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.
Abstract: Objective To evaluate if cardiac function and myocardial perfusion in acute ischemia myocardial transplanted by autologous bone mesenchymal stem cells (MSC) can be improved. Methods Sixteen New Zealand rabbits were studied.The left anterior descending coronary artery under the first diagonally branch was ligated to result in acute myocardial ischemia models,the sixteen models were divided into two groups with randomed number table. Control group(n=8): 0.6ml αminimum essential medium was injected into myocardium; transplanted group (n=8): 0.6ml medium of autologous MSC marked with 5-bromium,2-deoxy-uridine (BrdU) was injected into myocardium. Echocardiography were erformed to measure left ventricular ejection fraction(LVEF),as well as the displacement and strain of apex segment of left ventricle pre-ichemia,beforeand 4 weeks after treatment; the target myocardial tissues were harvested 4 weeks after treatment,double immunohistochemistry staining of anti-BrdU and anti-troponin T(TnT) were used to evaluate the survival and differentiation of implanted MSC; immunohistochemistry staining of anti-CD146 endothelium factor were used to evaluate the density of capillary vessels in treated myocardium. Results Double immunohistochemistry staining showed that positive cells were found in transplanted group and not found in control group. Anti-CD146 immunohistochemistry staining showed density of capillary vessels of transplanted group was significantly more than that of control group(Plt;0.05) ; LVEF,displacement and strain of cardiac apex of transplanted group improved significantly more than those of control group(Plt;0.05). Conclusion Transplanted to acute myocardium ischemia models of rabbits, MSC can differentiate into myocardium-like cells in myocardial microenvironment,and improve global and part cardiac systolic function and then improving perfusion of ischemia myocardium.
Objective To compare the effectiveness of autologous implantation between bone marrow stem cells and peripheral blood stem cells for treatment of lower limb ischemia. Methods From December 2004 to December 2005, 42 patients with unilateral lower limb ischemia were treated with both autologous bone marrow stem cell implantation(group A, n=21)and autologous peripheral blood stem cell implantation (group B, n=21). Fortytwo patients included 32 males and 10 females. The age ranged from 34 to 80 years, with a mean of 65.6 years. Of the patients, there were 28, 8 and 6 patients suffered from diabetic lower limb ischemia, Burger’s disese and atherosclotic occlusion, respectively. Ischemic history was from 3 months to 5 years, with amean of 2.1 years. A series of subjective indexes (such as improvement of pain, cold sensation and numbness) and objective indexes such as increase of ankle brachial index (ABI), transcutaneous oxygen pressure (TcPO2), angiography, amputation rate, and improvement of foot wound healing, were used to evaluate the effect. Results After 4 weeks of implantation, the rate of pain relief was 88.2% in group A and 89.5% in group B (Pgt;0.05) ; the rate of cold sensation relief was 94.4% in group A and 94.7% in group B（Pgt;0.05）; improvement of numbness was 69.2% and 66.7% respectively in groups A and B（Pgt;0.05）. Increaseof ABI was 38.1% in group A and 33.3% in group B（Pgt;0.05）; increase of TcPO2 was 85.7% and 90.5% respectively in groups A and B（Pgt;0.05）; angiography was performed in 12 patients (group A) and 9patients (group B), and the new formed collateral vessel rate was 83.3% in group A and 77.8% in group B（Pgt;0.05）; the amputation rate was 9.1% in groups A and B（Pgt;0.05）; the rate of improvement of foot wound healing was 60.0% in group A and 66.7% in group B(P＞0.05). Forty patients were followed up 3-15 months(mean 8 months). The improvement rate of subjective symptoms was 75.0% in group A and 70.0% in group B (Pgt;0.05); increase of ABI was 60.0% in group A and 65.0% in group B; increase of TcPO2 was 80.0% and 75.0% respectively in groups A and B; the new formed collateral vessel rate was 90.0% in group A and 84.6% in group B. All ulcers healed except 1 case in group B. Conclusion Bone marrow stem cell graft and peripheral blood stem cell graft are all effective in treatingower limb ischemia.
Objective To explore the mechanism of mesenchymal stem cells （MSCs） transplantation for chronic hindlimb ischemia in Lewis rats by using cell tracer technique. Methods MSCs were isolated and cultured by using density gradient centrifugation and adherence method respectively， then labeled by 5-bromo-2-deoxyuridine （BrdU）. Eight chronic hindlimb ischemia models of Lewis rats were prepared by using suture-occluded method and then divided randomly to MSCs transplantation group and control group， each group enrolled 4 rats， accepting MSCs transplantation and saline respectively. Then on 7 days and 14 days after transplantation， clinical observation， determination of blood flow， and angiography were performed on rats of the 2 groups. At the same time points after previous tests， rats of the 2 groups were sacrificed to get quadriceps tissues and gastrocnemius tissues to perform HE staining and BrdU immunohis-tochemistry. Results The 8 rats were all survived on 14 days after transplantation， with no tumor happened and necroses in the transplanted area. On 14 days after transplantation， the blood flow ratio of operated side to un-operated side in the hindlimb （1.773 vs. 1.279） of rats in MSCs transplantation group and control group increased， and the angiography results showed that there were no much increase in ratio of collateral vessels number （0.908 vs. 0.835）. There were no significant change in the quadriceps tissues and gastrocnemius tissues by HE staining. The BrdU positive kernels located in the inter-stitial substance cells and vascular endothelia cells， and divided differently in different parts of hindlimb at different time points， that the ratio of positive cells in gastrocnemius tissue was higher than those of quadriceps tissue on 7 days after transplantation， but lower on 14 days. Conclusions MSCs transplantation can increases the blood perfusion of hindlimb in the early stage of chronic hindlimb ischemia model， and the possible mechanism may be the paracrine effect of MSCs but not the number increase of collateral vessels.
ObjectiveTo evaluate the treatment results of Ilizarov microcirculation reconstruction technique for chronic wounds in the post-traumatic ischemia limbs.MethodsBetween January 2016 and July 2019, 7 cases of chronic wounds in the post-traumatic ischemia limbs were treated. There were 5 males and 2 females, with an average age of 42.4 years (range, 29-66 years). The duration of the wound ranged from 1 month to 2 years (mean, 7.7 months). The wounds located in the leg (3 cases) or in the foot and ankle (4 cases). The wound sizes ranged from 4.0 cm×2.2 cm to 12.0 cm×7.1 cm. There were 1 case of tibial varus, 3 cases of equinovarus, 1 case of scleroderma, and 2 cases of Volkmann’s ischemic contracture. After debridement, external fixators were used for tibial transverse transport, or correction of tibial varus and correction of equinovarus.ResultsAll patients were followed up 8-20 months, with an average of 13 months. The infection of wound surface was all controlled in 7 cases and the granulation tissue grew well; the wound surface healed directly in 5 cases and healed after skin grafting in 2 cases, and the wound healing time was 1-3 months (mean, 1.7 months). During the follow-up, there was no recurrence of the wound. Six cases of limb deformity were corrected.ConclusionFor the chronic wounds in the post-traumatic ischemia limbs, Ilizarov microcirculation reconstruction technique can effectively improve local circulation and facilitate the fresh granule growth and wound healing.
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.
Objective
To investigate the expressions of heat shock protein 27 (HSP27), Bcl-2, and Bax proteins of the nerve cells after spinal cord ischemia/reperfusion injury (SCII) in rats and their relationship.
Methods
Seventy adult male Sprague Dawley rats (weighing, 200-220 g) were randomly divided into the sham operated group (sham group, n=35) and the SCII group (n=35). Only the left renal artery was exposed with no occlusion of the abdominal aorta in the rats of sham group. The left renal artery was exposed with occlusion of the abdominal aorta for 20 minutes in the rats of SCII group. At 4, 8, and 12 hours and at 1, 2, 3, and 5 days, reperfusion treatment was performed in 5 rats respectively, and then the spinal cord tissue was harvested to detect the expressions of HSP27, Bcl-2, and Bax protein of the nerve cells by using immunohistochemistry staining.
Results
The HSP27 began to express at 4 hours, reached the peak at 3 days, and decreased at 5 days in SCII group; significant differences were found between at 3 and 5 days and at the other time points (P lt; 0.05). The Bcl-2 expression increased at 4 hours, reached the peak at 1 day and maintained a high level at 2 days, and then gradually decreased; significant differences were found between at 1 and 2 days and at the other time points (P lt; 0.05). The Bax expression reached the peak at 12 hours and 3 days, and decreased at 5 days; significant differences were found between at 12 hours and 3 days and at the other time points (P lt; 0.05). A little expression of each protein was observed in sham group at different time points; the expressions of HSP27, Bcl-2, and Bax proteins in SCII group were significantly higher than those in sham group at different time points (P lt; 0.05).
Conclusion
There may be the time window of self repair after SCII. High expression of HSP27 has an obvious protective effect on the SCII in rat, by promoting the expression of the anti-apoptotic protein Bcl-2 and reducing the expression of the pro-apoptotic protein Bax so as to inhibit spinal cord cell apoptosis.
ObjectiveTo explore performances of functional magnetic resonance imaging (MRI) in evaluation of hepatic warm ischemia-reperfusion injury.MethodThe relative references about the principle of functional MRI and its application in the assessment of hepatic warm ischemia-reperfusion injury were reviewed and summarized.ResultsThe main functional MRI techniques for the assessment of hepatic warm ischemia-reperfusion injury included the diffusion weighted imaging (DWI), intravoxel incoherent motion (IVIM), diffusion tensor imaging (DTI), blood oxygen level dependent (BOLD), dynamic contrast enhancement MRI (DCE-MRI), and T2 mapping, etc.. These techniques mainly used in the animal model with hepatic warm ischemia-reperfusion injury currently.ConclusionsFrom current results of researches of animal models, functional MRI is a non-invasive tool to accurately and quantitatively evaluate microscopic information changes of liver tissue in vivo. It can provide a useful information on further understanding of mechanism and prognosis of hepatic warm ischemia-reperfusion injury. With development of donation after cardiac death, functional MRI will play a more important role in evaluation of hepatic warm ischemia-reperfusion injury.
The aim of this study is to assess ischemia/reperfusion injury in carbon tetrachloride induced cirrhotic liver as compared to normal liver in the rats. Results showed that in cirrhotic liver, instead of diminishing the hepatic vein nitric oxide level increased significantly after ischemia from 8.04 μmol/L to 11.52 μmol/L and remained high till 5 hrs after reperfusion. The hepatic adenosine triphosphate (ATP) contents decreased as that seen in normal rat but did not restore to normal till the end of 5 hrs after reperfusion. Based on these findings, it is postulated that in cirrhotic liver, ischemia/reperfusion injury is aggrvated as evidenced by of nitric oxide, and extended diminishing in ATP.
ObjectiveTo summarize the mechanism of neutrophil extracellular traps (NETs) in hepatic ischemia-reperfusion injury (HIRI) and the research progress in targeting NETs to reduce HIRI, providing valuable reference for reducing HIRI. MethodThe related literatures at home and abroad about the role of NETs in the pathogenesis of HIRI and target NETs to alleviate HIRI were retrieved and reviewed. ResultsHIRI usually appeared in the process of liver surgery and was a common clinical problem, which occured in situations such as liver surgery, organ transplantation, liver ischemia and so on. This kind of injury would lead to tissue necrosis, inflammatory response and oxidative stress, which was a major cause of hepatic dysfunction and multiple organ failure after hepatic surgery, greatly increases the complications and mortality after hepatic surgery. NETs played a crucial role in the aseptic inflammatory response induced by hepatic ischemia/reperfusion. During hepatic ischemia-reperfusion, neutrophils promoted inflammatory cascade reactions and cytokine storms by forming NETs, exacerbating damage caused by hepatic ischemia-reperfusion. At present, some experimental and clinical studies had shown that inhibiting the formation of NETs or eliminating the formed NETs could alleviate the hepatic ischemia-reperfusion injury and improve the prognosis. ConclusionsTargeting NETs may become a new method for treating hepatic ischemia-reperfusion injury. In the future, it is foreseeable that more experiments and clinical trials will be conducted on targeted NETs for the treatment of hepatic ischemia-reperfusion injury. And gradually establish more comprehensive and effective treatment strategies, thereby providing new ways to improve the prognosis of hepatic surgery patients in clinical practice.
