【Animal Modeling】-animal model of dystrophic liver cirrhosis

  (1) Feeding method Weaned male rats are fed a choline-deficient low-protein and high-fat diet at a dose of 8-10g per day for 2-3 months. In addition to casein or soybeans as a protein source, the feed also uses sucrose, lard, vitamin powder, salt and a certain amount of L-cystine. The modeling process includes observing the overall activity of the animals every day, weighing the animals every week, collecting whole blood to prepare serum after modeling, weighing a part of liver tissue for biochemical testing, and preparing homogenate for liver and spleen. Weigh the organs, convert them into organ coefficients, and examine liver tissues by histomorphology.

  (2) Model characteristics: One month after modeling, about 20% of the animals died. After 2 months, the animal stopped body weight, developed ascites, bleeding and hair loss, and underwent a macro test. It shows typical liver nodules. Some have specific symptoms, such as spleen hypertrophy, retention of ascites, pancreatic hypertrophy, testicular atrophy and nephrosclerosis. Optical microscope showed that liver tissue showed small nodular fatty liver cirrhosis in the early stage of modeling. The appearance is liver lengthening, nodular or lobular cirrhosis.

  (3) Comparative medicine. Unbalanced diet and lack of special nutrients can lead to animal liver cell diseases. Experiments have shown that long-term feeding of choline-deficient food can cause liver fat, liver fibrosis and even liver cirrhosis in rats. This model uses weaned rats. This is because young rats have a high demand for choline during development and are naturally more susceptible to physical damage caused by choline deficiency than adult animals. But in fact, the sensitivity of choline deficiency depends on the content of choline oxidase in the body. This model is not suitable for studying human-related diseases in etiology, because human liver does not contain choline oxidase, and there is no problem of choline deficiency. However, due to the long replication cycle, complex feed preparation and high cost, this model is rarely used alone. In addition, male mice were used in the experiment because male animals are more uniform than female animals in the process of transforming into cirrhosis. Mixing a small amount of cysteine in the feed can promote the onset of liver cirrhosis.