Protective Effect of Extract of Ginkgo biloba 761 against Frostbite Injury in Rats.

When frostbite thaws, reperfusion injury has a crucial impact on tissue injury, and production of free radicals induces further tissue damage. This study examined whether extract of Ginkgo biloba 761 could ameliorate frostbite injury as a free radical scavenger.Seventy-five Fisher 344 rats were divided into five groups of 15, and frostbite injury was created in each animal by sandwiching the left hind foot between a frozen magnet (-78.5°C) and a room-temperature magnet. Group I received saline; groups II, III, and IV received extract of Ginkgo biloba 761 (200, 100, and 50 mg/kg, respectively); and group V received superoxide dismutase (12 mg/kg). All drugs were injected intraperitoneally three times at 24-hour intervals. The wound surface area was measured throughout the wound healing period. Wounds were also harvested at various times to count cells stained by monoclonal antibodies for 4-hydroxy-2-nonenal and 8-hydroxy-2'-deoxyguanosine.Compared to group I, the wound surface area was significantly smaller in groups II and III on days 1 and 3 after wound creation. Histologic examination revealed significantly more 4-hydroxy-2-nonenal-stained cells and 8-hydroxy-2'-deoxyguanosine-stained cells in group I compared to other groups on day 1. However, there was no difference in the total healing period among the groups. A higher dose test of extract of Ginkgo biloba 761 (300 mg/kg daily) induced animal death, probably because of toxicity.Extract of Ginkgo biloba 761 demonstrated a protective effect against frostbite in the present model and probably alleviated reperfusion injury by reducing tissue peroxidation.