Daidzein administration positively affects thyroid C cells and bone structure in orchidectomized middle-aged rats.

Abstract

SUMMARY:

Thyroid C cells hormone, calcitonine, inhibits bone resorption. We have demonstrated that daidzein treatment of orchidectomized rats (model for osteoporosis) stimulated C cells and increased trabecular bone mass. These results suggest that, besides direct action, daidzein may also affect bone structure indirectly through enhancement of thyroid C cell activity.

INTRODUCTION:

Thyroid C cells produce calcitonin (CT) which acts as an inhibitor of bone resorption. In this study, the influence of daidzein treatment on thyroid C cells, bone structure, and bone function in orchidectomized (Orx) middle-aged rats was investigated.

METHODS:

Sixteen-month-old Wistar rats were divided into Orx and sham-operated (SO) groups. Half the Orx rats were given subcutaneous injections of daidzein (30 mg/kg b.w./day) for 3 weeks. CT-immunopositive thyroid C cells were morphometrically analyzed. The metaphyseal region of the proximal tibia was measured histomorphometrically, and cancellous bone area (B.Ar), trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular separation (Tb.Sp) were calculated. Serum samples were analyzed for CT and osteocalcin (OC), calcium (Ca) and phosphorus concentrations, and urine samples for Ca levels.

RESULTS:

Treatment of Orx animals with daidzein significantly increased volume of C cells compared to the Orx rats. Daidzein also enhanced B.Ar, Tb.Th, and Tb.N and reduced Tb.Sp. The serum OC and urinary Ca concentrations decreased significantly in comparison with the Orx group.

CONCLUSIONS:

These findings indicate that daidzein treatment stimulates thyroid C cells, increase trabecular bone mass, and decrease bone turnover in Orx middle-aged rats, which is the model of male osteoporosis.

• Authors: B Filipović, B Sosić-Jurjević, V Ajdzanović, D Brkić, M Manojlović-Stojanoski, V Milosević, M Sekulić
• Journal: Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA (Osteoporos Int) Vol. 21 Issue 9 Pg. 1609-16 (Sep 2010) ISSN: 1433-2965 [Electronic] England
• PMID: 19859640 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers
• Bone Density Conservation Agents
• Isoflavones
• daidzein
• Calcitonin

Topics

• Animals
• Biomarkers (metabolism)
• Bone Density Conservation Agents (pharmacology, therapeutic use)
• Calcitonin (biosynthesis)
• Disease Models, Animal
• Drug Evaluation, Preclinical (methods)
• Isoflavones (pharmacology, therapeutic use)
• Male
• Orchiectomy
• Osteoporosis (drug therapy, pathology, physiopathology)
• Rats
• Rats, Wistar
• Thyroid Gland (drug effects, metabolism, pathology)
• Tibia (drug effects, pathology)