Combined effects of the administration of black-rice bran extracts and running training on bone mineral density and body compositions in rats

摘要

This study was designed to clarify the effects of administration of black rice bran extracts and running training on the bone mineral density (BMD) and body compositions in the rats. After a week of stabilization, twenty male 5 weeks old Wister-Kyoto (WKY) rats were randomly divided into four groups: control non-exercise group (CN group, n=5); control exercise group (CE group, n=5); non-exercise group fed to black rice bran extracts (BN group, n=5) and exercise group fed to black rice bran extracts (BE group, n=5). CN and CE groups were fed only a standard diet (CE-2, Oriental yeast, Japan), and black rice bran extracts were added at level of 10% to the foods of BN and BE groups. All rats were allowed free access to tap water and to have same-volume-feeding in all groups. Running exercise training was performed running training on the treadmill at 23 m/min, 60 min/day, 5 days/week for 8 weeks. End of the experimental period, rats were sacrificed, blood was drawn and low limb bones and several organs were removed. The body weight and fat mass around kidney of BN group were approximately 8% and 57%, respectively, higher than those of CN group (p<0.05 and p<0.01, respectively). Femoral and tibial bone length of BN group were approximately 1.9% and 2.1%, respectively, longer than those of CN group (p<0.01, respectively) though BMD of each group showed similar levels. Examination of the hepatic function, such as serum GOT, TP, Alb, and LDH showed similar levels among either groups except for decrease of GPT in BN group (p<0.05). On the other hand, running exercise in both feeding administration increased BMD, BMC and bone weight compared with those of both non-exercise group (p<0.05, p<0.01 and p<0.01, respectively) while body fat mass and body weight were decreased (p<0.001 and p<0.05, respectively). These results suggest that prolonged black-rice administration might improve the growth including body weight and bone length in the rats, and the cooperative treatment of running training has more beneficial effects on BMD and body composition.