Ko KM, Chen N, Leung HY, Leong EP, Poon MK, Chiu PY.
Department of Biochemistry,Hong Kong University of Science& Technology, Clear Water Bay,Hong Kong, China
Mitochondrial decay is a major cause of aging, leading to the subsequent death of aerobic organisms including humans. In the present study, we examined the effects of supplementation with schisandrin B (Sch B, a dibenzocyclooctadiene derivative isolated from the fruit of Schisandra chinensis), administered at 0.012% (w/w) of diet, starting from the age of 36 weeks, on age-dependent changes in mouse mitochondrial antioxidant status and functional ability in various tissues (brain, heart, liver, and kidney) up to the age of 120 weeks. We also monitored survival of male and female C57BL/6J mice. Aging caused progressive impairment in mitochondrial antioxidant status in various tissues, as evidenced by decreases in reduced glutathione and alpha-tocopherol levels, and Mn-superoxide dismutase activity. Impairments in mitochondrial antioxidant status were invariably associated with increases in mitochondria-driven reactive oxygen species (ROS) production in tissue homogenates, as well as decreased mitochondrial ATP-generation capacities (ATP-GCs), in all tested tissues. Diet supplementation with Sch B ameliorated impairment in mitochondrial antioxidant status during aging. The effects were more pronounced in younger than in older mice, when compared to age-matched non-supplemented controls. Sch B supplementation also suppressed mitochondria-driven ROS production and enhanced mitochondrial ATP-GC in various tissues during aging. The beneficial effects of Sch B supplementation on mitochondrial antioxidant status and functional ability were paralleled by survival improvement in aging male mice, when compared with controls. Sch B supplementation also improved the survival in female mice. In conclusion, long-term Sch B supplementation mitigated age-dependent impairments in mitochondrial antioxidant capacity and functional ability, thereby retarding the aging process in mice, particularly during early aging.