Establishment and evaluation of a mouse model of schistosomiasis liver disease induced by portal vein injection of worm eggs / 中国热带医学

ABSTRACT

@#Abstract: Objective　To construct a mouse model of Schistosoma japonicum liver disease induced by direct injection of Schistosoma japonicum eggs through the portal vein and evaluate its effectiveness, in order to provide a new animal model for schistosomiasis liver disease research. Methods　Fifteen 8-week-old C57BL/6 male mice were randomly divided into control group and egg injection group, with 5 in the control group and 10 in the egg injection group. On day -14, 5 000 live eggs were injected into the abdominal cavity of mice, and on day 0, the mice were anesthetized and the abdominal cavity was opened. 5 000 live eggs were injected through the portal vein, and the control group was injected with equal volume of phosphate buffer (PBS). 5 mice in the egg group were killed on day 10 and 30, respectively. The control group mice were killed on day 10, and their serum and liver tissue were collected. Hematoxylin eosin staining (HE) and Masson staining were performed, and alanine aminotransferase (ALT), aspartate aminotransferase (AST), and liver hydroxyproline (HYP) content were detected using a microplate spectrophotometer. Liver fibrosis-related genes, Th1 and Th2 type immune response-related genes were analyzed by real-time fluorescence quantitative PCR (qPCR). Liver injury, egg granuloma and fibrosis, and adaptive immune response were detected to evaluate the effect of portal vein injection of eggs while inducing mouse model of schistosomiasis liver disease. Results　The results showed that significant egg granulomas appeared in the liver of mice after injection of eggs into the portal vein for 10 and 30 days. There was no statistically significant difference in the area of egg granulomas between the 10-day group and the 30-day group (t=0.975, P=0.332). Masson staining and liver hydroxyproline content detection showed significant fibrosis in the liver. The qPCR results showed that, compared with the control group, the expression levels of fibrosis marker genes, such as α⁃Sma (alpha smooth muscle actin), Col1a1 (collagen type Ⅰ alpha 1), and Tgfb1 (transforming growth factor beta 1), were significantly increased (t=6.380, 7.533, 5.314; P=0.002, 0.001, 0.007), and then decreased on the 30th day, with no statistical difference compared to the control group (t=0.940, 1.529, 1.746; P=0.778, 0.543, 0.457). At the same time, the expression levels of Th1 type immune response-related genes, such as tumor necrosis factor alpha (Tnf), interferon gamma (Ifng), and Th2 type immune response-related genes, such as interleukin-5 (Il5), interleukin-13 (Il13), significantly increased 10 days after eggs injection (t=6.163, 4.589, 5.651, 5.367; P=0.003, 0.018, 0.020, 0.009). In addition, there was no significant change in the levels of AST and ALT in the serum of each group of mice (t=0.982, 3.450; P=0.771, 0.074. t=1.164, 0.564; P=0.697, 0.917). Conclusions　A mouse model of schistosomiasis liver disease induced by portal vein injection of worm eggs was constructed. The study provides a new modeling method for studying the mechanism of liver fibrosis in schistosomiasis..