Effect of Ligustrazine on liver injury after burn trauma

Advanced age heightens hepatic damage in a murine model of scald burn injury

BACKGROUND

Elderly burn patients exhibit a lower survival rate compared with younger counterparts. The liver is susceptible to damage after burn injury, which predisposes to poor outcomes. Lipid homeostasis and the antioxidant glutathione system play fundamental roles in preserving liver integrity. Herein, we explored changes in these major pathways associated with liver damage in the aging animals after burn injury.

METHODS

We compared liver enzymes, histology, lipid-peroxidation, and glutathione-metabolism profiles from young and aged female mice after a 15% total body surface area burn. Mice were euthanized at 24 hours after injury, and livers and serum were collected.

RESULTS

Aged burn animals exhibited elevated (p < 0.05) aspartate aminotransferase and alanine aminotransferase levels and increased inflammatory cell infiltration, edema, and necrosis compared with their younger counterparts. The percentage of adipophilin-stained area in livers from young sham, young burn, aged sham, and aged burn groups was 10%, 44%, 16%, and 78% (p < 0.05), respectively. Liver malondialdehyde levels were 1.4 ± 0.5 nmol/mg, 2.06 ± 0.2 nmol/mg, 1.81 ± 0.12 nmol/mg, and 3.45 ± 0.2 nmol/mg (p < 0.05) in young sham, young burn, aged sham, and aged burn mice, respectively. Oxidized glutathione (GSSG) content increased 50% in the young burn, and 88% in aged burn animals compared with the young sham group (p < 0.05). The reduced glutathione GSH/GSSG ratio was significantly reduced by 54% in aged burn mice compared with young sham animals (p < 0.05). Furthermore, glutathione peroxidase gene expression showed a 96% decrease in the aged burn group compared with young sham mice (p < 0.05).

CONCLUSION

Aged burn animals exhibit severe liver damage from heightened lipid peroxidation and inadequate antioxidative response. The increased peroxidation is associated with abundant lipid deposits in hepatic tissue postburn and a weak antioxidative response due to hepatic glutathione peroxidase downregulation. Further studies will focus on the functional significance of these findings concerning hepatic homeostasis.

Regulation of drug-metabolizing enzymes by local and systemic liver injuries

INTRODUCTION

Drug metabolism and disposition are critical in maintaining the chemical and functional homeostasis of xenobiotics/drugs and endobiotics. The liver plays an essential role in drug metabolism and disposition due to its abundant expression of drug-metabolizing enzymes (DMEs) and transporters. There is growing evidence to suggest that many hepatic and systemic diseases can affect drug metabolism and disposition by regulating the expression and/or activity of DMEs and transporters in the liver.

AREAS COVERED

This review focuses on the recent progress on the regulation of DMEs by local and systemic liver injuries. Liver ischemia and reperfusion (I/R) and sepsis are used as examples of local and systemic injury, respectively. The reciprocal effect of the expression and activity of DMEs on animals' sensitivity to local and systemic liver injuries is also discussed.

EXPERT OPINION

Local and systemic liver injuries have a major effect on the expression and activity of DMEs in the liver. Understanding the disease effect on DMEs is clinically important due to the concern of disease-drug interactions. Future studies are necessary to understand the mechanism by which liver injury regulates DMEs. Human studies are also urgently needed in order to determine whether the results in animals can be replicated in human patients.

Effects and mechanism of action of ligustrazine on isoprenaline-induced cardiomyocyte hypertrophy

The aim of the study is to explore the effects and mechanism of the action of ligustrazine on isoprenaline-induced cardiomyocyte hypertrophy. Primary culture of neonatal rat cardiomyocytes was used as the model, and isoprenaline was used to induce cardiomyocyte hypertrophy. Effects of different dosages of ligustrazine polysaccharide on the cardiomyocyte were observed. RT-PCR was used to detect the expression of atrial natriuretic factor (ANP) mRNA, and Western blot analysis was used to detect the CaN protein level in cardiomyocytes. After treating with ligustrazine, the significant increase of MDA content and decrease of SOD activity were inhibited in supernatant. Compared to the control group, ANP mRNA in isoprenaline-treated cardiomyocytes was significantly increased (P < 0.05); compared to the isoprenaline group, ANP mRNA was significantly decreased in all ligustrazine groups (P < 0.01). In all ligustrazine groups, the CaN expression was inhibited in isoprenaline-treated cardiomyocytes in a dose-dependent manner. In conclusion, ligustrazine has protective effects on isoprenaline-induced neonatal rat cardiomyocyte, which may be related to the decrease of CaN expression.

Melatonin protection against burn-induced liver injury. A review

Severe thermal injury may be complicated by dysfunction of organs distant from the original burn wound, including the liver, and represents a serious clinical problem. Although pathophysiology of burn-induced liver injury remains unclear, increasing evidence implicate activation of inflammatory response, oxidative stress, endothelial dysfunction and microcirculatory disorders as the main mechanisms of hepatic injury. Several studies suggest melatonin as a multifunctional indolamine that counteracts some of the pathophysiologic steps and displays significant beneficial effects against burn-induced cellular injury. This review summarizes the role of melatonin in restricting the burn-induced hepatic injury and focuses on its effects on oxidative stress, inflammatory response, endothelial dysfunction and microcirculatory disorders as well as on signaling pathways such as regulation of nuclear erythroid 2-related factor 2 (Nrf2) and nuclear factor-kappaB (NF-kB). Further studies are necessary to elucidate the modulating effect of melatonin on the transcription factor responsible for the regulation of the pro-inflammatory and antioxidant genes involved in burn injuries.

Effects of Ligustrazine on DNA damage and apoptosis induced by irradiation

Ligustrazine has been used to treat heart and blood vessel disease in China. In the present study, we investigated the potential action of Ligustrazine as a component of chuanxiong (a Chinese herb) in scavenging hydroxyl radical and superoxide radical as indicated in the ESR spin-trapping measurement. Treatment of Ligustrazine in mice decreased mortality after whole body γ-irradiation. The anti-radiation action of Ligustrazine was studied by measuring DNA damage (Comet assay and γ-H2AX formation) and apoptosis induced by irradiation. It was triggered by altering the level of DNA-PKcs protein, a critical component of DNA double-strand break (DSB) repair pathways in mice after irradiation. Consistently, the phosphorylation of Akt protein, a mediator of survival signaling, was concurrently increased by Ligustrazine treatment. Additionally, the cytokines along with the phosphorylation of the p38 protein which is activated by a variety of environmental stresses and inflammatory cytokines decreased in the Ligustrazine-treated group as compared to irradiation group. Our results suggest that Ligustrazine has radioprotective effect through its capabilities as a powerful antioxidant, in reducing reactive oxygen species (ROS) level induced by irradiation, minimizing DNA damage and apoptosis, and activating survival signal Akt pathways. This study will be of value in the development of novel radioprotective compounds.

Silk sericin ameliorates wound healing and its clinical efficacy in burn wounds

The aim of this study was to evaluate the effect of silk sericin, a protein from silkworm cocoon, on scratch wound healing in vitro. For applicable result in clinical use, we also study the efficacy of sericin added to a standard antimicrobial cream, silver zinc sulfadiazine, for open wound care in the treatment of second-degree burn wounds. In vitro scratch assays show that sericin at concentration 100 μg/mL can promote the migration of fibroblast L929 cells similar to epidermal growth factor (positive control) at 100 μg/mL. After 1 day of treatment, the length of scratch in wounds treated with sericin was significantly shorter than the length of negative control wounds (culture medium without sericin). For clinical study, a total of 29 patients with 65 burn wounds which covered no less than 15 % of total body surface area were randomly assigned to either control (wounds treated with silver zinc sulfadiazine cream) or treatment (wounds treated with silver zinc sulfadiazine with added sericin cream) group in this randomized, double-blind, standard-controlled study. The results showed that the average time to reach 70 % re-epithelialization of the burned surface and complete healing in the treatment group was significantly shorter, approximately 5-7 days, than in the control group. Regarding time for complete healing, control wounds took approximately 29.28 ± 9.27 days, while wounds treated with silver zinc sulfadiazine with added sericin cream took approximately 22.42 ± 6.33 days, (p = 0.001). No infection or severe reaction was found in any wounds. This is the first clinical study to show that silk sericin is safe and beneficial for burn wound treatment when it is added to silver sulfadiazine cream.

Effective melatonin protection of burn-induced hepatic disorders in rats

We studied the effect of melatonin on morphological and functional disorders using serum markers of liver dysfunction such as cholinesterase and gamma glutamyl transpeptidase, hepatic protein content and malondialdehyde in a burned-rat model. Melatonin (10 mg/kg (−1), i.p) was administered immediately and then 12 h after 30% of total body surface area burns of male Wistar rats. The burns induced an increase of hepatic malondialdehyde levels by 166% (p<0.001), and also vascular congestion, leukocyte infiltration around the central veins, intracellular vacuolization, hepatic cell degeneration and apoptotic bodies (Councilman’s bodies). These changes were associated with significantly reduced serum cholinesterase (36%), gamma glutamyl transpeptidase (76%), hepatic proteins (52%) and serum albumin (37%) (p<0.001–0.0001). Treatment with melatonin reduced elevated hepatic malondialdehyde values by 50% (p<0.01). Melatonin restricted degenerative alteration in the hepatocytes: it protected the burninduced decrease of serum gamma glutamyl transpeptidase activity by 48% (p<0.01), hepatic proteins by 64% (p<0.01), and serum activity of cholinesterase as the only marker of liver damaged synthetic function by 57% (p<0.0001) but did not exert any significant influence on serum albumin concentration. Melatonin repaired the pathomorphological lesions and functional disorders. It could restore liver damage following thermal injury in humans.

Melatonin Protection against Burn-Induced Hepatic Injury by Down-Regulation and Nuclear Factor Kappa B Activation

Melatonin exhibits a wide variety of biological activity including antioxidant and anti-inflammatory effects. We have previously reported its protective effect on hepatic oxidative hepatic injury in burns. In this study, we investigated the role of nuclear factor kappa B (NF-kB) in melatonin-mediated protection against liver injury by using the burned-rat model. Melatonin (N-acetyl-5-methoxytriptamin, 10mg/kg (-1), i.p.) was administered immediately and 12 hours after thermal skin injury. Hepatic NF-kB expression was determined by Western blotting. TNF-α level in liver homogenate was quantified using enzyme-linked immunosorbent assay (ELISA) kit. Plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were determined to assess liver injury at the 24th hour after burns. Thermal skin injury caused significant elevation of hepatic NF-kB expression by 48%, TNF-α level by 55% and plasma AST and ALT activities by 2- and 3-fold, respectively, in comparison with normal control rats. Treatment with melatonin decreased significantly elevated hepatic NF-kB activity and TNF-α, maintaining the levels close to the control values Melatonin suppressed the elevation of plasma AST and ALT activities (p<0.001), which remained significantly increased compared to controls. In conclusion, thermal skin injury causes hepatic NF-kB activation that may mediate the release of hepatic TNF-α and contribute to liver damage. Melatonin protects against burn-induced hepatic injury as to a certain extent this effect may result from the suppression of NF-kB-mediated inflammatory response.

Effect of ligustrazine on mice model of hepatic veno-occlusive disease induced by Gynura segetum

BACKGROUND AND AIM

To investigate the therapeutic effect of ligustrazine on hepatic veno-occlusive disease (HVOD) induced by Gynura segetum and the possible mechanism of it.

METHODS

Female Kunming mice (115) were randomly divided into four groups, gavaged with 30 g/kg per day Gynura segetum (group A), 30 g/kg per day Gynura segetum + 100 mg/kg per day ligustrazine (group B), 30 g/kg per day Gynura segetum + 200 mg/kg per day ligustrazine (group C) or 30 mL/kg per day phosphate-buffered saline (PBS) (group D). Thirty days later, all of the mice were killed. Blood samples and livers were harvested. Histological changes were evaluated by light microscopy. Liver function was measured, and the expression of tissue factor (TF), early growth response factor-1 (Egr-1) and nuclear factor-KBp65 (NF-KBp65) were determined by reverse transcription-polymerase chain reaction and Western blot.

RESULTS

A total of 24 mice in group A developed HVOD. Compared with the controls, they had increased liver ratio, serum total bilirubin (TBIL), direct bilirubin (DBIL), transaminase and decreased albumin (ALB) (P < 0.05). Administration of ligustrazine improved the clinical signs and biochemistry parameters in a dose-dependent manner. Compared with group A, the expression of TF, Egr-1 and NF-KB p65 decreased in groups B and C (P < 0.05).

CONCLUSION

Ligustrazine has a therapeutic effect on HVOD, improving clinical manifestations and liver function. The possible mechanism may be that ligustrazine could reduce the expression of TF by downregulating the expression of transcription factors: Egr-1 and NF-KB p65.

Tetramethylpyrazine inhibits production of nitric oxide and inducible nitric oxide synthase in lipopolysaccharide-induced N9 microglial cells through blockade of MAPK and PI3K/Akt signaling pathways, and suppression of intracellular reactive oxygen species

AIM OF THE STUDY

To determine the inhibitory effect of tetramethylpyrazine (TMP) on lipopolysaccharide (LPS)-induced over-production of nitric oxide (NO) and inducible nitric oxide synthase (iNOS) in N9 microglial cells.

MATERIALS AND METHODS

N9 cells were pretreated with vehicle or TMP and then exposed to LPS for the time indicated. Cell viability was determined by methylthiazoyltetrazolium (MTT) assay. Nitrite assay was performed by Griess reaction. Expression of iNOS mRNA was examined by RT-PCR. Protein levels of iNOS, p38 mitogen-activated protein kinase (MAPK), ERK1/2, JNK, phosphatidylinositol 3-kinase (PI3K) and Akt were determined by western blot analysis. Formation of reactive oxygen species (ROS) was evaluated by fluorescence image system.

RESULTS

TMP inhibited LPS-induced over-production of NO and iNOS in N9 cells. TMP also inhibited the NF-kappaB translocation from cytoplasm into nucleus of N9 cells. In addition, TMP showed blocking effect on the phosphorylation of p38 MAPK, ERK1/2, JNK and Akt, but not PI3K. Further, TMP suppressed the formation of intracellular ROS in LPS-induced N9 cells.

CONCLUSIONS

TMP inhibited production of NO and iNOS in LPS-induced N9 cells through blocking MAPK and PI3K/Akt activation and suppressing ROS production.

Hepatocellular damage following burn injury demonstrated by a more sensitive marker: alpha-glutathione S-transferase

Following burn injury, some complex reactions are initiated that are mainly managed by the liver and that can cause injury at the liver. Alpha glutathione S-transferase (alpha-GST) is a sensitive marker that is very sensitive in the monitoring of hepatocellular damage. We tried, in this study, to demonstrate liver injury in burn patients using alpha-GST. Forty-four patients with burn injury treated at the Burn Treatment and Care unit of the Atatürk University Medical School between July 2006 and July 2007 were included in the study. Patient data were collected. Three blood samples were taken from the patients (at admittance [first sample], 120 hours after admittance [second sample], and on the fourteenth day [third sample]) for the analysis of alpha-GST, alanine amino transferase, aspartate amino transferase activities, and albumin and c-reactive protein levels. There was a statistically significant difference between alpha-GST activities of the study group at admission (P<.001), on the fifth day (P<.001), and the 14th day (P<.001) and those of the control group. There was a decrease in alpha-GST activities during the hospitalization period. Alanine amino transferase and aspartate amino transferase activities in all three samples of the study group were not different from each other and from the values obtained from the control group. The albumin levels of the study group were significantly different from those of the control group. The c-reactive protein levels of the study group were different from those of the control group at admission, on the fifth day, and fourteenth day (P<.001, P<.001, and P<.01). Our findings suggest that burn injury causes liver injury, and alpha-GST can be used to demonstrate this.

Effect and mechanism of ligustrazine on Th1/Th2 cytokines in a rat asthma model

Ligustrazine is an alkaloid isolated from the rhizome of Chuanxiong (Ligusticum chuanxiong Hort), which is known to possess antioxidant, anti-inflammatory, anti-fibrosis and immunomodulative effects. It is used clinically to treat asthma as an assistant therapy of glucocorticoid. The purpose of this study was to explore the effects of intraperitoneal ligustrazine on Th1/Th2 cytokines in a rat asthma model and the underlying mechanism. SD rats were sensitized and challenged with ovalbumin (OVA) to establish an asthmatic model. Within 24 hours after the last ovalbumin challenge, changes in airway histology were observed. The concentrations of IL-4 and IFN-gamma in bronchoalveolar lavage fluid (BALF) were measured by enzyme linked immunosorbent assay (ELISA). The protein expressions of GATA-3 and T-bet in lung were measured by Western blot. The results showed that an increase of Th2 cytokine and an inhibition of Th1 cytokine were accompanied by an increased expression of GATA-3 protein and a decreased expression of T-bet protein in rat asthmatic airways compared to those in normal control group. Intraperitoneal ligustrazine administration could significantly lower the level of IL-4 in BALF and the expression of GATA-3 protein in lung and also increase the level of IFN-gamma and T-bet in asthmatic rats, resulting in a decreased percentage of eosinophils (EOS) in BALF and ameliorated airway inflammatory cell infiltration. In conclusion, ligustrazine inhibits OVA induced airway inflammation by modulating key master switches GATA-3 and T-bet that result in reversing the Th2 cytokine patterns in asthma.