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We investigated the combinatorial effects of whole-body vertical vibration (WBVV) with the primarily osteoanabolic parathyroid hormone (PTH) and the mainly antiresorptive strontium ranelate (SR) in a rat model of osteoporosis. Ovariectomies were performed on 76 three-month-old Sprague-Dawley rats (OVX, n = 76; NON-OVX, n = 12). After 8 weeks, the ovariectomized rats were divided into 6 groups. One group (OVX + PTH) received daily injections of PTH (40 µg/kg body weight/day) for 6 weeks. Another group (OVX + SR) was fed SR-supplemented chow (600 mg/kg body weight/day). Three groups (OVX + VIB, OVX + PTH + VIB, and OVX + SR + VIB) were treated with WBVV twice a day at 70 Hz for 15 min. Two groups (OVX + PTH + VIB, OVX + SR + VIB) were treated additionally with PTH and SR, respectively. The rats were killed at 14 weeks post-ovariectomy. The lumbar vertebrae and femora were removed for biomechanical and morphological assessment. PTH produced statistically significant improvements in biomechanical and structural properties, including bone mineral density (BMD) and trabecular bone quality. In contrast, SR treatment exerted mild effects, with significant effects in cortical thickness only. SR produced no significant improvement in biomechanical properties. WBVV as a single or an adjunctive therapy produced no significant improvements. In conclusion, vibration therapy administered as a single or dual treatment had no significant impact on bones affected by osteoporosis. PTH considerably improved bone quality in osteoporosis cases and is superior to treatment with SR.

Purpose: Management of hypogonadism-induced osteoporosis in elderly men is still a challenge. We investigated the short-term effects of parathyroid hormone (PTH) treatments on strength, micro-architecture, and mineral density of trochanteric region of orchiectomized rat femur., Methods: Eight-month-old male Sprague-Dawley rats (n = 44) were divided into two groups: (1) orchiectomized (ORX) and (2) sham group. Twelve weeks after orchiectomy, half of the orchiectomized animals were treated with daily subcutaneously injected PTH (0.040 mg/kg/BW) (ORX-PTH) for 5 weeks. The other half remained untreated (ORX). The sham-operated group was divided and treated in the same way (sham, sham-PTH). After 5 weeks, both femurs were excised for biomechanical and histomorphometric analysis, trabecular measurements, mineral content assessment, and immunofluorescence analysis., Results: The femoral trochanteric strength after PTH treatment was enhanced in the breaking test (ORX-F(max) = 158.7 N vs. ORX + PTH-F(max) = 202 N). Stiffness of treated ORX animals reached nearly the levels observed in untreated sham rats. PTH therapy improved the trabecular connectivity, width, and area (ORX-Tb.Ar = 47.79% vs. ORX + PTH-Tb.Ar = 68.47%, P < 0.05) in the proximal femur. The treated rats showed significantly improved mineral content in ashed femurs (ORX-mineral content = 43.73% vs. ORX + PTH-mineral content = 49.49%) when compared to the untreated animals. A comparison of widths of fluorescence bands in cortical bone of the subtrochanteric cross-sections showed a significant increase in oppositions after the PTH therapy., Conclusions: Our finding supports the hypothesis that PTH therapy seems to be a rational therapy in patients with hypogonadism induced bone loss and improves the bone strength of trochanteric region of rat femur.

Influence of human parathyroid hormone (hPTH 1-34) on muscle and bone healing was studied in either orchiectomized (Orx at 8 months of age) or sham-operated male rats. Eleven-month-old Sprague-Dawley rats underwent bilateral transverse metaphyseal osteotomy of tibia and were divided into four groups (n=12): 1) sham-vehicle, 2) sham group-PTH everyday, 3) Orx-vehicle, 4) Orx-PTH everyday, and 5) Orx-PTH every other day. PTH dosage was 40  μg/kg body weight. After 5 weeks, fiber cross-sectional area, capillary density, and enzyme activity (lactate dehydrogenase, citrate synthase, and complex I) were measured in soleus (MS), gastrocnemius (MG), and longissimus (ML) muscles; tibiae were analyzed by computed tomographical, histological, and gene expression analyses. The effect of PTH in all rats was increased serum osteocalcin, cortical and callus densities and callus area. In sham rats capillary density was increased in limb muscles (MS: 1.3-1.7, MG: 1.2-1.4 capillaries/fiber), and rate of osseous bridging of osteotomy was enhanced (67-100%). In Orx rats serum creatine kinase was decreased (6670-2847 U/l), and bone genes (Igf-1, osteoprotegerin, and receptor activator of nuclear factor kB ligand) were up-regulated. Cross-sectional area, enzyme activity, food intake, weight of body, visceral organs, adipose tissue, MG, and MS were not affected by PTH. PTH had a favorable effect on muscle capillary density and improved bone healing being more effective in sham rats and having no adverse systemic effect. The effect was less if PTH was applied every other day. The findings may show up trends for therapeutic treatment of male patients.

Unlabelled: We have examined the changes induced in the trochanteric region of femur of ovariectomized rat after administration of estradiol and parathyroid hormone. We have developed a reproducible biomechanical test and produced trochanteric fractures to evaluate stiffness and strength of this region in addition to histomorphometry., Introduction: We investigated the short-term effects of parathyroid hormone (PTH) and estrogen (E) on the strength of the rat trochanteric region in a new mechanical test., Methods: Forty-four 3-month-old female Sprague-Dawley rats were ovariectomized and 8 weeks later treated with soy-free diet (C), daily applications of orally supplied E (0.5 mg/kg food) or subcutaneously injected PTH (0.014 mg/kg), for 5 weeks, and an additional untreated group was added as sham-operated. The femurs were examined for biomechanical and histomorphometric changes., Results: Our new mechanical test was validated in a right-left comparison. The PTH treatment induced significantly superior biomechanical results (F (max) = 225.3 N, stiffness = 314.9 N/mm) compared to E (F (max) = 182.9 N, stiffness = 237.2 N/mm), C (F (max) = 166.03 N, stiffness = 235.56 N/mm), and sham (F (max) = 192.1 N, stiffness = 267.2 N/mm). Animals of the PTH group demonstrated a significantly improved trabecular bone structure and area (75.67%) in comparison to the E (61.04%) and C (57.18%) groups., Conclusion: Our new biomechanical test is valid and produces trochanteric fracture. Our results show that the short-term antiosteoporotic effects of PTH are in the trochanteric region of ovariectomized rat superior to E.

Study Design: This study is an experimental study in the rat osteopenia model., Objective: The aim of this study was to evaluate the short-term effects of daily application of parathyroid hormone (PTH) on bone quality and quantity using a new biomechanical compression test for intact rat lumbar vertebrae., Summary of Background Data: Because of their high clinical relevance, trabecular content and thick cortical shell vertebrae are of high interest for osteoporosis research. Biomechanical stability depends on both trabecular and cortical bone. Anabolic effects on bone after long-term application of PTH have already been proven., Methods: After an intraindividual comparison (n = 20), the capability of a new test to identify biomechanical properties of the mature rat model was assessed. In the following, 33 three-month-old rats were ovariectomized. After 10 weeks, the animals were divided into 3 groups. The control group (C) received no additional food supplementation. The other groups received hormone treatment with either estradiol (E) or PTH for another 5 weeks. The effects on bone biomechanical properties and bone microstructure were analyzed., Results: After establishing the new biomechanical test for intact rat lumbar vertebrae, PTH-treated (yield stress: 2.95 N/mm, elastic limit: 2.39 N/mm) and then E-treated (yield stress: 2.13 N/mm, elastic limit: 1.68 N/mm) animals showed superior biomechanical results. Compression strength was significantly improved in these rats in comparison to the control group rats (yield stress: 1.86 N/mm, elastic limit: 1.38 N/mm). In the microradiographic evaluation, PTH significantly improved the morphologic results to produce thicker trabeculae. E led to a more densely branched trabecular network, which was not as important as trabecular thickness for bone stability., Conclusion: After a short-term application, PTH is superior to E in recreating bone biomechanical propertiesand lumbar vertebral microstructure in advanced osteoporosis. The cortical shell and trabecular thickness are primarily responsible for the biomechanical strength of vertebrae.

This study aims to investigate the effects of two application frequencies of parathyroid hormone on the trochanteric region of rat femur. Forty-three-month-old female Sprague-Dawley rats were divided into 4 groups (n = 10/group). Three groups were ovariectomized, and 8 weeks later they were administered the following treatments (5 weeks): soy-free diet (OVX), subcutaneously injected PTH (0.040 mg/kg) 5 days a week (PTH 5x/w), subcutaneously injected PTH (0.040 mg/kg) every 2 days (PTH e2d), and a sham group. The values of the biomechanical and histomorphometric parameters showed higher results in 5x/w animals in comparison to the OVX and PTH 2ed groups. The ratio between bone diameter/marrow diameter (B.Dm/Ma.Dm) in subtrochanteric cross sections did not show any significant differences between PTH 5x/w and PTH e2d. The increased bone formation rate was observed under PTH treatment in both groups mainly at the endosteal side. The endosteum seems here to be one of the targets of PTH with an accelerate bone formation and a pronounced filling-in of intracortical cavities with higher intensity for the PTH 5x/w in comparison to PTH e2d rats. [ABSTRACT FROM AUTHOR]