The relationship of telmisartan with sclerostin in the osteoporosis model induced by ovariectomy in rats.

OBJECTIVES

Our aim is to explain the relationship between Ang II and Scl in osteoporotic (OP) rats and the contribution of Scl in the antiosteoporotic effect mechanism of angiotensin receptor blockers (ARB).

METHODS

This study consists of two sub-studies conducted on 4th and 12th weeks after ovariectomy. In study 1, treatment was started immediately after bilateral ovariectomy (OVX), while, in study 2, treatment was started 2 months after OVX. Two different doses of telmisartan (5 and 10 mg/kg) were administered with the aid of gavage for 30 days in both sub-study groups.

RESULTS

Serum and tissue Scl, osteocalcin, osteopontin and tartrate-resistant acid phosphatase mRNA expressions were higher and bone mineral densities (BMD) and bone-specific alkaline phosphatase (BALP) mRNA expressions were found to be lower in the OVX groups compared with the sham group. In OVX groups where two different doses of telmisartan were administered, BMD and BALP mRNA expressions increased and serum and tissue Scl decreased.

CONCLUSION

There may be a close relationship between angiotensin II and sclerostin in the development of osteoporosis. In this study, telmisartan administration showed an antiosteoporotic effect and significantly decreased the level of sclerostin. These results strongly support this relationship.