Vitamin C deficiency deteriorates bone microarchitecture and mineralization in a sex-specific manner in adult mice.

Vitamin C (VitC) is essential for bone health and low VitC serum levels increase the risk for skeletal fractures. If and how VitC affects bone mineralization is unclear. Using micro-computed tomography (μCT), histologic staining as well as quantitative backscattered electron imaging (qBEI) we assessed the effects of VitC on femoral structure and microarchitecture, bone formation and bone mineralization density distribution (BMDD) in the VitC incompetent Gulo -/- mouse model and wild-type mice. In particular, VitC supplemented, 20 week-old mice were compared to age-matched counterparts where dietary VitC intake was excluded from week 15. VitC depletion in Gulo -/- mice severely reduced cortical thickness of the diaphyseal shaft and bone volume around the growth plate (e.g., BV/TV of primary spongiosa -43%, p < 0.001). Loss of VitC also diminished the amount of newly formed bone tissue as visualized by histology and calcein labeling of the active mineralization front. BMDD analysis revealed a shift to higher calcium concentrations upon VitC supplementation including higher average (~10% increase in female mice, p < 0.001) and peak calcium concentrations in the epiphyseal and metaphyseal spongiosa. These findings suggest higher bone tissue age. Importantly, VitC has significantly more pronounced effects in female mice indicating a higher sensitivity of their skeleton to VitC deficiency. Our results reveal that VitC plays a key role in bone formation rate which directly affects mineralization. We propose that low VitC levels may contribute to the higher prevalence of bone degenerative diseases in females and suggest leveraging this vitamin against these conditions.