Animals
All experimental protocols were approved by the Institutional Animal Care and Use Committee of the Qingdao University. Male Sprague-Dawley rats weighing 260–280 g were purchased from Vital River Laboratory Animal Technology Co. Ltd (Beijing, China). The animals were maintained in standard‐housing open‐top cages at a specific pathogen-free facility at 23 ± 1°C with 50%–60% humidity at Qingdao University. Before the procedure, all animals were fasted for 24 h with free access to tap water.