To observe the pathological changes of wound dynamically and to discuss the changes of macrophage polarization of tuberculosis wounds by successfully constructing rat models of tuberculosis wounds.

Thirty-five SD rats(female, 8 weeks old)were injected with purified protein derivative(PPD), then 30 rats were selected, which were no inflammatory reaction or weak reaction in PPD experiment. The 30 rats were divided into experimental group (n=15) and negative control group (n=15) according to the random number table method. Thirty rats had been immunized and allergized with Freund′s complete adjuvant 6 weeks previously. Bacillus Calmette-Guérin (BCG) was intradermal injected to each experiment rat with the doses of 0.2 mL, 5×10⁷CFU/mL. PBS was intradermal injected to each rat in negative control group. The changes of wound were observed broadly. At 2, 6 and 11 days after injection, paraffin-embedded skin sections was did in each group (each time took five rats from each group), and hematoxylin-eosin staining was used to observe wound healing and infiltration of inflammatory cells in each group. The pathogenic microorganism was used to detecte and identify strains. Six days after injection, immunohistochemical staining was did, CD68-labeled macrophages, subtypes of M1 macrophage iNOS markers and M2 macrophages CD206 markers were used to analyze the expression of M1 and M2 macrophages by immunohistochemistry in the experimental group and the negative control group. All data were analyzed by t-test.

Apparent red, liquefaction, necrosis and ulceration were produced in the skin of rats injected with BCG. The appearance of tuberculousis wound from ulceration to healing was observed by the use of hematoxylin-eosin staining. The result of acid-fast staining was positive. The macrophage differentiation markers were counted by immunohistochemical staining in the peak period of tuberculousis wound: CD68, iNOS, CD206 in the experiment group were (84.8±3.4)/HP, (60.8±2.8)/HP, (13.2±2.2)/HP respectively, which were significantly higher than those in the control group (1.4±0.5)/HP、(0.4±0.50)/HP、(0.6±0.50)/HP, the differences were statistically significant (t=93.2, 95.5, 28.2, with P values below 0.05). iNOS [(60.8±2.8)/HP] in the experiment group were significantly higher than CD206 [(13.2±2.2)/HP] in the peak period of tuberculousis wound, the differences were statistically significant (t=27.6, P<0.05).

After sensitization of rats injected with BCG can effectively induce liquefaction and necrosis, the number of M1 macrophages in wound tissue at the peak of liquefaction necrosis was significantly higher than that of M2 macrophages, and significantly more than the negative control group. The experimental results suggest that the local microenvironment of wound tissue at the peak of liquefaction necrosis in tuberculous wounds can induce the change of macrophages to M1 type, which is beneficial to the effect of macrophages in killing M. tb effectively.