[Effect of mild moxibustion on macrophage number and collagen expression of raw surface tissue in chronic refractory skin ulcer rats].

Objective: To observe the effect of mild moxibustion on the number of macrophages and contents of collagen I and III in the raw surface tissue in chronic skin ulcer rats so as to study its mechanism underlying promoting scar formation.
Methods: Eighty male SD rats were randomly divided into normal (n = 8), model (n = 24), TDP (n = 24) and moxibustion (n = 24) groups. Chronic refractory skin ulcer was established by making an open wound at the back and local intramuscular injection of hydrocortisone sodium succinate. For rats of the TDP and moxibustion groups, TDP irradiation or mild moxibustion was applied to the raw surface, bilateral "Shenshu" (BL 23) and "Zusanli" (ST 36) for 15 min, once daily for 7, 10 and 14 days, respectively. The number of macrophages in the raw surface tissue was counted under light microscope after H. E. staining and col- lagen I and III expressions of the raw surface tissue were detected by immunohistochemistry.
Results: In comparison with the normal group, the numbers of macrophages in the raw surface tissue were increased significantly in the model group on day 7, 10 and 14 (P < 0.05); while compared with the model group, the numbers of macrophages were increased further obviously in the moxibustion group on day 7 and 10 and in the TDP group on day 10 after the treatment (P < 0.05). Compared with the model group, the numbers of macrophages in both TDP and moxibustion groups were down-regulated obviously (P < 0. 05). In regard to collagen I and III expression of the raw surface tissue, compared with the normal group, the collagen I protein expression level was down-regulated markedly in the model group on the 7th day (P < 0.01); whereas in comparison with the model group, the expression levels of collagen I and III were increased considerably in the TDP and moxibustion groups on day 7 and 14 after the treatment (P < 0.05, P < 0.01). The ratios of collagen I/III expression were remarkably higher in the model group than in the normal group on day 7 and 14 (P < 0.05), and significantly lower in the TDP group on day 7 and 14 and in the moxibustion group on day 14 than in the model group (P < 0.05, P < 0.01). The effects of moxibustion were obviously superior to those of TDP in up-regulating macrophage number on day 10, up-regulating collagen I and III expressions on day 14, and down-regulating macrophage number on day 14 after the treatment (P < 0.05, P < 0.01). No significant differences were found between the TDP and moxibustion groups in up-regulating macrophage number, and collagen I and III protein expressions, and in down-regulating the ratios of collagen I/III expression on day 7 after the treatment (P > 0.05).
Conclusion: Mild moxibustion can regulate the number of macrophages and strengthen the expression of collagen proteins in the raw surface tissue in the chronic skin ulcer rats, which may contribute to its effect in promoting wound healing and reducing scar formation.