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Effects of hindlimb unweighting on estrogen replete and deficient mice
Author(s) -
Crissey Jacqueline Marie,
Ferreira J Andries,
Brown Marybeth
Publication year - 2010
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.24.1_supplement.821.8
Subject(s) - endocrinology , medicine , estrogen , hindlimb , chemistry , muscle atrophy , skeletal muscle , atrophy , aromatase , biology , cancer , breast cancer
Skeletal muscle atrophy is often debilitating. In women the decline in lean muscle mass accelerates at the onset of menopause due in part to lower estrogen (E2) levels. We evaluated the role of E2 to regulate skeletal muscle mass and maintain contractile function over 14 days of hindlimb unloading (HU) and 3 days of reloading (REC) in E2 replete (estrogen receptor‐α knock‐out, ERαKO) and E2 deficient (aromatase knockout, ARKO) mice, compared to wild type (WT) animals. Mice were separated into 3 groups: 1) CON: ambulatory controls, 2) HU: 14days of HU, 3) REC: 14 days of HU + 3 days REC. We observed differential effects on body weight (BW) after HU and REC. BW significantly decreased in ARKO mice (−10.9%) and ERαKO (−10.5%) after HU, while BW of WT mice was not different. Neither ARKO nor ERαKO recovered to pre‐HU BW values following REC. Expected declines in muscle mass of soleus (SOL), plantaris (PLAN), gastrocnemius (GAS), and tibialis anterior (TA) in WT mice after HU ( Table 1) were observed. ARKO mice trended towards losing more muscle mass during HU and recovered slower than WT. 1 Percent atrophy of muscle mass loss in HU & REC compared to CON.WT SOL PLAN GAS TAHU −38 −20 −15 −11REC −18 −6 −6 −2ARKO SOL PLAN GAS TAHU −43 −30 −23 −12REC −34 −17 −19 −15ERαKO SOL PLAN GAS TAHU −46 −9 −15 −4REC −25 −7 −7 −8The ERαKO muscle mass profile resembled that of WT mice, suggesting that the presence of E2 rather than the absence of ERα mediates estrogen effects during HU and REC. These data suggest that estrogen deficiency slows skeletal muscle mass recovery. Support: HD‐058834 & University of MO Life Sciences Fellowship.