Oxidative stress causes liver injury via the damage of redox system and the apoptosis induced by mitochondria of broiler

The aim of this study was conducted to explore the effects of oxidative stress on the redox system, mitochondrial function, and apoptosis in liver of broilers. 144 one-day-old male Ross-308 broilers from the same batch had been prepared in advance and were divided into 3 treatments: normal control group (without intraperitoneal injection), normal saline group (intraperitoneal injection of normal saline), and hydrogen peroxide (H2O2) group (intraperitoneal injection of H2O2) with 6 replicates of 8 chickens each. The experimental period was 42 days. The injection volumes were 1.0 mL/kg of Ross-308 broiler body weight. On the 42nd day of the experimental period, two Ross-308 broilers were randomly selected from each cage, a total of 36 broilers were stunned by electric shock and slaughtered to collect liver samples. The results showed that compared with the non-injection group and the injection of saline group, H2O2 exposure elevated the relative weight of liver and the activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum of Ross-308 broilers (p < 0.05). Meanwhile, compared with the non-injection group and the injection of saline group, the H2O2 exposure increased the levels of reactive oxygen species (ROS), MDA, lipid peroxide (LPO) and protein carbonyl, decreased the activities of total superoxide dismutase (T-SOD), catalase (CAT), total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-Px) (p < 0.05). Compared with the non-injection group and the injection of saline group, the H2O2 exposure caused microvesicular steatosis and mitochondrial vacuolisation in the liver tissues of broilers. Additionally, after H2O2 exposure, the levels of nuclear factor erythroid 2-related factor 2 (Nrf2) positive cells were reduced and the relative percentage of hepatocyte apoptosis were increased in the liver tissues of broilers (p < 0.05). The conclusion of this study is that the oxidative stress induced by intraperitoneal injection of H2O2 could induce excessive production of ROS in broiler liver, which damage the antioxidant status and mitochondrial function of liver cells, leading to cell apoptosis.