Exploring the Molecular Mechanisms Underlying Icariin-Mediated Regulation of Fatty Acid-Binding Protein 4 Gene Expression in Postmenopausal Osteoporosis

Abstract

Objective: This work aimed to evaluate the therapeutic effects of icariin (ICA) on postmenopausal osteoporosis (PMOP) and explore its association with the fatty acid-binding protein 4 (FABP4) gene, providing novel insights into the mechanisms of osteoporosis. Materials and Methods: Forty-five healthy rats were randomly divided into three groups: Group S1 (icariin treatment), Group S2 (model), and Group S3 (sham surgery). Measurements included body weight, spatial structural parameters of tibia and lumbar vertebrae tissue, FABP4 gene expression, and Bone Gla protein (BGP) levels. Results: The body weight of rats in Group S1 was slightly lower than that of Group S2 at weeks 7 and 14, but the difference was not significant (p > 0.05). Lumbar vertebrae and femoral neck bone mineral density (BMD) were also slightly lower than those in Group S3, but the difference was not significant (p > 0.05). However, the spatial structural parameters of tibia and lumbar vertebrae tissue, including bone volume (BV), total bone volume (TV), trabecular thickness (Tb.Th), and trabecular connectivity density (Conn.D), were significantly higher in Group S1 than in Groups S2 and S3. FABP4 gene expression and trabecular separation (Tb.Sp) were significantly lower in Group S1 than in Groups S2 and S3 (p < 0.05). Additionally, the maximum bending and compressive loads of the tibia and serum BGP levels were significantly higher in Group S1 than in Groups S2 and S3 (p < 0.05). Conclusion: ICA effectively improved the strength of bone tissue in PMOP rats and enhanced the ultrastructural characteristics of trabecular bone. These effects may be associated with ICAs inhibition of FABP4 gene expression, increased serum BGP levels, and improved osteoblast activity. These findings provided important clues for further exploration of the mechanisms of PMOP treatment.