Temporal correlations of ferroptosis, inflammation and oxidative stress under acute ammonia exposure in brain tissue of yellow catfish (Pelteobagrus fulvidraco)

Ammonia is one of the most serious environmental stressors which severely affect fishery production. Ammonia toxicity to fish has a tight relationship with oxidative stress, inflammation and ferroptosis (a type of programmed cell death characterized by iron-dependent lipid peroxidation), but the temporal response of the above three in brain remains unclear. In the present study, yellow catfish were exposed to three concentrations of ammonia: low concentration (TA-N < 0.01 mg L-1, LA), middle concentration (TA-N 5.70 mg L-1, MA), high concentration (TA-N 28.50 mg L-1, HA) for 96 h. Brain was selected as target tissues for analysis. Results showed that ammonia stress resulted in firstly increased contents of hydroxyl radical at 1 h, total iron at 12 h, malondialdehyde at 48 h, respectively, and decreased contents of GSH at 3 h. The initial high expression levels of ferroptosis (GPX4, system xc- , TFR1) and inflammatory-related factors (NF-ƙB p65, TNF, COX-2, and LOX-15B), antioxidant enzymes genes (SOD and CAT) were observed at first hour upon MA or HA stress. Combining all, it suggested that brain fer-roptosis and inflammation were the first to be activated at the initial stage of ammonia stress, and then that provoked oxidative stress.

Automated summary

Ammonia is a serious environmental stressor that affects fishery production. This study reveals that ammonia toxicity to fish is related to oxidative stress, inflammation, and ferroptosis in the brain, but the temporal response of these three processes is still unknown.