Effect of supplementation with blueberry extract on the bone status of old mice

Introduction Supplementation with polyphenols of blueberries protect the cognition and have beneficial effects in therapy of cancer, obesity, diabetes and cardiovascular diseases [1]. In addition, several publications report positive effects on bone status in rat osteoporosis models [2], [3]]. Thus, we asked in the present study whether the long-term administration of blueberry polyphenol extract is able to reverse age-related bone alterations in a murine model of aging.

Methods Forty-two female mice of the NMRI strain were included in the study after approval by the government of the county (permit number FU/1062). The test group (n = 14; BB) received for 7 months chows that were enriched with 20 g of blueberry freeze-dried extract per kg chows. One control group was aged- and gender-matched but was fed with standard chows (old, n = 14). The second control group were young female NMRI mice fed with standard chows and sacrificed at an age of 4 months (young, n = 14). The mice of BB and old groups were euthanized at an age of 13 to 16 months. Femora and vertebrae were removed and used for biomechanical, radiological, cell and molecular biological methods as well as for transmission electron microscopy (TEM).

Results The biomechanical three-point bending test resulted in a reversion in maximal breaking force of the BB group compared to the age matched control group. No reversion was measured for bone microarchitecture determined by micro computed tomography. Additionally, osteoclast did not show any significant differences between BB and control groups by means of cell and molecular biology. Regarding the osteoblasts, the BB and old control group showed similar expression pattern of bone formation markers that were declined compared to the young controls. The osteocyte marker sclerostin was not regulated while expression of connexin-43 as marker for cell-cell communication was declined in BB and old control compared to young control. Using TEM, gap junctions were only found in the BB and young control group. Additionally, no alterations in mitochondria ultrastructure were observed between the groups. BB and old control group showed significant more osteocytes with age-related differences compared to young control e. g. form of the lacunae was spherically in the old compared to young animals.

Discussion In conclusion, supplementation with BB via oral administration did only reverse the biomechanical breaking force of compact bone but the impaired trabecular bone was not significantly rejuvenated.

Keywords Blueberry, aging, Biomechanics, Transmission electron microscopy, polyphenol

Korrespondenzadresse Katrin Susanne Lips, Justus-Liebig-Universität Gießen, Experimentelle Unfallchirurgie, Aulweg 128, 35392, Gießen, Deutschland, Germany

E-Mail [e-mail]

• 1 Ma L. et al. 2018 Int J Mol Sci. 19(9).
• 2 Devareddy L. et al. 2008; J Nutr Biochem 19 (10) 694-9
• 3 Li T. et al. 2014; J Orthop Surg Res 9: 56 .