Three time points were set in hypoxia group and naloxone group according to different time of hypoxia and reoxygenation: hypoxia 2 hours/reoxygenation 0 hour;

• 缺氧组和纳洛酮组又根据缺氧、复氧时间不同分为3个时间点:缺氧2h/复氧0h;