Objective To analyze the characteristics of Clostridioides difficile infection in tree shrews and BALB/c mice, and evaluate the applicability to use them as animal models for C. difficile infection.
Methods Tree shrews and BALB/c mice were used respectively. The animals were fed with antibiotics cocktails and infected by oral gavage of 105 CFU spores of RT078 C. difficile strain. The infection characteristics and manifestations of the animals within 7 days were observed, and the histopathological examination of the intestinal tissues were conducted.
Results The tcdA and tcdB genes were detected in all stool samples of tree shrews from the second day after gavage, while the positive rate of the virulence genes was 80% in BALB/c mice. Within 7 days of infection, No tree shrew and mouse died. The proportions of the animals with weight loss during the experiment was 8.80%±1.82% and 4.82%±2.19%, respectively. Comparison of the infection characteristics of the animals showed that 60% of the tree shrews had obvious diarrhea symptoms, but the BALB/c mice had no such symptom. The results of abdominal cavity anatomy showed obvious inflammation of intestinal mucosa and abdominal cavity in the tree shrews, but not in the ALB/c mice. The histopathological characteristics of the two kinds of animals were similar, manifested by the destruction of intestinal cells, the disorder of tissue structure and the infiltration of inflammatory cells. The lesions of ileum and colon occurred in tree shrews, while colon lesion occurred in BALB/c mice.
Conclusion Both tree shrews and BALB/c mice can be used as animal models for C. difficile infection. The clinical manifestations and disease manifestations of tree shrews might be similar to human diseases. The selection of animal as C. difficile infection model mainly depends on the observation indicators and research purpose of different studies.