Abstract
Icariin is a prenylated flavonol glycoside derived from the Chinese herb Epimedium sagittatum. This study investigated the mechanism by which icariin prevents H(2)O(2)-induced apoptosis in rat nucleus pulposus (NP) cells. NP cells were isolated from the rat intervertebral disc and they were divided into five groups after 3 passages: (A) blank control; (B) 200 μM H(2)O(2); (C) 200 μM H(2)O(2) + 20 μM icariin; (D) 20 μM icariin + 200 μM H(2)O(2) + 25 μM LY294002; (E) 200 μM H(2)O(2) + 25 μM LY294002. LY294002 is a selective inhibitor of the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway. NP cell viability, apoptosis rate, intracellular reactive oxygen species levels, and the expression of AKT, p-AKT, p53, Bcl-2, Bax, caspase-3 were estimated. The results show that, compared with the control group, H(2)O(2) significantly increased NP cell apoptosis and the level of intracellular ROS. Icariin pretreatment significantly decreased H(2)O(2)-induced apoptosis and intracellular ROS and upregulated p-Akt and BCL-2 and downregulated caspase-3 and Bax. LY294002 abolished the protective effects of icariin. Our results show that icariin can attenuate H2O2-induced apoptosis in rat nucleus pulposus cells and PI3K/AKT pathway is at least partly included in this protection effect.