# Metabolic Disruption in Osteoporotic Sheep: Evaluating Vitamin D Deficiency and Cortisone Effects via Biochemical Markers

## TL;DR

This study examines how vitamin D deficiency and cortisone affect bone metabolism in sheep with osteoporosis using biochemical markers.

## Contribution

The research identifies a unique biomarker signature from combined ovariectomy, diet, and glucocorticoids in an ovine osteoporosis model.

## Key findings

- OVXDS sheep showed severe bone density loss and metabolic changes not seen in other groups.
- OVXDS had suppressed bone turnover markers and low vitamin D levels at 3 months.
- By 8 months, OVXDS showed altered bone coupling patterns under chronic stress.

## Abstract

Background/Objectives: We evaluated serum and urinary biomarkers of bone and energy metabolism in an ovine osteoporosis model (Control, OVX, OVXD, OVXDS) at 0/3/8 months (M). Methods: Morning sampling; DXA (ROI ‘abdominal width’) and linear mixed models for repeated measures. Results: Only OVXDS showed severe DXA loss (Z-scores −3.29 at 3 M; −4.86 at 8 M), with ≈20% and ≈30% BMD reductions at 3 M and 8 M versus controls. OVX and OVXD remained within age-expected Z-score ranges at 8 M. At 3 M, OVXDS had hypocalcemia, markedly elevated UFEP, near-zero 25-OH-vitamin-D, and suppressed osteocalcin/NTX (depressed turnover). By 8 M, osteocalcin rose in OVXDS while NTX stayed low, consistent with altered coupling under chronic glucocorticoids and vitamin D deficiency. OVXD showed milder, later changes. Fructosamine and insulin were transiently higher in OVXDS at 3 M; IGF-1 was stable across groups/time. Conclusions: Combined ovariectomy, calcium/vitamin-D-deficient diet, and glucocorticoids produce the clearest biomarker signature and DXA loss. Assay cross-reactivity limited PTH/DKK-1/cathepsin-K measurement in sheep; we summarize DXA outcomes and expand assay limitations and future validation plans.