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The nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)inflammasome is an inflammatory protein complex, and can participate into the inflammatory response. Upon activation, these inflammasomes can lead to Caspase-1 activation, thereby inducing a cascade of inflammatory factor activation and further cell pyroptosis. Excessive activation of inflammasomes will induce the overexpression of inflammatory factors, persistently triggering immune dysregulation and inflammatory chain reactions, even causing severe damage. The recent studies have confirmed a close association between retinal diseases, such as diabetic retinopathy(DR), retinal ischemia-reperfusion injury(RIRI), and proliferative vitreoretinopathy(PVR)with immune dysregulation and inflammatory responses, which is serving as crucial factors in the progression of retinal diseases. This article reviews the NLRP3 inflammasome signaling pathway and its role in the occurrence and development of retinal diseases, in order to provide new ideas for the pathogenesis and prevention of retinal diseases.
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AIM: To investigate the protective effect and mechanism of Danlou tablet on retinal ischemia-reperfusion injury(RIRI)in mice.METHODS: A total of 40 ApoE-/- mice were fed with high fat diet for 6 wk, and the RIRI model was established by anterior chamber infusion of pressurized saline. The mice were divided into control group(normal saline for 8 wk), RIRI model group(normal saline for 8 wk), and low-, medium-, and high-dose Danlou tablets groups [1, 2, and 4 g/(kg·d), respectively, for 8 wk]. The morphological changes of retina were observed by hematoxylin-eosin(HE)staining, retinal cell apoptosis was detected by terminal-deoxynucleoitidyl transferase mediated Nick-End Labeling(TUNEL)staining. The Western-blot assay was used to detect the expression of retinal tissue sample Kelch-like ech-associated protein 1(Keap1), nuclear factor E2 related factor 2(Nrf2), heme oxygenase 1(HO-1), and superoxide dismutase(Sod2)proteins.RESULTS: Compared with the control group, the mouse retina was atrophic with thinning thickness and increasing cell apoptosis, down-regulation of Sod2 protein expression, and up-regulation of Keap1 protein expression in the RIRI model group(all P<0.01). Compared with the RIRI model group, the retinal thickness increased in the medium- and high-dose of Danlou tablets groups(all P<0.01), and the cell apoptosis of retina decreased in the low-, medium- and high-dose of Danlou tablets groups(all P<0.05). There were no significant differences in the expression of Keap1 and HO-1 proteins of mouse retina tissue in the low-dose of Danlou tablets group(P>0.05). The expression of Sod2, Nrf2 and HO-1 proteins up regulated, and the expression of Keap1 protein down regulated in the medium- and high-dose of Danlou tablets groups(all P<0.05).CONCLUSION: Danlou tablet can alleviate RIRI-induced atrophy and thinning of retina and retinal cell apoptosis by regulating Keap1-Nrf2/HO-1 signal pathway and reducing oxidative stress.
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Objective:To study the effects of resveratrol on the expressions of Caspase-3 and Bcl-2 in the retina tissue of the rats with retinal ischemia-reperfusion injury(RIRI),and to investigate the therapeutic effect of resveratrol on the RIRI and its mechanism.Methods:A total of 90 SD rats were randomly divided into sham operation group,model group and treatment group,30 rats in each group.The RIRI models were established by pressing the anterior chamber of the rats.The rats in model and treatment groups received ischemia-reperfusion for 1,6,12,24,and 48 h;the rats in treatment group were treated with micro-syringe intravitreal injection of 0.5 nmol·L-1of resveratrol 5 μL.The retinal tissue structure was observed by inverted microscope.The expression levels of Caspase-3 and Bcl-2 in retina tissue were detected by immunohistochemistry and Western blotting methods.Results:The retinal tissue edema of the rats in model group was found with vacuolar degeneration of the ganglion cells,and the arrangement of the cell layer was loose;the number of retinal ganglion cells was decreased,the boundary was blurred,and the nerve fiber layer thinned obviously.The degree of retinal tissue structure,the degree of injury and the degeneration of ganglion cells in treatment group were lighter than those in model group.The results of immunohistochemistry showed that the expressions of Caspase-3 and Bcl-2 in the retina tissue of the rats in treatment group were significantly increased compared with model group.The results of Western blotting method showed that the expression levels of Bcl-2 protein in the retina tissue of the rats in treatment group at different time points were increased compared with model group;and there were significant differences at 24 and 48 h(P<0.05);the expression levels of Caspase-3 protein in treatment group at different time points were lower than those in model group(P<0.05).Conclusion:Resveratrol can improve the retinal tissue structure of the RIRI rats,and its mechanism may be related to decreasing the expression level of Caspase-3 and increasing the expression level of Bcl-2 in the retinal tissue.
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Objective: To study the effects of resveratrol on the expressions of Caspase-3 and Bl-2 in the retina tissue of the rats with retinal ischemia-reperfusion injury (RIRI), and to investigate the therapeutic effect of resveratrol on the RIRI and its mechanism. Methods: A total of 90 SD rats were randomly divided into sham operation group, model group and treatment group, 30 rats in each group. The RIRI models were established by pressing the anterior chamber of the rats. The rats in model and treatment groups received ischemia-reperfusion for 1, 6, 12, 24, and 48 h; the rats in treatment group were treated with micro-syringe intravitreal injection of 0.5 nmol · L1 of resveratrol 5 μL. The retinal tissue structure was observed by inverted microscope. The expression levels of Caspase-3 and Bl-2 in retina tissue were detected by immunohistochemistry and Western blotting methods. Results: The retinal tissue edema of the rats in model group was found with vacuolar degeneration of the ganglion cells, and the arrangement of the cell layer was loose; the number of retinal ganglion cells was decreased, the boundary was blurred, and the nerve fiber layer thinned obviously. The degree of retinal tissue structure, the degree of injury and the degeneration of ganglion cells in treatment group were lighter than those in model group. The results of immunohistochemistry showed that the expressions of Caspase-3 and Bel-2 in the retina tissue of the rats in treatment group were significantly increased compared with model group. The results of Western blotting method showed that the expression levels of Bel-2 protein in the retina tissue of the rats in treatment group at different time points were increased compared with model group; and there were significant differences at 24 and 48 h (P<0.05); the expression levels of Caspase-3 protein in treatment group at different time points were lower than those in model group (P<0.05). Conclusion: Resveratrol can improve the retinal tissue structure of the RIRI rats, and its mechanism may be related to decreasing the expression level of Caspase-3 and increasing the expression level of Bcl-2 in the retinal tissue.
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Objective To investigate whether paraptosis and autophagy have an effect on acute retinal ischemia-reperfusion injury (RIRI) in an experimental rat model that recapitulates features of acute hypertensive glaucoma and to explore the possible underlying mechanisms.Methods A total of 30 adult male Sprague-Dawley rats were randomly divided into RIRI group and control group.The acute RIRI model was induced with normal saline in the right eye of rats from the RIRI group by anterior chamber perfusion,while the rats in the control group left untreated.On day 1,day 3,day 7,day 28 after RIRI model establishment,the changes in morphology of retinal ganglion cells (RGCs) were observed by transmission electron microscopy (TEM),and the expression of microtubule-associated protein 1 light chain 3 (LC3) was measured by immumofluorescence methods.Results When compared with the control group,the number of cytoplasmic vacuoles predominantly derived from the progressive swelling of mitochondria and/or endoplasmic reticulum (ER) in RGCs were increased in the RIRI group from day 1 to day 28 by TEM.And ultra-structural analyses showed the double-or multiple-membrane autophagosomes were markedly accumulated in the cytoplasm of RGCs following acute RIRI.The average number of autophagic vacuoles in the cytoplasm of RGCs was 0.79 per 50 μm2 in the control group,and the average number of autophagosomes reached to a maximum on day 7 after acute RIRI at 2.29 per 50 μm2,which was statistically significant compared with the control group (P ＜ 0.05).Compared to the control group,LC3 expression in the cytoplasm of RGCs was up-regulated on day 1 after acute RIRI,which sustained throughout the experimental period.The percentage of LC3 positive cells in the retinal ganglion cell layer was 15.90％ in the control group,and the data was 46.95％ and 52.30％ on day 1 and day 28 after RIRI,respectively,both which were statistically significant compared with the normal control group (both P ＜ 0.05).Conclusion Both paraptosis and autophagy participate in death of RGCs after acute RIRI.Programmed cell death in different cells,either coexistence of multiple-cell death form or a single-cell death form,participates in the pathogenesis of acute RIRI.
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Objective To investigate the effects of N-acetylserotonin (N-AS) on the expression of active caspase-3,Bcl-2 and Bax in rat retinas induced by retinal ischemia-reperfusion injury (RIRI).Methods Adult male Sprague-Dawley rats were randomly divided into the normal control group (6 cases),RIRI group (30 cases) and NAS group (30 cases),RIRI models in NAS group were established after giving NAS,the groups were sub-divided into 6 hours,12 hours,24 hours,48 hours and 72 hours group based on the time of RIRI.Morphologic changes were evaluated by HE staining.The expression of active caspase-3,Bcl-2 and Bax protein in the retina of rats was detected by immunohistochemistry.Results HE staining showed that the retinal structure in the normal control group was clear,and the cells in each layer were tightly packed;Each layer of retina was edema in the RIRI group after 6 hours and 12 hours,the edema gradually alleviated after 24 hours,the ganglion cells decreased gradually,the distribution was in disorder,with the prolongation of time,the retinal ganglion cells were defected;drug group of as Compared with RIRI group,the cell edema in the NAS group at 6 hours and 12 hours were obvious reduced,the cells in 24 hours,48 hours,72 hours group arranged regularly,the loss number of ganglion cells were reduced.The number of active caspase-3 positive cells in RIRI group increased at 6 hours after peffusion,the number was (561.15 ±37.19) cell ·mm-2,and reached the high level at 24 hours,the number was (1522.61 ±84.36) cell · mm-2,and then decreased gradually.The number of active caspase-3 positive cells in NAS group was significantly lower than that in RIRI group,the difference was statistically significant (all P ＜ 0.05).The expression of Bcl-2 positive cells in RIRI group began to decrease after 6 hours,and decreased to a low level at 24 hours,and the number of Bcl-2 positive cells in NAS group was significantly higher than that in RIRI group at each time point,the differences were statistically significant (all P ＜ 0.05).There were almost no Bax positive cells in the retina of the control normal group,and the Bax positive cells were found to be higher of the RIRI group at the 6 hours after RIRI,and reached the higher level at 24 hours,and decreased at 48 hours.The Bax positive cells of NAS group were significantly less than those in the RIRI group at different time points,and the differences were statistically significant (all P ＜0.05).Conclusion NAS can promote the expression of Bcl-2 protein in rat retina after RIRI,inhibit the expression of Bax protein,decrease the expression of active caspase-3 protein,alleviate cell apoptosis,and have neuroprotective effects.
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AIM: To observe the effect of curcumin on the retinal structure and the expressions of interleukin-23 (IL-23) and interleukin-17(IL-17) in the rat retina after retinal ischemia-reperfusion injury (RIRI).METHODS:A total of 60 male Sprague-Dawley(SD) rats were randomly divided into normal control group(NCG),model group(MG),low-dose curcumin group (LDCG) and high-dose curcumin group (HDCG) (n=15 per group).RIRI was generated by anterior chamber perfusion of normal saline to the right eye.Rats in LDCG and HDCG received an intraperitoneal injection of 20mg/kg/d and 100mg/kg/d curcumin respectively,at 30min before RIRI and once daily after RIRI.Retinal structure and inflammation were evaluated after hematoxylin and eosin-stained (HE) staining.Western-blot and enzyme-linked immunosorbent assay (ELISA) were used to measure the level of IL-23 and IL-17 expressions after RIRI.RESULTS: The retinal structure of NCG was normal.Retinal edema,empty spaces or loosely packed cells and inflammatory cell infiltration were observed in MG and LDCG groups,whereas the morphological changes in HDCG group were improved as compared to MG and LDCG groups.Western-blot assay and ELISA showed that IL-23 and IL-17 expressions increased significantly after RIRI (vs NCG,P<0.01).Moreover,curcumin reduced IL-23 and IL-17 expressions significantly (vs MG,P<0.01).CONCLUSION: Curcumin can inhibit leukocytes infiltration and improve the retinal pathologic changes.Furthermore,curcumin can reduce retinal IL-23 and IL-17 expressions significantly in a dose-dependent manner.
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Objective To study the protective effect and Bcl-2 expression of salvia miltiorrhiza pretreatment on retinal ischemia-reperfu-sion injury ( RIRI) . Methods One hundred and thirty two Wistar rats were randomly divided into the normal control group, the ischemia-reperfusion group and the salvia miltiorrhiza pretreatment group. The model of retinal ischemia-reperfusion injury was constructed by increas-ing the intraocular pressure. The ischemia-reperfusion and salvia miltiorrhiza pretreatment group were divided into five subgroups according to the different reperfusion time (6 h, 12 h, 24 h, 48 h and 72 h). Observe the histological changes in retina by HE staining. The SABC ( strept avidin-biotin complex) and Western-blot were used to measure changes of Bcl-2 protein levels in retinal. Results The positive ex-pression of Bcl-2 protein was weak in normal group. In the ischemia-reperfusion group and salvia miltiorrhiza pretreatment group, the expres-sion of Bcl-2 protein began to increase at 6 hours after reperfusion, reached the peak at 24 hours after reperfusion, began to decrease at 48 hours after reperfusion, and started to weaken at 72 hours after reperfusion. The variation tendency of the two groups were the same, however, the expression of Bcl-2 was significantly stronger in the salvia miltiorrhiza pretreatment group compared with ischemia-reperfusion group, and there was significant difference between the two groups (P<0. 01). Conclusion Salvia miltiorrhiza pretreatment can protect the retina by reducing retinal ganglion cells apoptosis in retinal ischemia-reperfusion injury. The mechanism may be achieved by regulating the expression of Bcl-2 protein.
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Background Retinal ischemia-reperfusion (RIR) injury is a common pathologic change.Its mechanism has not been identified.Objective This study was to investigate the relationship of microRNA-181a (miR-181a) ,tumor necrosis factor-α (TNF-α) and retinal ganglial cells (RGCs) in RIR injury.Methods RIR models were induced in 68 rats,then the rats were randomly divided into control group and RIR groups,including 0hour group,24-hour group and 72-hour group by random number table.Predicted target gene TNF-α was chosen,according to M iRanda,Targetscan and miRBase databases.Immunofluorescent labeling, Western blot and quantitative real-time PCR were used to identify the expression levels of miR-181a,TNF-α and RGCs.Immunofluorescent labeling of RGCs in retinal flat mounts was analyzed for RGCs counts.Results Compared with the control group, RGCs densitiy was obviously decreased in 24-hour and 72-hour RIR groups (P＜0.001).The expression level of mir-181a significantly decreased with reperfusion time in the RIR groups (P＜0.05).Futhermore, the expression level of miR181a was positively correlated with RGCs numbers (r=0.995 ,P=0.005).TNF-α and miR-181a were mainly located in inner layers of retina.As opposed to the changes in RGCs numbers and miR-181a expression,TNF-α in 24-hour group was obviously higher than that of the 0-hour group, though there was no statistical significance in overall correlation analysis.Conclusions In RIR,miR-181a may be involved in regulating RGCs apoptosis.TNF-α may be a target gene of miR-181 a.Interventions within 24 hours after reperfusion might be critical.Further study of miR181 a may help to explore new molecular targets for neuroprotection treatment.
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Background Recently,the study on the cause of optic nerve damage induced by glaucoma is of concern in ophthalmology.Some research showed that the immune system is associated with glaucoma-induced optic neuropathy.Acute ischemia-reperfusion is an ideal model of studying optic neuropathy.ObjectiveThe present study investigates the effect of T and B lymphocyte deficiency on the retinal neurocytes of mice with acute intraocular hypertension.Methods Sixteen SPF CB-17/Icr.Cg-Prkdc~(scid)Lyst~(bg)/CrlVR mice 6-8 week-old (severe combined immunodeficiency mouse,SCID) were used in this study and 16 age-matched SPF wild type (C57BL/6) mice served as controls.The ischemia-reperfusion injury models were induced in the right eyes of 10 SCID mice and 10 C57BL/6 mice through intra-anterior chamber infusion of balanced saline solution for 45minutes to increase the intraocular pressure to 104mmHg,and the left eyes served as model controls.The other 6 SCID mice and 6 C57BL/6 mice served as normal control group.10g/L (2μL) of FlouroGold was injected into the brains of the mice for the labeling of surviving retinal ganglion cells 21 days after ischemia-reperfusion.The thickness of retinal inner nuclear layer was measured by H&E staining under the fluorescent microscope 21 days after ischemic insult.The use of the animals followed the Standard of Association for Research in Vision and Ophthalmology.Results In normal control mice,the morphology of retinal ganglion cells (RGCs) and retinal structure were similar between SCID mice and C57BL/6 mice.The differences in the numbers of RGCs and retinal thickness were insignificant between the two types of mice(P＞0.05).In the experimental mice,the surviving RGCs were strikingly increased in SCID mice (91%±5%) compared with C57BL/6 mice(78%±5%)(P=0.003).The thickness of the retinal inner nuclear layer was obviously thinner in the model eyes (22.44±1.70μm) compared to model control eyes (31.06±3.75μm) in C57BL/6 mice(P=0.004),but no statistically significant difference was found between the model eyes and model control eyes in SCID mice (33.52±2.13μm vs 34.06±3.00μm) 21 days after ischemia-reperfusion injury(P＞0.05).Conclusion T and B lymphocytes deficient mice show a better tolerance to acute intraocular hypertension than the wild type C57BL/6 mice.