In this study, Syrian golden hamsters were used and divided randomly into thirteen groups: (1) Control group(C, n=9), hamsters were fed normally after a single intratracheal administration of physiological saline;

• 本研究选用雄性叙利亚金黄地鼠，随机分为以下13组：(1)对照组(C)9只，气管内一次性滴注生理盐水后常规饲养；