Objective: To investigate the methods for assessing angiogenesis in experimental liver fibrosis.
Methods: Male C57BL/6 mice were randomly divided into a normal (unmodeled) group and a liver fibrosis model group.The model was established by a 4-week course of 10% CCl4 solution (in olive oil) intraperitoneal injection. Liver vasculature was observed by magnetic resonance (MR),computed tomography (CT),synchrotron radiation X-ray,and von Willibrand factor(vWF) immunofluorescence staining. Liver inflammation and fibrosis were observed by staining with hematoxylin-eosin and Sirius red.The t-test and Pearson's correlation analysis were used for statistical analyses.
Results: Compared with the normal group,the model group had more robust inflammation and fibrosis in liver tissue.The liver tissue in the modeled mice showed significant deceases in MR signal intensity on T2WI before and after enhancement (386.67+/-69.04 vs.492.67+/-112.50,t =-2.456, P=0.026).The liver tissue in the modeled mice also showed significantly decreased enhancement CT values (P < 0.01).Synchrotron radiation X-ray imaging showed that the small vessels in the liver tissues of the modeled mice were significantly increased compared to that in the normal mice (P < 0.01).The MR T2W enhanced signal value (439.67+/-104.80, Pearson's r=0.714, P=0.009) and microvascular relative length (676.53+/-122.75, Pearson's r=0.791, P=0.002) were positive correlated with microvessel density (MVD) (14.50+/-5.95),as shown by detection of labeled vWF.The before and after CT enhancement difference (132.60+/-57.02, Pearson's r=-0.612, P=0.034) was negatively correlated with MVD.
Conclusion: s MR,CT and synchrotron radiation X-ray imaging can be used for assessing angiogenesis in liver fibrosis,and the findings from each are correlated with the traditional MVD detection method. The two-dimensional imaging of synchrotron radiation X-ray is more intuitive,and has been confirmed as an effective evaluation method for liver angiogenesis.