Objective: To investigate the underlying mechanism for the therapeutic effect of a traditional Chinese medicinal recipe, Antidotal and Myogenic Ointment (AMO), on the foot ulcer in diabetic rat using cDNA microarray technology.
Methods: 45 rats were made diabetic by i. p. injection of streptozocin. The treated animals were then fed for 6 months,and subjected to the dissection of distal popliteal artery after ligation of the vessels. Another month later, grade II burn injury was produced on the bottom of their foot as a model of diabetic foot ulcer. The rats were then randomly divided into three groups (15 each) to receive AMO, epidermal growth factor (EGF) and saline for 30 days, with dressing change in every 2 days. The area of ulcer wound and their healing rate were recorded before and after the treatment. Total RNA was extracted from the tissue samples collected near the wound, and the expression profile of cytokine genes demonstrated using the microarry for rats.
Results: In comparison with the saline group, difference in the level of expression was found in 25 genes (23 of them were up-regulated and 2 down-regulated) in EGF group, and 30 genes in AMO groups (29 of them up-regulated and 1 down-regulated ). In comparison with EGF group, difference in level of expression was found in 16 genes in AMO group, with 11 up-regulated and 5 down-regulated. Neurotrophic factors and chemotactic factors, etc were among the genes involved.
Conclusion: In comparison with EGF, AMO is more effective in the treatment of foot ulcer in diabetic rats. It is possible that AMO produces such effects through the regulation of balance in cytokine expression.