Immunosupressive mechanism of cornus officinalis glycosides on the corneal allograft rejection in rats

AIM: To investigate the influence of the cornus officinalis glycosides (COG) on immunological function of corneal transplantation model of rats, and to clarify the immunosuppressive mechanism of COG through observing the activation of lymphocytes in blood. METHODS: Wister rats were used as recipients and SD rats were used as corneal graft donors, then the corneal allografts transplantation model on the closed colony rats were set up. Splenocytes proliferation and mixed lymphocyte reaction of Wister rats activated by ConA were observed. The phenotype change of CD4, CD8, CD25 in blood in different time postoperatively were observed by the di-sign flow cytometry, and the rate of CD4/CD8 was calculated. RESULTS: 1. The COG suppressed the proliferation of T lymphocytes and one-way mixed lymphocyte reaction on the corneal allografting. 2. The phenotype change of lymphocytes in boold was as follows: there was no significant difference between the different time of the CD4, CD8 expression and the CD4/CD8 rate in blood of the control group. The CD4 positive cells expressed CD25 postoperatively increased obviously. The CD4/CD8 rate of medicine group had the tendency to decrease. The CD4 positive cells expressed CD25 postoperation in the medicine group were less than that in the control group obviously. CONCLUSION: The suppression of the T lymphocyte proliferation, mixed lymphocyte reaction, CD molecule expressed by the activated T lymphocytes and the IL-2 receptor expression may be the main immunosuppressive mechanisms of Cornus officinalis glycosides on the cell-mediated immunity.     

Effect of cornus officinalis glycosides ophthalmic solution on the corneal allograft rejection

AIM:To observe the effect of cornus of ficinalis glycosides(COG) ophthalmic solution on the corneal allograft rejection by topical instillation.METHODS:The corneal transplantation model on the closed colony rats was established. The rejection time of all animals was recorded and compared by slit-lamp microscope. The pathologic changes were measured by immunohistochemistry and scanning electron microscope.RESULTS:The histopathological and immunohistochemistry findings showed that the lymphocytes, neovascularity and the expression of ICAM-1 in COG-treated group were significantly fewer than that in control group at 15 d after operation.CONCLUSION:COG ophthalmic solution prevents and suppresses the corneal allograft rejection.     

Depressant effect and mechanism of atorvastatin on the chronic rejection of aortic allograft in rats

AIM: To investigate the depressant effect and mechanism of atorvastatin on the chronic rejection of aortic allograft in rats.METHODS: The models of abdominal aorta transplantation were made with micro-surgery in rats.The recipients were divided into three groups: allograft control group,atorvastatin-treated group and isograft control group.Vascular intimal thickness in all of the groups was observed by histological examination.The expression of proliferation cell nuclear antigenl(PCNA) and α-smooth muscle actin(α-SMA) were determined by immunohistochemistry.The content of nitric oxide was measured by nitrate reductase chromatometry.RESULTS: The vascular intimal thickness in atorvastatin-treated group (11.60%±2.40%) was lower than that in allograft control group (34.60%±6.40%,P<0.05) and higher than that in isograft control group (1.15%±0.65%,P<0.05).The expression level of PCNA was decreased in atorvastatin-treated group (4.80%±0.80%) than that in allograft control group (18.40%±1.80%,P<0.05) and higher than that in isograft group (1.20%±0.40%,P<0.05).CONCLUSION: The expression of PCNA in the transplanted aorta is suppressed by atorvastatin,which results in relief of chronic rejection of aortic allograft.     

Dexmedetomidine attenuates acute alcoholic hepatic injury in mice

AIM: To investigate the effects of dexmedetomidine (DEX) on acute alcoholic hepatic injury in mice and to explore the possible mechanisms. METHODS: Kunming mice (n=50) were randomly divided into 5 groups (n=10): normal saline control (NS) group, acute alcoholic hepatic injury model (E) group, low-dose (10 μg/kg) DEX (E+L) group, medium-dose (50 μg/kg) DEX (E+M) group and high-dose (100 μg/kg) DEX (E+H) group. The animals were sacrificed at 6 h after gavage of alcohol or normal saline. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD) were measured. The livers were removed for evaluation of histological characteristics and determining the content of tumor necrosis factor-α (TNF-α) amd interleukin-1β (IL-1β) in the liver tissues by ELISA. The expression levels of cytochrome P450 2E1 (CYP2E1) and nuclear factor-κB (NF-κB) in the liver tissues were evaluated by Western blot. RESULTS: Compared with NS group, the levels of ALT, AST and TG were obviously increased in E group, which were obviously decreased in E+M and E+H groups. Compared with NS group, the levels of TNF-α, IL-1β and MDA were obviously increase in E group, which were obviously decreased in E+M and E+H groups. Compared with NS group, the activity of SOD and the content of GSH were obviously decreased in E group, which were obviously increased in E+M and E+H groups. Compared with NS group, the expression of CYP2E1 and NF-κB was obviously increase in E group, which was obviously decreased in E+M and E+H groups. Compared with NS group, ethanol induced marked liver histological injury, which was less pronounced in E+M and E+H groups. CONCLUSION: DEX has a protective effect on mouse liver with acute alcoholic injury by the involvement in the processes of antioxidation and antiinflammation, and its mechanism may be associated with the inhibition of CYP2E1 and NF-κB expression.     

Paeoniflorin attenuates LPS-induced acute lung injury in mice

AIM: To investigate the mechanisms by which paeoniflorin (Pae) attenuates lipopolysaccharide(LPS)-induced acute lung injury in mice. METHODS: Male BALB/c mice were randomly divided into 4 groups: control,LPS, Pae+LPS, and Pae. Mice were administered intragastrically with double distilled water or Pae (20 mg/kg) once a day for 3 days. One hour after intragastrical treatment on the third day, LPS (20 mg/kg) or normal saline was injected intraperitoneally. Twelve hours after LPS challenge, the histological changes of the lung were observed, and histology score was also assessed. The myeloperoxidase (MPO),cytosolic phospholipase A₂ (cPLA₂) and phosphorylated cytosolic phospholipase A₂ (phospho-cPLA₂) in lung tissues were detected by Western blotting.RESULTS: LPS challenge resulted in acute lung injury, activated cPLA₂ and increased MPO content in lung. Pretreatment with paeoniflorin significantly attenuated lung injury induced by intraperitoneal injection of LPS. The levels of MPO and phospho-cPLA₂ in the lung tissues of the mice in Pae+LPS group were lower than those in LPS group (P<0.05).CONCLUSION: Pretreatment with paeoniflorin remarkably reduces LPS-induced acute lung injury through inhibiting phosphorylation of cPLA₂ and decreasing neutrophil infiltration in the lung. These findings provide a new strategy for the prevention and treatment of LPS-induced acute lung injury.     

Effects of cycloastragenol on cardiac fibrosis induced by isoproterenol in mice

AIM: To investigate the effects of cycloastragenol (CAG) on cardiac fibrosis in mice and the mechanism involved. METHODS: The mouse model of cardiac fibrosis induced by isoproterenol (ISO) was established and treated with high- and low-dose CAG. Cardiac function was measured by echocardiography, and heart sections were stained by Masson’s trichrome for fibrosis assessment. The expression of fibrosis-related factors was assayed using RT-qPCR, Western blot and immunohistochemistry. In addition, cardiac fibroblasts isolated from neonatal factors rat ventricles were cultured and administrated with ISO followed by CAG treatment, and then the expression profile of the factors above was assayed using RT-qPCR. RESULTS: Treatment with CAG significantly alleviated ISO-induced cardiac dysfunction and fibrosis, inhibited the mRNA expression of oxidative stress-related factors NADPH oxidase 4 and inducible nitric oxide synthase, and blocked the phosphorylation of proteins associated with nuclear factor-κB signaling pathway as well as the expression of transforming growth factor-β (TGF-β). In addition, it was demonstrated that CAG also inhibited the mRNA expression of the factors above in primary cardiac fibroblasts administrated with ISO. CONCLUSION: CAG markedly rescues ISO-induced cardiac dysfunction and fibrosis via inhibition of oxidative stress, inflammation and TGF-β levels.     

Sodium nitrite reduces lipopolysaccharide-induced acute lung injury in mice

AIM: To investigate the effect of sodium nitrite (SN) on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and its underlying mechanism in mice. METHODS: All male Institute of Cancer Research (ICR) mice were randomly divided into five groups: Control group; LPS group; and SN 4.8 nmol/L, SN 48 nmol/L, SN 480 nmol/L (ip) groups. Lung wet weight/dry weight (W/D) ratio and permeability were detected. Neutrophil infiltration in bronchoalveolar lavage fluid (BALF) was measured by cel1 counting and morphological changes in lung tissues were assayed by hematoxylin-eosin staining. The 1evels of interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α) in lung were detected. Nitric oxide (NO) level and nitric oxide synthase (NOS) activity in lung were measured according to the specification. RESULTS: Compared to lung in LPS-induced ALI mice, at doses of 4.8 nmol/L and 48 nmol/L, not 480 nmol/L, SN markedly decreased the lung W/D ratio, total leukocyte number and neutrophil percentage in the BALF, lung permeability, and TNF-α/IL-10 ratio, in lung. SN at dose of 480 nmol/L markedly increased the lung NO level compared to control group. In addition, SN decreased the total NOS and inducible NOS (iNOS) activities compared to LPS-induced ALI mice. CONCLUSION: These results indicate that the protective effect of SN against LPS-induced ALI in mice is associated with the low dose SN-induced NO, as well as the subsequent decrease in iNOS activity and TNF-α/IL-10 ratio.     

Cyanidin attenuates pressure overload-induced cardiac remodeling in mice via mitochondrial fusion enhancement

AIM To investigate the effect of cyanidin （Cyn） on pressure overload-induced cardiac remodeling and the underlying mechanism. METHODS Six-week-old male C57BL/6 mice （n=120） were divided into 4 groups： sham group （n=20）, sham+Cyn group （n=20）, transverse aortic constriction （TAC） group （n=40） and TAC+Cyn group （n=40）. The model of cardiac chronic pressure overload was induced by TAC, and the first day of TAC was defined as day 0. The animals in sham+Cyn group and TAC+Cyn group were treated with Cyn dissolved in DMSO and normal saline （5 mg·kg^-1·d^-1） for 5 d before TAC, while the animals in sham group and TAC group were treated with the same amount of DMSO and normal saline. Four weeks after TAC, the survival rate of the animals in each group was analyzed, the heart function of the mice was measured by ultrasound echocardiography, and the heart weight/body weight and lung weight/body weight were calculated. The cross-sectional area of the cardiomyocytes was measured by wheat germ agglutinin staining and hematoxylin-eosin staining. The degree of cardiac oxidative stress was evaluated by dihydroethidium staining and measurement of superoxide dismutase （SOD） and malondialdehyde （MDA） levels. The cardiomyocyte apoptosis was detected by TUNEL method. The mRNA expression levels of atrial natriuretic peptide （ANP）, brain natriuretic peptide （BNP） and β-myosin heavy chain （β-MHC） were detected by RT-qPCR, and the protein expression levels of Bax, Bcl-2, optic atrophy protein 1 （OPA1） and dynamin-related protein 1 （Drp1） were determined by Western blot. The mitochondrial morphological changes were observed by transmission electron microscopy. RESULTS Compared with TAC group, the survival rate of the mice in TAC+Cyn group was significantly increased （P<0.05）, the myocardial apoptosis, the cross-sectional area of myocardial cells, the heart weight/body weight, the lung weight/body weight, the level of reactive oxygen species and the MDA content were decreased （P<0.05）, and the SOD was activated （P<0.05）. M-mode ultrasound tests showed that Cyn treatment significantly increased left ventricular ejection fraction and left ventricular fractional shortening in the mice after TAC （P<0.05）, while left ventricular end-diastolic diameter and left ventricular posterior wall thickness in diastole were reduced （P<0.05）. Transmission electron microscopic observation showed that the number of myocardial mitochondria was increased and the mitochondrial area was decreased after TAC （P<0.05）, while treatment with Cyn increased the area of myocardial mitochondria and decreased the mitochondrial number （P<0.05）. Compared with sham group, the protein level of OPA1 in TAC group was significantly reduced （P<0.05）, while treatment with Cyn significantly increased the protein level of OPA1. CONCLUSION Cyanidin significantly increases the survival rate, improves the cardiac function and attenuates the cardiac remodeling of the mice after TAC. The mechanism may be related to the inhibition of myocardial mitochondrial OPA1 cleavage and the promotion of mitochondrial fusion.     

Human umbilical mesenchymal stem cell-derived exosome attenuates cardiac fibrosis in diabetic mice

AIM: To explore the protective effects of exosome secreted by human umbilical mesenchymal stem cells on cardiac fibrosis in diabetic mouse model. METHODS: Male C57BL/6 mice at 6~8 weeks of age were divided into 3 groups randomly:control group, diabetes mellitus (DM) group and DM+exosome group. To develop mouse DM mo-del, the mice were fed with high-fat diet for 5 weeks, followed by intraperitoneal injection of 45 mg/kg streptozocin once a week for 5 weeks. It was considered as a successful DM model that the blood glucose of the mice was ≥ 16.7 mmol/L. The mice in DM+exosome group were injected with exosome via tail vein. The mice in other 2 groups were injected with saline at the same volume. The heart function was evaluated by color Doppler echocardiography for small animals. The blood samples were collected from abdominal aortas. The blood glucose and non-esterified fatty acids were measured by biochemical colorimetric assay. HE staining was performed to observe the structural changes of myocardial fibers, and Masson staining was used to observe the cardiac fibrosis. RESULTS: The results of echocardiography showed that left ventricular end-diastolic dimension (LVIDd) and left ventricular end-systolic dimension (LVIDs) of diabetic mice were larger than those in control mice (P<0.05 and P<0.01, respectively). The ejection fraction (EF) and fractional shortening (FS) decreased in the diabetic mice (P<0.01). Exosome treatment significant decreased the LVIDs (P<0.01), but increased the EF and FS (P<0.01). The blood glucose and non-esterified fatty acids were significantly increased in the diabetic mice. The injection of the stem cell exosome significantly decreased the blood glucose and non-esterified fatty acids (P<0.01). HE staining observation showed that cardiomyocyte hypertrophy and fragmentation of cardiomyocyte in DM group were more se-rious than those in control group. Masson staining showed that the area of fibrosis in DM group was larger than that in control group (P<0.01), but that in DM+exosome group was reduced (P<0.01). CONCLUSION: Exosome secreted by human umbilical mesenchymal stem cells protects the DM model mice from cardiac fibrosis.     

Strain difference of susceptibility to caerulein-induced acute pancreatitis in mice

AIM: To study the difference of susceptibility to caerulein-induced acute pancreatitis (AP) among the mice of C57BL/6J, BALB/c and ICR strains.METHODS: Two-month-old female mice of C57BL/6J, BALB/c and ICR strains (12 mice for each strain) were divided into control group (n=6) and experimental group (n=6), respectively. The mice were intraperitoneally injected with caerulein (50 μg/ kg) in 1 h interval for 7 serial injections in total. The mice in control group were treated with saline according to the same procedure in experimental group. The blood samples were collected at 0 h, 3 h, 6 h, 9 h, 12 h and 24 h after the first injection of caerulein or saline for plasma α-amylase and lipase assays. The mice were sacrificed 24 h after AP induction, and the pancreatic tissues were harvested for further investigating the pathological changes and expression of inflammatory factors.RESULTS: After AP induction, the mice of BALB/c and ICR strains demonstrated more dramatic increase in plasma α-amylase activity and lipase activity than those of C57BL/6J mice. C57BL/6J mice showed milder morphological changes and lower expression of inflammatory factors in pancreata than those of BALB/c and ICR mice.CONCLUSION: The mice of C57BL/6J strain have less susceptibility to caerulein-induced AP than that of BALB/c and ICR mice.     

Experimental research on cardiac fibrosis induced by recombinant mouse interleukin-11 in mice

AIM To observe the effect of recombinant mouse interleukin-11 （rmIL-11）injected subcutaneously into mice on heart structure and function and to determine its pro-fibrotic effect. METHODS C57BL/6 mice were randomly divided into experimental group and control group.The mice in experimental group were injected subcutaneously with recombinant mouse IL-11 at the dose of 100 μg·kg^-1·d^-1 for 3 consecutive weeks, while the control group were given equal volume of normal saline in the same way. After the experiment was finished, the parameters of heart function were measured by echocardiography.The heart weight was weighed and the cardiac weight index (CWI) was calculated. HE staining and Masson's trichrome staining were performed to observe the pathological changes and the extent of myocardial fibrosis in mouse myocardia respectively, and the cardiac collagen volume fraction (CVF) was calculated. The expression levels of extracellular matrix proteins in the myocardial tissues of mice, including type Ⅰ collagen, type Ⅲ collagen and fibronectin, were determined by Western blot. RESULTS Left ventricular ejection fraction and left ventricular fraction shortening in experimental group were obviously lower than those in control group (P<0.01), however left ventricular end-diastolic diamension and left ventricular end systolic dimension were significantly higher than those in control group (P<0.05).Compared with control group, the CWI was increased (P<0.01), the myocardial arrangement was disorder, the necrosis of cardiac myocytes was increased, and excessive deposition of collagen was observed in the myocardial tissues in experimental group. Correspondingly, the CVF and protein levels of type Ⅰ collagen, type Ⅲ collagen and fibronectin in the left ventricle in experimental group were increased significantly (P<0.05). CONCLUSION Injection of rmIL-11 into the mice subcutaneously induces fibrogenesis in the heart, which implies that IL-11 is likely a novel pro-fibrotic factor.     

Mechanisms for protection of berberine against LPS-induced acute lung injury in mice

AIM:To investigate the mechanisms by which berberine attenuates LPS-induced acute lung injury, and provide a new strategy for the treatment of the lung injury due to LPS. METHODS:BALB/c mice were randomly assigned into three groups (control, LPS group, and berberine treatment group). Mice were administered intragastrically with distilled water (0.1 mL/10 g) or neutral sulfate berberine (50 mg/kg) once a day for 3 days, 1 h after intragastrical treatment on day 3, LPS (20 mg/kg) or normal saline was injected intraperitoneally (ip). All animals were sacrificed 12 h after LPS injection, the left lung tissue sections were prepared for histology analysis and the right lung were used to determine the ratio of wet to dry lung tissue weight (W/D). In another experiment, bronchoalveolar lavage fluid (BALF) was collected, and then the total protein content, and the amounts of white blood cells (WBC) and polymorphonuclear neutrophils (PMN) in BALF were determined. Furthermore, the phosphorylation of cytosolic phospholipase A₂ (cPLA₂) was detected with immunohistochemical analysis by using phospho-cPLA2(Ser505) antibody, and the contents of thromboxane B₂ (TXB₂) in BALF, malondialdehyde (MDA) in the lungs, and activity of superoxide dismutase (SOD) in lung tissues were also determined.RESULTS:LPS induced acute lung injury, activated cPLA₂, and increased TXB₂ content in the BALF and MDA level in the lung tissue. The pretreatment with berberine significantly attenuated lung injury, lung edema and protein leakage induced by intraperitoneal injection of LPS. The expression of phospho-cPLA₂ in the lung tissues and TXB₂ content in the BALF in the berberine treatment group were lower than those in LPS group (P<0.05). In addition, the content of MDA in the lung tissue was lower in the berberine treatment group than LPS group (P<0.05), but there was no significant difference in activity of lung SOD between the berberine treatment and LPS group (P>0.05). CONCLUSION:Pretreatment with berberine remarkably reduces the LPS-induced lung injury, which is, at least in part, through inhibiting phosphorylation of cPLA₂ and decreasing lipid peroxidation. These findings provide a new strategy for the prevention and treatment of LPS-induced acute lung injury.     

Establishment of an acute GVHD animal model in EL9611 erythroleukemia mice

AIM: To establish an acute graft-versus-host disease (GVHD) model in EL9611 erythroleukemia mice. METHODS: Using C57BL/6 (H-2^b) mice as the donor and BALB/c (H-2^d) mice as the recipient in allogeneic bone marrow transplantation (allo-BMT), the acute GVHD model was established. The mice were divided into leukemia group (n=10), radiation control group (leukemic mice given radiation without allo-BMT, n=4), GVHD group (leukemic mice given radiation+allo-BMT, n=10) and normal control group (n=4). In leukemia group, 2×10⁶/mouse EL9611 erythroleukemic cells were transfused via tail vein into BALB/c mice to build the erythroleukemia model. In GVHD group, 7 days after leukemic cell transfusion, the mice received total dose of 8.0 Gy γ of total body irradiation(TBI), and within 5 h, 2×10⁶ C57BL/6 bone marrow cells and 1×10⁷ C57BL/6 spleen cells per mouse were transfused via tail vein to build the acute GVHD model in EL9611 erythroleukemia mice. The clinical manifestations of posture, fur, stool and so on were observed. Pathological examination was conducted to examine the changes of liver, spleen, skin, small intestine and peripheral blood. The survival rate was also calculated. RESULTS: (1) In leukemia group, the mean survival time (MST) was (14.5±2.1) days,or (7.5±0.7) days when irradiation day was as day 0(P<0.01 compared with GVHD group). The death rate was 100% with no spontaneous remission. The dead mice showed splenohepatomegalia and high WBC count . Pathological examination showed disorganization of normal tissues and leukemic cell infiltration. (2) In radiation control group, MST was (9.0±0.7) d, with significant difference as compared with GVHD group and normal group (P<0.01). The death rate was 100%. Pathological examination showed hematopoiesis exhaustion. (3) In GVHD group, MST was (32.0±3.2) d (P<0.01 compared with other groups). The death rate was 100%, the symptoms were observed on day 10-13 after allo-BMT. Clinical manifestations and pathological examination corresponded to those of I degree to II degree of GVHD. CONCLUSION: Intravenous infusion of 2×10⁶/mouse EL9611 leukemic cell successfully establishes the EL9611 erythroleukemia animal model. Seven days after EL9611 leukemic cell transfusion, lethal dose of TBI and allo-BMT can successfully build the acute GVHD model of EL9611 leukemic mice.     

Effect of microRNA-7 knockdown on ConA-induced acute liver injury in mice

AIM: To study the effect of microRNA-7 (miR-7) knockdown (KD) on concanavalin A (ConA)-induced acute liver injury (ALI) in mice.METHODS: Wild type (WT) mice and miR-7KD mice were received ConA (30 mg/kg) to induced acute liver injury model by intraperitoneal injection, and the morphological changes, liver weight and weight index were measured 48 h later. The pathological changes of the liver tissues were observed by HE staining. The levels of serum alanine aminotransferase (ALT), IL-4 and IFN-γ were detected by ELISA. The proportional changes of CD4⁺ T cells and the relative levels of IL-4 and IFN-γ were analyzed by flow cytometry.RESULTS: The color of the liver tissue became lighter, and the weight and weight index were changed significantly in miR-7KD mice compared with control group (P<0.05). HE staining showed that the inflammatory cell infiltration was increased in the liver of miR-7KD mice. Moreover, the level of serum ALT was significantly increased (P<0.05). The serum level of IFN-γ elevated significantly (P<0.01), while the IL-4 levels decreased significantly (P<0.01) in the serum of miR-7KD mice. Furthermore, the proportion of CD4⁺ T cells and relative IFN-γ cells increased obviously (P<0.01).CONCLUSION: miR-7 knockdown promotes the pathogenesis of the ConA-induced acute liver injury in mice.     

Relationship between helper T lymphocytes immune deviation and class Ⅱ MHC antigen expression in acute rejection of transplanted heart

AIM: To observe the relationship between the immune deviation of Th1 and Th2 cell clones and class Ⅱ major histocompatibility complex (MHC) antigen expression in different stages of acute rejection in transplanted hearts. METHODS: Heart transplantation were performed in rats.Isografts and non-transplanted animals were used as control group. Donor class II MHC antigen expression were detected with monoclonal antibodies and immunostaining technique and the amount of type Ⅰ and Ⅱ cytokines mRNA expression were detected by semiquantitative RT-PCR in cardiac allografts. RESULTS: Myocardial IL-2 mRNA and donor class Ⅱ MHC antigen expression were significantly in-creased, accompanied with development of acute rejection (P<0.01). However, IL-4 mRNA decreased significantly (P<0.01). The immune deviation between type Ⅰ and Ⅱ cytokines mRNA expression occurred in the rejecting stage at which the cardiac allograft tissue infiltrated by multiple foci of lymphocytes and class Ⅱ MHC antigen became highly expressed. CONCLUSION: There was correlationship between Th cells immune deviation and donor class Ⅱ MHC antigen expression in the process of acute rejection in cardiac allografts. Immune deviation of T cells may facilitated the expression of donor MHC class Ⅱ antigen on transplanted heart.     

Effects of tanshinone IIA on cardiac monophasic action potential in acute cerebral ischemia rats

AIM: To investigate the effects of tanshinone IIA (Tan) on cardiac action potential in rats with acute cerebral ischemia (ACI). METHODS: ACI was established in rats accordingly. Animals were divided into 3 groups:sham group, ACI group, and ACI with Tan treatment group. The defect of neural function in each group was graded, electrocardiogram was measured, monophasic action potential was recorded, and the levels of cardiac troponin I (cTnI) and creatine kinase-MB (CK-MB) were examined by commercially available kits. RESULTS: Compared with ACI group, Tan significantly decreased the scores of the defect of neural function, reduced the incidence and duration of the abnormalities in electrocardiogram, prolonged the effective refractory period, action potential duration at 50% repolarization and action potential duration at 90% repolarization, and inhibited the elevation of cTnI and CK-MB levels. CONCLUSION: Tan maintains a stable heart rhythm in ACI rats, which may be related to its protective effect on ischemic myocardium.     

Hereditary extremely hypertriglyceridemic mice are more susceptible to acute pancreatitis

AIM:To investigate the susceptibility to pancreatitis in LPL deficient hypertriglyceridemic (HTG) mice and to establish an experimental animal model for study on HTG pancreatitis. METHODS:LPL deficient HTG mice was rescued by somatic gene transfer. Plasma amylase and pathological changes in pancreas were analyzed for comparison between LPL deficient HTG and wild type mice to assess the incidence of spontaneous pancreatitis. In addition, acute pancreatitis(AP) was induced by L-arginine for further assessment. RESULTS:According to pancreatic pathological scores, incidence of spontaneous pancreatitis was 34.5% in LPL deficient mice. The affected LPL deficient HTG mice showed typical morphological changes of pancreatitis with inflammatory infiltration and acinar necrosis, accompanying fibrosis or hemorrhage occasionally, while there was no pancreatitis in wild type mice. The severity of pathological changes correlated positively with plasma TG levels （r=0.604，P<0.05）. However, the amylase levels did not increase significantly. When AP inducer, L-arginine, was injected at low dose (2 g/kg body weight, ip), LPL deficient mice showed more severe pathological damage than wild type mice （P<0.01）, though there was no significant change in amylase levels. CONCLUSION:LPL deficient HTG mice developed spontaneous pancreatitis, and the susceptibility to L-arginine-induced pancreatitis increased. These findings show that HTG results in pancreatitis on mice as on human. Therefore, LPL deficient HTG mice would be a useful experimental model for study of HTG pancreatitis.     

Reduction of inflammatory-related factor expression in experimental acute pancreatitis in Egr-1 knockout mice

AIM: To observe the effects of Egr-1 gene knockout on the expression of inflammatory-related factors in pancreatic tissue in a mouse acute pancreatitis model. METHODS: The experimental pancreatitis was induced by high-dose of cearulein in wildtype mice and Egr-1 knockout mice. The pancreatitis indexes, such as serum amylase, pancreata edema, and myeloperoxidase(MPO) levels in pancreata and lungs were recorded. The mRNA levels of tissue factor(TF), plasminogen activator inhibitor(PAI-1), monocyte chemoattractant protein(MCP-1), Gro-1, IL-6 and ICAM-1 were measured by quantitative PCR. RESULTS: Contrary to wildtype mice, typical pancreatitis was not induced by high-dose cearulein in the Egr-1 knockout mice, not only markedly reduced edema in pancreata and lungs, but decreased MPO levels in lungs as well were found. Furthermore, the mRNA of TF, PAI, MCAP, ICAM-1 and IL-6 in pancreata were significantly decreased in Egr-1 knockout mice. CONCLUSION: The severity of pancreatitis and lung damage is ameliorated in Egr-1 knockout mice stimulated by high-dosage of cearulein, which was probably mediated by decreasing expression of inflammatory-related factors in pancreata, such as TF, PAI, MCP-1, ICAM-1 and IL-6.