Effect of glycyrrhizin (GL) on β-defensin production in tissues surrounding the burn area of thermally injured mice (134.44)

Abstract

Abstract The decreased production of antimicrobial peptides in tissues surrounding the burn area has been demonstrated in patients and animals with severe burn injury. Previously, sepsis stemming from burn wound infections with Pseudomonas aeruginosa was effectively controlled in burn mice treated with GL. Therefore, in this study, effects of GL on β-defensin production in tissues surrounding the burn area were examined. BALB/c mice with 25% TBSA of 3rd degree flame burn were treated i.p. with GL (Minophagen Pharmaceutical Co., Ltd., Tokyo, Japan) at various schedules after burn injury. Eight punch biopsies (8-mm diameter) per mouse were obtained from skin tissues surrounding the burn area of these mice 24 hrs after burn injury. The homogenates of 8 biopsies were assayed for MBD-1 and MBD-3 by ELISA. In the results, normal mouse skin homogenates consistently contained 0.8 ± 0.4 μg/ml of MBD-1 and 6.9 ± 1.8 μg/ml of MBD-3. However, MBD-1 and MBD-3 were not detected in homogenates of tissues surrounding the burn area. When 10 mg/kg of GL was administrated i.p. to mice 2 and 12 hrs after burn injury, the amounts of MBD-1 and MBD-3 in the homogenates of tissues surrounding the burn area recovered to the level shown in normal mouse tissue specimens. MBD production in skin tissues of normal mice was not influenced by GL treatment. These results indicate that, after treatment with GL, the decreased production of β-defensins in tissues surrounding the burn area is improved in thermally injured mice. This study was supported by SHC NA #8610.