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ORIGINAL ARTICLES
Published online: 2019-04-03
Submitted: 2019-01-31
Accepted: 2019-02-18
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Biochemical and immunohistochemical investigations on bone formation and remodelling in ovariectomized rats with tamoxifen citrate administration

Murat Baloğlu, Ebru Gökalp Özkorkmaz
DOI: 10.5603/FM.a2019.0035
·
Pubmed: 30949994

open access

Ahead of Print
ORIGINAL ARTICLES
Published online: 2019-04-03
Submitted: 2019-01-31
Accepted: 2019-02-18

Abstract

Osteoporosis results with the imbalance between osteoblastic formation and osteoclastic resorption, resulting in susceptibility to bone fractures.  Ovariectomy leads to osteoporosis by triggering alterations in bone formation and structure.   Tamoxifen as an anti-estrogen is used for adjuvant therapy especially in metastatic diseases and known to have a bone mass protective effect after ovariectomy. An animal model of ovariectomy induced osteoporosis after tamoxifen citrate administration was studied via biochemical and immunohistochemical methods. Female Wistar albino rats (n:45), selected according to their estrous cycle, were divided into three groups; (I) control, (II) ovarectomy, (III) ovarectomy + tamoxifen. Following ovariectomy, tamoxifen citrate (10 mg / kg) was given intraperitoneally daily for 8 weeks. At the end of the period, animals were sacrified under anesthesia, blood samples were taken to measure estrogen, calcium, and alkaline phosphate. Tibia bone samples were fixed in formalin solution and decalcified with 5% ethylene-diamine tetra acetic acid. After the routine histological follow up, samples were embedded in paraffin and cut with a microtome for semi-thin sections. Primary antibodies osteonectin and osteopontin were applied to sections and examined under light microscope. As a consequence, when estrogen and calcium data were compared there was a decrease in ovariectomy group with an increase in alkaline phosphatase (ALP). In ovarectomy + tamoxifen group, these values were close to the control group. Osteonectin was observed to promote bone formation by influencing collagen fiber formation, extracellular matrix development, osteoblast differentiation and the capacity to affect osteoclast activity. It has been suggested that osteopontin, the cytokine and cell binding protein, stimulates cellular signaling pathways, induces bone remodeling and acts in osteoporosis.

Abstract

Osteoporosis results with the imbalance between osteoblastic formation and osteoclastic resorption, resulting in susceptibility to bone fractures.  Ovariectomy leads to osteoporosis by triggering alterations in bone formation and structure.   Tamoxifen as an anti-estrogen is used for adjuvant therapy especially in metastatic diseases and known to have a bone mass protective effect after ovariectomy. An animal model of ovariectomy induced osteoporosis after tamoxifen citrate administration was studied via biochemical and immunohistochemical methods. Female Wistar albino rats (n:45), selected according to their estrous cycle, were divided into three groups; (I) control, (II) ovarectomy, (III) ovarectomy + tamoxifen. Following ovariectomy, tamoxifen citrate (10 mg / kg) was given intraperitoneally daily for 8 weeks. At the end of the period, animals were sacrified under anesthesia, blood samples were taken to measure estrogen, calcium, and alkaline phosphate. Tibia bone samples were fixed in formalin solution and decalcified with 5% ethylene-diamine tetra acetic acid. After the routine histological follow up, samples were embedded in paraffin and cut with a microtome for semi-thin sections. Primary antibodies osteonectin and osteopontin were applied to sections and examined under light microscope. As a consequence, when estrogen and calcium data were compared there was a decrease in ovariectomy group with an increase in alkaline phosphatase (ALP). In ovarectomy + tamoxifen group, these values were close to the control group. Osteonectin was observed to promote bone formation by influencing collagen fiber formation, extracellular matrix development, osteoblast differentiation and the capacity to affect osteoclast activity. It has been suggested that osteopontin, the cytokine and cell binding protein, stimulates cellular signaling pathways, induces bone remodeling and acts in osteoporosis.

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Keywords

ovariectomy, bone remodeling, tamoxifen, osteonectin, osteopontin

About this article
Title

Biochemical and immunohistochemical investigations on bone formation and remodelling in ovariectomized rats with tamoxifen citrate administration

Journal

Folia Morphologica

Issue

Ahead of Print

Published online

2019-04-03

DOI

10.5603/FM.a2019.0035

Pubmed

30949994

Keywords

ovariectomy
bone remodeling
tamoxifen
osteonectin
osteopontin

Authors

Murat Baloğlu
Ebru Gökalp Özkorkmaz

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