Tag Archives: animal

Taurine No Benefit in Calcium Deficient Rats

Abstract

Effects of taurine supplementation on bone mineral density in ovariectomized rats fed calcium deficient diet.

Taurine supplementation has been shown to have a beneficial effect on femur bone mineral content in ovariectomized rats. It therefore seemed desirable to find out whether the beneficial effect of taurine on ovariectomized rats fed calcium deficient diet could also be reproduced. Forty female Sprague-Dawley rats were divided into two groups. One group was OVX and the other group received sham operation (SHAM), and received either control diet or a taurine supplemented diet for 6 weeks. All rats were fed on calcium deficient diet (AIN-93: 50% level of calcium) and deionized water. Bone mineral density (BMD) and bone mineral content (BMC) were measured in spine and femur. The serum and urine concentrations of calcium and phosphorus were determined. Bone formation was measured by serum osteocalcin and alkaline phosphatase (ALP) concentrations. Bone resorption rate was measured by deoxypyridinoline (DPD) crosslinks immunoassay and corrected for creatinine. Urinary calcium and phosphorus excretion, osteocalcin in blood and cross link value were not significantly different among the groups. Within the OVX group, the taurine supplemented group had not higher femur bone mineral content than the control group. This study established the need for a study on the taurine effect on bone with different calcium levels.

Choi MJ
Nutr Res Pract 2009
PMID: 20016710 | Free Full Text

This experiment was originally designed to test the ability of a taurine supplement to minimize bone loss during postmenopausal model with low calcium intake. Sulfur is predominantly responsible for determining the net endogenous acid production from protein because it is the acid precursor that is oxidized to sulfuric acid (Frassetto et al., 1998). It would therefore make sense that a dietary supplement with excess sulfur-containing amino acids (taurine) could yield increased sulfuric acid production in the body. However, these data suggest that bone mineral density per weight was increased, without changes in bone resorption and bone formation, in the taurine supplemented group, and therefore have the potential to increase bone mineral density if either the study is extended or more taurine is supplemented. The beneficial effect of taurine on ovariectomized rats fed calcium deficient diet was not reproduced. Because in this study, the control and taurine groups consumed identical diets as in the previous study (besides the calcium content), and we do not know whether intestinal calcium absorption will be increased by more taurine supplement. These results indicate that no significant differences in spine and femur BMD were found due to 2% taurine diet in OVX rats fed calcium deficient diet for 6 weeks. No positive effects of taurine on bone mineral density were found in the present study. Our failure to see an association between taurine supplementation and bone mineral density may have been related to the fact that we used calcium deficient diet and the same amount of taurine. Further investigations of the relation between taurine and calcium intake level for bone mineral density are warranted.

Phloridzin Prevents Bone Loss in Ovariectomized Rats

Abstract

Prevention of bone loss by phloridzin, an apple polyphenol, in ovariectomized rats under inflammation conditions.

Aging and sex hormones related changes lead to inflammatory and oxidant conditions, which are involved in the pathogenesis of osteoporosis. Recent studies have suggested that polyphenols may exert a protective effect in such conditions. We assessed the effect of phloridzin (Phlo), a flavonoid exclusively found in apple, on bone metabolism in ovariectomized (OVX) or sham-operated (SH) rats with and without inflammation. Six-month-old Wistar rats were allocated to two equal groups that received either a control diet or a diet supplemented with 0.25% Phlo for 80 days. Three weeks before necropsy, inflammation was induced by subcutaneous injection of talc in 10 animals of each group. At necropsy, ovariectomy decreased both total (T-BMD) and metaphyseal (M-BMD) femoral bone mineral density (P < 0.01). Inflammation conditions, checked by an increase in the spleen weight and alpha1-acid glycoprotein concentration in OVX rats, exacerbated the decrease in T-BMD (g/cm2) (as well as M-BMD) observed in castrated animals (P < 0.05). Daily Phlo intake prevented ovariectomy-induced bone loss in conditions of inflammation as shown by T-BMD and M-BMD (P < 0.05). At the diaphyseal site, BMD was improved by Phlo in OVX rats with or without inflammation (P < 0.05). These results could be explained by changes in bone remodeling as the increased urinary deoxypyridinoline excretion in OVX and OVXinf animals was prevented by the polyphenol-rich diet (P < 0.001), while plasma osteocalcin concentration was similar in all experimental groups. In conclusion, Phlo consumption may provide protection against ovariectomy-induced osteopenia under inflammation conditions by improving inflammation markers and bone resorption.

Puel C, Quintin A, Mathey J, Obled C…
Calcif. Tissue Int. Nov 2005
PMID: 16307390

Autophagy Appears to Benefit Bones in Mice

Abstract

Suppression of autophagy in osteocytes mimics skeletal aging.

Bone mass declines with age but the mechanisms responsible remain unclear. Here we demonstrate that deletion of a conditional allele for Atg7, a gene essential for autophagy, from osteocytes caused low bone mass in 6-month-old male and female mice. Cancellous bone volume and cortical thickness were decreased, and cortical porosity increased, in conditional knock-out mice compared with control littermates. These changes were associated with low osteoclast number, osteoblast number, bone formation rate, and wall width in the cancellous bone of conditional knock-out mice. In addition, oxidative stress was higher in the bones of conditional knock-out mice as measured by reactive oxygen species levels in the bone marrow and by p66(shc) phosphorylation in L6 vertebra. Each of these changes has been previously demonstrated in the bones of old versus young adult mice. Thus, these results demonstrate that suppression of autophagy in osteocytes mimics, in many aspects, the impact of aging on the skeleton and suggest that a decline in autophagy with age may contribute to the low bone mass associated with aging.

Onal M, Piemontese M, Xiong J, Wang Y…
J. Biol. Chem. Jun 2013
PMID: 23645674

Moderate Caffeine May be Good for Bones

Abstract

Favorable effect of moderate dose caffeine on the skeletal system in ovariectomized rats.

Caffeine, a methylxanthine present in coffee, has been postulated to be responsible for an increased risk of osteoporosis in coffee drinkers; however, the data are inconsistent. The aim of the present study was to investigate the effects of a moderate dose of caffeine on the skeletal system of rats with normal and decreased estrogen level (developing osteoporosis due to estrogen deficiency).
The experiments were carried out on mature nonovariectomized and ovariectomized Wistar rats, divided into control rats and rats receiving caffeine once daily, 20 mg/kg p.o., for 4 wk. Serum bone turnover markers, bone mass, mass of bone mineral, calcium and phosphorus content, histomorphometric parameters, and bone mechanical properties were examined. Caffeine favorably affected the skeletal system of ovariectomized rats, slightly inhibiting the development of bone changes induced by estrogen deficiency (increasing bone mineralization, and improving the strength and structure of cancellous bone). Moreover, it favorably affected mechanical properties of compact bone. There were no significant effects of caffeine in rats with normal estrogen levels.
In conclusion, results of the present study indicate that low-to-moderate caffeine intake may exert some beneficial effects on the skeletal system of mature organisms.

Folwarczna J, Pytlik M, Zych M, Cegieła U…
Mol Nutr Food Res Oct 2013
PMID: 23754597

Nitroglycerin Reverses Bone Loss in Ovariectomized Rats

Abstract

Restoration of ovariectomy-induced osteopenia by nitroglycerin.

Nitric oxide (NO) is known to inhibit osteoclastic bone resorption. Previously, we demonstrated that the NO donor nitroglycerin (NG) prevented ovariectomy (OVX)-induced bone loss. The current study shows that NG restores ovariectomy-induced osteopenia. Twenty-four female Sprague-Dawley rats, 36 weeks of age, underwent OVX, and a further six rats were sham-operated. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometric (DXA) scanning prior to OVX, at 6 weeks postsurgery, and at 6 weeks posttreatment. OVX rats were then assigned to four groups and treated with either (1) vehicle, (2) 17-beta-estradiol, (3) NG (0.2 mg/kg/day), or (4) a combination of estrogen and NG (n = 6/group). During the first 6-week post-OVX period, there was a significant decrease in the BMD in all ovariectomized (OVXed) rats (-11.0%, P < 0.001). There were no significant changes in BMD during the entire 12-week period in sham-operated rats. During the second 6-week period (after developing bone loss), there was no further significant loss of BMD in OVXed controls. BMD loss and loss of femur weight produced by OVXed were restored by treatment with estrogen, NG, or the two agents together during the second 6-week period (P < 0.01). The effects of estrogen and NG together, however, were not additive. The BMD of rats treated with NG alone, at 12 weeks, was similar to that of animals treated with estrogen alone or with estrogen and NG, and was comparable to that of sham-operated rats. The increased urinary excretion of deoxypyridinolines caused by OVX was negated by estrogen, NG, and estrogen together with NG (P < 0.01). In contrast to estrogen, NG did not decrease the post-OVX-induced increase of serum osteocalcin levels, suggesting that NG may also have a positive effect on bone formation. In summary, the results suggest that the NO donor, NG, reverses the OVX-induced bone loss in rats, and these effects are likely due to decreased bone resorption and, perhaps, increased bone formation.

Wimalawansa SJ
Calcif. Tissue Int. Jan 2000
PMID: 10602846

Sophorae Fructus Inhibits Osteoclasts In Vitro

Abstract

Inhibition of IL-1beta and IL-6 in osteoblast-like cell by isoflavones extracted from Sophorae fructus.

Osteoporosis is recognized as one of the major hormonal deficiency diseases, especially in menopausal women and the elderly. When estrogen is reduced in the body, local factors such as IL-1beta and IL-6, which are known to be related with bone resorption, are increased and promote osteoclastogenesis, which is responsible for bone resorption. In the present study, we investigated whether glucosidic isoflavones (Isocal, PIII) extracted from Sophorae fructus affect the proliferation of osteoblasts and prevent osteoclastogenesis in vitro by attenuating upstream cytokines such as IL-1beta and IL-6 in a human osteoblastic cell line (MG-63) and in a primary osteoblastic culture from SD rat femurs. Interestingly, IL-1beta and IL-6 mRNA were significantly suppressed in osteoblast-like cells treated with 17beta-estradiol (E2) and PIII when compared to positive control (SDB), and this suppression was more effective at 10(-8)% than at the highest concentration of 10(-4)%. In addition, these were confirmed in protein levels using ELISA assay. In the cell line, the cells showed that E2 was the most effective in osteoblastic proliferation over the whole range of concentration (10(-4)%-10(-12)%), even though PIII also showed the second greatest effectiveness at 10(-8)%. Nitric oxide (NO) was significantly (p<0.05) upregulated in PIII and E2 over the concentration range 10(-6)% to 10(-8)% when compared to SDB, without showing any dose dependency. In bone marrow primary culture, we found by TRAP assay that PIII effectively suppressed osteoclastogenesis next to E2 in comparison with SDB and culture media (control). In conclusion, these results suggest that local bone-resorbing cytokines can be regulated by PIII at lower concentrations and that, therefore, PIII may preferentially induce anti-osteoporosis response by attenuating osteoclastic differentiation and by upregulating NO.

Joo SS, Kang HC, Lee MW, Choi YW…
Arch. Pharm. Res. Dec 2003
PMID: 14723336

Sophorae Fructus Inhibit Osteoclasts Rat Bone Cells

Abstract

Isoflavones extracted from Sophorae fructus upregulate IGF-I and TGF-beta and inhibit osteoclastogenesis in rat bone marrow cells.

Isoflavones have been a central subject in research on the natural phytoestrogens found in Leguminosae. Their effects on bone formation and remodeling are important in that they can act like estrogen by binding on estrogen receptors on the target cell surface. We, therefore, believed that isoflavones may help in the treatment of patients with estrogen deficiency disease such as estrogen replacement therapy (ERT) for osteoporosis. As commonly known, osteoporosis is one of the hormonal deficiency diseases, especially in menopausal women. When estrogen is no longer produced in the body a remarkable bone remodeling process occurs, and the associated events are regulated by growth factors in the osteoblast lineage. In the present study, we investigated whether isoflavones (Isocal) extracted from Sophorae fructus affect the growth factors IGF-I and TGF-beta that have been known to be related with bone formation. In the study, we found that the active control (PIII) effectively enhanced the level of nitric oxide (NO) and growth factors, and thereby inhibited osteoclastogenesis. The most efficient concentration was 10(-8)% within five days, whereas the comparative control (soybean isoflavone) was not as effective even at a lower concentration. In conclusion, the products which contain enriched glucosidic isoflavone and nutrient supplements such as shark cartilage and calcium can be used for osteoporosis therapy by enhancing the production of IGF-I and TGF-beta. Furthermore, the NO produced through endothelial constitutive NO synthase (ecNOS) may play a role in inhibiting bone reabsorption.

Joo SS, Won TJ, Kang HC, Lee DI
Arch. Pharm. Res. Jan 2004
PMID: 14969347

Sophorae Fructus Inhibits Resorption in Ovariectomized Rats

Abstract

Bone loss preventing effect of Sophorae Fructus on ovariectomized rats.

The preventive effects of Sophorae Fructus extracts (I: hot water extract and II: combination product using I) on bone loss in ovariectomized (OVX) rats were investigated. Sophorae Fructus extracts were orally administrated to OVX rats for 9 weeks. Ovariectomy caused the increase of body weight and deoxypyridinoline (Dpd: bone resorption marker) and decrease of calcium (Ca: bone formation marker) level in serum. Dpd level were significantly decreased and Ca levels were elevated at 9 weeks in Sophorae Fructus extracts administered groups after ovariectomy at a dose of 0.556 g/kg/day compared with control group. In administered groups, trabecular bone area (TBA) in the tibia and lumbar were also increased compared with control group in histomorphological analysis. The preventive or treatment effects of Sophorae Fructus extracts on bone loss in OVX rats appears to be due to suppression of bone turnover.

Shim JG, Yeom SH, Kim HJ, Choi YW…
Arch. Pharm. Res. Jan 2005
PMID: 15742817

Willow-Leafed Magnolia Inhibits Osteoclasts in Ovariectomized Mice

Abstract

Extract of Magnoliae Flos inhibits ovariectomy-induced osteoporosis by blocking osteoclastogenesis and reducing osteoclast-mediated bone resorption.

Bone homeostasis is maintained by a balance between bone resorption by osteoclasts and bone formation by osteoblasts. Osteoporosis occurs when osteoclast activity surpasses osteoblast activity. Pro-inflammatory cytokines stimulate osteoclast differentiation and activity by increasing production of macrophage-colony stimulating factor and receptor activator of nuclear factor-κB ligand (RANKL). In this study, we investigated whether Magnoliae Flos (MF), one of the most commonly used Chinese medicinal herbs for managing rhinitis, sinusitis and headache, could effectively inhibit osteoporosis. In ovariectomized (OVX) mice compared to sham mice, the body weight increased and serum levels of alkaline phosphatase (ALP), tartrate resistant acid phosphatase 5b, calcium, and osteocalcin were significantly elevated. However, orally administrated MF extract substantially inhibited the increased body weight and serum levels of bone turnover markers, without any evidence of tissue toxicity. MF extract treatment significantly reversed the morphometric parameters of ovariectomy-induced bone loss, including trabecular bone volume, thickness, number, separation, and bone density, to almost the same levels of the sham mice. Furthermore, MF extract reduced the RANKL-mediated osteoclast differentiation and bone resorption by inhibiting the activities of matrix metalloproteinases (MMPs) and cathepsin K in mouse bone marrow macrophages. MF extract appeared to increase ALP activity in murine osteoblastic cells. Taken together, MF extract may be a beneficial supplement for the blockade of osteoporosis progression, particularly for the management of postmenopausal osteoporosis.

Jun AY, Kim HJ, Park KK, Son KH…
Fitoterapia Dec 2012
PMID: 22981503

Davallia Formosana Inhibits Osteoclasts

Abstract

Ethanol Extracts of Fresh Davallia formosana (WL1101) Inhibit Osteoclast Differentiation by Suppressing RANKL-Induced Nuclear Factor- κ B Activation.

The rhizome of Davallia formosana is commonly used to treat bone disease including bone fracture, arthritis, and osteoporosis in Chinese herbal medicine. Here, we report the effects of WL1101, the ethanol extracts of fresh rhizomes of Davallia formosana on ovariectomy-induced osteoporosis. In addition, excess activated bone-resorbing osteoclasts play crucial roles in inflammation-induced bone loss diseases, including rheumatoid arthritis and osteoporosis. In this study, we examined the effects of WL1101 on receptor activator of nuclear factor- κ B ligand (RANKL)-induced osteoclastogenesis. Treatment with WL1101 significantly inhibited RANKL-stimulated osteoclastogenesis. Two isolated active compounds, ((-)-epicatechin) or WL14 (4-hydroxy-3-aminobenzoic acid) could also inhibit RANKL-induced osteoclastogenesis. WL1101 suppressed the RANKL-induced nuclear factor- κ B (NF- κ B) activation and nuclear translocation, which is the key process during osteoclastogenesis, by inhibiting the activation of I κ B kinase (IKK) and I κ B α . In animal model, oral administration of WL1101 (50 or 200 mg/kg/day) effectively decreased the excess bone resorption and significantly antagonized the trabecular bone loss in ovariectomized rats. Our results demonstrate that the ethanol extracts of fresh rhizomes of Davallia formosana inhibit osteoclast differentiation via the inhibition of NF- κ B activation and effectively ameliorate ovariectomy-induced osteoporosis. WL1101 may thus have therapeutic potential for the treatment of diseases associated with excessive osteoclastic activity.

Lin TH, Yang RS, Wang KC, Lu DH…
Evid Based Complement Alternat Med 2013
PMID: 24191169 | Free Full Text