Feeding blueberry diets to young rats dose-dependently inhibits bone resorption through suppression of RANKL in stromal cells.
Previous studies have demonstrated that weanling rats fed AIN-93G semi-purified diets supplemented with 10% whole blueberry (BB) powder for two weeks beginning on postnatal day 21 (PND21) significantly increased bone formation at PND35. However, the minimal level of dietary BB needed to produce these effects is, as yet, unknown. The current study examined the effects of three different levels of BB diet supplementation (1, 3, and 5%) for 35 days beginning on PND25 on bone quality, and osteoclastic bone resorption in female rats. Peripheral quantitative CT scan (pQCT) of tibia, demonstrated that bone mineral density (BMD) and content (BMC) were dose-dependently increased in BB-fed rats compared to controls (P<0.05). Significantly increased bone mass after feeding 5% BB extracts was also observed in a TEN (total enteral nutrition) rat model in which daily caloric and food intake was precisely controlled. Expression of RANKL (receptor activator of nuclear factor-κB ligand) a protein essential for osteoclast formation was dose-dependently decreased in the femur of BB animals. In addition, expression of PPARγ (peroxisome proliferator-activated receptor γ) which regulates bone marrow adipogenesis was suppressed in BB diet rats compared to non-BB diet controls. Finally, a set of in vitro cell cultures revealed that the inhibitory effect of BB diet rat serum on RANKL expression was more profound in mesenchymal stromal cells compared to its effect on mature osteoblasts, pre-adipocytes and osteocytes. These results suggest that inhibition of bone resorption may contribute to increased bone mass during early development after BB consumption.
Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America.
Jian
J
Zhang
Oxana P
OP
Lazarenko
Jie
J
Kang
Michael L
ML
Blackburn
Martin J J
MJ
Ronis
Thomas M
TM
Badger
Jin-Ran
JR
Chen
D017667:Adipocytes / Q000473:pathology; D000821:Animal Feed; D000818:Animals; D029798:Blueberry Plants; D001854:Bone Marrow Cells / Q000473:pathology; D001862:Bone Resorption / Q000178:diet therapy* / Q000378:metabolism* / Q000473:pathology; D001842:Bone and Bones / Q000378:metabolism / Q000473:pathology; D002454:Cell Differentiation; D002460:Cell Line; D004032:Diet; D019587:Dietary Supplements; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D005786:Gene Expression Regulation; D009929:Organ Size; D010010:Osteoclasts / Q000473:pathology; D053244:Osteoprotegerin / Q000378:metabolism; D047495:PPAR gamma / Q000235:genetics; D053245:RANK Ligand / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017154:Stromal Cells / Q000378:metabolism*
D053244:Osteoprotegerin; D047495:PPAR gamma; D053245:RANK Ligand