Apelin-13 Attenuates Iohexol-Induced Acute Kidney Injury in Rats

All animal experiments were reviewed and approved by the Institutional Animal Care and Use Committee of Central South University (NO. 100:2020sydw0899). Sprague-Dawley rats (male, 7 weeks, 220–240 g) were purchased and raised at the Department of Laboratory Animals of Central South University. All rats were housed in the pathogen-free animal facility with free access to food and water under a 12 h light-dark cycle and were acclimatized for 7 days before each animal experiment.
The rats were divided into five groups: control group (n = 5), 100 nM/kg apelin-13 group (n = 5), iohexol group (n = 5), iohexol + 10 nM/kg apelin-13 group (n = 5), and iohexol + 100 nM/kg apelin-13 group (n = 5). The model of rat CI-AKI was established as previously described [20 (link)]. Blood samples were collected from the orbital venous plexus through capillary glass tubes and used to measure serum creatinine (SCr) and blood urea nitrogen (BUN) before the rats were deprived of water. All rats that had been dehydrated for 48 h were injected intraperitoneally with furosemide (10 mL/kg) 30 min prior to the time point at which they were injected with iohexol (15 mL/kg). Apelin-13 (10 nM/kg, 100 nM/kg) was injected 10 min before the iohexol injection. Apelin-13 and iohexol were administered intravenously via rapid tail vein injection as previously described. The rats were sacrificed 24 h after the iohexol injection, and kidney tissues and blood samples were collected for further experiments (Figure S1).