Establishment of rat model of liver cirrhosis or liver cancer and its magnetic resonance images before and after superparamagnetic iron oxide enhancement

Objective To establish a rat model of liver cirrhosis or liver cancer, to determine the liver cancer detection rates of magnetic resonance imaging ( MRI) in liver cirrhosis before and after superparamagnetic iron oxide ( SPIO) enhancement, to analyse the changes in SPIO distribution in different lesions in the process of inducing liver cirrhosis and liver cancer in rats, and to investigate the feasibility of assessing the function of Kupffer cells by SPIO- enhanced MRI. Methods Thirty male Sprague- Dawley ( SD) rats were randomly divided into experimental group ( n = 20) and control group ( n = 10) . The experimental group was given 0. 1 mg / ml diethylnitrosamine ( DENA) solution by free drinking, while the control group drank sterilized saline. At 10 or 20 weeks after treatment, 10 rats were selected from the experimental group to undergo plain MRI scans and then SPIO- enhanced MRI performed one hour after injection of SPIO; the rats were sacrificed immediately after scans. At 20 weeks after treatment, the 10 rats in control group underwent MRI scans and were then sacrificed immediately. The obtained MR images were analyzed. Blood samples were taken to measure serum alanine aminotransferase ( ALT) and aspartate aminotransferase ( AST) levels. Liver samples were taken and subjected to HE staining and Perls' blue staining for pathological examination. Results Compared with the control group, the experimental group had significantly increased ALT and AST levels at 10 weeks ( P <0. 001) , and the ALT and AST levels were significantly higher at 20 weeks than at 10 weeks in the experimental group ( P < 0. 001) . The SPIO- enhanced MRI showed that the percentage of signal intensity loss ( PSIL) was the highest in normal liver tissue, followed by simple cirrhosis tissue and cirrhosis tissue distant from liver cancer, and was the lowest in liver cancer tissue; there were significant differences in PSIL between the four tissues ( P < 0. 001) . In the experimental rats examined at 20 weeks after treatment, the liver cancer detection rate on each sequence and lesion- to- liver contrast- to- noise ratio increased significantly after SPIO enhancement ( P < 0. 05) . The Perls' blue staining showed that there was a significant linear correlation between the number of blue dye particles and PSIL on each sequence after SPIO enhancement in various liver tissues ( P < 0. 01) . Conclusion DENA induces the SD rat model of liver cirrhosis or liver cancer by the process similar to the development and progression of liver cirrhosis and liver cancer in humans. SPIO- enhanced MRI not only can indirectly reflect the changes in number and function of Kupffer cells in various lesions, but is also conducive to the early detection of liver cancer nodules in liver cirrhosis, with important value and guiding significance for clinical treatment.