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 explore the mechanism of microvascular spasm after limb ischemia-reperfusion. METHODS: The rabbit hindlimb normothermic tourniquet ischemia model was employed. The tendon on the dorsum of the foot was exposed for observation of microvessels. The responses of arterioles on tendon surface to topical application of 10(-6) mol/L noradrenaline (NE) (a vasoconstrictor), 10(-6) mol/l acetylcholine(Ach) (an endothelium-dependent vasodilator) and 10(-4) mol/L nitroglycerin(NTG) (an endothelium-independent vasodilator) were observed at the period of ischemia and following 30 minutes of reperfusion after 2 hours and 5 hours of ischemia by use of intravital microscopy. RESULTS: No significant changes in the responses of arterioles to NE, Ach and NTG were noted following 30 minutes of reperfusion after 2 hours of ischemia compared with pre-ischemia. The constrictor responses of arterioles to NE were still not significantly altered following 30 minutes of reperfusion after 5 hours of ischemia, however, the dilation responses to Ach and NTG were significantly decreased (to Ach P lt; 0.01; to NTG, P lt; 0.05). CONCLUSION: Reperfusion after 5 hours of ischemia significantly impairs both the endothelium-dependent and endothelium-independent vasodilation, meanwhile preserves constrictor responses to NE, these may contribute to the genesis of the vasospasm in ischemia reperfusion.
ObjectiveTo investigate the effect of power-assisted intravascular shunt in replantation of amputated limbs of rabbits. MethodsEighty rabbits weighing 1.8-2.5 kg (male or female) were selected to establ ish the model of circular amputation at the hind groin, only femoral arteries and veins were completely preserved. After the femoral artery was clamped in 60 rabbits, the rabbits underwent power-assisted intravascular shunt with high-flow rate (group A, n=20), powerassisted intravascular shunt with low-flow rate (group B, n=20), and no power-assisted intravascular shunt (group C, n=20) to reconstruct blood supply; the femoral artery was not clamped in another 20 rabbits of sham group (group D). Before and after intravascular shunt (1, 3, 6, and 12 hours), the malondialdehyde (MDA), lactate dehydrogenase (LDH), and creatine kinase (CK) of the serum were determined. The myeloperoxidase (MPO), MDA, and wet to dry weight ratio (W/D ratio) of the gastrocnemius muscle were measured, and the thrombogenesis and survival rate of limb were observed. ResultsBefore intravascular shunt, MDA, LDH, and CK of the serum and MPO, MDA, and W/D ratio of the muscle showed no significant difference among 4 groups (P>0.05). At each time point after intravascular shunt, no significant difference was found in all indexes between groups A and D (P>0.05); the indexes of groups B and C were significantly higher than those of groups A and D (P<0.05); the values were the highest in group C (P<0.05), and reached the peak at 12 hours. All limbs of group A survived with low thrombosis rate, and less limbs could survive with high thrombosis rate in group C. ConclusionThe power-assisted intravascular shunt with high-flow rate can effective ensure the blood supply of the amputated limbs of rabbits with lower limb injury and higher survival rate of amputated limbs after replantation.
Objective To summarize the function of Kupffer cell for the ischemia reperfusion injury after liver’s transplatation. Methods The literatures which about the function of Kupffer cell for the ischemia reperfusion injury after liver’s transplatation were reviewed. Results Kupffer cells are the resident macrophages of the liver, which can be activated to generate a range of inflammatory mediators, including cytokines, reactive oxygen intermediates, chemokines, and other factors to startup the ischemia reperfusion injury （IRI）, and to cause the liver graft dysfunction. On the other hand, Kupffer cells can protect the ischemia reperfusion injury by release NO and HO-1. The CO, which is the byproduct of heme degradation by the heme oxygenases （HO-1），has the same function for IRI. Conclusions The Kupffer cells have bidirectional function for the ischemia reperfusion injury of liver’s transpatation. Thus, how to decrease the harmful factors and up-regulate the beneficial substances by Kupffer cells will be the key points in preventing IRI after liver transplantation in future.
Objective To investigate the molecular mechanism of multiple cellular factors expressed shortly after ischemia reperfusion (IR) injury from the pathway of nuclear factor kappa B (NF κB). Methods The isolated heart models were established and sixty six rats were randomly divided into experimental group and control group. The deoxyribonucleic acid (DNA) binding activities of NF κB, the inhibitory kappa B (IκBα) levels in cytoplasm and tumor necrosis factor α (TNF α) messenger ribonucleic acid (mRNA) expressions were determined after 5, 15 min ischemia in experimental group, both after 0, 5, 15, 30 min ischemia and concomitantly 5, 15, 30, 45, 60 min reperfusion in control group. Results Augment of DNA binding activities of NF κB and reduction of IκBα in cytoplasm shortly after ischemia results were observed in control group. The level of IκBα was restored after reperfusion, the DNA binding activities of NF κB was further augmented. DNA binding activities of NF κB and TNF α mRNA expressions were lower in experimental group than those in control group. Conclusions NF κB in IR myocardium is activated by two different pathways: p65 p50 heterodimers and p50 p50 homodimers. In addition, the results suggest that early activation of NF κB induced by ischemia in the myocardium could be a signal mechanism for controlling and regulating immediate gene expressions during ischemia reperfusion.
Objective To study the interaction and mechanism of prostaglandin I2 (PGI2) receptor/thromboxane A2 (TxA2) receptor (IP/TP) and cyclooxygenase-2 (COX-2) in ischemia reperfusion injury after liver transplantation of rat. Methods Rats were randomly divided into three groups: control group （n=16), orthotropic liver transplantation group （n=32) and nimesulide intervention group （n=32). The samples were obtained at 3 h, 6 h, 12 h and 24 h after operation. The expressions of COX-2, IP and TP mRNA were detected by RT-PCR. Immunohistochemistry was used to detect the localization and expression of COX-2. Hematoxylin Eosin staining was used to classify the injury extent of liver. Serum ALT and AST levels were detected to evaluate the changes of liver enzyme. Results COX-2 protein expression detected by immunohistochemistry in orthotropic liver transplantation group mainly distributed in the district of liver sinusoidal endothelial cells, liver cells and macrophage cells, which was significantly higher than control group and nimesulide intervention group. Expressions of IP mRNA, TP mRNA and COX-2 mRNA in the orthotropic liver transplantation group were significantly increased than those in control group (P＜0.05), and the ratio of IP/TP increased (P＜0.05). Expressions of IP mRNA and TP mRNA in nimesulide intervention group were significantly lower than that in the orthotropic liver transplantation group at 6 h and 12 h after operation (P＜0.05), and the ratio of IP/TP decreased at 3 h, 6 h and 24 h after operation (P＜0.05). The expression of COX-2 mRNA in nimesulide intervention group was significantly lower than that in the orthotropic liver transplantation group at 6 h, 12 h and 24 h after operation. In orthotropic liver transplantation group liver injury was obvious by HE staining, and more severve than that in nimesulide intervention group. Serum AST (each time) and ALT (3 h, 6 h and 12 h) levels in the orthotropic liver transplantation group were significantly higher than that in control group and nimesulide intervention group (P＜0.05) and peaked at 6 h after operation. Conclusion The balance of IP/TP takes part in and plays an important role in the ischemia reperfusion injury of liver transplantation. Changing imbalance of IP/TP may reduce liver transplantation ischemia reperfusion injury by inhibiting COX-2 expression.
ObjectiveTo explore the effect of hypertonic saline (HTS) pretreatment on levels of nitric oxide (NO) and endothelin-1(ET-1) and their correlation in hepatic ischemia reperfusion (HIR) injury in rats. MethodsThe HIR injury models were made by using Pringle, s maneuver in 45 healthy adult male Sprague-Dawley rats, which were randomly divided into three groups (n=15):sham operation (SO) group, HIR group, and HTS group. The animals were killed at 1, 6, and 24 h after reperfusion. The levels of serum NO and ET-1 were measured respectively, the correlation between NO level and ET-1 level at 6 h after reperfusion was analyzed. ResultsAt the time points of 1 h, 6 h, and 24 h after reperfusion, the serum NO levels in the HTS group and HIR group were all significantly lower than those in the SO group (P < 0.01), but the serum ET-1 levels were all significantly higher than those in the so group (P < 0.01). The serum NO levels at the time points of 1 h, 6 h, and 24 h in the HTS group were significantly higher than those at the same time in the HIR group (P < 0.01), but the serum ET-1 levels in the HTS group were significantly lower than those in the HIR group (P < 0.01). At all the time points, every detected goal had more marked level at the time point of 6 h after reperfusion. The NO level was negatively correlated with the ET-1 level. ConclusionsHTS could change levels of serum NO and ET-1 after HIR injury, and which has a negative correlation. Its mechanism might probably stimulate serum NO level and reduce the ET-1 level through some way so as to enable both dynamic balance to the benign development direction and achieve a protective effect.
ObjectiveTo discuss the protection effect of controlled reperfusion with Xuebijing injection on ischemia-reperfusion injury of rabbit hind limb, and provide a theoretical basis for prevention and treatment of limb ischemia reperfusion injury in clinical. MethodsThe big ear rabbit model of hind limb ischemia-reperfusion injury (ischemia 2 h, reperfusion 4 h) was made. Thirty healthy big ear rabbits were randomly divided into three groups: Xuebijing perfusion group (n=10): Xuebijing injection was given before reperfusion; Saline control group (n=10): surgical procedure with Xuebijing perfusion group, saline infusion was given before reperfusion; sham operation group (n=10): surgical procedure with Xuebijing perfusion group, ischemia and reperfusion was not performed. The activity of serum superoxide dismutase (SOD) and content of malondialdehyde (MDA) were detected. The ratio of blood flow (rBF) and ratio of blood volume (rBV) were tested. Results①Compared with the levels before operation, the activity of SOD and content of MDA had no significant differences after operation in the sham operation group (P > 0.05), the activity of SOD was obviously increased and the content of MDA was obviously decreased after reperfusion in the Xuebijing perfusion group (P < 0.01). Compared with the saline control group, the activity of SOD was obviously increased and the content of MDA was obviously decreased in the Xuebijing perfusion group.②Compared with the sham operation group, the rBF and rBV were obviously decreased in the Xuebijing perfusion group and the saline control group (P < 0.05); Compared with the saline control group, the rBF and rBV were obviously increased in the Xuebijing perfusion group (P < 0.05). ConclusionControlled reperfusion with Xuebijing injection could increase SOD activity in serum, reduce MDA content, it has a protective effect on hind limb ischemia-reperfusion injury in rabbits, and could effectively improve perfusion of hind limb.
OBJECTIVE: To study the hemorheology of island flap after ischemia-reperfusion injury and modulation of dexamethasone. METHODS: Sixty Wister rats were made ischemia-reperfusion injury model, and divided into two groups randomly(Group I: intraperitoneal injection of normal saline 2 ml/kg as control group; Group II: intraperitoneal injection of dexamethasone 5 mg/kg as experimental group). Flap survived areas were measured and neutrophil necrosis numbers in flaps were counted. Erythrocytes and neutrophil hemorheology were observed. RESULTS: Area survived flap in group II was larger than that in group I. Neutrophil necrosis numbers were less in group II than in group I (P lt; 0.05). Whole blood hyposhear viscosity, erythrocyte aggregation, Casson yield stress and nerutrophil adhesion ability were higher in group I than in group II (P lt; 0.05); and the neutrophil deformability was lower in group I than in group II. CONCLUSION: Flap inchemia-reperfusion can increase erythrocyte aggregation index and neutrophil adhesion ability. Dexamethasone can improve these and decrease neutrophil necrosis numbers, so as to prevent flap from ischemia-reperfusion injury.
Objective To study the protective effects of ischemic preconditioning(IP) duration against ischemic reperfusion injury of skeletal muscle. Methods Thirty-six Wister rats were made amputation-like models, which underwent temporary amputation at the level of the femur, excluding the femoral vessels. They were divided into 6 groups(n=6) according to different treatments before ischemiareperfusion: group A(4 hours of ischemiareperfusion); groups B, C, D, E(5, 10,15, 20 minutes of ischemia and 5, 10, 15, 20 minutes of reperfusion respectively, for 3 cycles, 4 hours ischemiareperfusion ); group F (no ischemia-reperfusion). The malondialdehyde(MDA), the extent of edema and necrosis of skeletal muscle were measured to observe protective effects of different ischemic preconditioning duration. Results Five minutes of ischemic preconditioning（IP5）could protect skeletal muscle of ischaemia against necrosis and the survival area of the muscle was 82.47%.The effects of IP10 and IP 15 were significantly superior to that of IP5 and the survival areas of the muscle were 89.03% and 89.49%. The effect of IP20(78.27%) was significantly inferior to that IP5. IP5 could reduce edema of skeletal muscle, the effect of IP10 was significantly superior to that of IP5. IP5, IP 10,and IP 15 could decrease the level of MDA, but IP20 did not decrease it. Conclusion The trend of protective effect of IP on ischemia-reperfusion injury of themuscle in rats first rise to the peak and then go down,10minutes ofIPis optimal.