A modified choline-deficient, ethionine-supplemented diet protocol effectively induces oval cells in mouse liver

Abstract

Several reliable and reproducible methods are available to induce oval cells in rat liver. Effective methods often involve inhibiting proliferation in hepatocytes using an alkylating agent, then subjecting the rat to partial hepatectomy (PH). The surgery is difficult to perform reproducibly in mice. Approaches that do not include partial hepatectomy, such as administration of D-galactosamine, are ineffective in mice. We found that a choline-deficient, ethionine-supplemented (CDE) diet, which is very effective in rats, leads to high morbidity and mortality when administered to mice. This article outlines an alternative protocol by which a CDE diet can be administered to mice. This diet is shown to be highly effective for oval cell induction, without causing high mortality. It takes less time and is at least as effective as other commonly used protocols for inducing oval cells in mice. Methods for inducing liver progenitor cells, or oval cells, in rodents have greatly advanced our knowledge of liver progenitor cell biology. These include feeding carcinogens such as diethylnitrosamine 1 and diaminobenzene or its derivatives 2 ; the administration of D-galactosamine 3 ; and the modified Solt-Farber regimen, which omits diethylnitrosamine, using only acetyl aminofluorene (AAF) coupled with partial hepatectomy (PH). 4 All are highly effective in rats. In mice, the only reliable and routinely used method of inducing oval cells is the administration of an alkylating drug 1,4-Bis [N,NЈ-di-(ethylene)-phosphamide] piperazine (DIPIN), before PH. 5 However, because they are much smaller, it is difficult to perform this surgical procedure in a reproducible fashion in mice. The ever-increasing availability of transgenic mice with specific genes, which are overexpressed or ablated by gene targeting, offers opportunities to identify extracellular and intracellular signaling pathways, which are important or essential for oval cell proliferation. A choline-deficient, ethionine-supplemented (CDE) diet is often used to induce oval cells in rats. [6][7][8] This diet is simple to administer and extremely effective, and by 3 weeks, substantial numbers of oval cells are induced. It is usually provided as a solid chow, either in pelleted form or as a powder. However, our experience shows that it cannot be applied to mice, because it causes severe morbidity and mortality. This article reports modifications to the standard CDE diet that were adopted by our laboratory to successfully induce oval cells in mice. MATERIALS AND METHODSAnimals and Diet. The strain of mice used was BDF1. Two cholinedeficient (CD) diets were tested. The first was a complete 0.07% CDE diet in pellet form obtained from Teklad Test Diets (Madison, WI). The other was the modified CD diet, in powder form, produced by ICN (Costa Mesa, CA Cat. #960209). Apart from ethionine, present in the Teklad, but not the ICN formulation, these 2 diets have essentially the same composition, and both have added trace minerals. To facilitate altering the severity of choline deficiency ...

Tumor Necrosis Factor–Like Weak Inducer of Apoptosis Is a Mitogen for Liver Progenitor Cells

“…Using the CDE model of hepatocellular injury and regeneration, which our laboratory pioneered for use in mice, 15 we now show that TWEAK signaling via its receptor Fn14 is essential for the early expansion of LPCs in response to CDE-induced liver injury. In livers from CDE diet-fed mice, LPCs proliferate outward from periportal regions, not in ducts or pseudoducts, but as streams of cells.…”

“…Four-week-old, male mice were administered a CDE diet. 15 Control animals received normal laboratory chow and drinking water. For TWEAK administration experiments (single injection), recombinant human tumor necrosis factor-like weak inducer of apoptosis (rhTWEAK; Biogen Idec, Inc., Cambridge, MA 17 ) or vehicle (0.1% bovine serum albumin in normal saline) was injected intraperitoneally into 2-week-CDE-pretreated mice at a final dose of 0.02 lg/ g of body weight.…”

“…Thus, we wished to further explore the relationship between TWEAK and LPCs with a different in vivo model of hepatic injury and LPC proliferation developed in our laboratory. 15 Additionally, we aimed to investigate the effects of TWEAK on LPC lines in vitro. We now demonstrate that TWEAK directly stimulates LPC mitosis in an Fn14-dependent and NFjB-dependent fashion and that this pathway plays a major role in the rapid growth phase of the LPC response to cholinedeficient, ethionine-supplemented (CDE) diet-induced injury and re-generation.…”

Differential lymphotoxin‐β and interferon gamma signaling during mouse liver regeneration induced by chronic and acute injury†

“…1 The CDE diet damages the liver parenchyma and prevents hepatocyte division, leading to activation and rapid induction of large numbers of oval cells in mice. 2 The replication response after PHx involves a rapid and highly coordinated series of biochemical events resulting in hepatocytes undergoing a relatively synchronized progression through the cell cycle. Immediately after the insult, immediate early genes are activated by transcription factors such as nuclear factor kappa B, activating protein 1 (AP1), and STAT-3.…”

Protective Effect of Soybean against Hepatocarcinogenesis Induced by DL-Ethionine

“…This study was planned to investigate the possible protective role of soybeans against the effect of DL-ethionine, which is a potent hepatocarcinogen (Lenzi et al, 1991;Novikoff et al, 1991;Tsujiuchi et al, 1995;Allen and Poirier, 1997;Hacker et al, 1998;Akhurst et al, 2001;Croager et al, 2002). This was attempted by studying some of the biochemical changes that occur in liver and serum, and histopathologic changes in the liver of rats treated with DLethionine in the presence or absence of soybean.…”