rough the ultramicroscopic observation on muscle and microcirculation, Group A,where a largeamount of DXM combined with heporin was given svstematically and locally into the femoral artery of the severed limb before replantation, and in Group B only heporin was given, and Group C and D ascontrol.The results showed that if the hormone and heparin were administred in large dosage, it wasadvantageous to reduce the tissues from reperfusion injury during delayed replantation.
Objective To evaluate the phenomena of apoptosis and its relevant mechanism during ischemia-reperfusion period. Methods The published papers to explore the apoptotic phenomena and its mechanism in organs or tissues which experienced ischemia-reperfusion injury were reviewed. Results Apoptosis was common in ischemia-reperfusioned organ or tissue. The severity of apoptosis was influenced by many factors such as ischemia, hypoxia, oxygen free radials, intracellular free calcium ion overloading, various cytokines, et al; and also was regulated by bcl-2 family, caspase family and NF-κB，et al. Conclusion Apoptosis is a common phenomenum in ischemiareperfusioned organ or tissue which is affected and regulated by various factors.
Objective To explore the effect of ischemia-reperfusion injury on the retinal functions of rats. Methods Seventy Wistar rats were selected, 20 of which were selected randomly and divided into two groups (control group and single-irrigated group). The rats were anesthetized and their anterior chambers of the right eyes were cannulated with a 7-gauge needle connected to a reservoir containing ringers balanced salt solution, which was maintained at the same level o f the eye for 1 hour. After that, ERG was recorded in both eyes of all rats. All the left rats were divided randomly into 10 groups and they were treated as the single-irrigated group. Retinal ischemia was induced by raising the reservoir to a height of 150 mm Hg. One hour later except the single ischemia group, all o f t he groups resumed perfusion after 3,6,12,and 24 hours and 3,5,7,14,and 21 days s eparately. ERG was recorded in both eyes of all rats.Results There was no difference in the results of ERG between left and right eyes in either the control group or the single-irrigated group. All the waves of ERG vanished in the single-ischemia group after 1 hour. In the ischemia-reperfusion groups, the waves of ERG partly recovered and the amplitude reduced persistently and progressively.Conclusion Ischemia-reperfusion injury may affect the function of the retina persistently and progressively. (Chin J Ocul Fundus Dis，2003，19：201-268)
ObjectiveTo investigate the effects of Krüppel-like factor 7 (KLF7) on the survival of retinal ganglion cells (RGCs) and electroretinogram (ERG) after retinal ischemia-reperfusion (RIR) injury in mice.MethodsA total of 126 male C57BL/6J mice were randomly divided into normal group, RIR group, normal-KLF7 group, normal-green fluorescent protein (GFP) group, RIR-KLF7 group and RIR-GFP group. At the age of 8 weeks, mice of normal-KLF7 group and RIR-KLF7 group were intravitreally injected 1ul of 1.0×1012 vg/ml adeno-associated virus overexpressing KLF7 (AAV2-KLF7-GFP). Mice of normal-GFP group and RIR-GFP group were injected adeno-associated virus of AAV2-GFP with the same titer. At the age of 11 weeks, RIR injury was induced in mice of RIR group, RIR-KLF7 group and RIR-GFP group, and intraocular pressure was measured. Retinal cryosections were used to access the efficacy of virus transfection 4 weeks after AAV2-KLF7-GFP transfer. 7 days after RIR injury, RGCs’ survival rate was observed and quantified by immunofluorescent staining. ERG was performed to observe the differences in amplitudes and incubation period of scotopic ERG a-, b-wave, oscillatory potentials (Ops), photopic negative responses (PhNR). Optomotor response was performed to observe the differences of visual acuity. Expression of KLF7 was detected by western blot 4 weeks after AAV2-KLF7-GFP transfer.ResultsCompared with normal group, RGCs’ survival rates, amplitudes of ERG a-, b-wave, Ops, PhNR and visual acuity of mice in RIR group were decreased, and the differences were statistically significant (t=12.860, 7.157, 5.735, 8.953, 4.744, 9.887; P＜0.05). With the increase of light intensity, the amplitudes of scotopic ERG a- and b-wave were gradually increased while the incubation period was gradually shortened. Compared with RIR group, RGCs’ survival rates, amplitudes of ERG a-, b-wave, Ops, PhNR and visual acuity of mice in RIR-KLF7 group were increased, and the differences were statistically significant (t=6.350, 3.253, 3.695, 5.825, 5.325, 4.591; P＜0.05). Protein level of KLF7 was up-regulated in normal-KLF7 group than those in normal group, and the difference was statistically significant (t=4.105, P＜0.01).ConclusionOverexpression of KLF7 can improve RGCs’ survival rates and preserve the electrophysiological function.
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 expression of nuclear factor (NF)-κB and intercellular adhesion molecule (ICAM)-1 in rat′s retina injured by ischemia-reperfusion, and the effect of pyrrolidine dithiocarbamate (PDTC) on the expression of NF-κB and ICAM-1. Method The model of retinal ischemia-reperfusion was set up in 60 SD rats, which were divided into two groups with 30 rats in each: ischemia-reperfusion group and ischemia-reperfussion with injection of PDTC group. The left cephalic artery of each rat was ligated, and the right side was the control. Every group was subdivided into group 1 hour, 6, 12, 24, 48, and 72 hours after ischemia-reperfusion injury, and with 5 rats in each group. mRNA of NF-κB and ICAM-1 mRNA was measured by in situ hybridization (ISH) method in rat′s retina. Every rat underwent electroretinography (ERG) at the corresponding time before executed by neck breaking. Results In ischemia-reperfusion group, expression of NF-κB and ICAM-1 was detected at the 6th hour after ischemia-reperfusion, reached the highest level at the 24th hour, and weakened gradually later. In ischemia-reperfusion with injection of PDTC group, expression of NF-κB and ICAM-1 was detected at the 12th hour after ischemia-reperfusion, and reached the highest level at the 24th hour but lower than that in ischemia-reperfusion group. No expression of NF-κB and ICAM-1 was found in the control group. The relative recovery rate of ERG a and b wave amplitude in ischemia-reperfusion groups was lower than that in ischemia-reperfusion with injection of PDTC group at every stage(P＜0.01 ). The lowest relative recovery rate of ERG a and b wave amplitude in different stages in both of the 2 groups was at the 24th hour(P＜0.01). Conclusions NF-κB and ICAM-1 may play an important role in retinal ischemia-reperfusion injury, as the inhibitor of NF-κB, PDTC may relieve the retinal ischemia-reperfusion injury. (Chin J Ocul Fundus Dis，2004，20：175-178)
Objective To observe the effects of basic fibroblast growth factor (bFGF) on the expression of heat shock protein 70 (HSP70) in ratrs retina after iscbemia/reperfusion injury.Methods The rat model of experimental retinal ischemia/reperfusion injury was made by increasing the intraocular pressure. Tweenty-four Wistar rats were divided into normal (3 rats) and operation group (21 rats) randomly. The latter group was subdivided into group 0 hour, 4, 8, 12, 24, 48 and 72 hours after reperfusion, in which the left eyes of the rats were in the ischemia/reperfusion groups and the right ones were in the treatment groups (bFGF 2 t~g intracameral injection). The expression of HSP70 was observed by strept avidin-biotin complex (SABC) immunohistochemistry. Results No HSP70 positive cells were found in normal group; a few of HSP70 positive cells were found 0 hour after reperfusion [20.8±4. 5) cells/mm2], and increased gradually until reached the peak 24 hours later [(111.2±4.4) cells/mm2] and then decreased gradually. Few HSP70 positive cells were found 72 hours after reperfusion. The amount of HSP70 positive cells increased in treatment group at all time courses, and the peak time was earlier and longer than that in ischemia group. HSP70 positive cells distributed extensively in retinal ganglion cell layer and inner nucleous layer. The difference of the amount of HSP70 positive cells between the two groups was significant (Plt;0.05) 8, 12, 24, 48 and 72 hours after reperfusion.Conclusion bFGF can enhance the expression of HSP70 in rat’s retina after retinal ischemia/reperfusion injury.(Chin J Ocul Fundus Dis，2004，20：37-39)
OBJECTIVE To determine the role of endogenous carbon monoxide(CO) in oxidant-mediated organ injury following limb ischemia-reperfusion (I/R) in rats. METHODS: Sixty-four SD rats were divided into 4 groups: Sham group, Sham + zinc protoporphyrin (ZnPP, an inhibitor of heme oxygenase activity), 2-hour ischemia followed by 4-hour reperfusion (I/R) group and I/R + ZnPP group. Carboxyhemoglobin (COHb) level in the artery blood, malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in the lung, heart, liver and kidney were detected. The 24-hour survival rate of rats was studied. RESULTS: Compared with the sham group, the COHb level and MDA content significantly increased, while the SOD activity and the survival rate significantly decreased in I/R group (P lt; 0.05). Compared with the I/R group, MDA content significantly increased, while the SOD activity, the 24-hour survival rate and COHb level significantly decreased in I/R + ZnPP group (P lt; 0.05, respectively). CONCLUSION: Limb I/R could lead to the oxidant-mediated multiple organ injury accompanied by the increase of CO level which play an important role in the defense against I/R-induced remote multiple organ injury in rats.
ObjectiveTo dynamically observe the effect of N-acetylserotonin (NAS) on the expression of tumor necrosis factor-α (TNF-α) protein in retina of retinal ischemia reperfusion injury (RIRI) rats, and to explore the mechanism.MethodsBy using random number table method, 90 healthy male Sprague-Dawley rats were divided into sham operation group (n=10), RIRI group (n=40), and NAS group (n=40). The right eye was as the experimental eye. In the RIRI group and NAS group, the anterior chamber high intraocular pressure method was used to establish the RIRI model. In the NAS group, 10 mg/kg NAS was injected intraperitoneally before modeling and 30 minutes after modeling. At 6, 12, 24, 72 h after modeling, hematoxylin-eosin staining was used to observe the pathological changes of the retina, and the retinal ganglion cells (RGC) were counted. Each group was detected by immunohistochemical staining and Western blot about the relative expression of TNF-α, nuclear factor E2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) protein in the rat retina. One-way analysis of variance was used for differences between groups. The general linear regression method was used to analyze the correlation between the relative expression changes of TNF-α protein and the changes of Nrf2 and HO-1 protein expression after NAS intervention.ResultsOptical microscope observation revealed that the retinal edema of rats in the RIRI group was observed at 6, 12, and 24 h after modeling; the thickness of the retina in the NAS group was significantly thinner than that in the RIRI group, and the difference was statistically significant (F=9.645, 477.150, 2.432; P＜0.01). At 6, 12, 24, and 72 h after modeling, the retinal RGC counts in the NAS group were significantly higher than those in the RIRI group, and the difference was statistically significant (F=12.225, 12.848, 117.655, 306.394; P＜0.05). The results of immunohistochemical staining and Western blot showed that 6 h after modeling, the relative expression of TNF-α protein in the retina of the RIRI group increased significantly compared with that in the sham operation group, reaching a higher level at 12 h, and decreased at 24 and 72 h. But all were significantly higher than the sham operation group, the difference was statistically significant (immunohistochemical staining: F=105.893, 1 356.076, 434.026, 337.351; P＜0.01; Western blot: F=92.906, 534.948, 327.600, 385.324; P＜0.01). At different time points after modeling, the relative expression of TNF-α protein in the retina of the NAS group was significantly lower than that of the RIRI group (immunohistochemical staining: F=15.408, 570.482, 21.070, 13.767; P＜0.05; Western blot: F=12.618, 115.735, 13.176, 111.108; P＜0.05), but still higher than the sham operation group (immunohistochemical staining: F=40.709, 151.032, 156.321, 216.035; P＜0.01; Western blot: F=33.943, 79.729, 74.057, 64.488; P＜0.01), the difference was statistically significant; 12 h after modeling, Nrf2 in the retina of the NAS group (immunohistochemical staining: F=51.122, P＜0.05; Western blot: F=33.972, P＜0.05), HO-1 (immunohistochemical staining: F=30.750, P＜0.05; Western blot: F=18.283, P＜0.05) protein relative expression was significantly higher than that of RIRI group, and the differences were statistically significant. The results of linear regression analysis showed that the difference in the number of TNF-α+ cells in the RIRI group and the NAS group was negatively correlated with the difference in the number of Nrf2+ and HO-1+ cells (r2=0.923, 0.936; P＜0.01).ConclusionsNAS can inhibit the expression of TNF-α protein in the retina of RIRI rats and reduce RIRI. The mechanism may be related to the Nrf2/HO-1 pathway.
Objective To investigate the damage to the retinal cells and apoptosis of retinal cells of rats after ischemia-reperfusion insult. Methods The retinal ischemia-reperfusion model was developed by increasing intraocular pressure to 109725 mm Hg in rat eyes. Morphological changes of the rat eyes were observed by means of routine histopathology with HE staining. Apoptosis of the retina was assayed by both DNA fragmentation gel-electrophoresis and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labelling (TUNEL). Results Compared with the normal control, no histopathological changes were revealed in the rat retinas 30 min after the ischemia and then reperfued for 24 h or 48 h. Retinal ganglion cell layer (RGL) and inner plaxiform layer (IPL) of the retina were observed, however, to become significantly thinner 60 min after the ischemia and then reperfued for 24 h or 48 h. Together with the pathological changes DNA ladder pattern was detected in the same group of the rats. Further, immunochemical stain of the eye demonstrated that TUNEL positive cells were localized in RGL and IPL of the retina. Conclusion Ischemia-reperfusion insult of the eye may remarkably damage the retina of the rat eye. The damage to the retinal cells is mainly localized within RGL and IPL and apoptosis is the important mechanism of the retinal disorder. (Chin J Ocul Fundus Dis, 2002, 18: 296-298)