Increased replication of human cytomegalovirus in retinal pigment epithelial cells by valproic acid depends on histone deacetylase inhibition

PURPOSE: Human cytomegalovirus (HCMV) replication depends on different cellular pathways, including histone acetylation and extracellular-signal regulated kinases 1 and 2 (Erk 1/2). In the present study, the influence of therapeutic valproic acid (VPA) concentrations was investigated on HCMV replication in retinal pigment epithelial (RPE) cells. METHODS: HCMV antigen expression and replication were detected by immunostaining, real-time RT-PCR, and determination of virus titers. Histone acetylation and Erk 1/2 phosphorylation were detected by Western blot. RESULTS: Pretreatment with VPA < or =1 mM enhanced HCMV antigen expression and replication by up to ninefold. In addition to histone deacetylase (HDAC) inhibition, VPA stimulated Erk 1/2 phosphorylation in RPE cells. Investigation of six VPA derivatives revealed that S-2-pentyl-4-pentynoic acid was the only derivative that induced histone hyperacetylation, indicating HDAC inhibition, in the observed concentrations < or =1 mM and that increased HCMV antigen expression. Other derivatives did not enhance HCMV replication in the tested concentrations, although some were found to induce Erk 1/2 phosphorylation. The mitogen-activated protein kinase kinase (MEK) inhibitor PD98059 inhibited VPA-induced Erk 1/2 phosphorylation but did not affect VPA-induced increased HCMV replication. In addition, the structurally nonrelated HDACI trichostatin A enhanced HCMV replication but did not affect Erk 1/2 phosphorylation in RPE cells. CONCLUSIONS: The data demonstrate that VPA stimulates HCMV replication by HDAC inhibition independent of Erk 1/2 phosphorylation in therapeutic concentrations in RPE cells. Therefore, patients at risk of HCMV retinitis who are treated with VPA or other HDAC inhibitors should be carefully monitored.     

视网膜缺血-再灌注损伤中小胶质细胞对微循环的破坏作用

目的　探讨视网膜缺血-再灌注损伤(retinal ischemia-reperfusion injury,RIRI)中小胶质细胞活化与视网膜微循环损伤的关系及作用机制。方法　160只雄性C57BL/6小鼠右眼均采用前房灌注建立RIRI模型为RIRI组，左眼不作处理为正常对照组。在损伤后24 h、48 h、72 h分别进行视网膜冰冻切片、视网膜铺片免疫荧光染色检测小胶质细胞的活化情况，检测相关缺氧因子及炎症因子的表达，与正常对照组比较，研究小胶质细胞的激活状态与微循环损伤的关系，并初步分析其作用机制。结果　视网膜微循环结构损伤观察结果显示，与正常对照组相比，RIRI后24 h组大部分血管仍呈正常形态；RIRI后48 h组，闭塞的血管数量增多；RIRI后72 h组，血管损伤明显加重。浅层毛细血管密度正常对照组，RIRI后24 h、48 h、72 h组间两两比较差异均无统计学意义（均为P>0.05）。而深层血管网毛细血管密度RIRI后72 h组与其余3组相比明显减少，差异均有统计学意义（均为P<0.05），其余3组间差异均无统计学意义（均为P>0.05）。视网膜冰冻切片检测显示，RIRI后24 h组与正常对照组各层视网膜中抗离子钙接头蛋白（ionized calcium bindingadaptor molecule-1，Iba-1）阳性细胞数差异无统计学意义（P>0.05）。RIRI后48 h组各层中Iba-1阳性细胞数与正常对照组及24 h组差异均有统计学意义（均为P<0.05）。RIRI后72 h组各层中Iba-1阳性细胞数与正常对照组、24 h组、48 h组差异均有统计学意义（均为P<0.05）。视网膜铺片结果显示，RIRI后48 h组和72 h组活化的小胶质细胞数明显增加，与正常对照组和RIRI后24 h组在两个层次毛细血管中差异均有统计学意义（均为P<0.05），而72 h组小胶质细胞的活化达到高峰值，与其余组差异均有统计学意义（均为P<0.05）。RT-PCR检测结果显示:血管内皮生长因子和缺氧诱导因子-1α的缺血缺氧因子，肿瘤坏死因子-α和白细胞介素-1β的炎症因子在正常对照组与RIRI后24 h组、48 h组、72 h组，组间比较差异均有统计学意义（均为P<0.05）。结论　激活的小胶质细胞在RIRI中发挥了对微循环的破坏作用，损伤早期抑制小胶质细胞的活化可能成为此类疾病治疗的新思路。     

Pioglitazone ameliorates retinal ischemia/reperfusion injury via suppressing NLRP3 inflammasome activities

AIM: To explore the role of Pioglitazone (Pio) on a mouse model of retinal ischemia/reperfusion (I/R) injury and to elucidate the potential mechanism. METHODS: Retinal ischemia was induced in mice by increasing the intraocular pressure, and Pio was administered 4h though periocular injection before I/R. The number of cells in the ganglion cell layer (GCL) was counted 7d after retinal I/R injury. Glial fibrillary acidic protein (GFAP), nuclear factor-kappa B (NF-κB), p38, phosphorylated-p38, PPAR-γ, interleukin-1β (IL-1β), Toll-like receptor 4 (TLR4), NLRP3, cleaved caspase-1, caspase-1 were determined by real-time polymerase chain reaction and Western blotting. RESULTS: Pio promoted the survival of retinal cells in GCL following retinal I/R injury (P<0.05). Besides, retinal I/R injury stimulated the expression of GFAP and TLR4, which were partially reversed by Pio treatment (P<0.05). Retinal I/R injury-upregulated expression of NLRP3, cleaved caspase-1, IL-1β was attenuated after Pio treatment (P<0.05). Moreover, I/R injury induced activation of NF-κB and p38 were inhibited by Pio treatment (P<0.05). CONCLUSION: Pio promotes retinal ganglion cells survival by suppressing I/R-induced activation of TLR4/NLRP3 inflammasomes via inhibiting NF-κB and p38 phosphorylation.     

The neuropeptide NAP provides neuroprotection against retinal ganglion cell damage after retinal ischemia and optic nerve crush

Background  NAP, an 8-amino acid peptide (NAPVSIPQ=Asn-Ala-Pro-Val-Ser-Ile-Pro-Gln) derived from activity-dependent neuroprotective protein (ADNP), plays an important role in neuronal differentiation and the survival of neurons in different pathological situations. We already discovered that NAP increases the survival of retinal ganglion cells (RGC) in vitro, and supports neurite outgrowth in retinal explants at femtomolar concentrations. The aim of this study was to investigate the effects of NAP on RGC survival after transient retinal ischemia and optic nerve crush. Methods  RGC of male Wistar rats were labelled retrogradely with 6 l FluoroGold injected stereotactically into both superior colliculi. Seven days later, retinal ischemia was induced by elevating the intraocular pressure to 120 mm Hg for 60 minutes or by crushing one optic nerve for 10 s after a partial orbitotomy. NAP was either injected intraperitoneally in the concentration of 100 mg/kg 1 day before, directly after, and on the first and the second days after damage, or intravitreally (0.05 or 0.5 μg/eye) directly after the optic nerve crush. Controls received the same concentrations of a control peptide. Densities of surviving RGC and activated microglial cells (AMC) were quantified in a masked fashion 10 days after damage by counting FluoroGold-labelled cells. Results  After retinal ischemia, intraperitoneal injections of NAP increased the number of surviving RGC by 40% (p < 0.005) compared to the control group. After optic nerve crush, NAP raised the number of surviving RGC by 31% (p = 0.07) when injected intraperitoneally and by 54% (p < 0.05) when administered intravitreally. Conclusions  NAP acts neuroprotectively in vivo after retinal ischemia and optic nerve crush, and may have potential in treating optic nerve diseases. Supported by the Ernst und Berta Grimmke Stiftung, Germany. IG is the incumbent of the Lily and Avraham Gildor Chair for the Investigation of Growth Factors and the Director of the Adams Super Center for Brain Research at Tel Aviv University and is the Chief Scientific Officer of Allon Therapeutics Inc., Vancouver, Canada. An erratum to this article can be found at     

Heterogeneous populations of microglia/macrophages in the retina and their activation after retinal ischemia and reperfusion injury

Activation of Microglia/macrophages has been observed in ischemia-reperfusion injury of the brain. This study was undertaken to investigate the different subpopulations of microglia/macrophages in the normal rat retina and their activation after retinal ischemia. Retinal ischemia was induced by elevation of intraocular pressure to 120 mmHg for 60 min. Microglia/macrophages were identified on frozen retinal sections by four antibodies, namely OX42, 5D4, OX6 and ED1. In the normal retina, there were heterogeneous populations of resident microglia/macrophages as characterized by their differences in morphology, antigen expression and distribution. OX42+ cells had delicate processes and were located in the inner layers of the retina, while 5D4+ cells were highly ramified and mostly scattered in the inner plexiform layer (IPL) and the outer plexiform layer. Few amoeboid ED1+ cells were also seen in the ganglion cell layer and IPL. OX6+ (MHC-II antigen presenting) cells were not detected in the normal retinas. Double labeling with OX42 and 5D4 antibodies on normal retinal sections showed few microglia exhibited positive labeling with both OX42 and 5D4, while the majority of the microglia were labeled with either OX42 or 5D4 antibodies. After retinal ischemia single labeling with these antibodies showed increased number of these antigen-expressing cells, disappearance of normal cellular processes, and rounding or amoeboid like appearance of the cell bodies. At 1 day after ischemia, there was a significant infiltration of round OX42+, ED1+ and OX6+ cells with loss of the cellular processes in the inner retina. From 3 to 14 days, all subpopulations of microglia/macrophages differentiated cellular processes and became dendritic again. Double labeling on retinas after 1 day of recovery showed OX42+ cells were co-labeled with ED1+ or OX6+ cells, but not with 5D4+ cells. Scattered amoeboid OX42+, 5D4+, and ED1+ cells were noted in the subretinal space 3-14 days after ischemia. In summary, there were heterogeneous populations of resident microglia/macrophages in the normal inner retina and they were activated early after ischemia-reperfusion injury and exhibited different antigenic expression which were further altered in the recovery phase.     

Heterogeneous populations of microglia/macrophages in the retina and their activation after retinal ischemia and reperfusion injury

Activation of Microglia/macrophages has been observed in ischemia-reperfusion injury of the brain. This study was undertaken to investigate the different subpopulations of microglia/macrophages in the normal rat retina and their activation after retinal ischemia. Retinal ischemia was induced by elevation of intraocular pressure to 120 mmHg for 60 min. Microglia/macrophages were identified on frozen retinal sections by four antibodies, namely OX42, 5D4, OX6 and ED1. In the normal retina, there were heterogeneous populations of resident microglia/macrophages as characterized by their differences in morphology, antigen expression and distribution. OX42+ cells had delicate processes and were located in the inner layers of the retina, while 5D4+ cells were highly ramified and mostly scattered in the inner plexiform layer (IPL) and the outer plexiform layer. Few amoeboid ED1+ cells were also seen in the ganglion cell layer and IPL. OX6+ (MHC-II antigen presenting) cells were not detected in the normal retinas. Double labeling with OX42 and 5D4 antibodies on normal retinal sections showed few microglia exhibited positive labeling with both OX42 and 5D4, while the majority of the microglia were labeled with either OX42 or 5D4 antibodies. After retinal ischemia single labeling with these antibodies showed increased number of these antigen-expressing cells, disappearance of normal cellular processes, and rounding or amoeboid like appearance of the cell bodies. At 1 day after ischemia, there was a significant infiltration of round OX42+, ED1+ and OX6+ cells with loss of the cellular processes in the inner retina. From 3 to 14 days, all subpopulations of microglia/macrophages differentiated cellular processes and became dendritic again. Double labeling on retinas after 1 day of recovery showed OX42+ cells were co-labeled with ED1+ or OX6+ cells, but not with 5D4+ cells. Scattered amoeboid OX42+, 5D4+, and ED1+ cells were noted in the subretinal space 3–14 days after ischemia. In summary, there were heterogeneous populations of resident microglia/macrophages in the normal inner retina and they were activated early after ischemia-reperfusion injury and exhibited different antigenic expression which were further altered in the recovery phase.     

Interleukin-6 in retinal ischemia reperfusion injury in rats

PURPOSE: To study the role of interleukin (IL)-6 after retinal ischemia-reperfusion (I/R) injury in rats. METHODS: Intraocular pressure of adult male Lewis albino rats was raised to create retinal ischemia for 1 hour. Retinal reperfusion was reestablished, and the animals were killed at various time points after the injury. Their eyes were enucleated and processed for immunohistochemistry to detect IL-6 and ED-1 (a marker of microglial/phagocytic cells), enzyme-linked immunosorbent assay (ELISA) of IL-6 protein, and semiquantitative real-time RT-PCR for IL-6 mRNA. The neuroprotective effect of IL-6 was evaluated by giving intravitreal injections of 150 or 300 ng rat recombinant IL-6 to eyes immediately after I/R injury and counting cresyl violet-stained retinal ganglion cell layer cells (RGCLCs) and fluorochrome-labeled retinal ganglion cells (RGCs) on flat preparations of retinas at 7 days. RESULTS: IL-6-positive cells appeared after I/R injury in the inner plexiform layer (IPL) and the inner nuclear layer (INL). Their numbers were significantly higher 18 hours after the injury, and most of these cells were also ED-1 positive. ELISA showed noticeable increases in endogenous retinal IL-6 protein levels 8 hours after I/R injury. Semiquantitative real-time RT-PCR showed significant increases in endogenous retinal IL-6 mRNA levels between 2 and 18 hours. Exogenously added IL-6 prevented between 50% and 70% of RGC loss after I/R injury. CONCLUSIONS: IL-6 is upregulated after retinal I/R injury, and its expression by microglia/phagocytic cells may protect RGC layer neurons from I/R injury. Exogenously added IL-6 protects the inner retina after I/R injury.     

视网膜缺血再灌注损伤和细胞因子的研究进展

视网膜缺血再灌注（retinal ischemia reperfusion,RIR)损伤是由多种因素，如自由基，炎性细胞因子，白细胞等介导的复杂病理生理过程，RIR损伤和细胞因子之间存在密切联系，一方面，RIR损伤可以诱导多种炎性细胞因子，如白细胞介素1和6的表达，另一方面，多种外源性神经营养因子，如碱性成纤维细胞生长因子，重组人肝细胞生长因子，脑源性神经生长因子等，具有保护RIR损伤的作用，研究RIR损伤和细胞因子关系具有重要意义，因此我们报告了国外有关RIR损伤和细胞因子的最新研究进展。     

Sildenafil (Viagra) evokes retinal arteriolar dilation: dual pathways via NOS activation and phosphodiesterase inhibition

PURPOSE: Sildenafil (Viagra; Pfizer, New York, NY), a selective phosphodiesterase type-5 (PDE5) inhibitor, is widely used to treat impotence by improving penile blood flow via elevation of cGMP. However, its effect on ocular circulation is controversial and whether retinal arterioles are responsive to this drug remains unclear. In this study, the direct reaction of retinal arterioles to sildenafil was examined and the signaling pathway underlying this vasomotor activity was probed. METHODS: Retinal arterioles from porcine eyes were isolated, cannulated, and pressurized without flow. Diameter changes in response to sildenafil were recorded using videomicroscopic techniques. RESULTS: Retinal arterioles (67 +/- 2 microm) dilated dose dependently to sildenafil (1 ng/mL to 1 microg/mL). This dilation was inhibited by the nitric oxide (NO) synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME), the guanylyl cyclase inhibitor 1H- [1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), the extracellular signal-regulated kinase (ERK) pathway inhibitor PD98059, the nonselective potassium channel blocker tetraethylammonium (TEA), and the selective adenosine triphosphate (ATP)-sensitive potassium (K(ATP)) channel blocker glibenclamide. The vasodilation elicited by the NO donor S-nitroso-N-acetylpenicillamine (SNAP) was inhibited by ODQ and TEA but was insensitive to PD98059. In the presence of L-NAME, the addition of SNAP (1 microM) produced modest vasodilation and the inhibited sildenafil response was subsequently restored. The restored dilation was insensitive to PD98059 but was blocked by TEA. CONCLUSIONS: Activation of NO synthase, through ERK signaling, leading to NO production and subsequent guanylyl cyclase activation and K(ATP) channel opening is the major vasodilatory pathway for sildenafil in retinal arterioles. Moreover, the elevated cGMP, from endogenous or exogenous NO, plays a permissive role for sildenafil to exert vasodilation through inhibition of the PDE5 pathway independent of ERK signaling.     

缺血预处理对大鼠视网膜缺血再灌注损伤保护作用

目的：探讨缺血预处理是否对视网膜缺血再灌注损伤有保护作用及其机理,方法：利用前房灌注生理盐水形成高眼压的视网膜缺血再灌注损伤的动物模型,视网膜缺血时间为1h分别于缺血前30min、24h或72h对大鼠一只眼5min短暂缺血即预处理,24h或72h后行视网膜电图（ERG）、电镜、光镜、丙二醛（MDA）及热休克蛋白70（HSP70）检测,或者一侧眼行5min假处理,24h后行1h缺血,24h或72h再行上述检测,所有对侧眼不作处理作对照,结果：与假处理相相比,缺血前24、72h进行预处理后的大鼠视网膜光镜、电镜表现损害明显减轻,ERGb波明显恢复（P＜0．01）,MDA含量降低（P＜0．01）,缺血前30min预处理的视网膜表现严重的损害,ERGb波几安全消失,结论：缺血预处理对视网膜缺血再灌注损伤有保护作用,且有一定时限性。     

Protective effects of pentoxifylline in retinal ischemia/reperfusion injury

We studied the effect of pentoxifylline on retinal lipid peroxidation and histopathologic changes due to ischemia/reperfusion (I/R). A total of 15 pigmented male guinea pigs were divided into 3 equal groups as control, sham and treatment groups. After application of high intraocular pressure for 90 min for the induction of retinal ischemia, 24-hour reperfusion was established in the sham and treatment groups. In the treatment and sham groups, either 45 mg/kg of pentoxifylline or saline was given 3 times at 8-hour intervals. Biochemical assay and histopathologic evaluation were performed on one randomly selected eye of each animal which was enucleated at the end of the reperfusion period, and retinal malondialdehyde (MDA) levels and thickness of the retinal tissue were determined for each group. The mean MDA level of the sham group was significantly higher versus the control and treatment groups (p < 0.001). When compared with the control group, the mean MDA level of the treatment group was slightly higher, but the difference was not statistically significant (p > 0.05). In comparison with the control group there was a significant increase in the thickness of the retina in the sham group (p < 0.0001), and no significant difference was found in the retinal thickness of the treatment group (p > 0.05). Pentoxifylline might have a preventive effect on the I/R injury of the retina.     

Acetylcholinesterase inhibition ameliorates retinal neovascularization and glial activation in oxygen-induced retinopathy

AIM: To investigate whether inhibition of acetylcholinesterase (AChE) by donepezil ameliorate aberrant retinal neovascularization (RNV) and abnormal glial activation in oxygen-induced retinopathy (OIR). METHODS: A mouse model of RNV was induced in postnatal day 7 (P7) mice by exposure to 75% oxygen. Donepezil was administrated to P12 mice by intraperitoneal injection. Expression and localization of AChE in mouse retinas were determined by immunofluorescence. RNV was evaluated by paraffin sectioning and hematoxylin and eosin (HE) staining. Activation of retinal Müller glial cells were examined by immunoblot of glial fibrillary acidic protein (GFAP). rMC-1, a retinal Müller cell line, was used for in vitro study. Expression of hypoxia-induced factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) were determined by Western-blot analysis, enzyme-linked immunosorbent assay (ELISA) or immunostaining. RESULTS: Aberrant RNV and glial activation was observed after OIR. Of note, retinal AChE was mainly expressed by retinal Müller glial cells and markedly increased in OIR mice. Systemic administration of donepezil significantly reduced RNV and abnormal glial activation in mice with OIR. Moreover, ischemia-induced HIF-1α accumulation and VEGF upregulation in OIR mouse retinas and cultured rMC-1 were significantly inhibited by donepezil intervention. CONCLUSION: AchE is implicated in RNV with OIR. Inhibition of AChE by donepeizl is likely to be a potential therapeutic approach for retinal neovascular diseases.     

SIRT1 is required for the neuroprotection of resveratrol on retinal ganglion cells after retinal ischemia-reperfusion injury in mice

Graefe's Archive for Clinical and Experimental Ophthalmology - Retinal ganglion cells (RGCs) loss is closely related to visual impairment in glaucoma, so the neuroprotection on RGCs is...     

Effect of trimetazidine on retinal ischemia/reperfusion injury in rats

PURPOSE: To investigate the effect of trimetazidine (TMZ), an antioxidant agent, on the ischemia/reperfusion (I/R) injury in rat retina histopathologically. METHODS: The retinal I/R model was carried out by the 4-vessel occlusion method on Wistar albino rats. Twenty-one rats were divided into 7 groups, each comprising 3 rats. The animals in groups 1, 2 and 3 underwent 30 min of ischemia + 4 h of reperfusion and were treated by the administration of saline, TMZ before reperfusion and TMZ before ischemia, respectively. The animals in groups 4, 5 and 6 underwent 90 min of ischemia + 4 h of reperfusion and were treated in the same way as those in groups 1, 2 and 3, respectively. The 7th group was sham operated. RESULTS: Thirty and 90 min of ischemia followed by 4 h of reperfusion induced retinal injury in the rat retina. Histopathologically, the inner plexiform and inner nuclear layers were the most affected parts. TMZ was able to reduce almost all retinal I/R damage when administered before ischemia. A cytoprotective effect of TMZ was partly observed in those animals which were treated before reperfusion. CONCLUSION: TMZ seemed to have a protective effect against retinal I/R injury in rats.     

JAK-STAT信号通路的激活对视网膜缺血-再灌注损伤的促进作用

背景 视网膜缺血-再灌注损伤(RIRI)是眼科临床上常见的多种视网膜血管性疾病共同的病理损伤过程,发病机制复杂.研究表明视网膜细胞凋亡和神经纤维变性是RIRI最终的共同通路.Janus激酶信号转导子与转录激活子(JAK-STAT)信号通路是近年来新发现的一条信号转导途径,参与多种病理生理过程,但该通路与RIRI病理过程的关系尚不明确. 目的 探讨JAK-STAT信号通路在大鼠RIRI过程中被激活的时程及其意义. 方法 采用随机数字表法将40只正常清洁级成年SD大鼠随机分为RIRI 6 h、12h、24 h和48 h组,大鼠的一侧眼采用前房生理盐水灌注法升高眼压以建立RIRI模型,正常对侧眼作为正常对照组.大鼠眼压升高至110 mmHg(1 mmHg=0.133 kPa)并能持续60 min视为造模成功.分别于造模后6、12、24和48 h处死大鼠并摘除大鼠眼球,采用免疫组织化学法检测各组大鼠视网膜中STAT3和JAK2蛋白的表达强度并定位;采用实时荧光定量PCR法检测大鼠视网膜中STAT3 mRNA和JAK2 mRNA相对表达量的动态变化,并与正常对照组检测结果进行比较.结果 免疫组织化学检测显示,JAK2和STAT3蛋白主要表达于视网膜内核层和视网膜神经节细胞(RGCs)层,正常对照组大鼠视网膜中JAK2和STAT3蛋白均呈弱阳性表达,呈黄色染色,RIRI模型大鼠视网膜中JAK2和STAT3蛋白表达均明显增强,呈棕黄色染色.各组间大鼠视网膜中JAK2和STAT3蛋白表达强度的总体比较差异均有统计学意义(F=88.735、96.625,均P＜0.01),RIRI后各时间点组大鼠视网膜中JAK2和STAT3蛋白表达强度均明显高于正常对照组,RIRI 12 h组大鼠视网膜中JAK2和STAT3蛋白表达强度达峰值,均明显高于正常对照组,差异均有统计学意义(JAK2:t=4.308、5.559、5.315、4.726,均P＜0.01;STAT3:=5.047、7.843、6.281、4.887,均P＜0.01).RIRI模型眼视网膜内层增厚、组织疏松,可见细胞空泡样变性及RGCs数量减少.实时荧光定量PCR显示,各组间大鼠视网膜中JAK2 mRNA和STAT3 mRNA总体比较差异均有统计学意义(F=111.239、129.539,均P＜0.01),RIRI 6、12、24和48 h组大鼠视网膜中JAK2 mRNA和STAT3 mRNA相对表达量较正常对照组均明显增加,差异均有统计意义(JAK2mRNA:t=3.504、5.102、4.679、4.213,均P＜0.01;STAT3 mRNA:t=6.541、8.787、5.693、5.898,均P＜0.01).结论 RIRI模型鼠视网膜形态发生病理改变,RGCs数量减少,同时大鼠视网膜中JAK2和STAT3表达上调,RIRI大鼠视网膜中JAK2和STAT3的表达变化与视网膜形态损伤趋势一致,提示JAK-STAT通路参与RIRI的病理损伤过程.     

AQP-1和VEGF在大鼠视网膜缺血再灌注损伤中的表达

目的:研究大鼠视网膜缺血再灌注损伤后水通道蛋白-1和血管内皮生长因子的表达情况并探讨二者在视网膜缺血再灌注损伤中表达的意义。方法:通过提高眼内压的方法建立大鼠视网膜缺血再灌注模型,于术后6,12,24,48h;3,7d用免疫组化的方法检测水通道蛋白-1和血管内皮生长因子在大鼠视网膜的表达情况,并以正常大鼠视网膜作为对照。结果:正常对照组大鼠视网膜未能检测到血管内皮生长因子的阳性表达,缺血再灌注12h后开始出现表达,48h达高峰,且差异具有统计学意义(P<0.01)。水通道蛋白-1在正常对照组可见到阳性表达,缺血再灌注组随时间增长表达不断增强,7d在外层视网膜也出现表达,差异有统计学意义(P<0.01)。结论:水通道蛋白-1和血管内皮生长因子在视网膜缺血性疾病中起着重要的作用,二者可能共同影响了视网膜的水代谢过程。     

Comparison of pre-treatment and post-treatment use of selenium in retinal ischemia reperfusion injury

AIM: To investigate the effects of selenium in rat retinal ischemia reperfusion (IR) model and compare pre-treatment and post-treatment use. METHODS: Selenium pre-treatment group (n=8) was treated with intraperitoneal (i.p.) selenium 0.5 mg/kg for 7d and terminated 24h after the IR injury. Selenium post-treatment group (n=8) was treated with i.p. selenium 0.5 mg/kg for 7d after the IR injury with termination at the end of the 7d period. Sham group (n=8) received i.p. saline injections identical to the selenium volume for 7d with termination 24h after the IR injury. Control group (n=8) received no intervention. Main outcome measures were retina superoxide dismutase (SOD), glutathione (GSH), total antioxidant status (TAS), malondialdehyde (MDA), DNA fragmentation levels, and immunohistological apoptosis evaluation. RESULTS: Compared to the Sham group, selenium pre-treatment had a statistical difference in all parameters except SOD. Post-treatment selenium also resulted in statistical differences in all parameters except the MDA levels. When comparing selenium groups, the pre-treatment selenium group had a statistically higher success in reduction of markers of cell damage such as MDA and DNA fragmentation. In contrast, the post-selenium treatment group had resulted in statistically higher levels of GSH. Histologically both selenium groups succeeded to limit retinal thickening and apoptosis. Pre-treatment use was statistically more successful in decreasing apoptosis in ganglion cell layer compared to post-treatment use. CONCLUSION: Selenium was successful in retinal protection in IR injuries. Pre-treatment efficacy was superior in terms of prevention of tissue damage and apoptosis.