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.
【Abstract】 Objective To investigate the protective role of recombinant human growth hormone (rhGH )in ischemic reperfusion injury of rat liver and its mechanism. Methods One hundred Male rats were randomly divided into two groups: the rhGH group and the control group. In the rhGH group, rhGH were injected （0.2U/100g weight） to rats seven days before the ischemic reperfusion injury, and in the control group, normal saline was injected instead. Serum levels of ALT， TNF-α and IL-1α were tested. Hepatic tissue was sectioned for to detect the level of EC and MDA, the expression of NF-κB and ICAM-1 mRNA on SEC. Ultrastructural characteristics histopathological characteristics were determined also. Results Serum levels of ALT, TNF-α, IL-1α and the contents of MDA in the control group were significantly higher than those in the rhGH group （P＜0.05）. Comparied with control group, rhGH also decreased NF-κB activation, and reduced the expression of ICAM-1 mRNA of SEC in the liver cells （P＜0.05）. Electronic microscopic revealed that the hepatic sinusoidal endothelial cells and the hepatocellular mitochondria were injured in the control group. Pretreatment with the rhGH was able to significantly improved the pathological changes. Conclusion rhGH might confer the protection to ischemic reperfusion injury of rat liver through reducing the expression of NF-κB to down-regulate cytokine (IL-1α,TNF-α), MDA and inhibition the expression of ICAM-1 mRNA.
【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.
Objective To investigate the protective effect of ischemic preconditioning (IP) on ischemicreperfusion injury of rat liver graft. MethodsMale Sprague Dawley rats were used as donors and recipients of orthotopic liver transplantation,the period of cold preservation and anhepatic phase were 100 min and 25 min respectively.Sixtyfour rats were randomly divided into 2 groups (n=32),control group: donor livers were flushed through the portal veins with physiological saline solution containing heparin only before harvested; IP group: before donor livers were harvested,the portal veins and hepatic arteries of them were interrupted for 10 min,and reflow was initiated for another 10 min,then did as control group.One half of each group were used to investigate 1 week survival rate of recipients,and another half of each group were used to take sample of blood and hepatic tissue after 2 hours of reperfusion of liver graft. ResultsOne week survival rate,amount of bile,serum NO and activity of antioxidase were higher in IP group than those in control group(P＜0.05),meanwhile,serum ALT,AST,LDH,TNF and superoxide in hepatic tissue were lower in IP group than those in control group (P＜0.05),and histological findings in IP group showed less injury than those in control group. Conclusion IP could increase production of serum NO,reduce the level of serum TNF and protect rat liver graft from ischemicreperfusion 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 study the protective effects of pre-storing glycogen on warm ischemia reperfusion injury during partial hepatectomy. Methods Thirty-eight patients were randomly divided into a trial group (n=19) and a control group (n=19). In the trial group, patients were given high concentration glucose intravenously during the 24 hours before the operation. The hepatic lesion was resected after portal triad clamping in the two groups. Liver function of all patients was measured before the operation and the first and fifth days after the operation. Normal hepatic tissue was biopsied to measured hepatic tissue glycogen contents before the operation and the change of superoxide dismutase (SOD) at the point of pre-ischemia, post-ischemia, and reperfusion 2 hour. Bcl-2 mRNA, a well known anti-apoptotic factor, was also detected using quantitative polymerase chain reaction. Results The hepatic tissue glycogen content of the trial group was significantly higher than that of the control group before the operation (Plt;0.01). Liver function of the trial group was significantly better than that of the control group on the first and fifth day after operation (Plt;0.05). There was significant difference in SOD activity between the two groups at the end of hepatic vascular occlusion and at the point of 2-hour reperfusion (Plt;0.05). Furthermore Bcl-2 mRNA expression of the trial group was notably up-regulated at the point of 2-hour reperfusion compared to the control group. Conclusion Pre-store storing glycogen might protect liver ischemia reperfusion injury caused by hepatic vascular occlusion during partial hepatectomy. The potential mechanism might be that pre-storing glycogen enhances Bcl-2 expression.
Objective To investigate the extent of hepatic ischemia reperfusion (HIR) injury in rat cirrhotic liver under different ischemic time，and find the time limit under which the rat with cirrhotic liver could tolerate. Methods At first，the cirrhosis of the rat were induced by carbon tetrachloride（CCl4）injected subcutaneously. Then these rats were randomly divided into four groups. Group A(n=6) was made by sham operation, group B, C, D(n=16) were respectively given 20, 30, 40min hepatic warm ischemia. The 7day survival rate, AST, ALT, TNF and liver, pulmonary pathology were observed. Results The 7-day survival rate was decreased with the increase of hepatic ischemic time. The survival rate of group B, C, D were respectively 100%, 60%, 40%. Between group C, D and group B there were significant differences（P＜0.05）. The level of AST and ALT in group D were （2 448.4±942.3）u/L and （1 189.0±403.4）u/L respectively, and those in group C were （2 185.1±1 732.9）u/L and （1 183.5±707.2）u/L respectively, which were higher than those in group B and A significantly（P＜0.01）. The level of TNF was increased significantly 4hr after reperfusion, as compared with that before operation 〔(0.177±0.139）u/ml〕, P＜0.01. TNF of group B, C, D were （0.399±0.216）u/ml, （0.671±0.351）u/ml and （0.789±0.371）u/ml respectively. At the same time the level of TNF in group C, D was higher than that in group B, A significantly（P＜0.01）. Liver and lung pathology showed increased damage with increasing ischemia. Conclusion Hepatic injury is induced by HIR in rats with cirrhotic liver, and its severity increases with the increase of ischemic time. There is a certain hepatic ischemic time between 20min and 30min, which can be tolerated by the rats with cirrhotic liver. TNF may be used as an indicator，showing the degree of HIR injury and foreseeing the result of injury.
ObjectiveTo observe the effects of overexpression of S100A4 protein on retinal capillary cells and retinal ganglion cells (RGC) after retinal ischemia-reperfusion injury (RIRI). MethodsOne hundred healthy adult male C57BL/6 mice were randomly divided into normal control group (group C), RIRI group, adeno-associated virus (AAV2)-S100A4 green fluorescent protein (GFP) intravitreal injection group (group S), RIRI+AAV2-GFP intravitreal injection group (group GIR), and RIRI+AAV2-S100A4-GFP intravitreal injection group (group SIR), with 20 mice in each group. The RIRI model was established using the high intraocular pressure anterior chamber method in the RIRI, GIR and SIR groups of mice. Eyes were enucleated 3 days after modelling by over anaesthesia. The number of retinal capillary endothelial cells and pericytes in the retinal capillaries of mice in each group was observed by retinal trypsinised sections and hematoxylin-eosin and periodic acid-Schiff staining; immunofluorescence staining was used to observe endothelial cell, pericyte coverage and RGC survival; The relative expression of Toll-like receptor 4 (TLR4), p38 MAPK and nuclear factor erythroid 2-related factor 2 (NRF2) in retinal tissues was measured by Western blot. One-way analysis of variance was used to compare data between groups. ResultsThree days after modeling, the endothelial cell to pericyte ratio in group C was compared with group S and SIR, and the difference was not statistically significant (F=106.30, P＞0.05); the SIR group was compared with group RIRI and GIR, and the difference was statistically significant (F=106.30, P＜0.000 1). Comparison of endothelial cell coverage in each group, the difference was not statistically significant (F=3.44, P＞0.05); compared with the pericyte coverage in group C, the RIRI group and the GIR group were significantly lower, and the difference was statistically significant (F=62.69, P＜0.001). Compared with the RGC survival rate in group C, it was significantly lower in RIRI and GIR groups, and the difference was statistically significant (F=171.60, P＜0.000 1); compared with RIRI and GIR groups, the RGC survival rate in SIR group was significantly higher, and the difference was statistically significant (F=171.60, P＜0.000 1). The relative expression levels of TLR4, p38 and NRF2 proteins were statistically significant among all groups (F=42.65, 20.78, 11.55; P＜0.05). ConclusionsPericytes are more sensitive to ischemia than endothelial cells after retinal RIRI in mice, and early vascular cell loss is dominated by pericytes rather than endothelial cells. The overexpression of S100A4 protein protects against loss of pericytes and RGC after RIRI by inhibiting the TLR4/p38/NRF2 signaling pathway.
Objective To study the effect of Kupffer cell on the liver ischemia/reperfusion injury.Methods The literature in recent years on the liver ischemia/reperfusin injury were reviewed.Results The activated kupffer cell can generate and release a variety of soluble toxic mediators, affect the liver microcirculation directly or indirectly. Conclusion Kupffer cell have important effect on liver ischemia/reperfusion injury.