Clinical and immunohistopathological aspects of venous ulcers treatment by Low-Intensity Pulsed Ultrasound (LIPUS)

Abstract

The immunological mechanisms that are triggered by Low-Intensity Pulsed Ultrasound (LIPUS) in wound healing are unknown. In the present study, experimental groups were used to assess the treatment of chronic venous ulcers with 30mW/cm2 SATA peripheral LIPUS three times per week compared to a daily treatment of 1% silver sulfadiazine (SDZ). The ulcers of the SDZ group (n=7) (G1) and LIPUS group (n=9) (G2) were photographed five times three months, and the images were analyzed using ImageJ software to quantify the total area (S), fibrin/sphacel area (yellow) and granulation area (red). The healing process was evaluated by the wound healing rate (WHR), granulation tissue rate (GTR) and fibrin/sphacel tissue rate (FTR). The ulcers were biopsied on days 1 and 45 and stained for collagen fiber quantification (picrosirius) and CD68+ protein and VEGF (vascular endothelial growth factor) expression using HRP-streptavidin (horseradish peroxidase-streptavidin). On day 90, G2 had a mean 41% decrease in the ulcer area, while no decrease was observed in G1 (p<0.05). An increased tendency toward positive labeling of collagen fibers and VEGF (p>0.05) was observed in G2 compared to G1, and the number of CD68+ cells was greater in G2 than in G1 (p<0.05). LIPUS presents superior activity compared to SDZ in stimulating the inflammatory and proliferative (angiogenesis and collagenesis, respectively) phases of chronic venous wound healing.