Reliability study on establishing a rat tuberculosis wound model using Bacillus Calmette-Guérin

Abstract

Objective: To evaluate the reliability of a rat tuberculous wound model established by injecting Bacillus Calmette-Guérin (BCG). Methods: The experimental research was conducted. According to the random number table, fifteen 6-week-old male Sprague-Dawley rats were divided into normal control group and infection group, with 3 rats in normal control group and 12 rats in infection group. Rats in infection group were injected with Freund's complete adjuvant, 3 weeks later, they were injected subcutaneously with BCG bacterial solution to establish a model of tuberculous wounds in rats; rats in normal control group did not receive any treatment. On the 8th, 15th, 32nd, and 43rd day of infection, the skin condition at the injection sites of the rats in infection group was observed roughly. Skin tissue at the injection sites of 3 rats in infection group at each corresponding time point stated above and skin tissue at the corresponding sites of the rats in normal control group were stained with hematoxylin-eosin to observe the cell arrangement, necrosis and inflammation. On 43rd day of infection, acid-fast staining was performed on the skin tissue at the injection sites of the rats in infection group to observe the distribution of bacteria. Results: On the 8th, 15th, 32nd, and 43rd day of infection, tuberculous wound lesions were gradually developed at the skin tissues at the injection sites of the rats in infection group. The cells of the diseased tissue of the rats in infection group arranged disorderly or concentrically, and the number of granulomas and necrotic cells gradually increased, while the skin tissue cells in the corresponding parts of the rats in normal control group arranged regularly with no inflammatory cell infiltration. On the 43rd day of infection, a large number of rod-shaped bacteria were observed in the skin tissue at the injection sites of the rats in infection group. Conclusions: The rat tuberculous wound model established using BCG is stable and reliable, which can meet the experimental requirements.