Copper Induces Apoptosis Through Endoplasmic Reticulum Stress in Skeletal Muscle of Broilers

The purpose of this research was to investigate whether copper (Cu) exposure could induce apoptosis via endoplasmic reticulum stress (ERS) in skeletal muscle of broilers. A total of 240 one-day-old chickens were randomly divided into four groups by free access; the diets are as follows: control diet (Cu 11 mg/kg, control group) and high level of Cu diets (Cu 110 mg/kg, group I; Cu 220 mg/kg, group II; Cu 330 mg/kg, group III). The skeletal muscle tissues were collected on day 49 for further examination. The content of Cu, histopathology, and the expression levels of the genes and proteins related to ERS and apoptosis were detected. Results showed that the Cu levels in skeletal muscle were increased in a dose-dependent manner. Meanwhile, the spaces between the muscle fibers were wider with the increase of Cu content, and the myolysis was observed in group III. Besides, the mRNA expression levels of GRP78, GRP94, eIF2α, ATF6, XBP1, CHOP, Caspase-12, and Caspase3 were markedly increased in treated groups compared with control group, and the protein expression levels of GRP78, Caspase3, Active-Caspase3 and JNK were significantly elevated with the increase of dietary Cu. In summary, these findings suggested that Cu could induce apoptosis through ERS in skeletal muscle of broilers.