Intravenous administration of glutathione protects parenchymal and non-parenchymal liver cells against reperfusion injury following rat liver transplantation

AIM:To investigate the effects of intravenous administration of the antioxidant glutathione (GSH) on reperfusion injury following liver transplantation. METHODS:Livers of male Lewis rats were transplanted after 24 h of hypothermic preservation in University of Wisconsin solution in a syngeneic setting.During a 2-h reperfusion period either saline (controls,n=8) or GSH (50 or 100 μmol/(h·kg),n=5 each) was continuously administered via the jugular vein. RESULTS:Two hours after starting reperfusion plasma ALT increased to 1 457±281 U/L (mean±SE) in controls but to only 908±187 U/L (P<0.05) in animals treated with 100 μmol GSH/(h·kg).No protection was conveyed by 50μmol GSH/(h·kg).Cytoprotection was confirmed by morphological findings on electron microscopy:GSH treatment prevented detachment of sinusoidal endothelial cells (SECs) as well as loss of microvilli and mitochondrial swelling of hepatocytes.Accordingly,postischemic bile flow increased 2-fold.Intravital fluorescence microscopy revealed a nearly complete restoration of sinusoidal blood flow and a significant reduction of leukocyte adherence to sinusoids and postsinusoidal venules.Following infusion of 50μmol and 100 μmol GSH/(h·kg),plasma GSH increased to 65±7 mol/L and 97±18 mol/L,but to only 20±3 mol/L in untreated recipients. Furthermore,plasma glutathione disulfide (GSSG) increased to 7.5±1.0 mol/L in animals treated with 100μmol/(h·kg) GSH but infusion of 50μmol GSH/(h·kg) did not raise levels of untreated controls (1.8±0.5 mol/L vs 2.2±0.2 mol/L). CONCLUSION:Plasma GSH levels above a critical level may act as a “sink” for ROS produced in the hepatic vasculature during reperfusion of liver grafts.Therefore,GSH can be considered a candidate antioxidant for the Drevention of reperfusion injury after liver transplantation,in particular since it has a low toxicity in humans.

The effect of adenovirus expressing wild-type p53 on 5-fluorouracil chemosensitivity is related to p53 status in pancreatic cancer cell lines

AIM:There are conflicting data about p53 function on cellular sensitivity to the cytotoxic action of 5-fluorouracil (5-FU). Therefore the objective of this study was to determine the combined effects of adenovirus-mediated wild-type (wt) p53 gene transfer and 5-FU chemotherapy on pancreatic cancer cells with different p53 gene status. METHODS:Human pancreatic cancer cell lines Capan-1^(p53mut), Capan-2^(p53wt),FAMPAC^(p53mut),PANC1^(p53mut),and rat pancreatic cancer cell lines AS^(p53wt) and DSL6A^(p53null) were used for in vitro studies.Following infection with different ratios of Ad- p53-particles (MOI) in combination with 5-FU,proliferation of tumor cells and apoptosis were quantified by cell proliferation assay (WST-1) and FACS (PI-staining).In addition,DSL6A syngeneic pancreatic tumor cells were inoculated subcutaneously in to Lewis rats for in vivo studies. Tumor size,apoptosis (TUNEL) and survival were determined. RESULTS:Ad-p53 gene transfer combined with 5-FU significantly inhibited tumor cell proliferation and substantially enhanced apoptosis in all four cell lines with an alteration in the p53 gene compared to those two cell lines containing wt-p53.In vivo experiments showed the most effective tumor regression in animals treated with Ad-p53 plus 5-FU.Both in vitro and in vivo analyses revealed that a sublethal dose of Ad-p53 augmented the apoptotic response induced by 5-FU. CONCLUSION:Our results suggest that Ad-p53 may synergistically enhance 5-FU-chemosensitivity most strikingly in pancreatic cancer cells lacking p53 function.These findings illustrate that the anticancer efficacy of this combination treatment is dependent on the p53 gene status of the target tumor cells.

Differential expression of cholangiocyte and ileal bile acid transporters following bile acid supplementation and depletion

AIM: We have previously demonstrated that cholangiocytes, the epithelial cells lining intrahepatic bile ducts,encode two functional bile acid transporters via alternative splicing of a single gene to facilitate bile acid vectorial transport. Cholangiocytes possess ASBT,an apical sodium-dependent bile acid transporter to take up bile acids,and t-ASBT,a basolateral alternatively spliced and truncated form of ASBT to efflux bile acids.Though hepatocyte and ileal bile acid transporters are in part regulated by the flux of bile acids, the effect of alterations in bile acid flux on the expression of t-ASBT in terminal ileocytes remains undear.Thus,we tested the hypothesis that expression of ASBT and t-ASBT in cholangiocytes and ileocytes was regulated by bile acid flux. METHODS: Expression of ASBT and t-ASBT message and protein in cholangiocytes and ileocytes isolated from pair- fed rats given control (C) and 1% taurocholate (TCA) or 5% cholestyramine (CY) enriched diets,were assessed by both quantitative RNase protection assays and quantitative immunoblotting.The data obtained from each of the control groups were pooled to reflect the changes observed following TCA and CY treatments with respect to the control diets. Cholangiocyte taurocholate uptake was determined using a novel microperfusion technique on intrahepatic bile duct units (IBDUs) derived from C,TCA and CY fed rats. RESULTS: In cholangiocytes,both ASBT and t-ASBT message RNA and protein were significantly decreased in response to TCA feeding compared to C diet.In contrast, message and protein of both bile acid transporters significantly increased following CY feeding compared to C diet.In the ileum,TCA feeding significantly up-regulated both ASBT and t-ASBT message and protein compared to C diet,while CY feeding significantly down-regulated message and protein of both bile acid transporters compared to C diet.As anticipated from alterations in cholangiocyte ASBT expression,the uptake of taurocholate in microperfused IBDUs derived from rats on TCA diet decreased 2.7-fold,whereas it increased 1.7-fold in those on CY diet compared to C diet fed groups. CONCLUSION: These data demonstrate that expression of ASBT and t-ASBT in cholangiocytes is regulated by a negative feedback loop while the expression of these transporters in terminal ileum is modified via positive feedback.Thus, while transcriptional regulatory mechanisms in response to alterations in bile acid pool size are operative in both cholangiocytes and ileocytes,each cell type responds differently to bile acid supplementation and depletion.

High IFN-α expression is associated with the induction of experimental autoimmune uveitis (EAU) in Fischer 344 rat

Th1-response plays a crucial role in determining pathogenesis of organ-specific autoimmune diseases. It is believed that both IL-12 and INF-alpha are initiators to regulate Th1-response. In our experimental autoimmune uveitis (EAU) model, both Lewis and Fischer 344 rats share the same MHC class II molecules, while Lewis rat is EAU susceptible and Fischer 344 rat is EAU resistant. However, under the same condition of immunization, if pertussis toxin (PTX) was injected intraperitoneally as an additional adjuvant, Fischer 344 rat can develop EAU. In this study we investigate which mechanisms are involved in the induction of EAU in CFA+R16+PTX-treated (CRP-treated) Fischer 344 rats. In vivo and in vitro data demonstrated that Th1-cytokine, IFN-gamma mRNA expression was significantly increased in disease target tissue-eyes and in draining lymph node cells of CRP-treated Fischer 344 rat. When IL-12 and IFN-alpha mRNA expression were compared in the experimental groups, only IFN-alpha mRNA expression was associated with EAU development. To distinguish the sources of IFN-alpha producing cells, it was observed that IFN-alpha expression was mainly produced by macrophages. It was further confirmed that normal macrophage from Fischer 344 rat was able to produce significant IFN-alpha in the presence of PTX. The data strongly suggested that IFN-alpha might be involved in initiating Th1-cell differentiation and in turn contribute to the induction of EAU. High IFN-alpha expression induced by PTX may represent a novel pathway to initiate Th1 response in Fischer 344 rat.

Ventricular remodeling by Scutellarein treatment in spontaneously hypertensive rats

OBJECTIVE: To observe reversal of ventricular remodeling by the protein kinase C inhibitor Scutellarein in spontaneously hypertensive rats (SHRs). METHODS: Twelve SHRs were randomly divided into two groups. Scutellarein and saline (10 mg x kg(-1) x d(-1)) were given by intraperitoneal injection to two groups of rats separately. Systolic blood pressure (SBP) and ventricular weight index (LVW/BW, RVW/BW) were measured. A polarization microscope and an image analyzer system (IAS) were used to observe changes in cardiovascular structure and to count the content of cardiac muscle interstitial collagen. RESULTS: The pathologic changes in the left ventricle in the Scutellarein group rats (SHR(D)) improved to varying degrees, including hypertrophy of the cardiac muscle and collagen volume fraction. CONCLUSION: Scutellarein can reverse ventricular remodeling, improve myocardial stiffness and protect heart cardiac muscle.

Endothelin-1, an important mitogen of smooth muscle cells of spontaneously hypertensive rats

OBJECTIVE: To study the features of vascular smooth muscle cell (VSMC) proliferation induced by endothelin-1 (ET-1). METHODS: VSMCs of spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats were cultured and treated with ET-1. Basic fibroblast growth factor (bFGF) gene expression was measured using both Northern blot and an enzyme-linked immunoassay. RESULTS: ET-1 resulted in an increase in bFGF transcripts at 8 - 24 h; bFGF levels were significantly higher in VSMCs treated with ET-1 than in those not treated. However, VSMCs growth responses in SHR and WKY were different. Smooth muscle cells of SHR were hyper-responsive to ET-1. Maximal bFGF mRNA levels were elevated 3.5-fold at 4 h of stimulation in WKY and 8-fold at 8h in SHR4. Moreover, the proliferation of VSMCs induced by ET-1 was inhibited by antisense phosphorothioate oligodeoxynucleotides (10 micromol/L AS-bFGF) but not sense bFGF oligomers at the same concentrations, being reduced by 80% in SHR and 40% in WKY vs control, respectively. Furthermore, the effect of AS-bFGF oligomers on SHR SMC proliferation is significantly greater than on WKY SMC proliferation. CONCLUSION: ET-1 may be required for exaggerated vascular growth responses in SHR and bFGF may be involved.

Influence of Valsartan on myocardial apoptosis in spontaneously hypertensive rats

OBJECTIVE: To explore the pathogenic changes of myocardial apoptosis in heart hypertrophy during hypertension and evaluate the anti-apoptosis effect of Valsartan. METHODS: Thirty spontaneously hypertensive rats (SHRs) were divided into two groups: 15 treated with Valsartan (20 mg x kg(-1) x d(-1)) (SHR + Valsartan group), the others with placebo (SHR + placebo group), with 15 normal Wistar rats as control. Systolic blood pressure was measured by the tail-cuff method. The observation period was from 8 to 16 weeks of age. Cardiac apoptosis was evaluated by a Terminal Deoxynucleotidyl Transferase-Mediated dUTP-biotin Nick End Labeling (TUNEL) assay. RESULTS: Mean blood pressure values were 127 +/- 2 mm Hg in controls, 163 +/- 6 mm Hg in the SHR + Valsartan group and 193 +/- 7 mm Hg in the SHR + placebo group at 16 weeks of age, whereas the blood pressure in 8-week-old SHR and Wistar rats were 175 +/- 3 mm Hg and 125 +/- 5 mm Hg, respectively. The ratio of the heart weight over body weight declined in Wistar (3.07 +/- 0.03 mg/g) and SHR + Valsartan groups (3.22 +/- 0.19 mg/g) compared with the SHR + placebo group (4.02 +/- 0.31 mg/g) (P

Endothelin receptor antagonist combined with a calcium channel blocker attenuates renal injury in spontaneous hypertensive rats with diabetes

OBJECTIVE: To investigate the effects of the mixed endothelin receptor antagonist, bosentan, combined with the long-acting calcium channel blocker, amlodipine, compared to the angiotensin-converting enzyme inhibitor, cilazapril, on the progressive renal injury in spontaneous hypertensive rats (SHR) with diabetes. METHODS: Diabetic hypertensive rats (SHR-DM) were induced by streptozotozin injected in male SHR (7-week-old),and divided into an untreated and three treated groups: 1) cilazapril treated group; 2) bosentan+amlodipine treated group; and 3) amlodipine treated group. Wistar Kyoto rats (WKY) and SHR rats served as normotensive and hypertensive control, respectively. The mean arterial blood pressure, renal function, endothelin and angiotensin II levels as well as the protein expression of renal extracellular matrix components and transforming growth factor (TGF)-beta1 were determined at the end of the 4th week. RESULTS: Mean arterial blood pressure significantly increased in SHR and SHR-DM rats compared to WKY rats. All the therapies reduced the blood pressure to normal levels. However, the enhanced urinary protein excretion, the decreased creatinine clearance as well as the increased plasma and intrarenal endothelin and angiotens in II levels were found in the untreated SHR-DM and prevented by treatment with bosentan+amlodipine and cilazapril. Similarly, these two kinds of therapies in SHR-DM abolished the overexpression of renal TGF-beta1 by Western blot analysis and reduced the accumulation of collagen type IV, laminin and fibronectin proteins by an immunochemical approach. Amlodipine monotherapy had no detectable effects on the above parameters. CONCLUSION: Bosentan combined with amlodipine can offer similar renoprotective effects on that of cilazapril and may be a potent therapy to attenuate renal injury by reducing renal protein levels of TGF-beta1 in diabetes with a hypertensive state.

Tong-xin-luo capsule inhibits left ventricular remodeling in spontaneously hypertensive rats by enhancing PPAR-γ expression and suppressing NF-κB activity

Background Tong-xin-luo capsule （TXL）, used as a traditional Chinese herb, offeres a therapeutic potential for treatment of cardiovascular diseases. It has been shown to exert a variety of pharmacological effects, including antihypertensive effects, and is able to improve ventricular remodeling. However, the mechanisms of its action are not completely understood. The aim of this study was to evaluate the molecular mechanisms of Tong-xin-luo capsule on left ventricular remodeling in spontaneously hypertensive rats （SHR）. Methods Sixteen eight-week-old SHRs were randomized into an SHR group （n=8） and a TXL group （n=8） that were given Tong-xin-luo capsule （1.5 mg·kg^-1·d^-1）. Eight Wistar Kyoto （WKY） rats fed with 0.9% NaCl served as the control group （WKY group）. Systolic blood pressure （BP）, body weight and heart rate were monitored once every two weeks. Ventricular remodeling was detected by histopathological examination. Nuclear factor kappa B P65 （NF-κB P65） and peroxisome proliferators activated receptor y （PPAR-γ） protein and phosphorylated inhibitor kappa a （IκBα） protein were detected by immunohistochemistry and western blot respectively. The physical interaction of the P65-P50 heterodimer with IκBα and NF-κB were measured by co-immunoprecipitation. PPAR-γ mRNA, collagen Ⅰ mRNA and collagen Ⅲ mHNA were measured by real-time PCR.Results TXL inhibited NF-κB P65 expression and ventricular remodeling and suppressed the activation of NF-κB compared with the SHR group （P〈0.01, P〈0.05）. TXL reduced IκBα phosphorylation, increased expression of PPAR-γ protein and enhanced the physical interaction of the P65-P50 heterodimer with IκBα. The mRNA expression of PPAR-γ was enhanced but the mRNA expression of collagen Ⅰ mRNA and collagen Ⅲ mRNA were suppressed by TXL. Conclusions In spontaneously hypertensive rats, TXL could inhibit ventricular remodeling induced by hypertension, and the inhibitory effect might be associated with the process of TXL increasing the expression of PPAR-γ that could result in the inhibition of the activation of NF-κB.

Effects of electroacupuncture at Taichong(LR 3) and Baihui(DU 20)on cardiac hypertrophy in rats with spontaneous hypertension

OBJECTIVE: To investigate the effects of electroacupuncture(EA) at Taichong(LR 3) and Baihui(DU 20)on myocardial hypertrophy in spontaneously hypertensive rats(SHRs).METHODS: Thirty-six SHRs were randomly assigned to model, EA, and Losartan groups, with twelve rats per group. Twelve Wistar Kyoto rats were selected as the normal control group. Systolic blood pressure(SBP) and cardiac function were measured in all rats.Expression levels of factors associated with the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin(PI3K/Akt/mTOR) pathway were evaluated by Western blotting and real-time PCR.Pathological changes of the heart tissue were observed by hematoxylin-eosin staining.RESULTS: After treatment, enhanced SBP was significantly decreased in the EA and Losartan groups compared with the model group(P < 0.01). Echocardiographic and morphological analyses revealed that enhanced end-diastolic interventricular septal thickness and left ventricular posterior wall thickness, as well as ratio of left ventricular weight to body weight were markedly diminished in the EA and Losartan groups(P < 0.01 or P < 0.05), while reduced left ventricular end-diastolic dimension and left ventricular ejection fraction were significantly ameliorated(P < 0.01). Real-time PCR and western blotting analyses showed that the expression levels of PI3K,Akt, and mT OR in SHRs were significantly up-regulated by EA and Losartan(P < 0.01), while the expression levels of PTEN and ANP were down-regulated(P < 0.01).CONCLUSION: EA at Taichong(LR 3) and Baihui(DU20) inhibited the development of cardiac hypertrophy and improved the cardiac function in SHRs, possibly through regulation of the PI3K/Akt/mTOR signalling pathway.

Mechanism and effect of Shijueming (Concha Haliotidis) on serum calcium in spontaneously hypertensive rats

OBJECTIVE： To observe the impact of Shijueming （Concha Haliotidis） on spontaneously hypertensive rats via blood pressure, serum calcium, vascular smooth muscle membrane L-type calcium channel α1 C subunit （CaL-α1C）, plasma membrane calci- um-ATPase （PMCA） mRNA expression, and the L-type calcium channel in vascular smooth muscle cells. METHODS： Twelve-week-old male rats with sponta- neous hypertension were divided into three groups： a Shijueming （Concha Haliotidis） group （group 1）, a nifedipine group （group 2）, and a dis- tilled water group （group 3）. All were given a four-week treatment. Blood pressure and dissocia- tive serum calcium were examined before treat- ment. Blood pressure was taken every week during treatment. Atomic absorption spectrometry was used to examine dissociative serum calcium. Re-verse transcription-polymerase chain reaction was used to examine the expression of CaL-α1C and PM- CA1 mRNA. The patch clamp technique was used to examine the electrophysiological characteristics of the vascular smooth muscle cell calcium chan- nels. RESULTS： After treatment, blood pressure of the Shijueming （Concha Halioticlis） group lowered but not significantly （P〉0.05）. Blood pressure of the nifedipine group lowered significantly （P〈0.05）. Blood pressure of the distilled water group re- mained high. The concentration of serum calcium in the Shijueming （Concha Haliotidis） and the dis- tilled water groups lowered （P〈0.05）. Expression of CaL-α1C mRNA in the nifedipine group decreased compared with the distilled water group （P〈0.01）. There was the decreasing trend in the Shijueming （Concha Haliotidis） group, but it was not statistically significant. Shijueming （Concha Haliotidis） also had effects on the expression of PMCA1 mRNA but with- out statistical significance. However, there was a significant decreasing effect on vascular smooth muscle cell Ica-L flow. CONCLUSION： This study indicated that Shijuem- ing （Concha Haliotidis） could increase serum calci- um and decrease blood pressure. It may work by in- fluencing calcium channels, expression of PMCA1 mRNA, and regulating ion calcium channels and calcium-ATPase.

Effect of Taichong(LR 3) acupuncture in spontaneously hypertensive rats

OBJECTIVE: To evaluate the effects of Taichong(LR3) acupuncture points(acupoints) on the expression of glucose transporter protein 1(GLUT1) in the hypothalamus of spontaneously hypertensive rats(SHRs) as measured by combined positron emission tomography and computed tomography(PETCT).METHODS: Spontaneously hypertensive rats(SHR)were divided into model, Taichong(LR 3) acupuncture, and sham groups. Additionally, Tokyo Wistar rats were used as the control group. Changes in blood pressure were recorded in different groups of rats before and after the corresponding treatment. Hematoxylin and eosin(HE) staining was used to study basic morphological changes, and immunohistochemistry was used to determine GLUT1 expression in the hypothalamus. Further,PET-CT was utilized to elucidate the antihypertensive mechanism after acupuncture at the Taichong(LR 3) acupoints.RESULTS: PET-CT indicated activation of the hypothalamus. Measurement of blood pressure showed that acupuncture at the Taichong(LR 3) acupoints lowered blood pressure. HE staining did not show any significant pathological changes, although differences in cell number were observed. Immunohistochemical analysis indicated a GLUT1 downregulation in the SHRs of the Taichong(LR 3) acupuncture group after the treatment.CONCLUSION: Acupuncture at Taichong(LR 3) acupoints lowered blood pressure in SHRs, with possible mechanisms being changes in cell number and GLUT1 expression in the hypothalamus.

Upregulation of the angiotensin-converting enzyme 2-angiotensin-(1-7)-Mas receptor axis by a combination of Yinyanghuo(Herba Epimedii Brevicornus) and Cheqianzi(Semen Plantaginis) improves erectile function in spontaneously hypertensive rats

OBJECTIVE:To evaluate the effects of a combination of Yinyanghuo(Herba Epimedii Brevicornus)(HEB)and Cheqianzi(Semen Plantaginis)(SP)on erectile dysfunction caused by essential hypertension in spontaneously hypertensive rats(SHRs),and to elucidate the role of the angiotensin-converting enzyme 2-angiotensin-(1-7)-Mas receptor(ACE2/Ang[1-7]/Mas receptor)axis in this process.METHODS:A total of 24 SHRs were randomly assigned to three groups:SHR-control,low-dose(12.5 g/kg)and high-dose(25 g/kg)HEB+SP(HEBSP).Eight Wistar-Kyoto rats were used as normal controls.HEBSP was administered by oral gavage for 28 d.Erectile function was measured once a week using the Heaton test.After 4 weeks of treatment,the corpus cavernosum was harvested from each rat to measure nitric oxide(NO),nitric oxide synthase(e NOS)and Ang(1-7)levels,as well as ACE2,Mas receptor and neuronal nitric oxide synthase(n NOS)protein expression.RESULTS:After 4 weeks of treatment,HEBSP significantly increased erectile function in the treated group compared with SHR-control group(P<0.01).Additionally,HEBSP treatment significantly increased cavernosal levels of Ang(1-7),e NOS and NO.Moreover,HEBSP significantly elevated the expression levels of ACE2,Mas receptor and n NOS.These beneficial effects were elevated in the high-dose HEBSP group.CONCLUSION:HEBSP improved erectile function in SHRs by upregulating the ACE2/Ang(1-7)/Mas receptor axis,e NOS and n NOS pathways.