Architectural Changes in Subchondral Bone and Its Compliance in Response to Estrogen and Progesterone: A Micro-Computed Tomography Study

Abstract

This study evaluates the effects of estrogen and progesterone on the subchondral bone micro-structural parameters using micro computed tomography (CT) in ovariectomized rats. Thirty-five 7-month-old Sprague-Dawley female rats were randomly divided into 5 groups and then ovariectomized bilaterally except the sham control group. The first and the second group acting as controls did not receive hormonal therapy, the third group received estrogen, the fourth group received progesterone, and the fifth group received combination of both hormones 10 weeks after surgery. Evaluations were done using micro-CT and serum levels of cartilage ologomeric matrix protein (COMP), collagen type I C-telopeptide (CTX-I), and osteocalcin (OC). Estrogen and progesterone combination is definitely beneficial than estrogen alone with regards to changes in level of bone mineral density, trabecular bone volume fraction, bone surface volume ratio, trabecular thickness, subchondral plate thickness and Young's elastic modulus. Estrogen and progesterone combination therapy was found to be convincing in terms of reducing the severity of osteoarthritis and regaining the strength of subchondral bone in this experimental model.