Objective To determine whether the different durations and times of the ischemic preconditioning affect the effectiveness of the ischemic preconditioning. Methods Ninety male Wistar rats were randomly divided into the control group and the eight preconditioned groups of 10 rats each. A transverse rectus abdominis musculocutaneous flap (TRAM) was elevated in each rat. The flaps were preconditioned by clamping the pedicle and reperfusing for 5 or 10 minutes per cycle. This was repeated for one or two cycles. The controls were simply perfused for 30 minutes. Each flap was then subjected to 4 hours of the global ischemia. Three rats in each group were killed for anestimate of the water content in the muscle and for observation on the muscularstructure under microscope. The flap surface survival areas of the other rats were calculated on the 7th postoperative day by the computerized video planimetry. Results The water content in the muscle was evidently reduced. The mean survival area of the flap in every preconditioned group increased by2-3 times compared with that of the controls(P＜0.001). The different proceduresof the ischemic preconditioning produced different protective effects. Conclusion The ischemic preconditioning is an available means to alleviate an ischemiareperfusion injury to the transverse rectus abdominis musculocutaneous flap in rats. The effect of the ischemic preconditioning is affected by the duration and time of the ischemic preconditioning.
Objective To observe the influences of depolarized arrest and hyperpolarized arrest on alternation of fluidity of myocardial cell membrane during cardiopulmonary bypass (CPB) and evaluate the protective effects on myocardium of hyperpolarized arrest. Methods Seventy-two felines were randomized into three groups, each group 24. Control group: 180 minutes of CPB was conducted without aortic and vena caval cross-clamping. Depolarized arrest group: hearts underwent 60 minutes of global ischemia after aortic cross-clamping (ACC) followed by 90 minutes of reperfusion. The cardioplegic solution consisted of St. Thomas solution (K+16mmol/L). Hyperpolarized arrest group: the protocol was the same as that in depolarized arrest group except that the cardioplegic solution consisted of St.Thomas solution with pinacidil (50 mmol/L,K+5mmol/L). Microviscosity, the reciprocal of fluidity of myocardial membrane was measured in all groups by using fluorescence polarization technique. (Results )Microvis cosity of myocardial cell in depolarized arrest group during ACC period was significantly higher than that before ACC and kept on rising during reperfusion period. Microviscosity of myocardial cell in hyperpolarized arrest group during ACC was trending up and reperfusion periods as well, but markedly lower compared to that in depolarized arrest group at corresponding time points(Plt;0.01). Conclusion Hyperpolarized arrest is more effective in protecting myocardial cells from ischemia-reperfusion injury than depolarized arrest during CPB by maintaining better fluidity of myocardial membrane.
【Abstract】 Objective To study the effects of ischemic preconditioning (IP) on the activity of nuclear factor-κB （NF-κB） and the expressions of TNF-α and intercellular adhesion molecule-1 (ICAM-1) during early reperfusion following liver transplantation in rats. Methods The models of rat orthotopic liver transplantation were established. The donor livers were stored for 2 hours in Ringers solution at 4 ℃ before transplantation. All rats were randomly divided into sham operation group （SO group）， control group and IP group. IP group was achieved by clamping the portal vein and hepatic artery of donor liver for 10 minutes followed by reperfusion for 10 minutes before harvesting. The activity of NF-κB and expressions of TNF-α and ICAM-1 at 1 h, 2 h, 4 h and 6 h after reperfusion were measured. Serum ALT, LDH were also determined. Results The liver function of recipients with IP were significantly improved. Compared with SO group， the graft NF-κB activity increased after transplantation in control group and IP group (P＜0.05), while compared with control group that was significantly attenuated at 1 h and 2 h in IP group. Similarly, hepatic levels of TNF-α and ICAM-1 were significantly elevated in control group and were reduced in IP group. Conclusion IP might down-regulated TNF-α and ICAM-1 expression in the grafts after orthotopic liver transplantation through depressed NF-κB activation， and attenuate neutrophil infiltration in the grafts after reperfusion.
【Abstract】 Objective To investigate the effect of verapamil on apoptosis, calcium and expressions of bcl-2 and c-myc of pancreatic cells in ischemia-reperfusion rat model. Methods Wistar rats were randomly divided into three groups: control group （n=10）; ischemia-reperfusion group （n=10）; verapamil treatment group （n=10）. The anterior mesenteric artery and the celiac artery of rats in both ischemia-reperfusion group and verapamil treatment group were occluded for 15 min followed by 12-hour reperfusion. Verapamil （1 mg／kg） was injected via caudal vein to the rats in verapamil treatment group 15 min before occlusion and 1 hour after the initiation of reperfusion, respectively; and ischemia-reperfusion group was given the same volume of salient twice intravenously. Pancreatic tissues were collected from the dead rats after twelve hours since the reperfusion. The pathologic characters of pancreatic tissue were observed under light microscope; The level of calcium in the tissue was measured by atomic absorption spectrometer; TUNEL was used to detect apoptosis of pancreatic cells; and the expressions of c-myc and bcl-2 in the cells were also analyzed by immunohistochemistry technique and flow cytometry. Results The pathologic change in verapamil treatment group was less conspicuous than that of ischemia-reperfusion group. Both the calcium level and the number of apoptotic cells in verapamil treatment group were less than those of ischemia-reperfusion group 〔（411.1±55.8） μg/g dry weight vs （470.9±31.9） μg/g dry weight, P＜0.05 and （9.5±2.9）% vs （18.4±3.1）% 〕, P＜0.05. After taking verapamil, the number of apoptotic cells decreased, whereas the expressions of bcl-2 and c-myc increased. The fluorescent indexes of bcl-2 and c-myc in verapamil treatment group were significantly higher than those of ischemia-reperfusion group (1.72±0.11 vs 1.41±0.07, P＜0.05; 1.76±0.19 vs 1.55±0.13, P＜0.05. Conclusion Ischemia-reperfusion injury can induce apoptosis of pancreatic cells. Verapamil could protect the injured pancreatic tissue by reducing the level of calcium, stimulating the expressions of bcl-2 and c-myc and inhibiting apoptosis of pancreatic cells.
【Abstract】Objective To study the protective effects of anisodamine on liver ischemia-reperfusion injury in rats. Methods One hundred and sixty male Wistar rats were randomly divided into the normal control (n=10), ischemiareperfusion (n=50), normal saline (n=50) and anisodamine (n=50, 2.0 mg/kg) groups. The animals were killed 1, 3, 6, 12, 24 hours after ischemia induced for 60 minutes and followed by reperfusion. Plasma endothelin-1 (ET-1), hyaluronic acid (HA), glutamic-pyruvic transaminase enzyme (ALT) were measured, and the hepatic histopathologic alterations were also observed. Results The plasma ET-1, HA and ALT concentrations were markedly increased after liver ischemiareperfusion.The hepatic congestion was significantly obvious. An intravenous injection of anisodamine before ischemiareperfusion could decrease the plasma HA and ALT concentrations and relieve the hepatic congestion. Conclusion Anisodamine can improve hepatic microcirculatory disturbances after reperfusion and have hepatoprotictive effects on rat liver ischemia-reperfusion injury.
Objective To summarize recent research advancement on gene therapy for hepatic ischemia-reperfusion injury (IRI). Methods Relevant references about basic and clinical researches of hepatic IRI were collected and reviewed. Results Recent experimental researches indicated that the expression of several genes and cytokines could protect hepatic cells by suppressing cell apoptosis, decreasing the production of oxyradical, remaining and improving portal venous flow, promoting bilifaction, self immunoloregulation and decreasing inflammatory reaction, so that it could decrease IRI. Conclusion IRI could be decreased by regulating the expressing of target genes or transducing relative genes in vivo, but the path of gene transfer and the selection and optimization of gene carrier still need more basic and clinical researches to prove.
Objective To investigate the maximum tolerance limit of rats to hepatic inflow occlusion with portal vein blood bypss (PBB) in normothermia. Methods First. A new animal model was established, the animal survival rate were calculated following 7 days of reperfusion after hepatic inflow occlusion of 30, 60, 90, 100, 110, 120 min or portal triad clamping (PTC) of 30 min. And then, the hepatic energy metabolism (RCR, P/O, ATP, AKBR) was studied following 30, 90, 120 min of ischemia or 1, 6, and 24 hours of reperfusion after the ischemia. According to the reversibility of the hepatic motochondrial function injury and maximum as long as a period of liver warm ischemia of all animal postoperative 7 days survial, the safe limit of rat to hepatic inflow occlusion was evaluated. Results The survival rate on postoperative 7 days was one hundred percent subjected to 30, 60 and 90 min of hepatic inflow occlusion, and 50, 30, 20 percent in 100, 110, 120 min, respectively, the survival rate in rats with 30 min of portal triad champing was about 40 percent. The parameters of hepatic motochondrial function reflecting the degree of liver damage to ischemia showed significantly different as compared to sham group. The functional lesion was exacerbated during inital reperfusion, then was restored progressively in PBB-30 min and PBB-90 min groups, but was maintained low level in PBB-120 min and PTC-30 min groups.Conclusion The 90 minutes is the maximum limit of rats to hepatic inflow occlusion in normothermia.
Objective To review the treatment methods and techniques of ischemia-reperfusion injury of flap. Methods Recent basic research l iterature concerning ischemia-reperfusion injury of flap was reviewed and analyzed in terms of treatment techniques. Results Ischemia-reperfusion injury is one of the leading causes of flap necrosis postoperatively. Interventions against any l ink of the ischemia-reperfusion injury progress could effectively reduce the damageand improve the survival rate of flaps. Conclusion Including production of reactive oxygen species, neutrophil infiltrationetc are thought to be the main mechanisms of ischemia-reperfusion injury. Treatment including medicine administration and physical intervention against any specific l ink of ischemia-reperfusion injury can interfere or block the whole progress, which reduce the damage of ischemia-reperfusion injury and improve the survival rate of animal flap models eventually.
Objective To investigate the protective effects of liposome prostaglandin E1（Lipo-PGE1） on myocardial ischemia-reperfusion injury （MIRI） during cardiopulmonary bypass （CPB）. Methods Thirty-two patients with clearly diagnosed heart valve disease and congenital heart disease such as atria septal defect （ASD） and ventricular septal defect （VSD） were selected in our hospital. The patients were randomly divided into two groups （16 patients in each group）, Lipo-PGE1 group： Lipo-PGE1（2ng/kg·min） was continuously pumped before starting of CPB until 2 h after ascending aortic off-clamping; control group： using the same volume of normal saline, arterial blood samples were taken before CPB, at 1, 2, 6 and 24 h after the ascending aortic off-clamping. The value of cardiac troponin I （cTnI）, creatine kinase MBmass （CK-MB）, interleukin-6 （IL-6）, tumour necrosis factor-α （TNF-α）, intercellular adhesion molecule-l（sICAM-1） were measured. Results cTnI, CK-MB, IL-6, TNF-α and sICAM-1 showed no significant difference in the two groups before CPB （P〉0. 05）. At 1,2, 6 and 24h after ascending aortic off-clamping, those values rose significantly than before CPB（P〈0. 01）, but Lipo-PGE1 group＇s values were lower than those in the control group （P〈0. 05）. Conclusions Lipo-PGE1 （2ng/kg·min） continuously pumped from before CPB to 2h after ascending aortic off-clamping can inhibit effectively the production of IL-6, TNF-α, and reduce the expression of sICAM-1, attenuate the process of inflammation, lighten the injuries of myocardial cells, and effectively protect the MIRI during CPB open heart surgeries.
【Abstract】ObjectiveOn the basis of traditional transplantation model, a successful model of pancreaticoduodenal transplantation (PDT) were established in rats, which is the foundation of basic and clinical transplantation research. Methods We improved the technique of microoperation on donor and harvested high-quality graft. The dual cuff technique was applied to end-to-end anastomose proximal part of abdominal aorta and portal vein with left renal aorta and vein of recipient, and distal part of abdominal aorta was connected with Y-tube. External secretion was performed by duodenum stoma. The PDT model was finished without blocking systemic circulation and portal vein system. Random blood glucose levels and drainage were monitored postoperatively to evaluate the function of endocrine and ectocrine. Results Thirty operations were done. The total procedure of transplantation lasted 2 hours. Moreover the operation on recipient and the reconstruction of vessels took only (26±5) and (25±5) minutes, respectively. The success rate was elevated to 100%. The ectocrine function was restored within 2 hours after operation. Except for 3 cases of non-function graft because of thrombosis in cannula, the glucose level of the remaining recipients was reduced to normal level 6 h or 24 h after transplantation. The survival rate of graft function was 90% (27/30). Conclusion This model is finished without special equipment and can recover the endocrine function in advance. It is a simple and stable model, which might be used in research of the theoretical problems involved in clinical pancreas transplantation.