Animal model

A total of 18 postnatal 5-day Sprague-Dawley (SD) rat male pups were supplied by the Experimental Animal Center of Nantong University. The study was approved by the Administration Committee of Experimental Animals of Nantong University. All the experimental procedures were performed according to the Chinese Guidelines for the Care and Use of Laboratory Animals. Rat pups were randomly separated into 3 groups (6 animals per group): sham operation (Sham group), LPS injection (LPS group), and ABPPk pre-administration followed by LPS injection (ABPPk group). Model of LPS-induced brain injury was referred to previously reported literatures (26-28). The rat pup was anesthetized by intraperitoneal injection of avertin (1.25% bromethol, 0.2 mL/10 g body weight) (AIBI Bio-Tech, Nanjing, China), then a volume of 2 µL LPS (1 mg/kg) was injected using a microsyringe which was inserted perpendicularly through the skull to the brain at the location of 1.0 mm posterior and 1.0 mm left to the bregma, and 2.0 mm deep in a stereotaxic apparatus (RWD 68019, RWD, Shenzhen, China). Rat pups in the ABPPk group were first administrated with 2.5 mg/kg ABPPk (total volume of 2 µL) at the same location, and then injected with 2 µL LPS (1 mg/kg) 10 min later. Rat pups in the Sham group only exposed the skulls, but no injections were given. All animals survived the intracerebral injection and no one was excluded.