The level of OVA-specific IgE in serum was determined by ELISA using specific kits from Cusabio (Wuhan, China). The levels of IL-4, IL-13, IL-1β, IL-18, and 5-HT in BALF, the content of melatonin in lung homogenate were measured by ELISA kits from Cloud-Clone Crop (Wuhan, China) according to the protocols from the manufacturer.