Effects of h-PTH on cancellous bone mass, connectivity, and bone strength in ovariectomized rats with and without sciatic-neurectomy

KASUKAWA, Y

doi:10.1016/s0736-0266(03)00215-8

Cited by 6 publications

(6 citation statements)

References 25 publications

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“…Seven-monthold female Wistar rats (Japan SLC, Inc., Shizuoka, Japan) were housed in a controlled environment with temperature maintained at 23°C ± 2°C and humidity at 50 ± 10% under a 12-hour light-dark cycle. The rats were allowed free access to tap water and commercial standard rodent chow (CE-7), containing 0.94% calcium, 0.96% phosphate, and 2.0 IU/g of vitamin D 3 (Clea Japan Inc., Tokyo, Japan) as in our previous studies (27,35). Rats underwent ovariectomy (OVX) or a sham operation under anesthesia with sodium pentobarbital (Dainippon Sumitomo Pharma Co. Ltd., Osaka, Japan).…”

Section: Methodsmentioning

confidence: 99%

Effects of alfacalcidol on muscle strength, muscle fatigue, and bone mineral density in normal and ovariectomized rats

et al. 2010

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Vitamin D affects not only bone but also muscle to prevent falls and osteoporotic fractures. However, these effects on muscle and the mechanisms of fall prevention are still unclear. The purpose of this study was to investigate the effects of alfacalcidol [1α(OH)D 3 ] on muscle strength, muscle fatigue, and bone mineral density (BMD) in ovariectomized rats. Seven-month-old female Wistar rats were orally administered 1α(OH)D 3 or its vehicle everyday for 4 weeks after ovariectomy (OVX) or sham operation. Calf muscle strength and fatigue were evaluated by electrical stimulation of the sciatic nerve under general anesthesia. 1α(OH)D 3 administration significantly increased the maximum muscle strength in the sham-operated (P < 0.01) and the OVX (P < 0.01) groups compared to their respective control groups. However, 1α(OH)D 3 administration did not significantly affect muscle fatigue in these groups. The BMD of the femur in the 1α(OH)D 3 -treated OVX group was significantly higher than that in the vehicle-treated OVX group (P = 0.04). These results suggested that 1α(OH)D 3 increases muscle strength but does not affect muscle fatigue in this rat model. The effectiveness of activated vitamin D in preventing bone fractures may be partly owing to its effect on muscle strength in addition to its known effect on bone metabolism.The active, hormonal form of vitamin D 1,25-dihydroxyvitamin D 3 [1,25(OH) 2 D 3 or calcitriol] and its prodrug 1α-hydroxyvitamin D 3 [1α(OH)D 3 or alfacalcidol] have been widely used to treat a variety of metabolic bone diseases, such as rickets/osteomalacia, renal osteodystrophy, and osteoporosis (8, 41). Activated vitamin D can prevent fractures by improving bone quality, bone metabolism, and bone mineral density (BMD) (7,22,40,45,50). However, its preventive effects on fractures were more significant than its effects on bone quality or BMD. Several recent meta-analyses have demonstrated that native or activated vitamin D has preventive effects on falls (2, 16). This preventive effect on falls contributes to a partial reduction of fractures by vitamin D in elderly osteoporotic individuals (3, 37). However, the mechanisms by which activated vitamin D prevents falls remain unknown. Several factors have been reported as physical risk factors for falls, including decreased muscle strength or function of lower extremity, impaired physical function such as single-leg standing, and postural imbalance with aging (26,28,34,36). Vitamin D may act directly on muscle tissue to exert its preventive effect on falls. It has been known that osteomalacia and rickets cause muscular atrophy and decrease muscle strength and that the muscular symptoms associated with these diseases quickly improve with vitamin D treatment (39, 43). These findings indicate a potential association between vitamin D and muscle tissue. Therefore, the effects of vitamin D on muscle tissue with regard to fall prevention have been of focus in aged and osteoporotic patients. Muscle function is defined by several factors, including mu...

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Section: Methodsmentioning

confidence: 99%

Effects of alfacalcidol on muscle strength, muscle fatigue, and bone mineral density in normal and ovariectomized rats

et al. 2010

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“…Six-month-old female Wistar rats (Clea Japan Inc., Tokyo, Japan) were housed in a controlled environment (temperature, 23 ± 2°C; humidity, 40 ± 20%) with a 12-h lightdark cycle. Rats were allowed ad libitum access to tap water and commercial standard rodent chow (CE-7; Clea Japan Inc., Tokyo, Japan) (23,30). Rats were randomized into the following four groups (n = 6-7 each): 1) control group, administered vehicle of alfacalcidol and vehicle of prednisolone; 2) PSL group, administered prednisolone and vehicle of alfacalcidol; 3) D group, administered alfacalcidol and vehicle of prednisolone; and 4) PSL+D group, administered prednisolone and alfacalcidol.…”

Section: Methodsmentioning

confidence: 99%

Effects of a vitamin D analog, alfacalcidol, on bone and skeletal muscle in glucocorticoid-treated rats

et al. 2010

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Glucocorticoids cause secondary osteoporosis and myopathy. The efficacy of vitamin D on osteoporotic fractures is thought to be through direct effects on bone and indirect effects on muscles that help to prevent falls. However, effects of vitamin D on muscles under glucocorticoid treatment remain unclear. Six-month-old female Wistar rats were randomized to four groups: vehicletreated controls; a prednisolone (PSL)-administered group (PSL group); an alfacalcidol-administered group (D group); and a group administered both PSL and alfacalcidol (PSL+D group). After a 4-week treatment period, maximum contractile strength and strength decrement index (SDI), an indicator of muscle fatigue, were measured in the calf muscle by electrical stimulation of the sciatic nerve. Cross-sectional area (CSA) of muscle fibers in the tibialis anterior muscle and bone mineral density (BMD) of the femur were evaluated. The PSL group showed significantly lower muscle strength, BMD and CSA of muscle fibers, and significantly higher SDI compared to the other three groups (P < 0.05). No significant differences were observed in any of these parameters among control, D, and PSL+D groups. These results suggest that in glucocorticoid-treated rats, alfacalcidol preserved not only BMD, but also muscle strength and muscle volume, and prevented muscle fatigue.

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“…There might also be compartment‐specific effects . In studies regarding PTH treatment during conditions of disuse, there are also some conflicting results . Some studies suggest that PTH is able to reduce bone loss resulting from disuse, whereas other studies show that disuse attenuates the effects of PTH .…”

Section: Introductionmentioning

confidence: 99%

The effect of PTH(1-34) on fracture healing during different loading conditions

Ellegaard

Kringelbach

Syberg

et al. 2013

Journal of Bone and Mineral Research

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Parathyroid hormone (PTH) and PTH(1-34) have been shown to promote bone healing in several animal studies. It is known that the mechanical environment is important in fracture healing. Furthermore, PTH and mechanical loading has been suggested to have synergistic effects on intact bone. The aim of the present study was to investigate whether the effect of PTH(1-34) on fracture healing in rats was influenced by reduced mechanical loading. For this purpose, we used female, 25-week-old ovariectomized rats. Animals were subjected to closed midshaft fracture of the right tibia 10 weeks after ovariectomy. Five days before fracture, half of the animals received Botulinum Toxin A injections in the muscles of the fractured leg to induce muscle paralysis (unloaded group), whereas the other half received saline injections (control group). For the following 8 weeks, half of the animals in each group received injections of hPTH(1-34) (20 mg/kg/day) and the other half received vehicle treatment. Fracture healing was assessed by radiology, dual-energy X-ray absorptiometry (DXA), histology, and bone strength analysis. We found that unloading reduced callus area significantly, whereas no effects of PTH(1-34) on callus area were seen in neither normally nor unloaded animals. PTH(1-34) increased callus bone mineral density (BMD) and bone mineral content (BMC) significantly, whereas unloading decreased callus BMD and BMC significantly. PTH(1-34) treatment increased bone volume of the callus in both unloaded and control animals. PTH(1-34) treatment increased ultimate force of the fracture by 63% in both control and unloaded animals and no interaction of the two interventions could be detected. PTH(1-34) was able to stimulate bone formation in normally loaded as well as unloaded intact bone. In conclusion, the study confirms the stimulatory effect of PTH(1-34) on fracture healing, and our data suggest that PTH(1-34) is able to promote fracture healing, as well as intact bone formation during conditions of reduced mechanical loading.

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Effects of h-PTH on cancellous bone mass, connectivity, and bone strength in ovariectomized rats with and without sciatic-neurectomy

Cited by 6 publications

References 25 publications

Effects of alfacalcidol on muscle strength, muscle fatigue, and bone mineral density in normal and ovariectomized rats

Effects of alfacalcidol on muscle strength, muscle fatigue, and bone mineral density in normal and ovariectomized rats

Effects of a vitamin D analog, alfacalcidol, on bone and skeletal muscle in glucocorticoid-treated rats

The effect of PTH(1-34) on fracture healing during different loading conditions

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