Lymphatic regeneration across an incisional wound: Inhibition by dexamethasone and aspirin, and acceleration by a micronized purified flavonoid fraction

Although the antiinflammatory and antiangiogenic properties of dexamethasone and acetylsalicylic acid have been studied extensively, their effects on lymphangiogenesis in regenerating tissues remain mostly unknown. We studied in rats the pharmacological modulation and the effect of a remote inflammatory stimulus on the lymphatic regeneration upon damage after a surgical procedure. A micronized purified flavonoid fraction bearing antiinflammatory and lymphagogue properties, was also used. An incisional wound and interruption of the afferent lymphatic vessels to the popliteal and axillary lymph nodes of adult rats were made in dorsal thigh and hypochondrium, respectively. The progress of lymphatic regeneration was evaluated 3, 7, 14 and 21 days after surgery. 99mTc-dextran lymphoscintigraphy and Evans blue dye uptake were used to evaluate the lymphatic flow and the kinetics of lymphatic regeneration. In control conditions, lymphatic regeneration took 14 days to be accomplished. In the presence of a remote inflammatory response, which conceivably yielded inflammatory mediators to the incisioned lymphatic vessels, that time was shortened to 7 days. In both conditions, lymphatic regeneration was inhibited by dexamethasone and acetylsalicylic acid and accelerated by the micronized purified flavonoid fraction. These findings indicate that lymphatic regeneration in an incisional wound may be significantly modulated by dexamethasone, aspirin and a micronized purified flavonoid fraction, and these results call our attention for the possibility to pharmacologically stimulate the recovery of a lymphatic failure due to a traumatic event, or to inhibit its function in order to limit the lymphatic spread of cytokines or neoplastic cells.