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Influence of exercise on bone remodeling-related hormones and cytokines in ovariectomized rats: a model of postmenopausal osteoporosis.

Li L, Chen X, Lv S, Dong M, Zhang L, Tu J, Yang J, Zhang L, Song Y, Xu L, Zou J - PLoS ONE (2014)

Bottom Line: The investigation revealed that compared to the control and the sham-operated groups, the OVX group showed significantly lower levels of TBV%, E2, and CT, but much higher levels of TRS%, TFS%, MAR, OSW, BGP, and PTH.The Ex-OVX group showed increased TBV% and serum levels of E2 and CT compared to the OVX group.Ovariectomy also led to a significant increase in IL-1β mRNA and protein levels in the bone marrow and IL-6 and Cox-2 protein levels in tibias.

View Article: PubMed Central - PubMed

Affiliation: School of Kinesiology, Shanghai University of Sport, Shanghai, China.

ABSTRACT
This study aims to explore the effects of exercise on postmenopausal osteoporosis and the mechanisms by which exercise affects bone remodeling. Sixty-three Wistar female rats were randomly divided into five groups: (1) control group, (2) sham-operated group, (3) OVX (Ovariectomy) group, (4) DES-OVX (Diethylstilbestrol-OVX) group, and (5) Ex-OVX (Exercise-OVX) group. The rat osteoporosis model was established through ovariectomy. The Ex-OVX rats were made to run 251.2 meters every day, 6 d/wk for 3 months in a running wheel. Trabecular bone volume (TBV%), total resorption surface (TRS%), trabecular formation surface (TFS%), mineralization rate (MAR), bone cortex mineralization rate (mAR), and osteoid seam width (OSW) were determined by bone histomorphometry. The mRNA and protein levels of interleukin-1β (IL-1β2), interleukin-6 (IL-6), and cyclooxygenase-2 (Cox-2) were determined by in situ hybridization and immunohistochemistry, respectively. Serum levels of estrogen estradiol (E2), calcitonin (CT), osteocalcin (BGP), and parathyroid hormone (PTH) were determined by ELISA assays. The investigation revealed that compared to the control and the sham-operated groups, the OVX group showed significantly lower levels of TBV%, E2, and CT, but much higher levels of TRS%, TFS%, MAR, OSW, BGP, and PTH. The Ex-OVX group showed increased TBV% and serum levels of E2 and CT compared to the OVX group. Ovariectomy also led to a significant increase in IL-1β mRNA and protein levels in the bone marrow and IL-6 and Cox-2 protein levels in tibias. In addition, the Ex-OVX group showed lower levels of IL-1 mRNA and protein, IL-6 mRNA, and Cox-2 mRNA and protein than those in the OVX group. The upshot of the study suggests that exercise can significantly increase bone mass in postmenopausal osteoporosis rat models by inhibiting bone resorption and increasing bone formation, especially in trabecular bones.

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Related in: MedlinePlus

TBV, TRS, and TFS percentages in the five groups.compared with the control group: □p<0.05, □□p<0.01; compared with the sham-operated: *p<0.05, **p<0.01; compared with the OVX group: △p<0.05, △△p<0.01; compared with the DES-OVX group: ▴▴p<0.01.
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pone-0112845-g001: TBV, TRS, and TFS percentages in the five groups.compared with the control group: □p<0.05, □□p<0.01; compared with the sham-operated: *p<0.05, **p<0.01; compared with the OVX group: △p<0.05, △△p<0.01; compared with the DES-OVX group: ▴▴p<0.01.

Mentions: As shown in Table 4 and Figure 1, the TBV% of the OVX group was significantly lower than the control and the sham-operated groups, which was accompanied by increased TRS, confirming that ovariectomy led to increased bone resorption and bone loss in rats. Moreover, the OVX group rats also showed higher levels of TFS%, MAR, mAR, and OSW than the control and sham-operated group rats (Table 5 and Figure 2), suggesting that these rats also displayed increased bone formation, which is likely caused by the coupling between bone resorption and formation. Thus, ovariectomized rats showed high bone turnover rate, with the increase in bone resorption being greater than that in bone formation. These findings are in accordance with previous studies and suggest that the surgery was successful in this study. To confirm these findings, we also treated ovariectomized rats with DES and found that DES almost completely reversed the bone loss and restored the bone parameters. In addition, none of the parameters was significantly different between the sham-operated group and the normal control group, which excludes the impact of surgical factors.


Influence of exercise on bone remodeling-related hormones and cytokines in ovariectomized rats: a model of postmenopausal osteoporosis.

Li L, Chen X, Lv S, Dong M, Zhang L, Tu J, Yang J, Zhang L, Song Y, Xu L, Zou J - PLoS ONE (2014)

TBV, TRS, and TFS percentages in the five groups.compared with the control group: □p<0.05, □□p<0.01; compared with the sham-operated: *p<0.05, **p<0.01; compared with the OVX group: △p<0.05, △△p<0.01; compared with the DES-OVX group: ▴▴p<0.01.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231162&req=5

pone-0112845-g001: TBV, TRS, and TFS percentages in the five groups.compared with the control group: □p<0.05, □□p<0.01; compared with the sham-operated: *p<0.05, **p<0.01; compared with the OVX group: △p<0.05, △△p<0.01; compared with the DES-OVX group: ▴▴p<0.01.
Mentions: As shown in Table 4 and Figure 1, the TBV% of the OVX group was significantly lower than the control and the sham-operated groups, which was accompanied by increased TRS, confirming that ovariectomy led to increased bone resorption and bone loss in rats. Moreover, the OVX group rats also showed higher levels of TFS%, MAR, mAR, and OSW than the control and sham-operated group rats (Table 5 and Figure 2), suggesting that these rats also displayed increased bone formation, which is likely caused by the coupling between bone resorption and formation. Thus, ovariectomized rats showed high bone turnover rate, with the increase in bone resorption being greater than that in bone formation. These findings are in accordance with previous studies and suggest that the surgery was successful in this study. To confirm these findings, we also treated ovariectomized rats with DES and found that DES almost completely reversed the bone loss and restored the bone parameters. In addition, none of the parameters was significantly different between the sham-operated group and the normal control group, which excludes the impact of surgical factors.

Bottom Line: The investigation revealed that compared to the control and the sham-operated groups, the OVX group showed significantly lower levels of TBV%, E2, and CT, but much higher levels of TRS%, TFS%, MAR, OSW, BGP, and PTH.The Ex-OVX group showed increased TBV% and serum levels of E2 and CT compared to the OVX group.Ovariectomy also led to a significant increase in IL-1β mRNA and protein levels in the bone marrow and IL-6 and Cox-2 protein levels in tibias.

View Article: PubMed Central - PubMed

Affiliation: School of Kinesiology, Shanghai University of Sport, Shanghai, China.

ABSTRACT
This study aims to explore the effects of exercise on postmenopausal osteoporosis and the mechanisms by which exercise affects bone remodeling. Sixty-three Wistar female rats were randomly divided into five groups: (1) control group, (2) sham-operated group, (3) OVX (Ovariectomy) group, (4) DES-OVX (Diethylstilbestrol-OVX) group, and (5) Ex-OVX (Exercise-OVX) group. The rat osteoporosis model was established through ovariectomy. The Ex-OVX rats were made to run 251.2 meters every day, 6 d/wk for 3 months in a running wheel. Trabecular bone volume (TBV%), total resorption surface (TRS%), trabecular formation surface (TFS%), mineralization rate (MAR), bone cortex mineralization rate (mAR), and osteoid seam width (OSW) were determined by bone histomorphometry. The mRNA and protein levels of interleukin-1β (IL-1β2), interleukin-6 (IL-6), and cyclooxygenase-2 (Cox-2) were determined by in situ hybridization and immunohistochemistry, respectively. Serum levels of estrogen estradiol (E2), calcitonin (CT), osteocalcin (BGP), and parathyroid hormone (PTH) were determined by ELISA assays. The investigation revealed that compared to the control and the sham-operated groups, the OVX group showed significantly lower levels of TBV%, E2, and CT, but much higher levels of TRS%, TFS%, MAR, OSW, BGP, and PTH. The Ex-OVX group showed increased TBV% and serum levels of E2 and CT compared to the OVX group. Ovariectomy also led to a significant increase in IL-1β mRNA and protein levels in the bone marrow and IL-6 and Cox-2 protein levels in tibias. In addition, the Ex-OVX group showed lower levels of IL-1 mRNA and protein, IL-6 mRNA, and Cox-2 mRNA and protein than those in the OVX group. The upshot of the study suggests that exercise can significantly increase bone mass in postmenopausal osteoporosis rat models by inhibiting bone resorption and increasing bone formation, especially in trabecular bones.

Show MeSH
Related in: MedlinePlus