Sonne Christian, Wolkers Hans, Rigét Frank F, Jensen Jens-Erik Beck, Teilmann Jenni, Jenssen Bjørn Munro, Fuglei Eva, Ahlstrøm Øystein, Dietz Rune, Muir Derek C G, Jørgensen Even H
Department of Arctic Environment, National Environmental Research Institute, University of Aarhus, Roskilde, Denmark.
Comp Biochem Physiol C Toxicol Pharmacol. 2009 Jan;149(1):97-103. doi: 10.1016/j.cbpc.2008.07.015. Epub 2008 Aug 3.
We investigated the impact from dietary OC (organochlorine) exposure and restricted feeding (emaciation) on bone mineral density (BMD; g hydroxy-apatite cm(-2)) in femoral, vertebrate, skull and baculum osteoid tissue from farmed Arctic blue foxes (Vulpes lagopus). For femur, also biomechanical properties during bending (displacement [mm], load [N], energy absorption [J] and stiffness [N/mm]) were measured. Sixteen foxes (EXP) were fed a wet food containing 7.7% OC-polluted minke whale (Balaenoptera acutorostrata) blubber in two periods of body fat deposition (Aug-Dec) and two periods of body fat mobilisation (Jan-July) in which the food contained less energy and only 2% blubber. SigmaOC food concentration in the food containing 7.7% whale blubber was 309 ng/g wet mass. This corresponded to a SigmaOC exposure of ca. 17 microg/kg body mass/d and a responding SigmaOC residue in subcutaneous adipose tissue of ca. 1700 ng/g live mass in the 8 EXP fat foxes euthanized after 16 months. A control group (CON) composed of 15 foxes were fed equal daily caloric amounts of clean pork (Sus scrofa) fat. After 16 months, 8 EXP and 7 CON foxes were euthanized (mean body mass=9.25 kg) while the remaining 8 EXP and 8 CON foxes were given restricted food rations for 6 months resulting in a body weight reduction (mean body mass=5.46 kg). The results showed that only BMD(skull) vs. BMD(vertebrae) were significantly correlated (R=0.68; p=0.03; n=10) probably due to a similar composition of trabecular and cortical osteoid tissue. No difference in any of the BMD measurements or femoral biomechanical properties was found between EXP and CON foxes although BMD baculum was 1.6-folds lower in the EXP group. However, lean summer foxes had significantly lower femoral biomechanical properties measured as displacement (mm), energy absorption (J) and time (s) biomechanical properties than fat winter foxes (all p<0.004). This indicates lower stiffness and softer bones from fasting which is in agreement with previous studies. Further, it should be kept in mind when studying bone tissues in Arctic mammals also in order to avoid confounding effects from body condition.
我们研究了膳食有机氯（OC）暴露和限食（消瘦）对养殖北极蓝狐（Vulpes lagopus）股骨、椎骨、颅骨和阴茎骨类骨质组织中骨矿物质密度（BMD；克羟基磷灰石/平方厘米）的影响。对于股骨，还测量了弯曲过程中的生物力学特性（位移[毫米]、负荷[牛顿]、能量吸收[焦耳]和刚度[牛顿/毫米]）。16只狐狸（实验组）在两个体脂沉积期（8月至12月）和两个体脂动员期（1月至7月）喂食含有7.7%受OC污染的小须鲸（Balaenoptera acutorostrata）鲸脂的湿粮，其中食物能量较低且仅含2%的鲸脂。含7.7%鲸脂的食物中总有机氯食物浓度为309纳克/克湿质量。这相当于约17微克/千克体重/天的总有机氯暴露量，在16个月后安乐死的8只实验组肥胖狐狸的皮下脂肪组织中相应的总有机氯残留量约为1700纳克/克活质量。由15只狐狸组成的对照组（对照组）每天喂食热量相等的干净猪（Sus scrofa）脂肪。16个月后，8只实验组和7只对照组狐狸被安乐死（平均体重=9.25千克），而其余8只实验组和8只对照组狐狸被限制喂食6个月，导致体重减轻（平均体重=5.46千克）。结果表明，只有BMD（颅骨）与BMD（椎骨）显著相关（R = 0.68；p = 0.03；n = 10），可能是由于小梁和皮质类骨质组织的组成相似。实验组和对照组狐狸在任何BMD测量值或股骨生物力学特性方面均未发现差异，尽管实验组阴茎骨的BMD低1.6倍。然而，瘦的夏季狐狸以位移（毫米）、能量吸收（焦耳）和时间（秒）生物力学特性衡量的股骨生物力学特性明显低于胖的冬季狐狸（所有p<0.004）。这表明禁食导致骨骼刚度降低和更软，这与先前的研究一致。此外，在研究北极哺乳动物的骨组织时也应牢记这一点，以避免身体状况产生的混杂效应。
