ObjectiveTo study the changes of levels of α subunits of stimulatory (Gsα) and inhibitory guanine nucleotide binding protein (Giα) in newborn guinea pig (0 2 days old) myocardium undergoing global ischemic reperfusion, and influences on the changes by St.Thomas Ⅱ and cold blood cardioplegic solution.MethodsThirty newborn guinea pigs were randomly assigned to three groups. GroupⅠ ( n = 10): the newborn hearts suffered by hypothermic global ischemia; group Ⅱ( n =10): the newborn hearts arrested by St. Thomas Ⅱ , and group Ⅲ ( n = 10): the newborn hearts arrested by cold blood cardioplegic solution. Levels of Gsα and Giα were investigated with Western blot analysis.ResultsNo differences of levels of Gsα and Giα were found in three groups before ischemia ( P gt;0.05). The level of Gsα after ischemia was significantly decreased than before ischemia in groupⅠand group Ⅱ ( P lt; 0 01), whereas no pronounced changes in group Ⅲ ( P gt;0.05) were noted after ischemia. The level of Gsα in group Ⅲ was not significantly changed after reperfusion compared with before ischemia( P gt;0 05), and it was much higher than those in groupⅠand group Ⅱ ( P lt; 0 01). Level of Giα was found not markedly changed in group Ⅲ after reperfusion compared with that before ischemia, but was notable higher in groupⅠand group Ⅱ( P lt;0.01). ConclusionsSignificant decrease of level of Gsα, whereas marked increase of level of Giα are found in myocardium of newborn guinea pig undergoing hypothermic (20℃) ischemic reperfusion. No impact of St. Thomas Ⅱ on these changes is verified, but recovery to the level of Gsα and Giα before ischemia is achieved by cold blood cardioplegic solution after ischemia and reperfusion. Unbalance between Gsα and Giα is the one of the mechanisms of ischemic reperfusion injury for immature myocardium.
ObjectiveTo observe the expression of Caspase-3, Caspase-8, Bcl-2, Bax in the rat retina of ocular ischemic syndrome (OIS). Methods30 Brown Norway rats were randomly divided into experimental group and control group, 15 rats in each group. The rats in experimental group were established a model through ligating the bilateral common carotid artery. At 3 months after modeling, the retinal thickness and ganglion cell (RGC) density were measured by hematoxylin eosin staining; the expression of Caspase 3, Caspase 8, Bax and Bcl-2 in the retina was measured by quantitative real-time reverse transcription polymerase chain reaction. ResultsThe RGC density in control group and experimental group was 61.97±9.07 and 38.1±5.98, respectively. Compared to the control group, the RGC density was diminished in the experimental group (t=3.059, P < 0.01). A significant decrease was found in the total retina (t=3.036), inner plexiform (t=3.715), inner nuclear (t=3.339) and outer plexiform (t=3.341) thickness (P < 0.05). However, no change of the thickness was evident in the outer nuclear layers (t=2.000, P > 0.05). The levels of protein and RNA expression of Caspase 3, Caspase 8 and Bax in the retina were increased in experimental group (F=17.036, 7.787, 11.431, 11.162, 17.763, 12.183; P < 0.05), while the Bcl-2 expression were decreased (F=10.298, 12.047; P < 0.05). ConclusionsThere is obvious expression of apoptosis-associated proteins in the rat retina of OIS. Caspase 3, Caspase 8 and Bax expression are increased, while Bcl-2 expression are decreased.
To investigate the role of platelet-activating factor (PAF), neutrophils in ischemia-reperfusion-induced liver injury and their possible mechanism, PAF and the degree of neutrophil infiltration in liver tissue and the preventive effects of PAF antagonist kadsurenone were evaluated in this study by means of a partial liver ischemia model, in which it was induced by clamping only left and median lobes of the liver without causing intestinal congestion. The present study was undertaken to find out the mechanism of liver ischemia-reperfusion injury and preventive effect of kadsurenone. The results indicate that in early stage of reperfusion liver injury possibly caused by the generation of free radicals, declined of autioxidant defence and increased Ca２＋ influx, and in the later stage of reperfusion injury was mainly mediated by accumulation of PAF in the liver, which elicits the release of polymorphonuclear leukocytes induced toxical free radical, endothelial damage, microcirculatory collapse. The authors conclude that the effectiveness of antagonist kadsurenone in protecting against ischemiareperfusioninduced liver injury is due not only to their action in preventing the direct effects of PAF, but also to their ability to inhibit both PAF priming and PAF dependent feedback processes, thus preventing escalation of auto generated inflammatory damage.
OBJECTIVE: To observe the changes of heme oxygenase-1 (HO-1) expression in the skeletal muscle after ischemia-reperfusion of hind limb in rats. METHODS: A model of hind limb ischemia was made by clamping femoral artery with a microvascular clip. Soleus muscle was obtained from the animals received sham operation, 4 h ischemia without reperfusion and 2 h, 4 h, 8 h, 16 h, 24 h reperfusion after 4 h ischemia. Soleus histology and malondialdehyde (MDA) content were measured. The levels of HO-1 mRNA and protein were measured in different time by Northern blotting, Western blotting and immunohistochemistry technique. RESULTS: After ischemia-reperfusion of limb, HO-1 mRNA increased at the 2nd hour, reached a peak at the 8th hour, and returned toward baseline at the 24th hour. The change of protein level was essentially in agreement with that of mRNA. Immunohistochemical results showed that HO-1 expressed primarily in skeletal muscle cytoplasma. There were no positive signals of mRNA and protein in sham group and in ischemia group. After limb reperfusion, MDA contents in the soleus muscle increased significantly when compared with that in the sham group (P lt; 0.05). MDA content of the 8th after reperfusion decreased significantly when compared with that of the 4 h after reperfusion (P lt; 0.05). CONCLUSION: Ischemia-reperfusion can induce HO-1 expression in skeletal muscle in rats, which may provide protection for injured tissue.
Objective To analyze the protective effects of heat-shock response on the retinae of the rats after retinal ischemic reperfusion injury.Method Twenty Wistar rats (20 eyes) were divided into 4 groups: intracameral perfusion group (group P), intracameral perfusion after quercetin injection group (group P+Q), intracameral perfusion after heat shock group (group P+H), and in tracameral perfusion after quercetin injection and heat shock group (group P+Q+H ). According to the standard program established by International Society for Clinical Visual Electrophysiology, we recorded the results of the dark-adapted electroretinogram (D-ERG ),oscillatory potentials (OPs),and light-adapted ERG (L-ERG) of the rats with intraocular hypertension after induced by heat shock response. The expressions of HSP 70 of the rats in all groups were observed by Western blotting.Results The expression of HSP 70 of the rats in group P+H was the highest in all groups, but the expressions of HSP70 in group P+Q and P+Q+H were inhibited significantly. The amplitudes of a and b wave of ERG and O2 wave of OPs decreased, and the delitescence of them were delayed significantly in rats after intracameral perfusion. The amplitude of b wave of D-ERG and O2 wave of OPs in group P+H were higher than which in group P. Zero hour after perfusion, the amplitudes of all waves in group P+H increased significantly (Plt;0.05). Twenty-four hours after perfusion, the retinal functional resumption of the rats in group P+H was better than which in group P. In group P+Q and P+Q+H, the delitescences of all waves of ERG and O2 wave of OPs were the longest and the amplitudes were the lowest, and some waves even disappeared.Conclusions The heat-shock response may improve the recovery ability of the retinal cells after injury of ischemic reperfusion.(Chin J Ocul Fundus Dis，2003，19：117-120)
Objective To establish a new model on isolated human cadaver testes with ischemiareperfusion (I/R). MethodsThirteen isolated cadaver testes contributed by 13 persons were preserved under 0℃-4℃ hypothermia and then reperfused under 37℃. Histological and histochemical changes were observed. Results4℃ cold ischemia in 12 hours induced only trivial swelling and vascular degeneration of endothelial cells (ECs), obvious pathologic changes occurred after 24 hours, including detachment of ECs, separation between basement membrane and seminiferous epithelium, degeneration and detachment of spermatogenous cell and edema of mesenchyme. Injury was worse along with the prolongation of cold preservation time. Changes of LDH and SDH activities were found by histochemical staining. Reperfusion following 6 hours ischemia induced tissue injury and unusual enzyme activity. All changes were more obvious after reperfusion following 12,18,24 or 36 hours cold ischemia.Conclusion This new model on isolated cadaver testes with ischemiareperfusion is successful, it can substitute other solid organs of human beings for I/R injury study.
Objective To study the efect of IH764-3 on ischemia-reperfusion (I/R) injury in rat liver. Methods Rats were divided into 3 groups, the control group was not subjected to ischemia and no treatment was given. I/R injury group was subjected to 40 minutes ischemia followed by reperfusion for 120 minutes. The IH7643 group (40mg/kg) was administred at ischemia and reperfusion. Results In the IH764-3 group, sereum levels of ALT, AST, AKP and γ-GT were significantly lower than those in the I/R group. Energy charge level recovery was significantly higher with IH7643 (P＜0.05), hepatic ultrastructure was better preserved with IH764-3. Conclusion IH764-3 may be useful in the treatment of hepatic ischemia reperfusion injury
Objective To investigate the effect of cold ischemia on the development of transplant arteriosclerosis (TA) in rat aortic isografts. Methods Aorta grafts from SD and Wister rats were stored in a cold perfusion solution for 0.5 hours and 4 hours respectively before being orthotopically transplanted to Wister recipients. After observation times ranging from 15 to 60 days, the grafts were examined by using histological and electron microscopy techniques. Regional changes in the lumen, intima and media layers were measured by using an image analysis system. Results Partial intima thickings were showed in control isografts at 60 day posttransplantation. Pronounced intima thickings were seen in experimental isografts and control allografts at the same time. The thicking neointimas consist mainly of monocyte/macrophage and smooth muscle cells (SMC). The broken interior elastic lamina (IEL) and necrosis SMC in media were detected in allogenic grafts. Conclusion The damage due to prolonged cold ischemia time is sufficient to cause pronouced graft arteriosclerosis.