Sahran Hassan
Research Mentor(s): Yuji Mishina
Mentor Department: Biological and Material Sciences
Authors: Nikan Mardani, Yuji Mishina
Session: Session 5 (2:00pm – 2:50pm)
Presentation Type: Poster 23
Abstract
Each bone in the human skeleton undergoes a continuous bone remodeling process through specialized osteoblasts (bone-forming cells) and osteoclasts (bone-destroying cells) to keep a healthy bone mineral density level. Osteoporosis is a disease characterized by a decrease in bone mineral density. To combat the disease, there are two treatment types: bone forming treatment (increases osteoblast activity) and antiresorptive treatment (decreases osteoclast activity). However, both of these treatment types are not very effective due to a coupling effect. Current bone forming treatments also increase osteoclast activity, and antiresorptive treatment similarly impair osteoblast activity, making both intended effects much less effective. Understanding the interactions between osteoblasts and osteoclasts would be beneficial in improving the efficiency of osteoporosis treatments. In particular, studying the mandible or jawbone may uncover novel insights into the bone remodeling process due to the uniqueness of the mandible to ultimately improve osteoporosis treatment. The lack of a cartilage template during formation, the ability to move in all three dimensions due to the temporomandibular joint and lack of adjacent bone articulation, the predictable compressive strains from activities like chewing and speaking, and the traumatic event of tooth eruption all make the mandible unique compared to other bones. This project uses genetically engineered mouse models because of similar genetic and physiological characteristics to humans to study the interactions between osteoblasts and osteoclasts in the alveolar molar region of the mandible at different stages during mouse development. The mice were genetically modified through a transgenic approach by integrating a red fluorescent protein (RFP) gene and a green fluorescent protein (GFP) gene into the mouse genome. With the RFP and GFP markers embedded into the mouse genome, osteoclasts appear red and osteoblasts appear green in hard tissue cryosections, making their locations easily locatable. In particular, this study analyzes the osteoblast-osteoclast interactions in the alveolar molar mandible region during 4 main stages of mouse development – 8, 10, 15, and 21 days after birth. Samples taken 10 days after birth are examined to see if tooth eruption plays a role on osteoblast/osteoclast concentration and interactions. Samples taken 21 days after birth are examined to see if transitioning from drinking milk to a hard diet will have any influence. The goal of testing across multiple stages of mouse development is to see whether certain stressors play a role on the concentration, location, or interaction of osteoblasts and osteoclasts in the mouse mandible.
