title: Ovariectomy-induced bone loss and the hematopoietic system.
abstract: To investigate the relationship of the hematopoietic system to the loss of bone due to ovarian hormone deficiency, we examined the effects of ovariectomy and estrogen administration on the thymus, spleen and the bone marrow, and on the proliferation of marrow progenitors of osteoclasts. We also assessed the effects of daily administration of interleukin-1 receptor antagonist (IL-1ra) on bone loss due to ovarian hormone deficiency. Ovariectomy resulted in decreased cancellous bone volume, increased trabecular osteoblast and osteoclast numbers, and increased serum alkaline phosphatase levels that were prevented by 17 beta-estradiol treatment. Thymus weight, spleen weight, thymus and spleen lymphocytes, and bone marrow monocytes and lymphocytes also increased significantly following ovariectomy, and the increases were suppressed by 17 beta-estradiol. Ovariectomy, in addition, caused a 4-fold increase in the number of tartrate resistant acid phosphatase (TRAP)-positive multinucleated cells formed in cultures of marrow cells and the increase was partially inhibited by 17 beta-estradiol. IL-1ra administration did not prevent the bone loss due to ovariectomy. Our findings indicate that ovariectomy-induced bone loss in the rat is accompanied by marked changes in the hematopoietic system, and that these changes are modulated by estrogen administration. In spite of the negative finding with IL-1ra, the nature of the involvement of the hematopoietic system in the pathogenesis of bone loss due to ovarian hormone deficiency merits continued exploration.
authors.affiliation: Department of Physiology, University of Texas Health Science Center 78284-7756.
authors.forename: D N
authors.initials: DN
authors.lastname: Kalu
authors.forename: E
authors.initials: E
authors.lastname: Salerno
authors.forename: C C
authors.initials: CC
authors.lastname: Liu
authors.forename: F
authors.initials: F
authors.lastname: Ferarro
authors.forename: B N
authors.initials: BN
authors.lastname: Arjmandi
authors.forename: M A
authors.initials: MA
authors.lastname: Salih
mesh_terms: D000135:Acid Phosphatase / Q000494:pharmacology; D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D015519:Bone Density; D001853:Bone Marrow / Q000033:anatomy & histology / Q000187:drug effects; D001854:Bone Marrow Cells; D001862:Bone Resorption / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology*; D001842:Bone and Bones / Q000187:drug effects / Q000473:pathology; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D006413:Hematopoietic System / Q000502:physiology*; D053590:Interleukin 1 Receptor Antagonist Protein; D010006:Osteoblasts / Q000166:cytology; D010010:Osteoclasts / Q000166:cytology; D010052:Ovariectomy; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D012795:Sialoglycoproteins / Q000494:pharmacology; D013154:Spleen / Q000033:anatomy & histology / Q000166:cytology / Q000187:drug effects; D013950:Thymus Gland / Q000033:anatomy & histology / Q000166:cytology / Q000187:drug effects
chemical_list: D053590:Interleukin 1 Receptor Antagonist Protein; D012795:Sialoglycoproteins; D004958:Estradiol; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase