Date of Award

Fall 12-10-2022

Degree Type


Degree Name

MS Biology




Jessica Cottrell, Ph.D.

Committee Member

Daniel Brian Nichols, Ph.D.

Committee Member

Constantine Bitsaktsis, Ph.D.


osteoblast, osteoclast, bone homeostasis, osteogenesis, 3D bone model, bone organoid


Bone is a dynamic tissue that undergoes formation, degradation, and repair in a constant state of remodeling. Bone remodeling is performed and regulated by three cell types: osteoblasts, osteocytes, and osteoclasts. Bone homeostasis, the balance of bone formation and resorption, is regulated by biologically active substances secreted by the three bone cell types, as well as circulating hormones and proteins in the body. Insulin is the main anabolic hormone in the body, and its effects on bone homeostasis and regulation are still being uncovered. Magnesium is a trace element that is critical to bone homeostasis. It affects the secretion of hormones that regulate bone cell function and affects structural formation of mineralized bone. However, the exact effects of magnesium on bone cells, as well as ideal concentrations of magnesium in the body are still being elucidated. In this research, we hypothesized that insulin or magnesium would have dose-dependent positive effect on bone formation in a 3D model, based on current knowledge regarding both substances. To evaluate this hypothesis, 3D model bone organoids were developed and treated with increasing doses of insulin or magnesium chloride for 21 days. Spent cell media was collected at 7, 14, and 21 days of post-treatment to evaluate osteoblast and osteoclast function via alkaline phosphatase activity and CTX-liberation, respectively. Bone organoids were harvested at days 14 and 21 to evaluate COX-2 protein expression and calcium deposition. Our data shows that insulin and magnesium showed some dose-dependent effects on osteoblast activity. Overall, our data shows that the effects of insulin and magnesium may differ in a 3D organoid model compared to a 2D monoculture or in vivo conditions, which is important to establish for future research using 3D organoid models to evaluate these key substances.

Available for download on Tuesday, December 14, 2027