Dose Dependent Results in an Induced Model of Chronic Hepatitis with CCl4 in Mice

Animal models have been used for several decades to study fibrogenesis and to validate anti-fibrotic effects of potential therapeutic approaches. Until now, mainly the rat models were in extensively used, while the mice models were less investigated. The present study investigated the dose of carbon tetrachloride, and the time which were suitable for a model of experimental toxic chronic hepatitis in mice. The study was conducted on four groups, of 16 Swiss female mice each. The animals were orally treated with carbon tetrachloride, in different doses; three groups received carbon tetrachloride, diluted in sunflower oil, in dose of 0.5 ml/kg, 1ml/kg, and respectively 1.5ml/kg, while the control group received sunflower oil only. The administrations were made 3 times a week, in the days 1, 3 and 5, every week, until the end of the study. Four animals from each group were euthanized at 2, 4, 6 and respectively 8 weeks. Blood samples were collected subjected to hematological analyses, then after euthanasia the animals were subject to gross examination and histopathology. The clinical and hematological investigations showed no variations among experimental groups. The gross and microscopic examination of liver revealed a complex pattern. The dose had no major influence on the microscopic lesions pattern; on the other hand, the lesions had a time-related evolution. Thus, microvesicular steatosis was found starting with the fourth week and the sparsely small necrotic areas were visible from the sixth week. The necrotic areas were surrounded by inflammatory cells infiltrate, increased number of Kupffer cells was found constantly within all liver tissue. In the eight week, the fibrotic lesions were clearly visible. Fibrosis was accomplished by alteration of liver parenchyma and, at the highest dose; fibrotic lesions were associated with sparsely distributed mineralization areas. The mice model of chronic hepatitis induced with carbon tetrachloride was a viable method, the lesions were similar to those described in rats, and comparable with the lesions found in human patients. Fibrotic lesions became visible after eight weeks; the doses above 1ml /kg, are not recommended because they were associated with mineralization areas.