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Temperature Enhanced Extremity Lengthening is Growth Rate Dependent
Author(s) -
Kerby Jenna,
Gray Miles,
Tamski Holly,
Heaberlin Aaron,
Crow Nathaniel,
Ion Gabriela,
Serrat Maria
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.686.5
Subject(s) - elongation , growth rate , weaning , medicine , zoology , surgery , biology , materials science , mathematics , geometry , metallurgy , ultimate tensile strength
Limb length inequality is a potentially disabling condition with few noninvasive treatment options. Our lab has previously shown that unilateral heat increases bone elongation rate, suggesting that temperature therapy could be a non‐surgical way to promote limb length equalization. Treatment age is important because we have shown that temperature effects occur primarily when growth is most rapid. We compared heat effects on limb lengthening during early (3‐5 weeks age) and late (5‐7 weeks age) phases of post‐weaning growth in mice (N=24). We tested the hypothesis that heat‐induced limb elongation varies with postnatal growth rate. Female mice (N=6 per age) were treated with 40C unilateral heat for 40 minutes per day for 14 days. Controls (N=6 per age) were not treated. Tibial elongation rate, measured by fluorochrome labeling, was over two‐fold greater during the early phase. Bone elongation rate reflected overall body growth rate, with lower absolute heat‐induced differences during the later phase. Relative increases in extremity length on the heat‐treated side were similar during early and late phases, suggesting that a heat‐induced growth response is still possible during later postnatal growth. These results are important for designing therapies to treat children with linear growth disorders at different stages of development by demonstrating that treatments may not be restricted to early growth phases. Supported by ASBMR GAP, WV‐NASA, UK‐CCTS (NIH UL1TR000117), and NIH/NIAMS R15AR067451‐01.