(P17-17-26) Effects of Pinto Bean Supplementation on Markers of Bone Health in a Mouse Model of Postmenopausal Osteoporosis

Objectives: This study examined the effects of pinto bean (PB) supplementation on bone minerals and gene expression in ovariectomized (OVX) mice, a model of postmenopausal osteoporosis.

Methods: Forty-eight 3-month-old female C57BL/6 mice were either sham-operated or OVX and randomly assigned to two dietary treatment groups (n = 12/group): control (AIN-93M) or 10% (wt/wt) PB diet for 90 d. Dual-energy x-ray absorptiometry was performed to assess whole body, femur, and L4 vertebrae bone mineral content (BMC) and density (BMD). Tibial gene expression related to inflammation (interleukin (Il)-1β) and bone remodeling markers [i.e., gamma-carboxyglutamate protein (Bglap2) and secreted phosphoprotein 1 (Spp1)] were assessed using qPCR. Global gene expression of the tibia was assessed using RNA sequencing. Data were analyzed using two-way ANOVA (GraphPad Prism) with diet and surgery (Sham or OVX) as factors, and p < 0.05 was considered statistically significant.

Results: As expected, OVX significantly reduced whole-body, femur, and L4 BMC and BMD. PB had no significant effect on these parameters but tended (p = 0.096) to increase L4 BMD. OVX mice also tend to increase Il-1β (p = 0.070) and decrease Spp1 (p = 0.064) expression, while PB had no effect on these genes. Bulk RNA sequencing and gene ontology analysis revealed that OVX and PB supplementation modulated pathways related to bone metabolism. The pathway modulation was associated with reduction in differential gene expression of fibrillin-2 (Fbn2) in OVX mice consistent with estrogen-deficiency–induced impairment of bone matrix integrity. PB supplementation increased the expression of collagen type X alpha 1 chain (Col10a1), collagen type IX alpha 1 chain (Col9a1), and prostaglandin-endoperoxide synthase 2 (Ptgs2), suggesting improved osteoblast activity and bone formation.

Conclusions: OVX-induced estrogen deficiency impaired bone mineral and altered bone-related gene expression. PB supplementation had modest effects on bone mineral but enhanced the expression of genes associated with osteoblast function, suggesting a partial supportive role in estrogen-deficient bone.

Funding Sources: NIH-NIA/NICCH, B. Pass Scholarship, and Jim and Lynne Williams Professorship