Establishment and comparison of three kinds of chronic bacterial cystitis models in mice

Cystitis is a common urinary system disease in women. However, there are currently no effective treatment options except antibiotics. Therefore, establishing an effective and stable animal model is helpful for further study of cystitis. In this study, we established three chronic cystitis models from C57BL/6 female mice inoculated with urinary tract pathogenic Escherichia UTI89 through urethral perfusion: CPP co-infection group, seven days interval repeated infection group, and two consecutive days repeated infection group. The three models were successfully constructed, and the survival rates of the three models were 66%, 75%, 100%, respectively. The bladder infection rates of the surviving mice were 100%, 100%, 50%, respectively. H&E staining showed that the inflammation and damage were the most severe in seven days interval repeated infection group. Sirius red staining showed that the degree of fibrosis was the highest in CPP co-infection group. Immunofluorescence staining of bladder inflammatory cells showed that inflammatory cells and macrophages in the CPP co-infection group and the seven days interval repeated infection group expressed more. Basal layer epithelial cell staining showed that the epithelial cells of the three infection models had different degrees of proliferation. The three strategies can all prepare mouse chronic cystitis models with their own characteristics, and these models can be used for experimental studies related to different levels of bladder infection and fibrosis, laying a foundation for further research on the mechanism of chronic cystitis.