Progesterone stimulates the proliferation of female and male cholangiocytes via autocrine/paracrine mechanisms

During cholestatic liver diseases, cholangiocytes express neuroendocrine phenotypes and respond to a number of hormones and neuropeptides by paracrine and autocrine mechanisms. We examined whether the neuroendocrine hormone progesterone is produced by and targeted to cholangiocytes, thereby regulating biliary proliferation during cholestasis. Nuclear (PR-A and PR-B) and membrane (PRGMC1, PRGMC2, and mPRalpha) progesterone receptor expression was evaluated in liver sections and cholangiocytes from normal and bile duct ligation (BDL) rats, and NRC cells (normal rat cholangiocyte line). In vivo, normal rats were chronically treated with progesterone for 1 wk, or immediately after BDL, rats were treated with a neutralizing progesterone antibody for 1 wk. Cholangiocyte growth was measured by evaluating the number of bile ducts in liver sections. The expression of the progesterone synthesis pathway was evaluated in liver sections, cholangiocytes and NRC. Progesterone secretion was evaluated in supernatants from normal and BDL cholangiocytes and NRC. In vitro, NRC were stimulated with progesterone and cholangiocyte supernatants in the presence or absence of antiprogesterone antibody. Aminoglutethimide was used to block progesterone synthesis. Cholangiocytes and NRC express the PR-B nuclear receptor and PRGMC1, PRGMC2, and mPRalpha. In vivo, progesterone increased the number of bile ducts of normal rats, whereas antiprogesterone antibody inhibited cholangiocyte growth stimulated by BDL. Normal and BDL cholangiocytes expressed the biosynthetic pathway for and secrete progesterone. In vitro, 1) progesterone increased NRC proliferation; 2) cholangiocyte supernatants increased NRC proliferation, which was partially inhibited by preincubation with antiprogesterone; and 3) inhibition of progesterone steroidogenesis prevented NRC proliferation. In conclusion, progesterone may be an important autocrine/paracrine regulator of cholangiocyte proliferation.     

Potential chemoprevention of diethylnitrosamine-initiated and 2-acetylaminofluorene-promoted hepatocarcinogenesis by zerumbone from the rhizomes of the subtropical ginger (Zingiber zerumbet)

Zerumbone (ZER), a monosesquiterpene found in the subtropical ginger (Zingiber zerumbet Smith), possesses antiproliferative properties to several cancer cells lines, including the cervical, skin and colon cancers. In this study, the antitumourigenic effects of ZER were assessed in rats induced to develop liver cancer with a single intraperitoneal injection of diethylnitrosamine (DEN, 200 mg/kg) and dietary 2-acetylaminofluorene (AAF) (0.02%). The rats also received intraperitoneal ZER injections at 15, 30 or 60 mg/kg body wt. twice a week for 11 weeks, beginning week four post-DEN injection. The hepatocytes of positive control (DEN/AAF) rats were smaller with larger hyperchromatic nuclei than normal, showing cytoplasmic granulation and intracytoplasmic violaceous material, which were characteristics of hepatocarcinogenesis. Histopathological evaluations showed that ZER protects the rat liver from the carcinogenic effects of DEN and AAF. Serum alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (AP) and alpha-fetoprotein (AFP) were significantly lower (P < 0.05) in ZER-treated than untreated rats with liver cancer. The liver malondialdehyde (MDA) concentrations significantly (P < 0.05) increased in the untreated DEN/AAF rats indicating hepatic lipid peroxidation. There was also significant (P < 0.05) reduction in the hepatic tissue glutathione (GSH) concentrations. The liver sections of untreated DEN/AAF rats also showed abundant proliferating cell nuclear antigen (PCNA), while in ZER-treated rats the expression of this antigen was significantly (P < 0.05) lowered. By the TUNEL assay, there were significantly (P < 0.05) higher numbers of apoptotic cells in DEN/AAF rats treated with ZER than those untreated. Zerumbone treatment had also increased Bax and decreased Bcl-2 protein expression in the livers of DEN/AAF rats, which suggested increased apoptosis. Even after 11 weeks of ZER treatment, there was no evidence of abnormality in the liver of normal rats. This study suggests that ZER reduces oxidative stress, inhibits proliferation, induces mitochondria-regulated apoptosis, thus minimising DEN/AAF-induced carcinogenesis in rat liver. Therefore, ZER has great potential in the treatment of liver cancers.     

Beneficial effect of quercetin on cholestatic liver injury

Bile duct obstruction and subsequent cholestasis are associated with hepatocellular injury, cholangiocyte proliferation, stellate cell activation, Kupffer cell activation, oxidative stress, inflammation and fibrosis. Flavonoids have been shown to confer beneficial health effects, including hepatoprotection. However, the molecular mechanism of flavonoid-mediated hepatoprotection is incompletely understood. In this study, we report the protective effect of quercetin on cholestatic liver injury. Cholestasis was produced by bile duct ligation (BDL) in male Sprague–Dawley rats for 3 weeks. Daily oral administration of quercetin was started 1 week before injury and lasted for 4 weeks. In comparison with the control group, the BDL group showed liver injury, as evidenced by histological changes, and elevation in serum biochemicals, ductular reaction, fibrosis, inflammation and oxidative stress. These pathophysiological changes were attenuated by daily quercetin supplementation. Quercetin alleviated BDL-induced transforming growth factor beta-1 (TGF-β1), interleukin-1 beta, connective tissue growth factor and collagen expression. The antifibrotic effect of quercetin was accompanied by reductions in α-smooth muscle actin-positive matrix-producing cells and Smad 2/3 activity critical to the fibrogenic potential of TGF-β1. Quercetin also attenuated BDL-induced oxidative stress, leukocyte accumulation, nuclear factor (NF)-κB activation and proinflammatory cytokine production. Further studies demonstrated an inhibitory effect of quercetin on MyD88 and TGF-β-activated kinase-1 critical for linking toll-like receptor (TLR) and NF-κB. Taken together, the hepatoprotective, anti-inflammatory and antifibrotic effects of quercetin seem to be multifactorial. The beneficial effects of daily quercetin supplementation are associated with antioxidative and anti-inflammatory potential as well as down-regulation of NF-κB and TGF-β/Smad signaling, probably via interference with TLR signaling.     

Oxidative stress and apoptosis in preeclampsia

We aimed to determine the oxidative stress and antioxidant status in preeclamptic placenta. Also, we investigated the apoptotic index of villous trophoblast and proliferation index of cytotrophoblasts. The study included 32 pregnant with preeclampsia and 31 normotensive healthy pregnant women. Malondialdehyde (MDA) and total antioxidant status (TAS) levels were measured in the placenta. For detection of apoptosis and proliferation in trophoblast, apoptosis protease activating factor 1 (APAF-1) and Ki-67 were used. Placental MDA levels in preeclamptic women were significantly higher than normal pregnancies (p = 0.002). There was no significant difference between the groups in the TAS levels of placenta (p = 0.773). Also, the apoptotic index in villous trophoblasts increased (p < 0.001), but proliferation index did not change in preeclampsia (p = 0.850). Increased oxidative stress and apoptosis in pathological placenta are not balanced by antioxidant systems and proliferation mechanisms.     

Synthesis,characterization and biological evaluation of novel chalcone sulfonamide hybrids as potent intestinal alkaline phosphatase inhibitors

Alkaline phosphatase (AP) and ecto-5′-nucleotidase (e5′NT) belong to same family that hydrolyze the extracellular nucleotides and ensure the bioavailability of nucleotides and nucleosides at purinergic receptors. During pathophysiological conditions, the over expression of AP and e5′NT lead to an increased production of adenosine that enhance tumor proliferation, invasiveness, neoangiogenesis and disrupts the body antitumor response. As both enzymes are abundantly expressed in above mentioned conditions, therefore it is of great interest to synthesize and develop potent inhibitors of these enzymes that augment the antitumor therapy. Herein we reported the synthesis and biological activity of a new series of chalcone-sulfonamide hybrids (4a-j). These derivatives were then evaluated for their inhibitory potential against two members of ecto-nucleotidase family, e5′NT (human and rat) and APs isozyme (intestinal and tissue nonspecific). Only six derivatives were found to inhibit both human and rat e5′NT enzymes. Compounds 4e and 4d showed maximum inhibition of human and rat e5′NT with an IC₅₀ ± SEM = 0.26 ± 0.01 and 0.33 ± 0.004 μM, respectively. Moreover, on APs, these derivatives were identified as the selective inhibitors of calf intestinal AP (c-IAP). The derivative 4a exhibited maximum inhibition of c-IAP with an IC₅₀ ± SEM = 0.12 ± 0.02 μM. In conclusion, these chalcone-sulfonamide hybrids exhibited dual inhibition of both family of isozymes but was more selective towards c-IAP enzyme.     

Hybrid liposomes inhibit the growth of Cholangiocarcinoma by induction of cell cycle arrest in G1 phase

Specific accumulation and cell cycle arrest were observed in human cholangiocarcinoma cells by hybrid liposomes composed of 90 mol % l-α-dimyristoylphosphatidylcholine (DMPC) and 10 mol % polyoxyethylene(21)dodecyl ether (C₁₂(EO)₂₁) without affecting normal cholangiocytes.     

Quercetin in vesicular delivery systems: Evaluation in combating arsenic-induced acute liver toxicity associated gene expression in rat model

Arsenic, the environmental toxicant causes oxidative damage to liver and produces hepatic fibrosis. The theme of our study was to evaluate the therapeutic efficacy of liposomal and nanocapsulated herbal polyphenolic antioxidant Quercetin (QC) in combating arsenic induced hepatic oxidative stress, fibrosis associated upregulation of its gene expression and plasma TGF ß (transforming growth factor ß) in rat model.A single dose of Arsenic (sodium arsenite-NaAsO₂, 13 mg/kg b.wt) in oral route causes the generation of reactive oxygen species (ROS), arsenic accumulation in liver, hepatotoxicity and decrease in hepatic plasma membrane microviscosity and antioxidant enzyme levels in liver. Arsenic causes fibrosis associated elevation of its gene expression in liver, plasma TGF ß (from normal value 75.2 ± 8.67 ng/ml to 196.2 ± 12.07 ng/ml) and release of cytochrome c in cytoplasm. Among the two vesicular delivery systems formulated with QC, polylactide nanocapsules showed a promising result compared to liposomal delivery system in controlling arsenic induced alteration of those parameters. A single dose of 0.5 ml of nanocapsulated QC suspension (QC 2.71 mg/kg b.wt) when injected to rats 1 h after arsenic administration orally protects liver from arsenic induced deterioration of antioxidant levels as well as oxidative stress associated gene expression of liver. Histopathological examination also confirmed the pathological improvement in liver. Nanocapsulated plant origin flavonoidal compound may be a potent formulation in combating arsenic induced upregulation of gene expression of liver fibrosis through a complete protection against oxidative attack in hepatic cells of rat liver.     

Importance of the core structure of flavones in promoting inhibition of the mitochondrial respiratory chain

Flavonoids are a large group of polyphenolic compounds that have received considerable attention because of their biological and physiological importance. The flavone (2-phenyl-4H-1-benzopyran-4one) used in this work is found in some cereal grains and generates several biological activities, including: apoptosis induction, cell cycle arrest, caspase activation and inhibition of tumor cell proliferation. However, its effects on the hepatic mitochondrial metabolism are still unknown. We evaluated the effect of flavone on the metabolism of mitochondria isolated from rat liver. Polarographic experiments using 200 μmol L^?1 flavone and rat liver mitochondria oxidizing glutamate or succinate indicated that both substrates underwent: (i) reduction of state 3 respiration; (ii) stimulation of state 4 respiration; (iii) reduction of the respiratory control coefficient; and (iv) reduction of the ADP/O ratio. An analysis of the activity of enzymatic complexes in the respiratory chain showed that flavone acts between complexes I and III. Flavone reduced the membrane electric potential at doses of 100, 150 and 200 μmol L^?1. Flavone at certain doses (75–200 μmol L^?1) reduced mitochondrial swelling in the presence of valinomycin and KNO₃, suggesting that flavone could induce changes in mitochondrial membrane properties. These results demonstrate that the inhibition of mitochondrial enzymes in the respiratory chain coupled with the effects on membrane properties are promoted by the core structure of flavones, and these effects may be in part responsible for the cytotoxic effects of flavones.     

Newcastle disease virus (NDV) induces protein oxidation and nitration in brain and liver of chicken: Ameliorative effect of vitamin E

The present study was aimed at investigating the therapeutic efficacy of vitamin E on oxidative injury in brain and liver of Newcastle disease virus (NDV) challenged chickens. We have analyzed the xanthine oxidase (XOD) activity; uric acid (UA) levels and superoxide radical generation by using electron spin resonance spectroscopy. Further, protein oxidation, nitration and apoptosis were evaluated in the brain and liver of the control, NDV-infected and NDV + Vit. E treated groups. A significant elevation was observed in XOD activity and UA levels in brain (p < 0.001) and liver (p < 0.05) of NDV infected birds when compared to controls. Further, significant increase in the production of superoxides, enhanced intracellular protein carbonyls and nitrates were observed in the brain and liver of NDV-infected birds over healthy subjects. Apoptosis studies also suggested that a larger number of TUNEL positive cells were observed in brain and a moderately in liver of NDV-infected chickens. However, all these perturbations were significantly ameliorated in NDV + Vit. E treated chickens as compared to NDV-infected birds. Taken together, our results suggested that NDV-induced neuronal and hepatic damage at least in part mediates oxidative stress and on the other hand, supplementation of vitamin E mitigates NDV-induced oxidative damage thereby protects brain and liver of chickens. These findings could provide new insights into the understanding of NDV pathogenesis and therapeutic effects of dietary antioxidants.     

Anti-apoptotic activity of gentiopicroside in d-galactosamine/lipopolysaccharide-induced murine fulminant hepatic failure

This study investigated the hepatoprotective effects of gentiopicroside on d-galactosamine (d-GalN) and lipopolysaccharide (LPS)-induced fulminant hepatic failure. Mice were administrated orally with gentiopicroside (40 or 80 mg/kg body weight) at 12 h and 1 h before d-GalN (700 mg/kg)/LPS (10 μg/kg) injection. Gentiopicroside markedly reduced the increases in serum aminotransferase activities and lipid peroxidation. The glutathione content decreased in d-GalN/LPS alone group, and this decrease was attenuated by gentiopicroside. Increases in serum tumor necrosis factor-α (TNF-α), which were observed in d-GalN/LPS alone group, were significantly reduced by gentiopicroside. Importantly, gentiopicroside attenuated d-GalN/LPS-induced apoptosis of hepatocytes, as estimated by the caspase-3 cleavage, poly(ADP-ribose) polymerase (PARP) cleavage, and DNA fragmentation. d-GalN/LPS-induced caspase-8 and -9 activation was significantly suppressed by gentiopicroside. Moreover, increased cytosolic cytochrome c protein was reduced by gentiopicroside. Also, the increased ratio of Bax and Bcl-2 protein was significantly attenuated by gentiopicroside. After 6 h of d-GalN/LPS injection, phosphorylated c-jun N-terminal kinase (JNK) and extracellular signal regulated kinase (ERK) was significantly increased, whereas phosphorylation JNK and ERK were attenuated by gentiopicroside. Our results suggest that gentiopicroside offers remarkable hepatoprotection against damage induced by d-GalN/LPS related with its anti-apoptotic activities.     

Significant hepatic expression of IL-2 and IL-8 in biliary atresia compared with other neonatal cholestatic disorders

ObjectivesAlthough the exact etiology of biliary atresia (BA) is still elusive, inflammation plays a key role. Release of proinflammatory cytokines from activated immune cells perpetuates the injury and causes biliary destruction. We aimed to study interleukin (IL)-2 and IL-8 expression in liver tissue of BA patients compared with other neonatal cholestatic disorders.MethodsThe study included 59 infants with neonatal cholestasis in two groups; BA group (n = 31) and non-BA group (n = 28) with cholestatic disorders other than BA as controls. Demographic, clinical, laboratory, and histopathological parameters were collected. IL-2 and IL-8 immunostaining was performed. Immunostaining in portal cellular infiltrate was scored as positive or negative and expressed as the mean cell count in three portal tracts.ResultsThe mean value of IL-2 and IL-8 positive inflammatory cells was significantly higher in BA than in non-BA group (P-values of 0.004 and 0.002 respectively). IL-2 correlated significantly with IL-8 immunostaining in both BA and non-BA group (P < 0.0001 for both). Furthermore, both cytokines in both groups correlated significantly with inflammatory activity in liver biopsy while there was no significant correlation with the other studied parameters. Yet, there was a trend of increased expression of IL-2 and IL-8 with increasing stage of fibrosis in BA group. This trend was not observed in non-BA group.ConclusionThe significantly higher expression of IL-2 and IL-8 in patients with BA compared to non-BA suggests a potential role for these cytokines in the pathogenesis in therapy of this devastating neonatal hepatic disorder.     

Taurocholic acid feeding prevents tumor necrosis factor-alpha-induced damage of cholangiocytes by a PI3K-mediated pathway

Cholangiopathies, such as primary biliary cirrhosis and primary sclerosis cholangitis, are characterized at the end stage by ductopenia due to increased cholangiocyte apoptosis and decreased cholangiocyte proliferation. Although cholangiocyte proliferation is associated with an increased number of intra-hepatic bile ducts and secretin-stimulated ductal secretion, ductopenia is coupled with decreased ductal mass and secretin-induced ductal secretory activity. We have shown that a single injection of actinomycin D + tumor necrosis factor-alpha (TNF-alpha ) to bile duct-ligated (BDL) rats induces cholangiocyte injury, which is characterized by loss of cholangiocyte proliferation, and secretory activity and by an increase in cholangiocyte apoptosis. We also have shown that taurocholic acid both in vivo and in vitro stimulates cholangiocyte proliferation. We hypothesize that taurocholic acid feeding protects cholangiocytes against TNF-alpha -induced apoptosis through a phosphatidylinositol-3-kinase (PI3K)-dependent pathway. Immediately after BDL, rats were fed taurocholic acid or control diet in the absence/presence of daily injections of wortmannin for 1 week. Seven days later, control-fed or taurocholic acid-fed rats were treated with a single intraperitoneal injection of actinomycin D + TNF-alpha . Twenty-four hours later we evaluated: (i) cholangiocyte apoptosis and proliferation in liver sections and (ii) basal and secretin-stimulated bile and bicarbonate secretion in bile fistula rats. Taurocholic acid feeding prevented TNF-alpha -induced increases in cholangiocyte apoptosis and decreases in growth and secretin-stimulated bile and bicarbonate secretion, changes that were blocked by PI3K inhibition. The PI3K survival pathway is important in bile acid protection against immune-mediated cholangiocyte injury in cholestatic liver diseases.     

Necrotic cell death and suppression of T-cell immunity characterized acute liver failure due to drug-induced liver injury

Background & aims: The aim of this study was to investigate the clinical characteristics and pathophysiology of drug-induced liver injury (DILI) – acute liver failure (ALF). Methods: The patients with acute liver injury (ALI) including ALF from 2009 to 2014 were analyzed. The hepatic encephalopathy (HE) development rate was compared with the findings from a national survey in Japan. The serum cytokines levels and the findings of a liver function test were evaluated in the DILI patients. Results: The HE development rate substantially decreased for autoimmune hepatitis (AIH) – and undetermined cause-induced ALI owing to the early prediction system, but not in DILI-ALI. Among the DILI-ALF and AIH-ALF cases, the CK-18 fragment (1480.1 U/L, 3945.4 U/L), IL-8 (82.9 pg/mL, 207.5 pg/mL), IP-10 (1379.6 pg/mL, 3731.2 pg/mL) and MIP-1β (1017.7 pg/mL, 2273.3 pg/mL) levels were lower in the DILI-ALF cases. Among the DILI-ALI and DILI-ALF cases, IL-4 (19.8 pg/mL, 25.4 pg/mL) and RANTES (14028.0 pg/mL, 17804.7 pg/mL) were higher in DILI-ALI, and HMGB-1 (397.1 pg/μL, 326.2 pg/μL) and HGF (2.41 ng/mL, 0.55 ng/mL) were higher in DILI-ALF. We observed that HGF independently associated with DLI-ALF development. Conclusions: Despite the low grade apoptosis and inflammation, DILI patients progressed to ALF comparable with that of the AIH patients.     

Pregnancy and maternal iron deficiency stimulate hepatic CRBPII expression in rats

Iron deficiency impairs vitamin A (VA) metabolism in the rat but the mechanisms involved are unknown and the effect during development has not been investigated. We investigated the effect of pregnancy and maternal iron deficiency on VA metabolism in the mother and fetus. 54 rats were fed either a control or iron deficient diet for 2 weeks prior to mating and throughout pregnancy. Another 15 female rats followed the same diet and were used as non-pregnant controls. Maternal liver, placenta and fetal liver were collected at d21 for total VA, retinol and retinyl ester (RE) measurement and VA metabolic gene expression analysis. Iron deficiency increased maternal hepatic RE (P < .05) and total VA (P < .0001), fetal liver RE (P < .05), and decreased placenta total VA (P < .05). Pregnancy increased Cellular Retinol Binding Protein (CRBP)-II gene expression by 7 fold (P = .001), decreased VA levels (P = .0004) and VA metabolic gene expression (P < .0001) in the liver. Iron deficiency increased hepatic CRBPII expression by a further 2 fold (P = .044) and RBP4 by ~ 20% (P = .005), increased RBPR2 and decreased CRBPII, LRAT, and TTR in fetal liver, while it had no effect on VA metabolic gene expression in the placenta. Hepatic CRBPII expression is increased by pregnancy and further increased by iron deficiency, which may play an important role in VA metabolism and homeostasis. Maternal iron deficiency also alters VA metabolism in the fetus, which is likely to have consequences for development.     

Stereotactic body radiation therapy in hepatocellular carcinoma: Optimal treatment strategies based on liver segmentation and functional hepatic reserve

AimTo discuss current dosage for stereotactic body radiation therapy (SBRT) in hepatocellular carcinoma (HCC) patients and suggest alternative treatment strategies according to liver segmentation as defined by the Couinaud classification.BackgroundSBRT is a safe and effective alternative treatment for HCC patients who are unable to undergo liver ablation/resection. However, the SBRT fractionation schemes and treatment planning strategies are not well established.Materials and methodsIn this article, the latest developments and key findings from research studies exploring the efficacy of SBRT fractionation schemes for treatment of HCC are reviewed. Patients’ characteristics, fractionation schemes, treatment outcomes and toxicities were compiled. Special attention was focused on SBRT fractionation approaches that take into consideration liver segmentation according to the Couinaud classification and functional hepatic reserve based on Child–Pugh (CP) liver cirrhosis classification.ResultsThe most common SBRT fractionation schemes for HCC were 3 × 10–20 Gy, 4–6 × 8–10 Gy, and 10 × 5–5.5 Gy. Based on previous SBRT studies, and in consideration of tumor size and CP classification, we proposed 3 × 15–25 Gy for patients with tumor size <3 cm and adequate liver reserve (CP-A score 5), 5 × 10–12 Gy for patients with tumor sizes between 3 and 5 cm or inadequate liver reserve (CP-A score 6), and 10 × 5–5.5 Gy for patients with tumor size >5 cm or CP-B score.ConclusionsTreatment schemes in SBRT for HCC vary according to liver segmentation and functional hepatic reserve. Further prospective studies may be necessary to identify the optimal dose of SBRT for HCC.     

Role of carbon monoxide and nitric oxide in adult rat hepatocytes proliferating in vitro: Effects of CAS 1609

During liver regeneration in vivo carbon monoxide (CO) and nitric oxide (NO) are supposed to play a significant role. We raise the question whether CO and NO are involved in the growth process of cultured hepatocytes. Rat hepatocytes were stimulated into proliferation, growth being estimated by DNA content, mRNA by quantitative RT-PCR, and inducible NO synthase (iNOS) activity by GC–MS. Dexamethasone proved obligatory for fast proliferation. It suppressed the spontaneous rise of iNOS-mRNA in cultures devoid of glucocorticoids, but did not counteract the rise in mRNA in actively dividing cultures. Expression of iNOS-mRNA and cell growth were further enhanced by LiCl (10 mM). NOS activity was completely suppressed by the iNOS-specific inhibitors N-(3-(aminomethyl)benzyl) acetamidine (1400 W,100 μM) and l-N⁶-(1-iminoethyl)lysine (l-NIL, 500 μM), however, without a decrease in hepatocyte growth. Proliferation was attenuated only by very high concentrations (>0.5 mM) of N-nitro-l-arginine methyl ester (l-NAME) and asymmetric dimethylarginine (ADMA). Various NO donors (at 100 μM) did not stimulate cell growth. The furoxan CAS 1609 stimulated growth, decreased iNOS-mRNA expression and transiently increased haem oxygenase-1 (HO-1)-mRNA without releasing considerable amounts of NO. 1H-[1,2,4]Oxadiazolo[4,3,-α]quinoxalin-1-one (ODQ) attenuated the action of CAS 1609. Proliferation was stimulated by Co-protoporphyrin and tricarbonyldichlororuthenium(II) dimer (CORM-2). We conclude that CAS 1609 triggers hepatocyte mitosis most likely via direct, NO-independent induction of HO-1 expression, pointing to CO as a growth-promoting signal in the proliferation cascade in cultured hepatocytes.     

Cellular and molecular mechanisms of 17β-estradiol postconditioning protection against gastric mucosal injury induced by ischemia/reperfusion in rats

AimsTo investigate the protective effects of 17β-estradiol postconditioning against ischemia/reperfusion (I–R)-induced gastric mucosal injury in rats.Main methodsThe animal model of gastric ischemia/reperfusion was established by clamping of the celiac artery for 30 min and reperfusion for 30 min, 1 h, 3 h, 6 h, 12 h or 24 h. 17β-estradiol at doses of 5, 50 or 100 μg/kg (rat) was administered via peripheral veins 2 min before reperfusion. In a subgroup of rats, the estrogen receptor antagonist fulvestrant (Ful, 2 mg/kg) was intravenously injected prior to 17β-estradiol administration. Histological and immunohistochemical methods were employed to assess the gastric mucosal injury index and gastric mucosal cell apoptosis and proliferation. The malondialdehyde (MDA) concentration, superoxide dismutase (SOD) activity, xanthine oxidase (XOD) activity and hydroxyl free radical (–OH) inhibitory ability were determined by colorimetric assays. Subsequently, the expression of Bcl-2 and Bax in rat gastric mucosa was examined by western blotting.Key findings17β-estradiol dose-dependently inhibited gastric I–R (GI–R) injury, and 17β-estradiol (50 μg/kg) markedly attenuated GI–R injury 1 h after reperfusion. 17β-estradiol inhibited gastric mucosal cell apoptosis and promoted gastric mucosal cell proliferation in addition to increasing SOD activity and –OH inhibitory ability and decreasing the MDA content and XOD activity. The Bax protein level increased 1 h after GI–R and was markedly reduced by intravenous administration of 17β-estradiol. In contrast, the level of Bcl-2 protein decreased 1 h after GI–R and was restored to normal levels by intravenous administration of 17β-estradiol. These effects of 17β-estradiol were inhibited by pretreatment with fulvestrant.Significance17β-estradiol postconditioning should be investigated further as a possible strategy against gastric mucosal injury.     

Long-term tillage effects on soil organic carbon and dissolved organic carbon in a purple paddy soil of Southwest China

The impact of conservation tillage practices on soil carbon has been of great interest in recent years. Conservation tillage might have the potential to enhance soil carbon accumulation and alter the depth distribution of soil carbon compared to conventional tillage based systems. Changes in the soil organic carbon (SOC) as influenced by tillage, are more noticeable under long-term rather than short-term tillage practices. The objective of this study was to determine the impacts of long-term tillage on SOC and dissolved organic carbon (DOC) status after 19 years of four tillage treatments in a Hydragric Anthrosol. In this experiment four tillage systems included conventional tillage with rotation of rice and winter fallow system (CTF), conventional tillage with rotation of rice and rape system (CTR), no-till and ridge culture with rotation of rice and rape system (NT) and tillage and ridge culture with rotation of rice and rape system (TR). Soils were sampled in the spring of 2009 and sectioned into 0–10, 10–20, 20–30, 30–40, 40–50 and 50–60 cm depth, respectively.Tillage effect on SOC was observed, and SOC concentrations were much larger under NT than the other three tillage methods in all soil depths from 0 to 60 cm. The mean SOC concentration at 0–60 cm soil depth followed the sequence: NT (22.74 g kg^?1) > CTF (14.57 g kg^?1) > TR (13.10 g kg^?1) > CTR (11.92 g kg^?1). SOC concentrations under NT were significantly higher than TR and CTR (P < 0.01), and higher than CTF treatment (P < 0.05). The SOC storage was calculated on equivalent soil mass basis. Results showed that the highest SOC storage at 0–60 cm depth presented in NT, which was 158.52 Mg C ha^?1, followed by CTF (106.74 Mg C ha^?1), TR (93.11 Mg C ha^?1) and CTR (88.60 Mg C ha^?1). Compared with conventional tillage (CTF), the total SOC storage in NT increased by 48.51%, but decreased by 16.99% and 12.77% under CTR and TR treatments, respectively. The effect of tillage on DOC was significant at 0–10 cm soil layer, and DOC concentration was much higher under CTF than the other three treatments (P < 0.01). Throughout 0–60 cm soil depth, DOC concentrations were 32.92, 32.63, 26.79 and 22.10 mg kg^?1 under NT, CTF, CTR and TR, and the differences among the four treatments were not significant (P > 0.05). In conclusion, NT increased SOC concentration and storage compared to conventional tillage operation but not for DOC.