METHODS: Male Sprague-Dawley rats were exposed to CIH for 21 days (intermittent hypoxia for 60 s with 21% O2 and for 30 s with 10% O2 cyclically repeated for 8 h/day). We randomly assigned 56 male rats to a normoxia group (RA), an untreated CIH group (uCIH), and CIH groups treated with saline (CIH-S), dimethyl sulfoxide (CIH-D), apocynin (CIH-A), N-acetyl cysteine (CIH-N), and fasudil (CIH-F). Rats in the RA group were exposed to room-air stimulation, whereas rats in the other groups were exposed to CIH stimulation. BP was monitored at the start and of each week. After the experiment, renal sympathetic nerve activity (RSNA) was recorded, and serum and renal tissues were used for molecular biological and biochemical detection.