Design and optimization of cranberry extract loaded bile salt augmented liposomes for targeting of MCP-1/STAT3/VEGF signaling pathway in DMN-intoxicated liver in rats

Cranberry extract (CBE) is a major source of the antioxidant polyphenolics but suffers from limited bioavailability. The goal of this research was to encapsulate the nutraceutical (CBE), into bile salt augmented liposomes (BSALs) as a promising oral delivery system to potentiate its hepatoprotective impact against dimethylnitrosamine (DMN) induced liver injury in rats. The inclusion of bile salt in the liposomal structure can enhance their stability within the gastrointestinal tract and promote CBE permeability. CBE loaded BSALs formulations were fabricated utilizing a (2³) factorial design to explore the impact of phospholipid type (X₁), phospholipid amount (X₂), and sodium glycocholate (SGC) amount (X₃) on BSALs properties, namely; entrapment efficiency percent, (EE%); vesicle size, (VS); polydispersity index; (PDI); zeta potential, (ZP); and release efficiency percent, (RE%). The optimum formulation (F1) exhibited spherical vesicles with EE% of 71.27 ± 0.32%, VS; 148.60 ± 6.46 nm, PDI; 0.38 ± 0.02, ZP; −18.27 ± 0.67 mV and RE%; 61.96 ± 1.07%. Compared to CBE solution, F1 had attenuated DMN-induced hepatic injury, as evidenced by the significant decrease in serum level of ALT, AST, ALP, MDA, and elevation of GSH level, as well as SOD and GPX activities. Furthermore, F1 exhibited an anti-inflammatory character by suppressing TNF-α, MCP-1, and IL-6, as well as downregulation of VEGF-C, STAT-3, and IFN-γ mRNA levels. This study verified that when CBE was integrated into BSALs, F1, its hepatoprotective effect was significantly potentiated to protect the liver against DMN-induced damage. Therefore, F1 could be deliberated as an antioxidant, antiproliferative, and antifibrotic therapy to slow down the progression of hepatic damage.

Zinc Oxide Nanoparticles Ameliorate Dimethylnitrosamine-Induced Renal Toxicity in Rat

Dimethylnitrosamine (DMN) is an established carcinogen. It is toxic to several organs, viz., the liver, kidney, and lungs, and immune system. Several drugs have been used in the past to modulate its toxicity using experimental animal models. The present study was designed to investigate the effect of zinc oxide nanoparticles (ZnONPs) on renal toxicity caused by DMN in laboratory rat. Since oxidative mechanisms are mainly involved in its toxicity, the proposed study focuses on the amelioration of oxidative stress response by ZnONPs, if any. The present results show that administration of ZnONPs (50 mg/kg body weight/rat) to DMN (2 μl/100 g body weight/rat)-treated rats diminuted the concentration of malonaldehyde, H₂O₂, and NO in the kidney. However, reduced glutathione (GSH) concentration increased after ZnONP treatment. Results on glutathione S-transferase and glutathione peroxidase favored its antioxidative effects. These results are supported by the recovery of oxidative DNA damage and less pronounced histopathological changes in the kidney. It is hypothesized that ZnONPs might be toxic to renal tissue; however, its strong therapeutic/antioxidative potential helps in ameliorating DMN-induced renal toxicity in rat.

Cnidoscolus aconitifolius leaf extract and ascorbate confer amelioration and protection against dimethyl nitrosamine-induced renal toxicity and testicular abnormalities in rats

Extracts of Cnidoscolus aconitifolius (CA) have been reported to possess medicinal properties ranging from potential hepatoprotective, anti-diabetic, and anti-cardiovascular. In our previous study, gas chromatography mass spectroscopy check of CA extract showed the inclusion of 2,4-bis(1,1-dimethylethyl)-phenol, a phenolic phyto-compound that constitutes about 45 %, carotene and linoleic acid sources, and silicon-rich components. Hence we compare the preventive and ameliorative potentials of CA with ascorbate in dimethyl nitrosamine (DMN)-induced renal toxicity and sperm abnormalities in rats. Renal toxicity was investigated by quantifying the levels and activities of endogenous antioxidant parameters. Renal damage marked by significant reduction in GSH level, as well as significant elevation in MDA concentration, and activities of GPx, GST, CAT, and SOD were restored after the intervention of CA and ascorbate. Also, there was decrease in live sperm, sperm concentration, sperm gross and individual motility, and normal sperm morphology, following DMN administration. Based on the gathered results, it is concluded that ascorbate and CA demonstrate comparable ameliorative and protective effects against DMN-induced renal and testicular toxicities in rats.

Metabolism of N-nitrosodimethylamine, methylation of macromolecules, and development of hepatic fibrosis in rodent models

Hepatic fibrosis and cirrhosis are chronic diseases affecting liver and a major health problem throughout the world. The hallmark of fibrosis and cirrhosis is inordinate synthesis and deposition of fibril forming collagens in the extracellular matrix of the liver leading to nodule formation and loss of normal architecture. Hepatic stellate cells play a crucial role in the pathogenesis and progression of liver fibrosis through secretion of several potent fibrogenic factors that trigger hepatocytes, portal fibrocytes, and bone marrow-derived fibroblasts to synthesize and deposit several connective tissue proteins, especially collagens between hepatocytes and space of Disse. Regulation of various events involved in the activation and transformation of hepatic stellate cells seems to be an appropriate strategy for the arrest of hepatic fibrosis and liver cirrhosis. In order to unravel the molecular mechanisms involved in the pathogenesis and progression of hepatic fibrosis, to determine proper and potent targets to arrest fibrosis, and to discover powerful therapeutic agents, a quick and reproducible animal model of hepatic fibrosis and liver cirrhosis that display all decompensating features of human condition is required. This review thoroughly evaluates the biochemical, histological, and pathological features of N-nitrosodimethylamine-induced model of liver injury, hepatic fibrosis, and early cirrhosis in rodents.

Zinc oxide nanoparticles inhibit dimethylnitrosamine induced liver injury in rat

Dimethylnitrosamine (DMN) is a potent hepatotoxic, carcinogenic and mutagenic compound. It induces massive liver cell necrosis and death in experimental animals. Several drugs have been tested in the past for their protective behavior against DMN toxicity. However, it is for the first time that therapeutic intervention of ZnONPs (zinc oxide nanoparticles) has been studied against its toxicity. Present results show that a post treatment of ZnONPs (50 mg/kg) to DMN (2 μl/100 g body weight) treated rats reduces lipid peroxidation, oxidative stress and fibrosis in the liver. It diminishes serum ALT (alanine transaminases), AST (aspartate transaminases) and LDH (lactate dehydrogenase) showing improvement in liver function. Reduced values of proinflammatory cytokines viz. TNF-α and IL-12 also support its protective effects. Histopathological observations also indicate improvement in liver cell morphology. It is postulated that ZnONPs offer protection through selective toxicity to proliferating tissue including adenomatous islands formed in the liver. Zinc metallothionein (Zn-MT) induced by ZnONPs may also contribute in the amelioration of DMN induced toxic effects. Diminution of oxidative stress by ZnONPs remains to be the key mechanism involved in its protective effects. However, toxicity of ZnONPs in the liver needs to be monitored simultaneously.

Influence of resveratrol on liver fibrosis induced by dimethylnitrosamine in male rats

Liver fibrosis is a significant health problem which represents the liver’s scarring process and response to injury through deposition of collagen and extracellular matrix, and ultimately leads to cirrhosis. Resveratrol is a naturally occurring phytoalexin found predominantly in grapes. This study aimed to investigate the antifibrotic role of resveratrol on dimethylnitrosamine (DMN)-induced liver fibrosis in rats. Rats were divided into four groups and treated for three weeks; control, resveratrol administered orally (20 mg/kg daily), DMN intraperitoneally injected (10 mg/kg 3 days/week), and the last group was pre-treated daily with resveratrol then injected with DMN, 3 days/week. DMN administration induced severe liver pathological alterations. However, oral administration of resveratrol before DMN significantly prevented the induced loss in body weight, as well as the increase in liver weight which arise from DMN administration. Resveratrol has also inhibited the elevation of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and bilirubin levels. Furthermore, resveratrol significantly increased hepatic reduced glutathione (GSH) levels and reduced the levels of malondialdehyde (MDA) due to its antioxidants effect as well as increased serum protein levels. In addition, DMN induced elevation in hydroxyproline content. On the other hand, hydroxyproline level was significantly reduced in the resveratrol pretreated rats. Resveratrol has also remarkably maintained the normal liver lobular architecture. Moreover, resveratrol had displayed potent potentials to prevent collagen deposition, lymphocytic infiltration, necrosis, steatosis, vascular damage, blood hypertention, cholangiocyte proliferation. It can be concluded that resveratrol has a marked protective role on DMN-induced liver fibrosis in rats, and can be considered as antiproliferative, antihypertensive, as well as antifibrotic agent and may be used to block the development of liver fibrosis.

Silibinin alleviates N-nitrosodimethylamine-induced glutathione dysregulation and hepatotoxicity in rats

The present study was designed to evaluate the hepatoprotective and antioxidant potentials of silibinin (SBN) against N-nitrosodimethylamine (DMN)-induced toxic insults in the rat liver. The liver damage was induced in Wistar albino rats by repeated administration of DMN (10 mg·kg(-1) b.w., i.p.) on 3 consecutive days per week for 3 weeks. SBN (100 mg·kg(-1) b.w., p.o.) was given daily to the DMN treated rats for two weeks. The marker enzymes of liver toxicity and second-line enzymic and non-enzymic antioxidants were evaluated in serum and liver tissues before and after SBN treatment. Histopathology of the liver was evaluated by H & E staining. The DMN treatment produced a progressive increase in all the serum marker enzymes (AST, ALT, ALP, LDH, and γ-GT), peaking on Day 21. This treatment produced highly significant decreases in all the second-line antioxidant parameters (GSH, GST, GR, GPx, and vitamins C and E). The SBN treatment significantly reversed the DMN-induced damages, towards normalcy. Histopathological studies confirmed the development of liver toxicity in DMN-treated rats, which was reversed by SBN treatment in corroboration with the aforementioned biochemical results, indicating the hepatoprotective and antioxidant properties of SBN. In conclusion, the DMN-induced degenerative changes in the liver were alleviated by SBN treatment and this protective ability may be attributed to its antioxidant, free radical scavenging, and membrane stabilizing properties.

Umbilical cord-derived mesenchymal stem cells alleviate liver fibrosis in rats

AIM: To evaluate the efficacy of umbilical cord-derived mesenchymal stem cells (UC-MSCs) transplantation in the treatment of liver fibrosis.

METHODS: Cultured human UC-MSCs were isolated and transfused into rats with liver fibrosis induced by dimethylnitrosamine (DMN). The effects of UC-MSCs transfusion on liver fibrosis were then evaluated by histopathology; serum interleukin (IL)-4 and IL-10 levels were also measured. Furthermore, Kupffer cells (KCs) in fibrotic livers were isolated and cultured to analyze their phenotype. Moreover, UC-MSCs were co-cultured with KCs in vitro to assess the effects of UC-MSCs on KCs’ phenotype, and IL-4 and IL-10 levels were measured in cell culture supernatants. Finally, UC-MSCs and KCs were cultured in the presence of IL-4 antibodies to block the effects of this cytokine, followed by phenotypical analysis of KCs.

RESULTS: UC-MSCs transfused into rats were recruited by the injured liver and alleviated liver fibrosis, increasing serum IL-4 and IL-10 levels. Interestingly, UC-MSCs promoted mobilization of KCs not only in fibrotic livers, but also in vitro. Co-culture of UC-MSCs with KCs resulted in increased production of IL-4 and IL-10. The addition of IL-4 antibodies into the co-culture system resulted in decreased KC mobilization.

CONCLUSION: UC-MSCs could increase IL-4 and promote mobilization of KCs both in vitro and in vivo, subsequently alleviating the liver fibrosis induced by DMN.

Free radical scavenging, antioxidant and cancer chemoprevention by grape seed proanthocyanidin: an overview

A large number of investigations have demonstrated a broad spectrum of pharmacological and therapeutic benefits of grape seed proanthocyanidins (GSP) against oxidative stress and degenerative diseases including cardiovascular dysfunctions, acute and chronic stress, gastrointestinal distress, neurological disorders, pancreatitis, various stages of neoplastic processes and carcinogenesis including detoxification of carcinogenic metabolites. GSP exhibited potent free radical scavenging abilities in both in vitro and in vivo models. GSP exerted significant in vivo protection against structurally diverse drug and chemical-induced hepatotoxicity, cardiotoxicity, neurotoxicity, nephrotoxicity and spleentoxicity. GSP also protected against idarubicin and 4-hydroxyperoxy-cyclophosphamide-induced cytotoxicity toward human normal liver cells. GSP exhibited selective cytotoxicity toward selected human cancer cells, while enhancing the growth and viability of normal cells. GSP exhibited potent modulatory effects of pro-apoptotic and apoptotic regulatory bcl-XL, p53, c-myc, c-JUN, JNK-1 and CD36 genes. Long-term exposure to GSP may serve as a novel chemoprotectant against three stages of DMN-induced liver carcinogenesis and tumorigenesis including initiation, promotion and progression. GSP may selectively protect against oxidative stress, genomic integrity and cell death patterns in vivo. These results demonstrate that GSP may serve as a novel therapeutic intervention against carcinogenesis.

A new style of dimethylnitrosamine induced fulminant hepatitis in mice

BACKGROUND

There is still no suitable mice model that can completely mimic the human fulminant hepatitis, which sets a block for drug effect evaluation and mechanism researching of human fulminant hepatitis.

OBJECTIVES

The aim of this study was to establish an animal model able to mimic the main features of human fulminant hepatitis.

MATERIALS AND METHODS

Dimethylnitrosamine (DMN) was peritoneally injected to mice for liver injury induction. Serum biochemicals, and Prothrombin Time were tested, and Prothrombin activity was calculated, the liver tissue pathological changes were evaluated via macroscopic view observation, HE staining, immunochemical staining, and electron microscopy observation. The mRNA levels of TNF-a, Fas, and IL-1beta were tested with quantitative PCR assay.

RESULTS

The serum levels of both ALT and AST were elevated significantly and showed a high plateau. Liver pathological changes were progressed before 48 hours post DMN injection and then started to restore. The mRNA and protein expression levels of TNF-α and IL-1β were significantly elevated. The PT started to extend from 36 hours and PTA was lower than 40% from then on.

CONCLUSIONS

This kind of DMN induced mice liver injury is similar to human fulminant hepatitis in main features. This work provided a mice model which could mimic human fulminant hepatitis, and could be valuable for fulminant hepatitis mechanism research and liver protection drug evaluation.

Alleviation of Dimethylnitrosamine-Induced Liver Injury and Fibrosis by Supplementation of Anabasis articulata Extract in Rats

Anabasis articulata (Forssk) Moq. (Chenopodiaceae) is an herb, grows in Egypt, and used in folk medicine to treat diabetes, fever, and kidney infections. The protective and therapeutic effects of the ethanol extract of A. articulata aerial parts were evaluated against dimethylnitrosamine (DMN)-induced liver fibrosis, compared with the standard drug, silymarin. Hepatic hydroxyproline content, serum transforming growth factor-β1 (TGF-β1), interleukin 10 (IL-10) and fructosamine were measured as liver fibrosis markers. Hepatic malondialdehyde (MDA), nitric oxide (NO), catalase (CAT), glutathione reductase (GR) and glutathione content (GSH) were measured as oxidant/antioxidant markers. Parallel histopathological investigations were also performed. Protective and therapeutic administration of A. articulata (100 mg/kg daily for 4 weeks), markedly prevented DMN-induced loss in body and liver weights. The extract significantly inhibited the elevation of hepatic hydroxyproline, NO and MDA (P < 0.05), as well as serum fructosamine, and TGF-β1 (P < 0.05) induced by DMN while it restored IL-10 to normal level in both protective and therapeutic groups. Furthermore, A. articulata prevented the depletion in CAT, GR, and GSH levels (P ≤ 0.05). In addition, oral administration of A. articulata extract and silymarin to both protective and therapeutic groups reduced the increase in liver function enzyme activities; alanine and aspartate amintransferases, gamma-glutamyl transferase in addition to alkaline phosphatase, and caused significant increase in serum albumin concentration as compared to DMN group. These data corresponded closely with those obtained for the drug silymarin. Histopathological studies confirmed the biochemical data and revealed remarkable improvement in liver architecture. Thus, it could be concluded that, A. articulata extract exhibited in vivo hepatoprotective and therapeutic effects against DMN-induced liver injury and may act as a useful agent in controlling the progression of hepatic fibrosis through reduction of oxidative stress and improving liver function.

Pharmacokinetics of dl-praeruptorin A after single-dose intravenous administration to rats with liver cirrhosis

BACKGROUND AND THE PURPOSE OF THE STUDY

As a novel drug in the treatment of cardiac diseases, dl-praeruptorin A (Pd-Ia) is the major active component of traditional herbal medicine Peucedanum praeruptorum Dunn and is metabolized primarily via cytochrome P450 isozymes (CYP) 3A1 and 3A2 in rats. In the present study, the influence of liver cirrhosis on pharmacokinetics of Pd-Ia and hepatic mRNA expression of CYP3A1 and 3A2 in rats with experimental liver cirrhosis (LC rats) were evaluated.

METHODS

Pd-Ia was given intravenously (5 mg kg(-1)) to LC rats induced by dimethylnitrosamine and pharmacokinetic variables were measured. Enzyme kinetic metabolism of Pd-Ia in rat hepatic microsomes was also investigated and hepatic mRNA expression of CYP3A1 and 3A2 were measured by real-time PCR.

RESULTS AND MAJOR CONCLUSION

After intravenous administration in LC rats, the area under the plasma concentration-time curve from time zero to infinity (AUC0-8) was significantly greater than that in control rats, which might be due to slower rate of the hepatic blood flow and significant slower hepatic intrinsic clearance (CL(int)) in rats. The decreased metabolic clearance of Pd-Ia in LC rats might be at least partly caused by the decreased levels of CYP3A1 and 3A2 responsible for Pd-Ia metabolism. These findings may provide new insights into the inter- and intra-individual pharmacokinetic variability of Pd-Ia.

Antifibrotic effects of green tea on in vitro and in vivo models of liver fibrosis

AIM: To examine the protective effect of green tea extract (GT) on hepatic fibrosis in vitro and in vivo in dimethylnitrosamine (DMN)-induced rats.

METHODS: HSC-T6, a rat hepatic stellate cell line, was used as an in vitro assay system. Cell proliferation, collagen content, and type 1 collagen expression were examined in activated HSC-T6 cells. Collagen was determined by estimating the hydroxyproline content. In rats with DMN-induced hepatic fibrosis, serum aspartate aminotransferase and alanine aminotransferase concentrations, liver hydroxyproline and lipid peroxides were determined. Pathologic changes were examined by hematoxylin & eosin staining.

RESULTS: GT administration prevented the development of hepatic fibrosis in the rat model of DMN-induced liver fibrosis. These results were confirmed both by liver histology and by quantitative measurement of hepatic hydroxyproline content, a marker of liver collagen deposition. Accordingly, inhibition of proliferation, reduced collagen deposition, and type 1 collagen expression were observed in activated HSC-T6 cells following GT treatment. These results imply that GT reduced the proliferation of activated HSC and down regulated the collagen content and expression of collagen type 1, thereby ameliorating hepatic fibrosis.

CONCLUSION: This study demonstrates that green tea administration can effectively improve liver fibrosis caused by DMN, and may be used as a therapeutic option and preventive measure against hepatic fibrosis.

Therapeutic effects of Lanyuzan granules on hepatic fibrosis in rats

AIM: To explore the curative effects of Lanyuzan granules on hepatic fibrosis in dimethylnitrosamine (DMN)-induced SD rat model and its mechanism.

METHODS: Forty-five female SD rats were randomly divided into six groups: a control group (n = 5), a model group (n = 8), three treatment groups with different dosage of Lanyuzan granules (n = 8), and a positive control group (n = 8). In the following 30 days, an intraperitoneal injection of dimethylnitrosamine (DMN) 10 mg/kg was performed in five groups every three days, except in the control group. On the thirty-first day, the five indexes of hepatic function, serum concentrations of ALT, AST and ALB, the expressions of a-smooth muscle actin (a-SMA) and matrix metalloproteinase-2 (MMP-2) were measured. Moreover, pathological changes were observed on liver tissue with HE staining.

RESULTS: In liver fibrosis model group, serum concentrations of ALT and AST were significantly higher and concentration of ALB was significantly lower (P < 0.05), while significant increase in a-SMA expression and significant decrease in MMP-2 expression were observed compared with the normal group (182.042 ± 0.658 vs 60.879 ± 0.987; 145.612 ± 4.66 vs 74.824 ± 9.004; 16.078 ± 0.633 vs 28.971 ± 0.443; 161.667 ± 26.766 vs 80.167 ± 10.135; 5.994 ± 1.360 vs 8.270 ± 0.289, all P < 0.05). Decreased ALT and AST serum concentrations, significantly increased ALB concentration, lowered a-SMA expression and elevated MMP-2 expression in liver tissue, were observed in Lanyuzan granules treatment group compared with model control group (87.856 ± 8.526, 106.69 ± 0.987, 136.11 ± 0.329 vs 182.042 ± 0.658; 94.208 ± 2.017, 107.602 ± 20.014, 118.847 ± 5.486 vs 145.612 ± 4.66; 23.412 ± 0.775, 19.653 ± 0.775, 18.635 ± 0.221 vs 16.078 ± 0.633; 109.958 ± 3.607, 117.833 ± 6.600, 119.833 ± 6.167 vs 161.667 ± 26.766; 11.610 ± 0.523, 10.367 ± 0.714 vs 5.994 ± 1.360, all P < 0.05). No notable difference was observed between low dosage group and model control group. The pathological observation showed hepatic fibrosis was alleviated markedly.

CONCLUSION: Lanyuzan granules may play a part in the alleviation of inflammation and the protection of liver by markedly relieving and inhibiting the formation of hepatic fibrosis induced by dimethylnitrosamine.

Effects of kidney-tonifying liver-emoliating formula on connective tissue growth factor mRNA expression in hepatic fibrosis rats

AIM: To investigate effects of kidney-tonifying liver-emoliating formula (KTLEF) on expression of connective tissue growth factor (CTGF) mRNA in dimethylnitrosamine-induced hepatic fibrosis rats and thereby to elucidate its therapeutic effects and its underlying molecular mechanism.

METHODS: Forty male Wistar rats were randomly assigned to normal control group (n = 10), model group (n = 15) and KTLEF-treated group (n = 15). Except the normal control group, all the rats received intraperitoneal DMN injection once a day for 3 successive days for 4 wk. Then only the model group was given KTLEF for anther 4 wk. Rats were all executed at week 8. The serum liver fibrosis markers, such as HA, LN and Ⅳ-C, were measured using ELISA and RIA. The Hepatic inflammatory necrosis and collagen deposition were determined by HE staining and Sirius red staining, and CTGF mRNA expression was detected using RT-PCR.

RESULTS: The rat model of liver fibrosis induced by DMN was successfully constructed. Serum HA, LN and Ⅳ-C levels were significantly declined in BSRGF-treated group compared with those in the model-group (HA: 319.75 ± 63.23 pg/L vs 434.44 ± 98.81 pg/L; LN: 44.83 ± 4.09 pg/L vs 70.67±6.32 pg/L; Ⅳ-C: 52.79 ± 5.71 pg/L vs 79.39 ± 10.52 pg/L, all P < 0.01). The expression level of CTGF mRNA was lower in the KTLEF-treated group than that in the fibrosis model group (CTGF/β-actin: 0.76 ± 0.10 vs 1.08 ± 0.17, P < 0.01), and the least in the normal control group.

CONCLUSION: The expression of CTGF mRNA is increased in the hepatic fibrosis rats, and is supposed to be one possible mechanism of hepatic fibrosis. KTLEF can significantly inhibit CTGF mRNA expression and then effectively counteract hepatic fibrosis.

Preventive effect of Qianggan-Rongxian Decoction on rat liver fibrosis

AIM: To study the preventive effects of Qianggan-Rongxian Decoction on liver fibrosis induced by dimethylnitrosamine (DMN) in rats.

METHODS: Male Wistar rats were randomly divided into hepatic fibrosis model group, control group and 3 treatment groups (12 rats in each group). Except for the normal control group, all the rats received 1% DMN (10 &mgr;L/kg body weight, i.p), 3 times a week for 4 wk. The rats in the 3 treatment groups including a high-dose DMN group (10 mL/kg), a medium-dose DMN group (7 mL/kg), and a low-dose DMN group (4 mL/kg) were daily gavaged with Qianggan-Rongxian Decoction, and the rats in the model and normal control groups were given saline vehicle. Enzyme-linked immunosorbent assay (ELISA) was used to determine the changes in serum hyaluronic acid (HA), laminin (LN), and type IV collagen levels. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were measured using routine laboratory methods. Pathologic changes, particularly fibrosis, were examined by hematoxylin and eosin (HE) and Sirius red staining. Hepatic stellate cells (HSC) were examined by transmission electron microscopy.

RESULTS: Compared with the model control group, the serum levels of HA, LN, type IV collagen, ALT and AST were decreased markedly in the other groups after treatment with Qianggan-Rongxian Decoction, especially in the medium-dose DMN group (P < 0.05). Moreover, the area-density percentage of collagen fibrosis was lower in the Qianggan-Rongxian Decoction treatment groups than in the model group, and a more significant drop was observed in the medium-dose DMN group (P < 0.05).

CONCLUSION: Qianggan-Rongxian Decoction can inhibit hepatic fibrosis due to chronic liver injury, delay the development of cirrhosis, and notably ameliorate liver function. It may be used as a safe and effective thera-peutic drug for patients with fibrosis.

Iron deposition and fat accumulation in dimethylnitrosamine-induced liver fibrosis in rat

AIM: To investigate if iron deposition and fat accumulation in the liver play a pathogenetic role in dimethylnitrosamine (DMN)-induced liver fibrosis in rat.

METHODS: Thirty rats were treated with DMN at does consecutive days of 10 μL/kg daily, i.p., for 3 consecutive day each week for 4 wk. Rats (n = 30) were sacrificed on the first day (model group A) and 21^st d (model group B) after cessation of DMN injection. The control group (n = 10) received an equivalent amount of saline. Liver tissues were stained with hematoxylin & eosin (HE) and Masson and Prussian blue assay and oberserved under electron microscopy. Serum alanine aminotransferase (ALT) and liver tissue hydroxyproline (Hyp) content were tested.

RESULTS: The liver fibrosis did not automatically reverse, which was similar to previous reports, the perilobular deposition of iron accompanied with collagen showed marked characteristics at both the first and 21^st d after cessation of DMN injection. However, fat accumulation in hepatocytes occurred only at the 21^st d after cessation of DMN injection.

CONCLUSION: Iron deposition and fat accumulation may play important roles in pathological changes in DMN-induced rat liver fibrosis. The detailed mechanisms of these characteristics need further research.

Gene expression profiles of hepatic cell-type specific marker genes in progression of liver fibrosis

AIM: To determine the gene expression profile data for the whole liver during development of dimethylni-trosamine (DMN)-induced hepatic fibrosis.

METHODS: Marker genes were identified for different types of hepatic cells, including hepatic stellate cells (HSCs), Kupffer cells (including other inflammatory cells), and hepatocytes, using independent temporal DNA microarray data obtained from isolated hepatic cells.

RESULTS: The cell-type analysis of gene expression gave several key results and led to formation of three hypotheses: (1) changes in the expression of HSC-specific marker genes during fibrosis were similar to gene expression data in in vitro cultured HSCs, suggesting a major role of the self-activating characteristics of HSCs in formation of fibrosis; (2) expression of mast cell-specific marker genes reached a peak during liver fibrosis, suggesting a possible role of mast cells in formation of fibrosis; and (3) abnormal expression of hepatocyte-specific marker genes was found across several metabolic pathways during fibrosis, including sulfur-containing amino acid metabolism, fatty acid metabolism, and drug metabolism, suggesting a mechanistic relationship between these abnormalities and symptoms of liver fibrosis.

CONCLUSION: Analysis of marker genes for specific hepatic cell types can identify the key aspects of fibrogenesis. Sequential activation of inflammatory cells and the self-supporting properties of HSCs play an important role in development of fibrosis.

An herbal formula, CGX, exerts hepatotherapeutic effects on dimethylnitrosamine-induced chronic liver injury model in rats

AIM: To evaluate the therapeutic effect of Chunggan extract (CGX), a modified traditional Chinese hepatotherapeutic herbal, on the dimethylnitrosamine (DMN)-induced chronic liver injury model in rats.

METHODS: Liver injuries were induced in Wistar rats by injection of DMN (ip, 10 mg/mL per kg) for 3 consecutive days per week for 4 wk. The rats were administered with CGX (po, 100 or 200 mg/kg per day) or distilled water as a control daily for 4 wk starting from the 15^th d of the DMN treatment. Biochemical parameters (serum albumin, bilirubin, ALP, AST and ALT), lipid peroxides, hydroxyproline, as well as histological changes in liver tissues were analyzed. In addition, gene expression of TNF-α, TGF-β, TIMP-1, TIMP-2, PDGF-β, and MMP-2, all of which are known to be associated with liver fibrosis, were analyzed using real-time PCR.

RESULTS: CGX administration restored the spleen weight to normal after having been increased by DMN treatment. Biochemical analysis of the serum demonstrated that CGX significantly decreased the serum level of ALP (P < 0.05), ALT (P < 0.01), and AST (P < 0.01) that had been elevated by DMN treatment. CGX administration moderately lowered lipid peroxide production and markedly lowered hydroxyproline generation caused by DMN treatment in accordance with histopathological examination. DMN treatment induced a highly up-regulated expression of TNF-α, TGF-β, TIMP-1, TIMP-2, PDGF-β, and MMP-2. Of these, the gene expression encoding PDGF-β and MMP-2 was still further enhanced 2 wk after secession of the 4-wk DMN treatment, and was remarkably ameliorated by CGX administration.

CONCLUSION: CGX exhibits hepatotherapeutic proper-ties against chronic hepatocellular destruction and consequential liver fibrosis.

Inhibitory effects of bear bile powder on dimethylnitrosamine-induced liver fibrosis in rats

AIM: To investigate the inhibitory effect of bear bile powder on rat liver fibrosis induced by dimethylnitrosamine (DMN).

METHODS: A total of 30 rats were randomly divided into 3 groups: normal control group, model group, and bear bile group (10 in every group). The rat liver fibro-sis model was induced by peritoneal injection of DMN (10 g/L) for 4 wk. At the same time, the rats in the bear bile group received bear bile powder (400 mg/kg) orally once a day for 4 wk. Then the activities of serum alanine transaminase (ALT), aspartate transaminase (AST), and the contents of total protein (TP) were detected. Meanwhile, the pathological changes of liver tissues were observed under light microscope after HE staining, and the area density of collagenous fiber were examined. The amount and distribution of Kupffer cell (KC) and hepatic stellate cell (HSC) were detected by immunohistochemical SP method through the distribution of ED1 and α-smooth muscle actin (α-SMA).

RESULTS: Compared with that in the model group, the level of serum ALT was decreased, and AST was significantly decreased (4 370.87±1 338.60 nkat/L vs 5 741.15±1 000.20 nkat/L, P <0.05) in the bear bile group. The TP content and the ratio of liver to body weigh were increased. The area density of collagenous fiber was notably decreased (6.73±1.31 vs 9.90±1.93, P <0.01). The pathological changes were lighter, and the occurrence rate of diffused liver fibrosis was lower in the bear bile group than those in the model group. The fibrous septa became thin or disappeared, and the expressions of ED1 and α-SMA were markedly reduced in the bear bile group.

CONCLUSION: The bear bile powder can prevent DMN-induced rat liver fibrosis, and the mechanism may relate to its inhibition on the activation of the HSC and KC.

Therapeutic role of ethanolic extract of Boschniakia Rossica in dimethylnitrosamine-induced liver fibrosis in rats

AIM: To study the effect of Boschniakia Rossica ethanolic extract (BREE) in rat liver fibrosis induced by dimethylnitrosamine (DMN).

METHODS: Hepatic fibrosis was induced by DMN administration intraperitoneally. Thirty-five male Wistar rats were randomly divided into three groups: normal control group (GA, n = 10), hepatic fibrosis model group (GB, n = 15) and BREE treatment group (GC, n = 10). From the 1st to 3rd wk, rats in GB and GC were treated with DMN (10 g/L) intraperitoneally in the first three days of each week, while rats in GA were treated with normal saline. From the 4th to 7th wk, rats in GC were treated with 50 g/L BREE (10 mL/kg) intragastrically each day, while rats in GA and GB were treated with normal saline. At the 1st d of the 8th wk, all the rats were sacrificed and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX), the contents of malondialdehyde (MDA), hyaluronic acid (HA), type Ⅲ procollagen (PC Ⅲ), type Ⅳ collagen (Ⅳ.C) in serum were examined. The expression of alpha smooth muscle actin (α-SMA) in liver was also analyzed.

RESULTS: The activity of SOD (98.58±17.36 kNU/L, 9.99±1.69 kNU/L) and GSH-PX (117.37±45.24 U, 12.43±2.99 U) in serum and liver tissue in GB was significantly lower than those in GA (SOD: 129.05±18.55 kNU/L, 19.94±5.87 kNU/L; GSH-PX: 173.79±25.76 U, 22.66±6.99 U)(P < 0.01), while the contents of MDA in GB (10.87±1.23 μmol/L, 1.38±0.37 μmol/L) were higher than those in GA (6.63±1.05 μmol/L, 0.91±0.25 μmol/L)(P < 0.01). The concentrations of serum HA (394.83±103.28 μg/L), PC Ⅲ (13.30±1.88 mg/L) and Ⅳ.C (2.43±1.32 mg/L) in GB were markedly higher than those in GA (186.54±39.87 μg/L, 6.99±1.55 mg/L, 1.18±0.79 mg/L, P < 0.01). The concentrations of serum HA (115.87±13.96 μg/L), PC Ⅲ (6.67±1.86 mg/L) and Ⅳ.C (1.62±0.50 mg/L) in GC were significantly lower than those in GB (P < 0.05), while the activity of SOD (134.29±21.93 kNU/L, 18.99±6.86 kNU/L) and GSH-PX (171.82±37.50 U, 23.57±7.19 U) in serum and liver tissue increased significantly (P < 0.01). The contents of MDA in serum and tissue in GC (8.68±2.32 μmol/L, 0.97±0.22 μmol/L) was lower than those in GB (10.87±1.23, 1.38±0.37 μmol/L)(P < 0.01). The fibrosis index and α-SMA expression in liver decreased in GC too.

CONCLUSION: BREE plays an anti-fibrogenic role in the DMN-induced liver fibrosis of rat by its anti-oxidative effect and inhibition on hepatic stellate cells activation.

Distribution of Kupffer cells and hepatic stellate cells in dimethylnitrosamine-induced liver fibrosis in rats

AIM: To investigate the distribution and significance of Kupffer cells (KCs) and hepatic stellate cells (HSCs) in dimethylnitrosamine(DMN)-induced liver fibrosis in rats.

METHODS: Rat liver fibrosis was induced by peritoneal injection of DMN (10 g/L) for 4 wk. The activities of serum alanine transaminase (ALT), aspartate transaminase (AST), the contents of total proteins (TP), the ratio of liver/body weight and the area density of collagenous fiber were examined 4 and 7 wk after injection. Meanwhile, the pathological changes of the liver tissues were observed under light microscope. The expression of ED1 and α-smooth muscle actin (α-SMA) were detected by immunohistochemical SP method.

RESULTS: Compared with those in the control group, the levels of ALT and AST were significantly elevated 4 and 7 wk after injection (4 wk: 1201.91±215.04, 5741.15±1000.20 nkat/L vs 398.91±106.35, 1365.27±435.09 nkat/L, P <0.01; 7 wk: 745.15±413.42, 2355.47±1418.62 nkat/L vs 289.72±43.01, 1018.54±215.04 nkat/L, P <0.05). TP content was significantly decreased 4 wk after injection (50.32±9.81 g/L vs 69.67±6.09 g/L, P <0.01), but returned to normal after 7 wk. The ratio of liver/body weight was decreased (4 wk: 2.156±0.539% vs 2.950±0.147%, P <0.01; 7 wk: 2.250±0.638% vs 2.863±0.158%, P <0.01), but the area density of collagenous fiber was increased 4 and 7 wk after injection (9.90±1.93% vs 1.27±0.28%, P <0.01; 9.20±0.97% vs 1.46±0.67%, P <0.01). Diffuse cirrhosis was observed in most model rats after 4 wk and it was still significant after 7 wk. The ED1 and α-SMA positive cells aggregated prominently in the fibrotic tissue and septa in the model rats.

CONCLUSION: DMN induces obviously liver disfunction and diffuse cirrhosis in rats, and KCs are closely associated with the activation of HSCs.

Comparison of Thy1.1 with OV6 in hepatic oval cell marking during formation and reversion of rat cirrhosis induced by dimethylnitrosamine

AIM: To screen the best marker for hepatic oval cells (HOC) by comparing the dynamic changes of Thy1.1 and OV6 expression in the hepatic tissue during the formation and reversion of dimethylnitrosamine (DMN)-induced cirrhosis in rats.

METHODS: Rat cirrhosis model was induced by DMN treatment (12 times in 4 weeks). The degree of liver fibrosis was determined by collagen staining. The expression of OV6 and Thy1.1 in various hepatic cells were examined by immunohistochemistry. Thy1.1 positive cells were enumerated under light microscope, and the cell protein was quantified by Western blot.

RESULTS: The most typical cirrhosis in the model was observed at the 4th week after DMN injection, which was combined with large area of hemorrhage and putrescence. These changes started to alleviate at the 6th week with a few incomplete fiber septa. The inflammation was lessened distinctly at the 8th week, mainly manifested as incomplete fiber septa. OV6 positive cells were presented in both HOC and normal cholangial epithelia. There were no Thy1.1 positively stained cells in the normal tissues. Very few Thy1.1 positive cells started to appear on the 3rd day, dispersed at the 2^nd week, increased significantly at the 4^th week around the fiber septa, reached the peak at the 6^th week (i. e. 2 week after stopping DMN injection) which was distributed mainly in the periportal district, and decreased at the 8^th week. The results of Western blot and the number of HOC were consistent with each other.

CONCLUSION: During the formation and reversion of the rat cirrhosis, Thy1.1 is superior to OV6 in marking HOC with better specificity and sensitivity.

Effects of musuwan on TIMP-1 and MMP-2 expression in dimethylnitrosamine-induced liver fibrosis in rats

AIM: To investigate the effects of musuwan on the expression of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase 1 (TIMP-1) in rat liver fibrosis induced by dimethylnitrosamine (DMN).

METHODS: Male SD rats were randomly divided into three groups: normal control group (n = 10), model group (n = 10) and musuwan group (n = 10). In all the rats, except those in control group, DMN (10 mg/kg) were given by intraperitoneal injection to establish fibrosis model. Rats in the musuwan group were subsequently treated with musuwan (3.125 g/kg, stomach perfusion). Blood from the heart was collected for the examinations of liver function, serum hyaluronic acid (HA), superoxide dismutase (SOD), and malonaldehyde (MDA). MMP-2, and TIMP-1 mRNA were detected by reverse transcription polymerase chain reaction.

RESULTS: Compared with those in control group, serum ALP, MDA, and HA were significantly higher, whereas serum levels of Alb and SOD were significantly lower. In musuwan treated rats, serum ALP, MDA, and HA were remarkably reduced, while Alb and SOD were markedly elevated. The levels of MMP-2 and TIMP-1 mRNA in model group were significantly higher than those in control group (0.70±0.22 vs 0.63±0.08, P = 0.02; 1.38±0.48 vs 0.99±0.14, P = 0.02). Musuwan significantly down-regulated TIMP-1 mRNA (0.71±0.34 vs 0.99±0.14, P = 0.03); however, the level of MMP-2 mRNA showed no significant difference between musuwan group and model group.

CONCLUSION: Musuwan can effectively inhibit the expression of TIMP-1, but not MMP-2, in DMN-induced liver fibrosis in rats.