CCl4-induced liver fibrosis
Liver fibrosis occurs in most types of chronic liver diseases like Hepatitis B and C, viral infections by CMV or EBV, alcoholic liver disease, non-alcoholic fatty liver disease, haemochromatosis, Wilson’s disease and many more. In humans, researchers were already able to show that liver fibrosis is reversible, fostering the development of anti-fibrotic drugs. To test the efficacy of these new drugs, proper preclinical models are needed. To model liver fibrosis in vivo, mice can be systemically injected with carbon tetrachloride (CCl4). CCl4 is an organochloride and known as one of the most potent hepatotoxins and as such inducing liver fibrosis.
C57Bl/6 mice at an age of 7 weeks are intraperitoneally treated three times per week with CCl4 or vehicle for a total of 9 weeks to induce liver fibrosis.
Next to the liver to body weight ratio, liver disease markers can be analyzed in the liver, including, but not limited to Col1a1, Acta2, hydroxyproline and smooth muscle actin. Markers can be evaluated on mRNA and protein level by real time RT-PCR, protein assays as well as qualitative and quantitative immunofluorescent labeling.
Figure: Expression levels of typical liver disease markers after CCl4 treatment. mRNA expression levels of Col1a1 (A) and Acta2 (B). Levels are presented as x-fold change using the 2^(-ΔΔCT) method in relation to the HKG HPRT and vehicle. C: Hydroxyproline protein levels in ng/µl. Quantification of Col1a1 (D) and SMA (E, smooth muscle actin) immunoreactive (IR) area in percent. A-E: All markers were measured in the liver after 9 weeks of CCl4 or vehicle treatment. Unpaired t-test; n = 5/6 per group; mean + SEM; *p<0.05, **p<0.01, ***p<0.001.