Lutein Suppresses Oxidative Stress and Inflammation by Nrf2 Activation in an Osteoporosis Rat Model

BACKGROUND Osteoporosis is a major health risk for women worldwide. Osteoporosis is caused by an imbalance between bone resorption and formation. Hormonal imbalance and increased redox signaling cause bone deterioration. MATERIAL AND METHODS Oxidative stress was determined through assessment of ROS, lipid peroxide levels, and antioxidant activity. Inflammatory protein markers and Nrf2-related protein expressions were determined through Western blot analysis. Interleukin expressions were determined using ELSA. RESULTS In the present study, we showed that supplementation of lutein protects the ovariectomized (OVX) rats against oxidative stress through its antioxidant protection. OVX rats showed an increase in oxidative stress markers. Lutein treatment significantly decreased the lipid peroxidation levels and ROS in the OVX rats. OVX rats showed inflammatory responses through NF-κB activation and increased inflammatory cytokines (TNF-α, IL-6, IL-8). Further, there was significant upregulation in osteoclast-specific marker NFATc1 in OVX rats compared to sham rats. Lutein supplementation activated Nrf2 driven antioxidant gene expression (HO-1, NQO1) and protected OVX rats against inflammatory responses. CONCLUSIONS We showed the critical role of Lutein in protection against osteoporosis in OVX rats by downregulation of inflammation and osteoclast-specific marker (NFATc1) expression through Nrf2 activation.