Methods nature fade were divided into 7 groups.Sodium nitrite and dexamethasone were injection via abdominal,preventive drug was used in other normal control group.

• 方法将小鼠随机分为7组,除正常对照组外,给予自然衰老及腹腔注射亚硝酸钠和地塞米松处置,给药组预防性给药。