The Role Of Platelet Rich Plasma And Quercetin In Alleviating Dimethylnitrosamine-Induced Acute Spleen Injury Through Regulating Oxidative Stress, Inflammation And Apoptosis

Objective: Excessive oxidative stress is implicated in spleen injury. Platelet-rich plasma (PRP) and quercetin (QUR) have been shown to protect cells against oxidative stress. This study was designed to investigate their effect on dimethyl nitrosamine (DMN) induced spleen injury in male rats. Methods: Forty male Wistar rats were divided into four groups; Group (1): Negative control group (Con), Group (2): DMN group, DMN was given intraperitonealy at a dose of 4 mg/kg b. wt/day for four weeks for sub-chronic injury of spleen tissue, Group (3): DMN+PRP, rats were injected intraperitonealy with DMN at a dose of 4 mg/kg b. wt/day for four weeks then treated i. v. by single dose 50 μL of PRP, then left for a period of four weeks without any treatments, Group(4): DMN+QUR, rats received intraperitonealy DMN at a dose of 4 mg/kg b. wt/day for four weeks, then treated with quercetin orally at a dose of 50 mg/kg b. wt. in aqueous suspension daily using an intragastric tube for four weeks. Results: DMN inoculation resulted in significant elevations of oxidative stress, as evidenced by the increased malondialdehyde, hydrogen peroxide and xanthine oxidase levels associated with a significant decrease in Superoxide dismutase and catalase activities in the spleen tissue as compared to the normal control group. Moreover, DMN caused an up-regulation in the values of the splenic C-reactive protein (CRP), interleuckin-6 (IL-6), nuclear factor kappa B (NF-κB), leukotriene-C4 (LT-C4), P53 and Fas levels with a significant decline in anti-apoptotic protein B-cell lymphoma 2 level as compared to the normal control group. PRP and QUR significantly attenuated the DMN-evoked spleen oxidative stress and modulated the activities of antioxidant enzymes as compared to DMN group. In addition, treatment of DMN group with PRP or QUR resulted in an improvement in CRP, IL-6, NF-κB, LT-C4, P53 and Fas levels as compared to DMN group. Caspase-3 expression was positive in DMN group while no difference was present in control, PRP and Quercetin groups. However, the VEGF immunopositive reaction was found in DMN, PRP and Quercetin groups compared to control group. Histopathological results showed degeneration, haemorrhage, inflammatory cells and necrotoic areas in splenic tissue from DMN group compared to the treated groups where signs of recovery were observed in the whole splenic tissue. Conclusion: These data suggest that PRP and QUR protect rat spleen from DMN-induced oxidative stress, probably via their antioxidant activity, anti-inflammatory and anti-apoptotic effects. So, PRP and QUR are promising pharmacological agents for preventing the potential spleen injury of DMN following occupational or environmental exposures.

Issues on carcinogen contaminated antihypertensive drugs and constructing drug safety management system

European Medicines Agency withdrew valsartan from European market in July 2018 because it was contaminated with carcinogen, N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA). Medicines and Healthcare Products Regulatory Agency also found the same contamination and withdrew it from England market. US Food and Drug Administration followed the action after confirming its contamination. Ministry of Food and Drug Safety (MFDS) conducted testing all the valsartans at Korean market and withdrew some of them from market after confirming the contamination with NDMA. MFDS provided the pharmaceutical companies and laboratory institutions with the manual for testing both NDMA and NDEA and educated relevant personnels. MFDS also evaluated the health impact of the contaminated valsartan on the hypertensive patients who took the valsartan, which was shown to be very low risk of additional cancer incidence. MFDS pronounced strengthening of the safety management for the raw materials of the medicines. For guaranteeing the safety of medicines, more comprehensive drug safety management system from developing new drugs to consuming the medicines should be established. For achieving such a goal, active participation of all the stakeholders of the medicines including governmental agencies including MFDS and Ministry of Health and Welfare, the National Assembly, healthcare professionals, pharmaceutical companies, mass media, and general population including patients should be needed.

Research on mechanism of effect of total flavonoidsextracted from Polygonum perfoliatum L.onanti-hepatic fibrosis in rats / 中国药理学通报

Aim Based on the effect of total flavonoids extracted from Polygonum perfoliatum L.(TFP) against dimethylnitrosamine(DMN)-induced hepatic fibrosis(HF), to investigate the anti-fibrotic mechanism of TFP.Methods Ninety SD rats were divided into normal group, model group, colchicines(0.1 mg·kg-1) group, and TFP(200, 100, 50 mg·kg-1) group.Except the rats of normal group, other rats were injected intraperitoneally with volume fraction 0.5% DMN solution(2 mL·kg-1) for eight weeks, once every two days.From the first day of modeling, each administration group was given the corresponding dose of drugs to intervene, and the normal group and model group were given an equal volume of solvent, once a day.At the end of the eighth week, the blood and liver tissues were collected.Liver tissue was taken at a fixed position, and the degree of liver tissue was observed by HE staining.The contents of serum ALT, AST, SOD and MDA were measured using colorimetric method;the levels of serum HA, LN, PCⅢand Ⅳ-C were detected using enzyme-linked immunosorbent assay(ELISA);the levels of TNF-α, IL-1β and IL-6 in liver tissues were detected by ELISA;the expression of α-SMA, TGF-β1, p-JAK2 and p-STAT3 were detected by Western blot.Results Compared with the model group, TFP(200, 100, 50 mg·kg-1) could improve the liver tissue lesions, reduce the expression of ALT, AST, HA, LN, PCⅢ, IV-C and MDA, increase SOD activity, reduce the levels of TNF-α, IL-1β and IL-6, and inhibit the expression of α-SMA, TGF-β1, JAK2, STAT3, p-JAK2 and p-STAT3.Conclusion TFP could inhibit DMN-induced HF of rats, which may be involved with antioxidant and inhibiting expression of TGF-β1, JAK2/STAT3 signaling pathway and inflammatory response.

Antifibrotic effect of total flavonoids of Astmgali Radix on dimethylnitrosamine-induced liver cirrhosis in rats / 中国结合医学杂志

<p><b>OBJECTIVE</b>To study the effect of total flavonoids of Astmgali Radix (TFA) on liver cirrhosis induced with dimethylnitrosamine (DMN) in rats, and the effect on peroxisome proliferator-activated receptor γ (PPARγ), uncoupling protein 2 (UCP2) and farnesoid X receptor (FXR).</p><p><b>METHODS</b>Fifty-three Sprague-Dawley rats were randomly divided into a control group (10 rats) and a DMN group (43 rats). Rats in the DMN group were given DMN for 4 weeks and divided randomly into a model group (14 rats), a low-dosage TFA group (14 rats) and a high-dosage TFA group (15 rats) in the 3rd week. Rats were given TFA for 4 weeks at the dosage of 15 and 30 mg/kg in the low- and high-TFA groups, respectively. At the end of the experiment blood and liver samples were collected. Serum liver function and liver tissue hydroxyproline content were determined. hematoxylin-eosin (HE), Sirus red and immunohistochemical stainings of collagen I, smooth muscle actin (α-SMA) was conducted in paraffinembedded liver tissue slices. Real time polymerase chain reaction (PCR) was adopted to determine PPARγ, UCP2 and FXR mRNA levels. Western blot was adopted to determine protein levels of collagen I, α-SMA, PPARγ, UCP2 and FXR.</p><p><b>RESULTS</b>Compared with the model group, TFA increased the ratio of liver/body weight (low-TFA group P<0.05, high-TFA group P<0.01), improved liver biochemical indices (P<0.01 for ALT, AST, GGT in both groups, P<0.05 for albumin and TBil in the high-TFA group) and reduced liver tissue hydroxproline content (P<0.01 in both groups) in treatment groups significantly. HE staining showed that TFA alleviated liver pathological changes markedly and Sirus red staining showed that TFA reduced collagen deposition, alleviated formation and extent of liver pseudolobule. Collagen I and α-SMA immunohistochemical staining showed that staining area and extent markedly decreased in TFA groups compared with the model group. TFA could increase PPARγ, it regulated target UCP2, and FXR levels significantly compared with the model group (in the low-TFA group all P<0.05, in the high group all P<0.01).</p><p><b>CONCLUSION</b>TFA could improve liver function, alleviate liver pathological changes, and reduce collagen deposition and formation of liver pseudolobule in rats with liver cirrhosis. The antifibrotic effect of TFA was through regulating PPARγ signal pathway and the interaction with FXR.</p>

Silibinin alleviates N-nitrosodimethylamine-induced glutathione dysregulation and hepatotoxicity in rats / 中国天然药物

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.

Diferenciação de células-tronco em hepatócitos e desenvolvimento de modelo pré-clínico de fibrose hepática para ensaios de terapia celular / Mesenchymal stem cell differentiation in hepatocytes and development of pre-clinic model of hepatic fibrosis for cellular therapy assays

Este trabalho teve como objetivo desenvolver um protocolo para a diferenciação in vitro de células-tronco mesenquimais (CTM) em hepatócitos e a padronização de um modelo animal de fibrose hepática induzida por dimetilnitrosamina (DMN) para ensaios pré-clínicos de transplante de CTM. CTM isoladas de fontes variadas apresentaram morfologia fibroblastóide e aderência ao plástico e o padrão de marcadores de superfície celular esperado na análise por citometria de fluxo. A capacidade de diferenciação osteogênica e adipogênica dessas células foi comprovada pelas colorações de vermelho de alizarina, oil red e azul de toluidina, respectivamente, confirmando, que as células isoladas para este estudo se comportaram como CTM conforme proposto pela Sociedade Internacional de Pesquisa em Células-tronco. A diferenciação hepática foi avaliada quanto à morfologia e capacidade das células diferenciadas de estocar glicogênio confirmada por PAS (ácido periódico-Schiff), de sintetizar albumina confirmada por imunofluorescência, além da capacidade de expressar genes hepato-específicos verificada por ensaios de PCR em tempo real. Com base na literatura para diferenciação hepática, diferentes protocolos de um, dois e três passos foram testados. CTM humanas mostraram capacidade de produzir e estocar glicogênio e de sintetizar albumina, apenas quando diferenciadas com protocolos de três etapas, porém sem uma expressão aumentada dos genes hepato-específicos albumina, α-fetoproteína e c-Met. Uma etapa de diferenciação endodérmica, previamente aplicada à diferenciação hepática, aumentou a capacidade de produzir e estocar glicogênio das CTM diferenciadas. Para a padronização do modelo de fibrose hepática induzida por DMN, foram realizados experimentos de dose-resposta e foi verificado o efeito da hepatectomia em modelos mistos DMN/hepatectomia. A injúria hepática e o efeito do transplante de CTM foram avaliados por análise macroscópica dos fígados, histologia das biópsias de fígados corados com HE e tricromo de Masson e parâmetros bioquímicos séricos. Alterações macroscópicas, histológicas e nos níveis séricos de fosfatase alcalina indicam a indução da fibrose hepática nos ratos Wistar tratados com DMN na dose de 10 µg/g de peso animal por três dias consecutivos durante quatro semanas, mas não observamos nenhum efeito induzido pela hepatectomia. Porém, este modelo com DMN se mostra semelhante a estágios iniciais de uma fibrose hepática. O transplante de 1 x 107 CTM de veia de cordão umbilical humano (VCUH) no modelo de injúria hepática induzida por DMN não resultou em melhora da fibrose, diminuição dos níveis séricos de fosfatase alcalina e nem em ganho de peso dos animais quando comparados aos animais tratados com PBSA após a injúria hepática (grupo placebo). Em conjunto, esses resultados sugerem que CTM humanas se diferenciam após tratamentos mais complexos, onde os indutores hepatogênicos são sequencialmente adicionados ao meio de modo a mimetizar a sinalização durante o desenvolvimento embrionário. O transplante de CTM de VCUH parece não ter efeito positivo em um modelo pré-clínico de injúria hepática similar a estágios iniciais de fibrose. Financiado por CNPq (573578/2008-7) e FAPESP (2007/54260-2)

This study aimed to develop an in vitro differentiation protocol of mesenchymal (MSC) stem cells to hepatocytes and to standardize an animal model for hepatic fibrosis induced by dimethylnitrosamine (DMN) for preclinical transplant assays of MSC. MSC isolated from various sources presented fibroblastoid morphology, plastic adherence, and the expected pattern of cell surface markers by flow cytometry analysis. The capacity of osteogenic, adipogenic and chondrogenic differentiation of these cells was confirmed by alizarin red, oil red and toluidine blue staining, respectively, confirming that the cells isolated for this study behave as MSC, as proposed by the International Society for Stem Cell Research. Hepatogenic differentiation was evaluated by analysis of cell morphology, capacity to store glycogen confirmed by PAS (periodic acid-Schiff), albumin synthesis confirmed by immunofluorescence, as well as hepatic-specific gene expression verified by real time PCR assays. Based on the published literature on hepatic differentiation, several protocols of one, two, and three steps were tested. Human MSC differentiated solely when treated in a three step-protocol, showing the ability to produce and store glycogen and synthesize albumin; however the expression of hepatic-specific genes such as albumin, α-fetoprotein and c-Met was not increased. An endoderm differentiation stage, added to the hepatic differentiation protocol, increased the capacity to produce and store glycogen of differentiated MSC. In order to standardize the model of liver fibrosis induced by DMN, dose-response experiments were performed and the effect of hepatectomy in mixed models DMN/hepatectomy was observed. Severity of liver injury and the effect of cell transplantation were evaluated by macroscopic analysis of the livers, histology of liver biopsies stained with HE and Masson's trichrome, and evaluation of serum biochemical parameters. The macroscopic and histological observations, and altered alkaline phosphatase serum levels indicated the success in inducing liver fibrosis in DMN-treated rats at a dose of 10 µg/g of animal weight for three consecutive days, during four weeks, without any additional effect upon hepatectomy. Transplanting 1 x 107 umbilical cord MSC in the model of liver injury induced by DMN did not result in improvement of the fibrosis, decrease of alkaline phosphatase serum levels, or in weight gain of the treated animals compared to animals treated with PBSA after liver injury (placebo group). Together, these results suggest that human MSC are capable of differentiating to hepatocyte-like cells after more complex protocols, where hepatogenic inducers are sequentially added to the medium in order to mimic signaling that occurs during fetal development. Transplantation of undifferentiated umbilical cord MSC did not have any positive effect in a preclinical liver injury model characterized by an early stage of fibrosis. Supported by CNPq (573578/2008-7) and FAPESP (2007/54260-2)

Dynamic expressions and it's significance of small heterodimer partner in rat models of liver fibrosis / 中华传染病杂志

Objective To observe the expressions of small heterodimer partner (SHP) in rat model of hepatic fibrosis and its role in fibrosis.Methods A total of 30 healthy male SD rats were divided into two groups: 6 rats in control group and 24 rats in model group.The model group was further divided into four subgroups which were sacrificed at different time points,2,4,6 and 8 weeks after intraperitoneal injection of dimethylnitrosamine (DMN).After establishment of the rat model,blood samples and liver tissue specimens were collected at week 2,4,6 and 8 respectively.The sections of liver tissue were stained with HE and Masson and then were observed under optical microscope.The expressions of SHP mRNA and protein were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot,respectively.The comparison of means among the groups was performed by univariate ANOVA.Results The hepatic fibrosis was most obvious at 4 weeks and 6 weeks after the intraperitoneal injection.In model groups,alanine aminotransferase (ALT) and aspartateaminotransferase (AST) levels gradually increased and reached a peak at week 4,which were (169.2±16.2) and (193.3±31.1) U/L,respectively.Meanwhile,albumin level in the model group decreased gradually,reaching the nadir at week 6,and the differences were statistically significant at all selected time points between the model group and control group (FAST =83.10,FALT =104.63,FAlb =54.24; all P＜0.05).After modeling,the expression of SHP mRNA and protein in model group were significantly increased than those in control group,and reached a peak at week 4 (0.4494±0.0555 and 1.1155 ±0.1546,respectively),then both mRNA and protein levels decreased gradually at week 6 and 8 which obviously lower than the control group.Transforming growth factor (TGF)β1 mRNA expression level also increased gradually,reaching a peak at week 4 (0.9625±0.1196),and the differences between model subgroups and control group were statistically significant (F=25.740,171.383,118.393 and 94.343; all P＜0.05).Linear correlation analysis showed that SHP mRNA was positively correlated with TGFβ1 mRNA (r=0.593,P＜0.01).Conclusion During the progression of hepatic fibrosis,the SHP expression increases at the beginning and then turns to decrease,which suggests that SHP may play an important role in the development of hepatic fibrosis.

Dynamic expressions of exchange protein directly activated by cyclic adenosine monophosphate in rat model of liver fibrosis / 中华传染病杂志

Objective To investigate the dynamic expressions of exchange protein directly activated by cyclic adenosine monophosphate (cAMP) (Epac) in rat model of hepatic fibrosis(HF).Methods Forty-two male SD rats were divided into control group (n = 6) and model group (n = 36)which was divided into six subgroups of day 4, week 1, week 2, week 4,week 6 and week 8 with six rats in each subgroup. The rat model of HF was established by intraperitoneal injection of dimethylnitrosamine (DMN). The pathological changes of liver were observed by Hematoxylin-Eosin and Masson staining. Reverse transcription-polymerase chain reaction (RT-PCR),immunohistochemistry and Western blot were employed to detect the mRNA and protein expressions of Epac1, Epac2 and transforming gronth factor (TGF)β1 during the process of modeling and localization in the liver. The statistical analysis was done using one-factor ANOVA, LSD-t test,Dunnett T3 test and Pearson linear correlation analysis. Results Rat model of liver fibrosis was established successfully. In control group, Epac1 (0. 031 28±0. 008 96) and Epac2 protein (0.034 43±0. 002 45) mainly expressed in the cytoplasm of hepatocytes. In model group, the level of Epac1 decreased at day 4 (0. 023 97±0. 003 81) and week 1 (0. 015 81±0. 002 48) ,then began to increase at week 2 of modeling and peaked at week 6 (0. 039 54±0. 001 43), which had statistical significance compared to the control group (t= 5.47,11.58 and - 6.18, respectively; all P＜0.05). Epac2 protein expression declined after modeling, reached the lowest level at week 4 (0. 011 21 ±0. 001 32), which had statistical significance compared to the control group (t= 24. 50, P＜0. 05). TGFβ1 protein expression increased after modeling and peaked at week 4 (0. 011 30±0.001 03) which had statistical significance (t= -23. 36, P＜0. 05) compared to the control group (0. 002 08 ±0. 000 18). The expressions of Epac1, Epac2 and TGFβ1 mRNA were consistent with the trend of protein levels.Correlation analysis showed that Epac1 protein was positively correlated with the course of HF (r =0. 703, P＜0.01 ), while Epac2 protein was negatively correlated (r = - 0. 409, P＜0.05). Conclusions During the progression of HF, Epac1 expression tends to decrease firstly and increase afterwards,while Epac2 expression declines continually. Epac may be involved in the pathogenesis of HF.

Expression and distribution of connexin 32 in rat liver with experimentally induced fibrosis / Expressão e distribuição da conexina 32 em fígados de ratos com fibrose induzida experimentalmente

The connexin 32 (Cx32) is a protein that forms the channels that promote the gap junction intercellular communication (GJIC) in the liver, allowing the diffusion of small molecules through cytosol from cell-to-cell. Hepatic fibrosis is characterized by a disruption of normal tissue architeture by cellular lesions, and may alter the GJIC. This work aimed to study the expression and distribution of Cx32 in liver fibrosis induced by the oral administration of dimethylnitrosamine in female Wistar rats. The necropsy of the rats was carried out after five weeks of drug administration. They presented a hepatic fibrosis state. Sections from livers with fibrosis and from control livers were submitted to immunohistochemical, Real Time-PCR and Western-Blot analysis to Cx32. In fibrotic livers the Cxs were diffusely scattered in the cytoplasm, contrasting with the control livers, where the Cx32 formed junction plaques at the cell membrane. Also it was found a decrease in the gene expression of Cx32 without reduction in the protein quantity when compared with controls. These results suggest that there the mechanism of intercellular communication between hepatocytes was reduced by the fibrotic process, which may predispose to the occurrence of a neoplastic process, taken in account that connexins are considered tumor suppressing genes.

A conexina 32 (Cx32) é uma proteína que constitui os canais que promovem as comunicações intercelulares via junções comunicantes (CIJC) no fígado, permitindo difusão de pequenas moléculas citoplasmáticas de uma célula à outra. A fibrose hepática caracteriza-se pela alteração da arquitetura normal do fígado e podem alterar as CIJCs. O objetivo deste trabalho foi estudar a expressão e distribuição de Cx32 na fibrose hepática. O objetivo do presente trabalho foi estudar a expressão e distribuição da Cx32 em fígados com fibrose induzida pela administração oral de dimetilnitrosamina em fêmeas de ratos Wistar. A necropsia foi realizada após cinco semanas da última administração da droga e observou-se um quadro de fibrose hepática. Amostras dos fígados com fibrose e de animais controle foram submetidas à análise imunoistoquímica, por Real Time-PCR e por Western-Blot verificando-se a presença de Cx32 difusa e dispersa no citoplasma dos fígados com fibrose. No grupo controle a Cx32 localizou-se na membrana citoplasmática com a formação de placas juncionais. O fígado com fibrose também revelou diminuição da expressão gênica de Cx32, embora sem a redução da quantidade do produto protéico, quando comparado ao grupo controle. Estes resultados sugerem que o mecanismo de comunicação intercelular entre os hepatócitos reduziu-se durante o processo fibrótico, o que pode predispor a ocorrência de processos neoplásicos, uma vez que as conexinas são consideradas genes supressores de tumores.

Inhibitory Effect of Ethanol Extract of Cassia mimosoides Linn. on Dimethylnitrosamine-induced Hepatic Fibrosis in Rats / 中药新药与临床药理

Objective To observe the inhibitory effect of ethanol extract of Cassia mimosoides Linn. (EE-CML) on dimethylnitrosamine-induced hepatic fibrosis in rats and to explore its therapeutic mechanism. Methods Sixty male SD rats were equally divided into 6 groups: normal group, model group, high-, middle-and low-dose EE-CML groups (at the doses of 12.6 g/kg, 4. 2 g/kg, and 1.4 g/kg respectively) and colchicine (0. 2 mg/kg). Intervention treatment with EE-CML by gastric gavage was carried out in the rats with hepatic fibrosis which was induced by dimethylnitresamine simulta-neously and their effects were compared with the group treated with colchicine. The model group and the normal group were giv-en the same volume of saline once a day. Four weeks after treatment, hepatic function, levels of serum hyaluronic acid (HA), serum laminin (LN), serum aminoterminal propeptide of type Ⅲ procollagen (PCⅢ), hepatic hydroxyproline (Hyp), and histopathological changes in rats were assayed and examined. Results Compared with those in the model group, in the differences of serum alanine aminotransferase (ALT) level in three EE-CML groups and serum aspartate aminotrans-ferase (AST) level in high dose EE-CML group were statistically significant (P < 0. 05) ; hepatic Hyp level and serum HA, LN and PCⅢNP contents in EE-CML groups were significantly lower than those in the model group (P < 0. 05). Hepatic fi-brosis of rats in EE-CML groups alleviated significantly, and the differences compared with that in the model group were sta-tistically significant (P < 0. 05). Conclusion Ethanol extract of Cassia mimosoides shows significant inhibitory effect on the dimethylnitrosamine-induced hepatic fibrosis in rats, and the inhibitory mechanism may be related to the protection on hepatic cells and the inhibition on collagen fiber synthesis.

Effects of Excretory/Secretory Products from Clonorchis sinensis and the Carcinogen Dimethylnitrosamine on the Proliferation and Cell Cycle Modulation of Human Epithelial HEK293T Cells

Clonorchis sinensis is one of the most prevalent parasitic helminths in Korea. Although cholangiocarcinoma can be induced by C. sinensis infection, the underlying mechanism is not clearly understood. To assess the role of C. sinensis infection in carcinogenesis, an in vitro system was established using the human epithelial cell line HEK293T. In cells exposed to the excretory/secretory products (ESP) of C. sinensis and the carcinogen dimethylnitrosamine (DMN), cellular proliferation and the proportion of cells in the G2/M phase increased. Moreover, the expression of the cell cycle proteins E2F1, p-pRb, and cyclin B was dramatically increased when ESP and DMN were added together. Similarly, the transcription factor E2F1 showed its highest level of activity when ESP and DMN were added simultaneously. These findings indicate that DMN and ESP synergistically affect the regulation of cell cycle-related proteins. Our results suggest that exposure to C. sinensis and a small amount of a carcinogen such as DMN can promote carcinogenesis in the bile duct epithelium via uncontrolled cellular proliferation and the upregulation of cell cycle-related proteins.

Cell cycle protein profile of the hepatic stellate cells (HSCs) in dimethylnitrosamine-induced rat hepatic fibrosis

Cell cycle regulating proteins are known to have close relation with the proliferation of the mammalian cells. In injured liver, the number of HSCs is increased from proliferation. However, the expression of cell cycle proteins of HSCs during proliferation remains unevaluated. Therefore, cell cycle protein profiles of HSCs were studied in dimethyl-nitrosamine (DMN)-induced rat liver fibrosis model. Sprague-Dawley rats were intraperitoneally injected of DMN and the animals were sacrificed every week up to 4 weeks. HSCs were separated and the number of the cells in S phase was counted to evaluate the cell proliferation by flow cytometry. The expression of cyclin A, cyclin B, cyclin D1, cdk2, cdk4, cdc2, proliferating cell nuclear antigen (PCNA), p21Cip/WAF1, and p27 was examined with immunoblotting analysis. Portion of S-phase cells peaked 7days after DMN injection. At that time, cyclin A, and PCNA showed significant increase in HSCs compared to untreated HSCs (114% and 116%, respectively, P<0.001). p21Cip/WAF1 was decreased significantly in DMN-treated HSCs compared to control cells (88%, P<0.001). The increase of cyclin A, and PCNA and the decrease of p21Cip/WAF1 seem to play important roles in the proliferation of HSCs during the early period of DMN treatment.

Suppressive Effects of Antioxidant DA-9601 on Hepatic Fibrosis in Rats / 대한간학회지

BACKGROUND/AIMS: Oxidative stress is one of the important underlying mechanisms of hepatic fibrosis. DA-9601, the ethanol extracts of Artemisia asiatica, has been reported to possess strong antioxidative and cytoprotective actions. We tried to evaluate whether antioxidant can ameliorate dimethylnitrosamine (DMN)-induced hepatic fibrosis. METHODS: Rat hepatic fibrosis was induced by intraperitoneal administrations of 10 mg DMN six times. Additionally, rats of one group were started daily with DA-9601 30 mg/kg containing diets and another group was fed a pellet diet containing DA-9601 100 mg/kg. The immunohistochemical studies for collagen, alpha-smooth muscle actin (alpha-SMA), and fibronectin, the measurements of hepatic malondialdehyde (MDA) and collagens, and the changes of liver function profiles were performed. Hepatic stellate cells (HSC) were isolated and in vitro effects of DA-9601 on HSC activations were measured. RESULTS: DA-9601 significantly attenuated the loss of body weights (p<0.05), the reduction of liver wet weights (p<0.05), and the elevation of liver enzymes provoked by DMN administrations. DMN injections caused the severe fibrosis of portal tract, hepatic inflammation, and significant oxidative damages, but DA-9601 treatment significantly reduced the mean scores of hepatic fibrosis, the amounts of hepatic collagens, and hepatic MDA levels. The prominent decreases in the expressions of collagens type I and III, alpha-SMA, and fibronectin or hepatic inflammations were observed in DA-9601-treated groups dose-dependently and similar efficacy was also proven in in vitro HSC experiment. CONCLUSIONS: DA-9601 effectively protected rat liver tissues against the DMN-induced hepatic fibrosis. Antioxidant could be considered as a supplementary therapeutic for alleviating the hepatic fibrosis.

An experimental study of prophylactic and therapeutic effects of oxymatrine on dimethylnitrosamine-induced rat liver fibrosis / 中华消化杂志

Objective To investigate the prophylactic and therapeutic effect of oxymatrine(OM) on experimental liver fibrosis and to reveal its mechanism. Methods By establishing models of dimethylnitrosamine(DMN) induced liver fibrosis in rats, we observed the effect of oxymatrine on liver/weight index, serum and tissue biochemical indexes, content of liver hydroxyproline, expression of TGF?1 mRNA, electromicroscopic changes and tissue pathology. Results There was a decline of serum AST, ALT and liver hydroxyproline in oxymatrine group, compared to those of the DMN group( P

Protective Effect of Pentoxifylline and Ciprofloxacin on Dimethylnitrosamine-induced Hepatic Fibrosis in Rats / 대한간학회지

BACKGROUND/AIMS: Hepatic fibrosis is known to be a predisposing condition of cirrhosis for which there is no proven effective therapy. The aim of this study was to investigate the effect of pentoxifylline and ciprofloxacin on biochemical and histological features of rat hepatic fibrosis induced by dimethylnitrosamine (DMN). METHODS: Seventy male Sprague-Dawley rats were divided into four groups including control (n = 10), DMN (n = 20), DMN plus pentoxifylline (n = 20) and DMN plus ciprofloxacin (n = 20). The rats were injected intraperitoneally with normal saline in the control group and the aforementioned chemicals in the study groups three times a week for 3 weeks. Two rats of the control group, and fives of each study group were sacrificed weekly after the beginning of experiment. From sacrified rats the following parameters of hepatic fibrosis were determined: AST, ALT, cytokines IL-1beta, TNF-alpha and INF-gamma, and histological features of hepatic tissue. RESULT: Rat weight, serological and histological findings were distinctively improved in two treated groups compared with untreated DMN group(p<0.05), The antifibrogenic activity between treated groups was rather better in the group treated with pentoxifylline than in the group treated with ciprofloxacin. During the first and second weeks after experiment the distribution of hepatic stellate cells in treated groups was limited, whereas DMN group showed their diffuse distribution. At the third week DMN group displayed micronodular cirrhosis, but treated groups showed only mild centrilobular fibrotic areas without developing cirrhosis. CONCLUSION: Our results indicate that pentoxifylline and cirprofloxacin may be protective against DMN induced rat hepatic fibrogenesis, while accompanying the inhibition of hepatic stellate cells during the early stage of hepatic fibrogenesis.

Dimethylnitrosamine-Induced Liver Cirrhosis and Expression of Hepatocyte Growth Factor (HGF), its Receptor c-Met, and the Transforming Growth Factor (TGF)-beta1 in Sprague-Dawley Rats

BACKGROUND: Liver fibrosis and cirrhosis are the ultimate histologic consequences of chronic liver damage. Efforts have been made to study the mechanisms of cirrhosis and to discover effective therapeutic strategies. However, to date, no animal model reproduces the disease in man. The purpose of this work is to establish a model of DMN-induced liver cirrhosis for treatment of liver cirrhosis, to understand the basic characteristics of DMN-induced liver cirrhosis, and to confirm the expression of HGF, its receptor c-Met, and TGF-beta1 in Sprague-Dawley rats. METHODS: Five-week-old male Sprague-Dawley rats (n=56) were used for this study. Liver cirrhosis was induced in the rats by using DMN (1 ml/kg body weight, i.p.) given 3 consecutive days a week for 6 weeks. Changes in the portal vein pressure were measured by a venous catheter during the duration of the DMN-treatment. The levels of serum albumin, bilirubin, and ammonia were determined in a clinical laboratory by routive methods. Pieces of the median lobe were cut and fixed in 10% buffered neutral formalin, embedded in paraffin, and stained by hematoxylin-eosin (H&E) & masson-trichrome (M&T). Changes in the extracellular matrix were measured by image analysis and hydroxyproline content. Immunohistochemical staining of alpa-smooth muscle actin was performed to confirm the activation ofhepatic stellate cells. Northern blot analyses were performed to confirm the expression of HGF and TGF-beta1 and western blotting was performed c-Met, HGF receptor. RESULTS: Pressures in the portal vein were significantly increased during the DMN-treatment time (p<0.05). Biochemical parameters were significantly correlated with the progression of liver cirrhosis. H&E staining of 4-week DMN-treated rats demonstrated fibrous tissue bridging between the periportal and the pericentral areas with gradual widening of fibrous bands. Both the extracellular matrix measured by image analysis of the M&T staining and the hydroxyproline content rose continuously throughout the 6 weeks of DMN treatment. alpa-smooth muscle actin was observed in the stellate cells of DMN-treated rats. The northern blot analyses showed that the expression of HGF mRNA decreased with the progression of DMN-induced liver cirrhosis but that of TGF-beta1 mRNA did not. The western blot analyses showed that the expression of the c-Met receptor protein increased continuously, but the expression of HGF mRNA a decreased. CONCLUSION:The model of cirrhosis induced by chronic, discontinuous treatment with a low dose of DMN in rats was simple and predictable and displayed many of the features of human cirrhosis. The decrease in the expression of HGF mRNA may be responsible for the reduced hepatocyte regeneration in liver cirrhosis. The expression of the c-Met protein was related with the decreased expression of HGF. The exact significance of TGF-beta1 was not determined in this study.

Cellular Distribution of TGF-beta1 Peptide in Dimethylnitrosamine Induced Fibrosis of Rat Liver

Recently attention has been focused on the biology of transforming growth factor-beta1 (TGF-beta1). TGF-beta1, a potent regulator of cell proliferation, stimulates the proliferation of many cell types of mesenchymal origin and inhibits the growth of many epithelial cells. But its cellular distribution and temporal expression remain unknown. The aim of this study was to investigate immunohistochemically the cellular distribution and temporal expression of TGF-beta1 during rat hepatic fibrosis induced by dimethylnitrosamine (DMN). At an early stage of liver fibrosis, there was evidence of multiple centrilobular hemorrhagic necrosis with parenchymal lobular collapse, and at a late stage, there was septal fibrosis with micronodule formation of the parenchyme. TGF-beta1 peptide was first expressed in centrilobular clusters of macrophage which were surrounded by many TGF-beta1 negative fat-storing cells (FSCs). Along with the progression of fibrosis, the TGF-beta1 peptide was expressed in the alpha-smooth muscle actin positive FSCs and also in some peripherally located hepatocytes of micronodules. Serum IFN-gamma was detected in the serum 2 weeks after an initial administration of DMN had reached the peak level at the 4th week and then markedly decreased at the 5th week. We think that TGF-beta1 peptide is produced by macrophages influenced by soluble IFN-gamma, and is expressed in the -smooth muscle actin positive mesenchymal cells and regenerating hepatocytes, and that this cytokine may have an important role in the synthesis of the extracellular matrix and in the regulation of hepatocytic regeneration.

Inhibitory Effect of Ethanol Extract of Cassia mimosoides Linn. on Dimethylnitrosamine- induced Hepatic Fibrosis in Rats / 中药新药与临床药理

Objective To observe the inhibitory effect of ethanol extract of Cassia mimosoides Linn. (EE-CML) on dimethylnitrosamine-induced hepatic fibrosis in rats and to explore its therapeutic mechanism. Methods Sixty male SD rats were equally divided into 6 groups: normal group, model group, high-, middle-and low-dose EE-CML groups (at the doses of 12.6 g/kg, 4.2 g/kg, and 1.4 g/kg respectively) and colchicine (0.2 mg/kg). Intervention treatment with EE-CML by gastric gavage was carried out in the rats with hepatic fibrosis which was induced by dimethylnitrosamine simultaneously and their effects were compared with the group treated with colchicine. The model group and the normal group were given the same volume of saline once a day. Four weeks after treatment, hepatic function, levels of serum hyaluronic acid (HA), serum laminin (LN), serum aminoterminal propeptide of type III procollagen (PCIII), hepatic hydroxyproline (Hyp), and histopathological changes in rats were assayed and examined. Results Compared with those in the model group, in the differences of serum alanine aminotransferase (ALT) level in three EE-CML groups and serum aspartate aminotransferase (AST) level in high dose EE-CML group were statistically significant (P

A Pathological Study of Phenol Induced Hepatic and Gastrointestinal Lesions

In an attempt to elucidate the pathological effects of phenol, the present study was undertaken in male Sprague-Dawley rats. The control group of animals was fed a basal diet, and potable underground water. The experimental group of animals was fed a basal diet and potable underground water containing 30ppm, 60ppm, and 1% phenol with once a week administration of dimethylnitrosamine(DMN) 10 mg/kg I.P. Each group of animals was sacrificed on the 3rd, 6th, and 9th month. The liver and gastrointestinal tract were examined light microscopically, along with transmission electron microscopic studies of the liver and scanning electron microscopic studies of the gastric mucosa. The results were as follows: 1) In the acute phenol intoxicated group, the liver showed fatty changes in the hepatocytes with mitochondrial membrane destruction and myelin figure formation. 2) In the chronic phenol intoxicated group, fatty changes in the liver were observed. In addition, there was chronic inflammation in the gastrointestinal tract, with gastric mucosal erosion and central necrosis of the hepatic lobules, especially in the high phenol contaminated water treated group. 3) As a result of the examination under the light microscope, the DMN treated group showed hyperplastic nodules and liver cell dysplasia, the degree of which was proportional to the duration of the experiment, and was more severe in the DMN + phenol treated group. 4) As a result of the examination under the electron microscope, fatty changes in the liver, pleomorphism of the mitochondria and loss or shortness of bile canalicular microvilli in the DMN + phenol treated group were more severe than in the group treated only with DMN. In summary, the results obtained by the present study indicate chronic highly concentrated phenol intoxication induce liver cell necrosis and chronic inflammatory with a hepatotoxin such as DMN.

Effects of carbon tetrachloride on structures in hepatocytes following DMN induced hepatotoxicity / 영남의대학술지

The purpose of this study was to evaluate the influence of high dose carbon tetrachloride (CCI4) on the hepatotoxic effect of dimethylnitrosamine (DMN) which induces acute hemorrhagic necrosis in liver. Rats were injected intraperitoneally DMN dissolved in physiologic saline by a dose of 40 mg/kg. For changes related to CCI⁴ pretreatment, rats were injected intraperitoneally CCI⁴ dissolved in olive oil by a dose of 0.4 mg/kg, and then injected DMN. The livers were extracted from the rats 3, 6, 12, 24, 48, 72, and 120 hours after CCI⁴ and/ or DMN injection. Liver tissues were examined with light and electron microscopes. The results were summarized as follows; Light microscopic findings: Severe centrilobular hemorrhagic necrosis developed from 12 hours after injection of DMN and continued to 120 hours. On injection of DMN after CCI4 pretreatment, Massive necrosis occurred early. But active regenerative changes were produced in 24 hours. In 120 hours, the liver recovered in almost normal appearance. The degree of necrosis in pretreated group was similar to that in DMN injection only, and the time of recovery was faster in pretreated group. Electron microscopic findings: The early change was mainly disorganization of RER in DMN injection, and clumping and vesicular dilatation of ER in injection of CCI4. In pretreatment group, the early change was similar in appearance with CCI4 group, but severer in degree. According to the results, it was revealed that acute toxic effect of DMN was recovered more rapidly in pretreatment group. Thus it was suggested that CCI4 had protective effect in DMN hepatotoxicity.