Osteoporosis leads to increased fracture risk. Dysregulation of osteoblast and osteoclast lead to a high-turnover phenotype, which reduces bone mass and lowers bone mineral content. Therefore, osteoporotic fractures are a huge clinical challenge. This study utilised 32 female Marino sheep with an osteoporotic bone status to examine bone healing in the iliac crest drill-hole. Animals were divided into 4 groups: 1) non-operated control group (K group). 2) Bilaterally ovariectomised (O group). 3) Bilaterally ovariectomised and treated with special diet deficient of calcium and Vitamin D (OD group). 4) In addition to treatment in 3 this group received a biweekly dosage of glucocorticoid treatment (ODS group). Bone defects were 7.5 mm diameter 20 mm length and healing was examined at two time points (M=month) 5M and 8M. Histographs were evaluation using Movat pentachrom staining and quantified with ImageJ V 1.47 software. Statistical analysis ran in IBM SPSS V. 21. Qualitatively, K group showed cortical bridging by 5M and trabecular bone formation by 8M. However, treatment combinations affected cortical bone bridging and trabecular bone formation. Cartilaginous tissue was present after 8M mostly in OVXDS. Histomorphometrical analysis showed that healing progressed from 5M to 8M in the K group through higher total ossified tissue (TOT) and lower total cartilage tissue (TCT). TOT was lowest in the OVXDS compared to other groups. Further, OVXD group had higher osteoid portion when compared with all other groups. Nonetheless, OVXD and OVXDS showed cartilage remnant at 8M in contrast to both K and OVX groups. Osteoblast and osteoclast specific staining and molecular markers are currently being analysed to identify discrepancies in healing regulation under the influence of estrogen deficiency, malnutrition and glucocorticoid treatment.
Disclosure: The authors declared no competing interests. This work was supported by The DFG (German Research Foundation) as trans regional Collaborative Research Centres (SFB Transregio 079).