Immunolocalization of sclerostin synthesized by osteocytes in relation to bone remodeling in the interradicular septa of ovariectomized rats.
This study aimed at elucidating whether estrogen deficiency would affect the synthesis of an osteocyte-derived factor, sclerostin, in the mesial region of alveolar bone. Eight 9-week-old Wistar female rats were ovariectomized (OVX) and eight other rats were Sham-operated (Sham). After 4 weeks, the interradicular septa of mandibular first molar were embedded in paraffin and then histochemically examined. Sclerostin-positive osteocytes were located in the superficial layer of the mesial region of Sham bones, whereas the OVX mesial region showed less sclerostin-reactive osteocytes. There was no significant difference in the distribution of estrogen receptor α and terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labeling -positive cells in the groups studied. The Sham mesial region featured many osteoclasts, and OVX specimens showed numerous osteoclasts in association with intense immunolabeling of the receptor activator of the nuclear factor kB ligand. Contrary to the observations in Sham specimens, a complex meshwork of cement lines was seen in the OVX mesial region, accompanied by an irregularly distributed osteocytic lacunar-canalicular system. In conclusion, estrogen deficiency appears to inhibit osteocyte-derived sclerostin synthesis in the mesial region of the interradicular septum, in a process that seems to be mediated by accelerated bone remodeling rather than by direct effects on osteocytes.
Department of Developmental Biology of Hard Tissue, Graduate School of Dental Medicine, Hokkaido University, Kita-ku, Sapporo, Japan.
Ying
Y
Guo
Minqi
M
Li
Liu
L
Zhusheng
Tamaki
T
Yamada
Muneteru
M
Sasaki
Tomoka
T
Hasegawa
Hiromi
H
Hongo
Chihiro
C
Tabata
Reiko
R
Suzuki
Kimimitsu
K
Oda
Tsuneyuki
T
Yamamoto
Masamitsu
M
Kawanami
Norio
N
Amizuka
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000096:biosynthesis* / Q000235:genetics; D016723:Bone Remodeling / Q000187:drug effects*; D001842:Bone and Bones / Q000378:metabolism; D056657:Cathepsin K / Q000235:genetics / Q000378:metabolism; D004967:Estrogens / Q000172:deficiency / Q000494:pharmacology; D005260:Female; D005819:Genetic Markers / Q000235:genetics; D020287:In Situ Nick-End Labeling; D007527:Isoenzymes / Q000378:metabolism; D010010:Osteoclasts / Q000378:metabolism*; D010011:Osteocytes / Q000187:drug effects* / Q000378:metabolism*; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism; D000071681:Tartrate-Resistant Acid Phosphatase; D000097983:ERRalpha Estrogen-Related Receptor
D000135:Acid Phosphatase; D019485:Bone Morphogenetic Proteins; D056657:Cathepsin K; D004967:Estrogens; D005819:Genetic Markers; D007527:Isoenzymes; D011960:Receptors, Estrogen; D000071681:Tartrate-Resistant Acid Phosphatase; D000097983:ERRalpha Estrogen-Related Receptor; C486031:Sost protein, rat; C534133:Ctsk protein, rat