Gibberellic acid induced oxidative stress, endoplasmic reticulum stress, and apoptosis in the livers of gibel carp (Carassius auratus gibelio)

Gibberellic acid (GA3), one of the most plant growth stimulator, is widely applied in agricultural regions and in beer industry. However, GA3 residue remained in soil and water can cause toxicity to all organisms. In this study, we investigated the mechanisms of GA3-induced hepatic injury in gibel carp (Carassius auratus gibelio). We found that GA3 exposure caused oxidative stress, endoplasmic reticulum stress (ERS), and apoptosis. The gibel carp exposed to GA3 exhibited significant alteration in erythrocyte nuclei. GA3 induced liver damage, as indicated by increasing the aminopherase activities. GA3 led to oxidative stress by increasing malondialdehyde content and decreasing the activities of CAT and GPx. GA3 stimulated ERS and increased the expression of grp78, perk, eif2s1 alpha, chop, atf4, ire1 alpha, xbp1, and atf6. Additionally, GA3 down-regulated the level of anti-apoptotic gene Bcl2 and up-regulated the levels of pro-apoptotic genes bax and caspase-3. Overall results demonstrated that GA3 caused hepatic injury in gibel carp by increasing oxidative stress, ERS, and apoptosis.