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Positive impact of low-dose, high-energy radiation on bone in partial- and/or full-weightbearing mice.

ABSTRACT: Astronauts traveling beyond low Earth orbit will be exposed to galactic cosmic radiation (GCR); understanding how high energy ionizing radiation modifies the bone response to mechanical unloading is important to assuring crew health. To investigate this, we exposed 4-mo-old female Balb/cBYJ mice to an acute space-relevant dose of 0.5?Gy ⁵⁶Fe or sham (n?=?~8/group); 4 days later, half of the mice were also subjected to a ground-based analog for 1/6?g (partial weightbearing) (G/6) for 21 days. Microcomputed tomography (µ-CT) of the distal femur reveals that ⁵⁶Fe exposure resulted in 65-78% greater volume and improved microarchitecture of cancellous bone after 21?d compared to sham controls. Radiation also leads to significant increases in three measures of energy absorption at the mid-shaft femur and an increase in stiffness of the L4 vertebra. No significant effects of radiation on bone formation indices are detected; however, G/6 leads to reduced % mineralizing surface on the inner mid-tibial bone surface. In separate groups allowed 21 days of weightbearing recovery from G/6 and/or ⁵⁶Fe exposure, radiation-exposed mice still exhibit greater bone mass and improved microarchitecture vs. sham control. However, femoral bone energy absorption values are no longer higher in the ⁵⁶Fe-exposed WB mice vs. sham controls. We provide evidence for persistent positive impacts of high-LET radiation exposure preceding a period of full or partial weightbearing on bone mass and microarchitecture in the distal femur and, for full weightbearing mice only and more transiently, cortical bone energy absorption values.

SUBMITTER: Bokhari RS

PROVIDER: S-EPMC6547738 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Positive impact of low-dose, high-energy radiation on bone in partial- and/or full-weightbearing mice.

Bokhari Rihana S RS Metzger Corinne E CE Black Jeremy M JM Franklin Katherine A KA Boudreaux Ramon D RD Allen Matthew R MR Macias Brandon R BR Hogan Harry A HA Braby Leslie A LA Bloomfield Susan A SA

NPJ microgravity 20190604

Astronauts traveling beyond low Earth orbit will be exposed to galactic cosmic radiation (GCR); understanding how high energy ionizing radiation modifies the bone response to mechanical unloading is important to assuring crew health. To investigate this, we exposed 4-mo-old female Balb/cBYJ mice to an acute space-relevant dose of 0.5 Gy <sup>56</sup>Fe or sham (<i>n</i> = ~8/group); 4 days later, half of the mice were also subjected to a ground-based analog for 1/6 g (partial weightbearing) (G/6 ...[more]

PMID: 31231675

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Dataset Information

Positive impact of low-dose, high-energy radiation on bone in partial- and/or full-weightbearing mice.

Publications

Positive impact of low-dose, high-energy radiation on bone in partial- and/or full-weightbearing mice.

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