogenmediated action at a molecular level will provide insight into the controversies surrounding hormon e replacement therapy.
Objective： To observe the effect of estrogen on the expr ession of pigment epithelium derived factor (PEDF) in cultured retinal Muuml;ller cells under the anoxic condition． Methods：After the anoxic retinal Muuml;ll er cells were tre ated with estrogen (E2) with the concentration of 10-6、10-5 and 10-7 mmol/L, t he level of expression of PEDF mRNA and the protein was detected by reverse tran scriptionpolymerase chain reaction and Western blotting analysis. Results：Th e expression of PEDF mRNA and protein decreased 24 hours after anoxia. E2 with t he concentration of 10-5 and 10-6 mmol/L inhibited the decrease of expression of PEDF mRNA and protein induced by anoxia, which related to the concentration of E2． Conclusion：strogen can regulate the expression of PEDF, which ma y play an important role in the regulation of retinal neovascularization．