Molecular cloning and functional characterization of the porcine extracellular domain of Receptor Activator of NF-κB Ligand (sRANKL)

Can we induce osteoporosis in animals comparable to the human situation?

Osteoporosis is a chronic systemic bone disease of growing relevance due to the on-going demographic change. Since the underlying regulatory mechanisms of this critical illness are still not fully understood and treatment options are not satisfactorily resolved, there is still a great need for osteoporosis research in general and animal models in particular. Ovariectomized rodents are standard animal models for postmenopausal osteoporosis and highly attractive due to the possibility to specifically modify their genetic background. However, some aspects can only be addressed in large animal models; such as metaphyseal fracture healing and advancement of orthopedic implants. Among other large animal models sheep in particular have been proven invaluable for osteoporosis research in this context. In conclusion, today we are able to influence the bone metabolism in animals causing a more or less pronounced systemic bone loss and structural deterioration comparable to the situation found in patients suffering from osteoporosis. However, there is no perfect model for osteoporosis, but a variety of models appropriate for answering specific questions. Though, the appropriateness of an animal model is not only defined in regard to the similarity to human physiology and the disease itself, but also in regard to acquisition, housing requirements, handling, costs, and particularly ethical concerns and animal welfare.

The effect of rotative stress on CAII, FAS, FASL, OSCAR, and TRAP gene expression in osteoclasts

This study was designed to explore the effects of rotative stress on carbonic anhydrase II (CAII), TNF receptor superfamily member 6 (FAS), FAS ligand (FASL), osteoclast-associated receptor (OSCAR), and tartrate-resistant acid phosphatase (TRAP) gene expression in osteoclasts. Osteoclasts were induced from RAW264.7 cells cultured in medium containing recombinant murine soluble receptor activator of NF-Kβ ligand (sRANKL). The mRNA and protein expression of CAII, FAS, FASL, OSCAR, and TRAP genes in osteoclasts was detected by RT-PCR and Western blot, respectively, after osteoclasts were loaded at various rotative stress strengths and times. No significant differences in mRNA and protein expression were observed between any of the control groups (P > 0.05). Importantly, rotative stress had a significant effect on the mRNA and protein expression of these genes (P < 0.05). We found a negative relationship between rotative stress strength and prolonged loading time and the expression of FAS/FASL genes in osteoclasts. In addition, there was a positive relationship between rotative stress strength and prolonged loading time and the expression of CAII, OSCAR, or TRAP genes in osteoclasts. Based on these results, rotative stress has a significant effect on CAII, FAS, FASL, OSCAR, and TRAP gene expression in osteoclasts.