Maternal Exposure to Hesperidin and Naringin Flavanones Exerts Transient Effects to Tibia Bone Microstructure in Female CD‐1 Offspring

Abstract

BackgroundFood bioactives may provide a dietary strategy to support healthy bone development. In a developing mouse model, early life but not maternal exposure to soy isoflavones sets a trajectory for higher bone mineral density (BMD), improved bone structure and greater bone strength in female offspring at adulthood. Other bioactives such as citrus flavanones (i.e. hesperidin, (HSP); naringin, (NAR)) have been shown to exert bone‐sparing effects in adult and aging rodents but whether maternal or early life exposure to citrus flavanones changes the trajectory of bone development to result in stronger, healthier bones at adulthood has not been investigated.ObjectiveTo determine whether maternal and early life exposure to a diet with HSP and NAR results in improved bone microstructure, higher BMD, and greater biomechanical bone strength in female mouse offspring at adulthood.Methods5‐wk‐old female CD‐1 mice were fed the AIN‐93G control (CON, n=10) diet alone or with 0.5% HSP + 0.25% NAR (HSP+NAR, n=8) for 5 weeks preconception, and through pregnancy and lactation. HSP and NAR were added to CON diet at the expense of cornstarch, at doses reflecting moderate (400 mL) to high (1 L) orange or grapefruit juice consumption. At weaning, all female offspring were fed CON diet until 6 months of age. At 2, 4 and 6 months of age, right tibias were scanned using in vivo micro‐computed tomography (μCT) to assess trabecular and cortical bone microstructure. Ex vivo μCT scanning of the second lumbar vertebrae (LV2) and femurs was performed to assess site‐specific effects and to determine bone microstructure at skeletal sites rich in trabecular and cortical bone, respectively. Dual energy x‐ray absorptiometry (pSabre, Orthometrix) and biomechanical strength testing (Model 4442, Instron Corp.) were used to assess BMD (whole tibia and femur, LV2) and strength properties (tibia and femur midpoints, LV2), respectively.ResultsLitter size and weight at postnatal age of 9, 16 and 21 days were similar (p>0.05) between CON and HSP+NAR groups. Food intake and body weights remained similar (p>0.05) between CON and HSP+NAR offspring throughout the study. At 2 and 4 months of age, compromised trabecular (bone volume fraction, trabecular number and separation, connectivity density) but not cortical bone microstructure was observed at the proximal tibias of HSP+NAR versus CON offspring (p<0.05). At 6 months, these differences in trabecular structure at the proximal tibia had disappeared; BMD, trabecular or cortical bone microstructure, and biomechanical bone strength did not differ (p>0.05) between HSP+NAR and CON offspring at all skeletal sites assessed.ConclusionMaternal and early life exposure to HSP+NAR does not enhance bone development in female CD‐1 offspring. Compromised trabecular bone structure during early life does not persist into adulthood, and BMD and strength of the tibia is not altered at 6 months of age, representing adulthood.Support or Funding InformationThis research was funded by the Canadian Institutes of Health Research (Grant #130544) and the Canada Foundation for Innovation (Grant #222084) for purchase of the micro‐computed tomography system.