کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5890360 1568152 2014 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Temporal changes in systemic and local expression of bone turnover markers during six months of sclerostin antibody administration to ovariectomized rats
ترجمه فارسی عنوان
تغییرات موقتی در بیان سیستمیک و محلی مارکرهای گردش استخوان طی شش ماه تزریق آنتی بادی اسکلروزین به موشهای تخمدان
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شناسی تکاملی
چکیده انگلیسی


- Scl-Ab administration to mature OVX rats increased bone formation and bone volume.
- Stimulation of bone formation was greater after 6 versus 26 weeks of Scl-Ab administration.
- Scl-Ab administration decreased bone resorption parameters through 26 weeks.
- Skeletal expression of numerous osteocyte genes was increased by Scl-Ab administration, with sost showing the greatest induction.
- Increased skeletal sost expression may contribute to the attenuation of anabolic responses to Scl-Ab with longer-term administration.

Sclerostin (Scl) is an osteocyte protein that decreases bone formation, and its inhibition by neutralizing antibodies (Scl-Ab) increases bone formation, mass and strength. We investigated the effects of Scl-Ab in mature ovariectomized (OVX) rats with a mechanistic focus on longer-term responses of osteoclasts, osteoblasts and osteocytes. Four-month-old Sprague-Dawley rats had OVX or sham surgery. Two months later, sham controls received sc vehicle while OVX rats received vehicle (OVX-Veh) or Scl-Ab (25 mg/kg) once weekly for 6 or 26 weeks followed by necropsy (n = 12/group). Terminal blood was collected for biochemistry, non-adherent marrow cells were harvested from femurs for ex vivo osteoclast formation assays, and vertebrae and tibiae were collected for dynamic histomorphometry and mRNA analyses. Scl-Ab treatment led to progressively thicker but fewer trabeculae in the vertebra, leading to increased trabecular bone volume and reduced trabecular surfaces. Scl-Ab also increased cortical bone volume in the tibia, via early periosteal expansion and progressive endocortical contraction. Scl-Ab significantly reduced parameters of bone resorption at week 6 relative to OVX-Veh controls, including reduced serum TRACP-5b, reduced capacity of marrow cells to form osteoclasts ex vivo, and > 80% reductions in vertebral trabecular and tibial endocortical eroded surfaces. At week 26, serum TRACP-5b and ex vivo osteoclast formation were no longer reduced in the Scl-Ab group, but eroded surfaces remained > 80% lower than in OVX-Veh controls without evidence for altered skeletal mRNA expression of opg or rankl. Scl-Ab significantly increased parameters of bone formation at week 6 relative to OVX-Veh controls, including increases in serum P1NP and osteocalcin, and increased trabecular, endocortical and periosteal bone formation rates (BFRs). At week 26, surface-referent trabecular BFR remained significantly increased in the Scl-Ab group versus OVX-Veh controls, but after adjusting for a reduced extent of trabecular surfaces, overall (referent-independent) trabecular BFR was no longer significantly elevated. Similarly, serum P1NP and osteocalcin were no longer significantly increased in the Scl-Ab group at week 26. Tibial endocortical and periosteal BFR were increased at week 6 in the Scl-Ab group versus OVX-Veh controls, while at week 26 only endocortical BFR remained increased. The Scl-Ab group exhibited significant increments in skeletal mRNA expression of several osteocyte genes, with sost showing the greatest induction in both the tibia and vertebra. We propose that Scl-Ab administration, and/or the gains in bone volume that result, may have increased osteocytic expression of Scl as a possible means of regulating gains in bone mass.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Bone - Volume 67, October 2014, Pages 305-313
نویسندگان
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