Suppression by Hydrangeae Dulcis Folium of D-galactosamine-induced liver injury in vitro and in vivo

Hydrangeae Dulcis Folium, the fermented and dried leaves of Hydrangea macrophylla SER. var. thunbergii MAKINO, suppressed D-galactosamine-induced liver injury by 85.2% when added to the diet at 1% and fed to rats for fifteen days. The hepatoprotective effect is more potent than that of a milk thistle extract and turmeric powder. Some fractionated extracts showed hepatoprotective activity in the D-galactosamine-induced in vitro liver injury model.     

Suppression of lipopolysaccharide-induced liver injury by various types of tea and coffee in D-galactosamine-sensitized rats

Extracts of various types of tea and coffee significantly suppressed lipopolysaccharide (LPS)-induced liver injury, as assessed by the plasma enzyme activities, in D-galactosamine-sensitized rats when administered orally once before injecting the drugs. There was a significant negative correlation between the caffeine levels of these extracts and liver injury. Authentic caffeine also had a hepatoprotective effect. These results suggest that caffeine-containing beverages generally suppress LPS-induced liver injury according to their caffeine content.     

Dosing-time-dependent differences in lipopolysaccharide-induced liver injury in rats

Dosing-time-dependent differences in lipopolysaccharide (LPS)-induced liver injury were examined in rats housed under a 12 h light:dark (LD) cycle. LPS (5 mg/kg) was intravenously injected into different groups of rats at 2, 14, or 20 h after light on (HALO). Elevations in serum liver enzymes after 14 HALO were significantly greater than those after 2 HALO. These parameters were lower in rats given LPS at 20 HALO, compared to 14 HALO. The number of polymorphonuclear cells (PMN) in the liver and the amount of hepatic myeloperoxidase activity, which reflects the number of PMN in liver tissues, was significantly greater in the 14 than in the 2 HALO group. In addition, hepatic interleukin-6 (IL-6) production in the 14 HALO group was enhanced compared to that in the 2 HALO trial. These results suggest that LPS-induced liver injury is greater during the early active than during the early resting period. Dosing-time-dependent variation in the accumulation of PMN in the liver and, potentially, subsequent IL-6 production in liver tissues might be involved in this phenomenon.     

New type of anti-diabetic compounds from the processed leaves of Hydrangea macrophylla var. thunbergii (Hydrangeae Dulcis Folium)

Two 3-phenyldihydroisocoumarins (hydrangenol and phyllodulcin), a 3-phenylisocoumarin (thunberginol A), and a stilbene (hydrangeaic acid) from the processed leaves of Hydrangea macrophylla var. thunbergii (Hydrangeae Dulcis Folium) promoted adipogenesis of 3T3-L1 cells. Hydrangenol, a principal constituent, significantly increased the amount of adiponectin released into the medium and mRNA levels of adiponectin, peroxisome proliferator-activated receptor gamma2 (PPARgamma2), and glucose transporter 4 (GLUT4), while it decreased the expression of interleukin 6 (IL-6) mRNA. Furthermore, hydrangenol significantly lowered blood glucose and free fatty acid levels 2 weeks after its administration at a dose of 200 mg/kg/d in KK-A(y) mice.     

Suppression of D-galactosamine-induced liver injury by mushrooms in rats

Six species of edible mushroom were found to suppress D-galactosamine-induced enhancement of plasma alanine and aspartate aminotransferase activities when powdered mushrooms were added to the diet (5%) and fed to rats for 2 wk. Grifola frondosa exhibited the most potent effect in a dose-dependent manner. A significant effect was observed only from the water-soluble low-molecular-weight fraction of G. frondosa. The results indicate that several mushrooms possess a protective effect against liver injury induced by D-galactosamine.     

Structure-requirements of isocoumarins, phthalides, and stilbenes from Hydrangeae Dulcis Folium for inhibitory activity on histamine release from rat peritoneal mast cells.

We examined the structure-activity relationships of isocoumarins, phthalides and stilbenes isolated from Hydrangeae Dulcis Folium and related compounds for the inhibition of histamine release in rat peritoneal mast cells. The activities of isocoumarins such as thunberginols A and B were more potent than those of dihydroisocoumarins such as hydrangenol and thunberginol G. The double bond at the 3-position seemed to be essential to potentiate the activity. The hydroxyl groups at the 8-, 3'- and 4'-positions of isocoumarin were essential for the activity, while the hydroxyl group at the 6-position was scarcely needed. Since the activities of benzylidenephthalides such as thunberginol F were more potent than those of hydramacrophyllols A and B, the presence of a double bond at the 3-position was needed to increase the activity. Moreover, the hydroxyl group at the 8-position was essential for the activity. On the time course study, thunberginols A, B and F completely inhibited histamine release by pretreatment at 100 microM for 1 to 15 min, whereas DSCG inhibited histamine release only following 1-min pretreatment at 1000 microM. These results suggested that the mechanisms of the inhibitory effect of thunberginols are different from that of DSCG.     

Effect of sun ginseng methanol extract on lipopolysaccharide-induced liver injury in rats

Sun ginseng (SG) is heat-processed Panax ginseng C.A. Meyer steamed at 120 °C, which has ginsenoside-Rg₃, -Rk₁, and -Rg₅ as its main ginsenoside components. The effect of SG on lipopolysaccharide (LPS)-induced liver injury in rats was investigated in this study. Intravenous injection of LPS induced excessive nitric oxide (^·NO) generation in serum and increased the hepatic mitochondrial thiobarbituric acid-reactive substance (TBA-RS) level. However, the elevated TBA-RS level was significantly lowered by 15 consecutive days of SG administrations. In addition, up-regulated hepatic inducible nitric oxide synthase and heme oxygenase 1 levels in LPS-treated control rats were significantly lowered and increased, respectively, by 100 mg/kg body weight/day of SG administration. These antioxidant effects were thought to be partially related to the deactivation of nuclear factor-κB by SG administration.     

Suppression of voluntary ethanol consumption in rats by gamma-butyrolactone

The effect of gamma-butyrolactone (GBL) on voluntary ethanol intake was studied in a group of Wistar rats in which a stable preference had been induced by exposure to increasing ethanol concentrations. These rats drank 60% of their daily fluid intake as 15% ethanol solution, corresponding to about 6 g ethanol/kg/day. GBL, injected intraperitoneally at the dose of 200 mg/kg, twice daily for 3 consecutive days, decreased ethanol intake by about 80% on the days of treatment, but did not reduce total fluid intake. Ethanol intake remained significantly reduced up to the 5th day following cessation of GBL administration. GBL, up to a concentration of 10(-3) M, inhibited neither alcohol-dehydrogenase nor aldehyde-dehydrogenase in rat liver homogenates, nor dopamine-beta-hydroxylase in homogenates of adrenal medulla or hypothalamus of rats. It is suggested that inhibition of firing in dopaminergic neurons mediates the suppressant effect of GBL on ethanol preference.     

Dexmedetomidine attenuates lipopolysaccharide-induced acute liver injury in rats by inhibiting caveolin-1 downstream signaling pathway

Objective: The aim of the present study is to investigate the anti-injury and anti-inflammatory effects of dexmedetomidine (Dex) in acute liver injury induced by lipopolysaccharide (LPS) in Sprague–Dawley rats and its possible mechanism.Methods: The acute liver injury model of male rats was established by injecting LPS into tail vein. The mean arterial pressure (MAP) of rats was recorded at 0–7 h, and lactic acid was detected at different time points. Wet/dry weight ratio (W/D) was calculated. Pathological changes of rat liver were observed by HE staining. ALT and AST levels in serum were detected. The activities of myeloperoxidase (MPO) and superoxide dismutase (SOD) in liver tissue homogenate and the levels of IL-1β and IL-18 in serum were detected by ELISA. Protein levels of Caveolin-1 (Cav-1), TLR-4 and NLRP3 in liver tissue were tested by immunohistochemistry method. The expression of Cav-1, TLR-4 and NLRP3 mRNA in liver tissue was detected by quantitative polymerase chain reaction (qPCR) to explore its related mechanism.Results: Compared with NS group, serum lactic acid, W/D of liver tissue, MPO, SOD, IL-1β and IL-18 were significantly increased and MAP decreased significantly in LPS group and D+L group. However, compared with NS group, D group showed no significant difference in various indicators. Compared with LPS group, MPO, SOD, IL-1β and IL-18 were significantly decreased and MAP was significantly increased in D+L group. D+L group could significantly increase the level of Cav-1 protein and decrease the level of TLR-4 and NLRP3 protein in liver tissue caused by sepsis. The expression of Cav-1 mRNA was significantly up-regulated and the expression of TLR-4 and NLRP3 mRNA was inhibited in D+L group.Conclusion: Dex pretreatment protects against LPS-induced actue liver injury via inhibiting the activation of the NLRP3 signaling pathway by up-regulating the expression of Cav-1 by sepsis.     

Inhibitory effects of thunberginols A and B isolated from Hydrangeae Dulcis Folium on mRNA expression of cytokines and on activation of activator protein-1 in RBL-2H3 cells

Previously, thunberginols A and B from the processed leaves of Hydrangeae macrophylla var. thunbergii (Hydrangea dulcis folium) substantially inhibited the degranulation caused by antigen and calcium ionophore A23187, and the release of tumor necrosis factor (TNF)-α and interleukin (IL)-4 by antigen in RBL-2H3 cells. In the present study, we examined the effect of thunberginol B on the expression of mRNA of several cytokines [ILs-2, 3, 4 and 13, TNF-α and granulocyte/macrophage-colony stimulating factor (GM-CSF)] and effects of thunberginols A and B on activator protein (AP)-1 composed of c-jun and c-fos, which is essential for the expression of the cytokine mRNA, in RBL-2H3 cells. Thunberginol B inhibited up-regulated genes of all cytokines, and thunberginols A and B (30 μM) inhibited the phosphorylation of c-jun and expression of c-fos mRNA and phosphorylation of extracellular signal-regulated kinases (ERK1/2). In addition, the profile of gene expression by thunberginol B was similar to that by luteolin, a natural flavone with a potent anti-allergic effect.     

Marginal zinc deficiency increased the susceptibility to acute lipopolysaccharide-induced liver injury in rats

Lipopolysaccharide (LPS) triggers a global activation of inflammatory responses leading to liver injury in humans. Zinc pretreatment has been shown to prevent LPS-induced hepatic necrosis. In North America, suboptimal zinc status is more common than once realized. However, the effect of inadequate zinc nutrition on the host's susceptibility to LPS-induced liver injury is not known. The objective of this study was to determine whether marginal zinc deficiency would render rats more susceptible to LPS-induced liver injury. Weanling Sprague-Dawley rats were assigned to one of three dietary treatment groups: marginally low zinc ad libitum (Z3; 3 mg zinc/kg diet), adequate zinc ad libitum (Z30; 30 mg zinc/kg diet), or adequate zinc pair-fed (Z30P) group. After 6 weeks, each dietary treatment group was further divided into LPS-control (saline) groups (C-Z3, C-Z30P, C-Z30) and LPS-treatment (1 mg/kg body weight, intraperitoneal, 8 hrs) groups (LPS-Z3, LPS-Z30P, LPS-Z30). LPS reduced the serum zinc concentration and increased the liver zinc concentration regardless of dietary zinc intake. Serum alanine aminotransferase level was higher in the LPS-Z3 rats than in the LPS-Z30P and LPS-Z30 rats. LPS also induced hepatocyte necrosis and neutrophil infiltration into the liver sinusoids. This LPS-induced liver damage was more severe in the LPS-Z3 rats than in the LPS-Z30P and LPS-Z30 rats. Together these findings have demonstrated that marginal zinc deficiency increased the susceptibility to LPS-induced liver injury in rats. These results indicate that patients with sepsis who have suboptimal zinc nutrition status may be at higher risk of developing greater liver damage.     

Suppression of an ethanol withdrawal syndrome in rats by 3-hydroxybutyrate

An ethanol withdrawal syndrome was elicited by withholding ethanol from physically dependent, male Sprague-Dawley rats. Ethanol dependence had been induced by intragastric administration of ethanol at a dosage of 9 to 15 grams per kilogram per day over a four-day period. Oral administration of 3-hydroxybutyrate, a compound which is elevated in blood of ethanol dependent rats and is a substrate of both the cerebral small-pool and large-pool Krebs-cycle, was effective in suppressing the tremulous component of the ethanol withdrawal syndrome. 3-Hydroxybutyrate did not function as a central nervous system depressant at the dose levels employed.     

Adrenomedullin ameliorates lipopolysaccharide-induced acute lung injury in rats

Adrenomedullin (AM), an endogenous peptide, has been shown to have a variety of protective effects on the cardiovascular system. However, the effect of AM on acute lung injury remains unknown. Accordingly, we investigated whether AM infusion ameliorates lipopolysaccharide (LPS)-induced acute lung injury in rats. Rats were randomized to receive continuous intravenous infusion of AM (0.1 microg x kg(-1) x min(-1)) or vehicle through a microosmotic pump. The animals were intratracheally injected with either LPS (1 mg/kg) or saline. At 6 and 18 h after intratracheal instillation, we performed histological examination and bronchoalveolar lavage and assessed the lung wet/dry weight ratio as an index of acute lung injury. Then we measured the numbers of total cells and neutrophils and the levels of tumor necrosis factor (TNF)-alpha and cytokine-induced neutrophil chemoattractant (CINC) in bronchoalveolar lavage fluid (BALF). In addition, we evaluated BALF total protein and albumin levels as indexes of lung permeability. LPS instillation caused severe acute lung injury, as indicated by the histological findings and the lung wet/dry weight ratio. However, AM infusion attenuated these LPS-induced abnormalities. AM decreased the numbers of total cells and neutrophils and the levels of TNF-alpha and CINC in BALF. AM also reduced BALF total protein and albumin levels. In addition, AM significantly suppressed apoptosis of alveolar wall cells as indicated by cleaved caspase-3 staining. In conclusion, continuous infusion of AM ameliorated LPS-induced acute lung injury in rats. This beneficial effect of AM on acute lung injury may be mediated by inhibition of inflammation, hyperpermeability, and alveolar wall cell apoptosis.     

Acteoside inhibits apoptosis in D-galactosamine and lipopolysaccharide-induced liver injury.

We assessed the effect of acteoside, a naturally occurring antioxidative phenylethanoid, on hepatic apoptosis and the subsequent liver failure induced by D-Galactosamine (D-GalN) and lipopolysaccharide (LPS). A co-administration of D-GalN (700 mg/kg) and LPS (35 microg/kg) to mice evoked typical hepatic apoptosis characterized by DNA fragmentation and apoptotic body formation, resulting in fulminant hepatitis and lethality of mice. Pre-administration of acteoside at 10 or 50 mg/kg subcutaneously at 12 and 1 h prior to D-GalN/LPS intoxication significantly inhibited hepatic apoptosis, hepatitis and lethality. Tumor necrosis factor-alpha (TNF-alpha) secreted from LPS-stimulated macrophages is an important mediator of apoptosis in this model. Acteoside showed no apparent effect on the marked elevation of serum TNF-alpha, but it partially prevented in vitro TNF-alpha (100 ng/ml)-induced cell death in D-GalN (0.5 mM)-sensitized hepatocytes at the concentrations of 50, 100 and 200 microM. These results indicated that D-GalN/LPS-induced hepatic apoptosis can be blocked by an exogenous antioxidant, suggesting the involvement of reactive oxygen intermediates (ROIs) in TNF-alpha-dependent hepatic apoptosis.     

Suppression of an ethanol withdrawal syndrome in rats by butyrate, lactate and beta-hydroxybutyrate

Butyrate, lactate and beta-hydroxybutyrate, compounds which may be elevated in blood of ethanol dependent rats and substrates of the cerebral small-pool Krebs-cycle, were tested for their ability to suppress an ethanol withdrawal syndrome. Male Sprague-Dawley rats were rendered physically dependent on ethanol by intragastric administration of ethanol at a dosage of 9 to 15 grams per kilogram per day over a 4-day period. Oral administration of a mixture of butyrate, lactate and beta-hydroxybutyrate was effective in suppressing the tremulous component of the ethanol withdrawal syndrome.     

Role of ICAM-1 in chronic ethanol consumption-enhanced liver injury after gut ischemia-reperfusion in rats

Intercellular adhesion molecule-1 (ICAM-1) has been implicated in the hepatic microvascular dysfunction elicited by gut ischemia-reperfusion (I/R). Although the effects of chronic ethanol (EtOH) consumption on the liver are well known, it remains unclear whether this condition renders the hepatic microcirculation more vulnerable to the deleterious effects of gut and/or hepatic I/R. The objectives of this study were to determine whether chronic EtOH consumption alters the severity of gut I/R-induced hepatic microvascular dysfunction and hepatocellular injury and to determine whether ICAM-1 contributes to this response. Male Wistar rats, pair fed for 6 wk a liquid diet containing EtOH or an isocaloric control diet, were exposed to gut I/R. Intravital video microscopy was used to monitor leukocyte recruitment in the hepatic microcirculation, the number of nonperfused sinusoids (NPS), and plasma concentrations of endotoxin and tumor necrosis factor-alpha. Plasma alanine aminotransferase (ALT) levels were measured 6 h after the onset of reperfusion. In control rats, gut I/R elicited increases in the number of stationary leukocytes, NPS, and plasma endotoxin, tumor necrosis factor-alpha, and ALT. In EtOH-fed rats, the gut I/R-induced increases in NPS and leukostasis were blunted in the midzonal region, while exaggerated leukostasis was noted in the pericentral region and terminal hepatic venules. Chronic EtOH consumption also enhanced the gut I/R-induced increase in plasma endotoxin and ALT. The exaggerated responses to gut I/R normally seen in EtOH-fed rats were largely prevented by pretreatment with a blocking anti-ICAM-1 monoclonal antibody. In conclusion, these results suggest that chronic EtOH consumption enhances gut I/R-induced hepatic microvascular dysfunction and hepatocellular injury in the pericentral region and terminal hepatic venules via an enhanced hepatic expression of ICAM-1.