Date of Completion


Embargo Period



Hicham Drissi and Ann Delany

Field of Study

Biomedical Science


Master of Science

Open Access

Open Access


The skeleton is formed via intramembranous ossification and endochondral ossification. Endochondral ossification, which is the focus of this research, is the process by which the long bones of the skeleton undergo chondrogenesis followed by osteogenesis. The objective of this project is to define the genetic profiles of two types of clastic cells in endochondral ossification: osteoclasts and chondroclasts, which are responsible for breaking down bone and calcified cartilage, respectively. The goal of this project is to validate the hypothesis that these two very similar cells types, which arise from a common precursor, are distinguished by a pattern of differentially expressed genes in response to the interaction with the two different microenvironments in which these cells are found. In order to carry out this experiment, E18.5 embryos were sectioned and stained for tartrate-resistant acid phosphatase (TRAP). TRAP-positive cells were captured using laser capture microdissection. Cells were then lysed so that the RNA could be isolated and transcribed to cDNA, which was linearly amplified, so that qPCR could be performed. A list of candidate genes was chosen for qPCR analysis. Results indicated that there are differences in the expression profiles between chondroclasts and osteoclasts. These results supported the hypothesis that chondroclasts and osteoclasts have distinct genomic profiles at timepoint E18.5 during embryonic development. Identifying and testing the functional differences in the genomic profile of these two cell types will be instrumental in developing new strategies to target these cells in diseases such as osteoarthritis and osteoporosis.

Major Advisor

Marc Hansen