Dimethylnitrosamine-Induced Liver Fibrosis and Recovery in NOD/SCID Mice

Abstract

ABSTRACT. There is a need for a new liver fibrosis model of immunodeficient mice to study the effects of cell therapy on liver disease because there are not many animal models available to study the effects of cell therapy. In this study, we induced liver fibrosis using dimethylnitrosamine (DMN) in NOD/SCID mice to create an animal model for liver disease. DMN (5 mg/kg, i.p.) was injected intraperitoneally for three consecutive days per week for 6 or 8 weeks, and the mice were sacrificed at weeks 0, 4 and 8 after the last DMN injection. The 6-week DMN-treated group gradually recovered from serum biochemical changes, histopathological toxic effects and lesions in the liver at weeks 4 and 8 after the last DMN injection. However, the progression of liver fibrosis and toxic levels were maintained in the 8-week DMN-treated group at week 4 after the last DMN injection. The increases in iron and extracellular matrix (collagen) in the DMN-treated group were confirmed by Prussian blue (PB) and Masson's trichrome (MT) staining, respectively. Additionally, activation of hepatic stellate cells was observed by alpha smooth muscle actin (-SMA) immunostaining and western blot. In conclusion, treatment of NOD/SCID mice with 5 mg/kg of DMN for 8 weeks can be used to induce an appropriate animal model of disease for liver fibrosis. This model may be useful for evaluation of the efficacy and safety of cell therapies such as human mesenchymal stem cell therapy.KEY WORDS: animal model, dimethylnitrosamine, liver fibrosis, NOD/SCID mice.

Anchoring Hepatic Gene Expression with Development of Fibrosis and Neoplasia in a Toxicant-induced Fish Model of Liver Injury

“…In a comparative model, Hobbie et al (2011) reported that Japanese medaka fish ( Oryzias latipes ) exposed to DMN developed morphological hepatic changes similar to those observed in human fibrotic livers and the well-established DMN-induced rat model of hepatic fibrosis (Ala-Kokko et al, 1987; Jezequel et al, 1987; Ohara et al, 2007; Hobbie et al, 2011; Hyon et al, 2011). Currently, knowledge of the mechanisms of hepatic fibrosis and progression to neoplasia in fish is limited.…”

“…Dimethynitrosamine (DMN) is a potent carcinogenic hepatotoxin previously used in rodents to model human hepatic fibrosis, cirrhosis, and HCC (Ala-Kokko et al 1987; Jezequel et al 1987; George et al 2001; Tada et al 2001; Hyon et al 2011). In a comparative model, Hobbie et al (2011) reported that Japanese medaka fish ( Oryzias latipes ) exposed to DMN developed morphological hepatic changes similar to those observed in human fibrotic livers and the well-established DMN-induced rat model of hepatic fibrosis (Ala-Kokko et al 1987; Jezequel et al 1987; Ohara et al 2007; Hobbie et al 2011; Hyon et al 2011). Currently, knowledge of the mechanisms of hepatic fibrosis and progression to neoplasia in fish is limited.…”

Protection against Acute Hepatocellular Injury Afforded by Liver Fibrosis Is Independent of T Lymphocytes

“…This is of prime importance in order to achieve adequate experimental observations in immunodeficient animals with liver fibrosis, for example in hepatocellular carcinoma models. Indeed, high mortality rate was consistently observed in a dimethylnitrosamine (DMN) model using NOD-SCID mice and also in a Foxn1 nu/nu mice model using IP injections of TAA [27, 33]. In the present study, using step-wise increased dosage of TAA and a more continuous delivery through drinking water, toxicity of TAA was reduced without undermining the extent of its fibrogenic impact.…”

“…Recently, Hyon et al . showed that liver fibrosis in NOD-SCID mice (lacking both T and B cells) also needed a longer treatment period to reach adequate degrees of fibrosis [33]. Since both the delivery method and genetic background of the animals differed, we cannot conclude as to why Foxn1 nu/nu mice took longer to achieve similar level of fibrosis; however, the less aggressive TAA regimen is likely to influence the development of fibrosis.…”

Diferenciação de células-tronco em hepatócitos e desenvolvimento de modelo pré-clínico de fibrose hepática para ensaios de terapia celular

“…Em um primeiro momento, optamos por estabelecer um modelo experimental baseado naquele desenvolvido por Ozawa e colaboradores (Ozawa et al, 2006) . Também tratados com três injeções ip consecutivas por semana de DMN 10 µg/g, porém durante quatro semanas, os níveis séricos de ALT, AST, FA e BT de ratos Sprague-Dawley aumentaram com o tempo de tratamento com DMN (Saha et al, 2007) (Hyon et al, 2011;Ying et al, 1980). (Ozawa et al, 2006), histológicas (Choi et al, 2010;Yue et al, 2010) e aumento dos níveis séricos de FA (Shin et al, 2010) observados na literatura, mas a hepatectomia não parece contribuir para o agravamento das lesões.…”