The effect of strain and exercise on hypothalamic gene expression in C57BL/6J and DBA/2J mice

Open Access
Irizarry, Nicole
Area of Honors:
Bachelor of Science
Document Type:
Thesis Supervisors:
  • Teresa Caroldean Lang, Thesis Supervisor
  • Stephen Jacob Piazza, Honors Advisor
  • hypothalamus
  • exercise
  • inbred mice
  • genetics
Osteoporosis is a degenerative bone disease of major concern in the aging population of the United States. Within the past 10 years, researchers have begun to consider the neurological influences that may contribute to osteoporosis, and the important hormonal patterns that influence prevalence of osteoporosis. Exercise has been shown to have a positive impact on factors indicative of improved bone quality in studies that have examined gene expression in bone tissue, however little work has specifically addressed altered gene expression in brain tissue as a result of exercise. The following study utilized 180 day old C57BL/6 (B6) and DBA/2J (D2) mice under two exercise treatment conditions: treadmill running and tower climbing and a sedentary non-exercised control. Ninety female mice were randomized into groups, with 15 mice from each strain in each exercise treatment and control group. RNA was extracted from the hypothalamus of each mouse and, after quality determination, from the six best samples, two samples were pooled onto three gene chips for each strain by treatment group three samples were pooled on to a gene chip from each treatment group in order to measure gene expression. Gene expression was compared across groups to determine the effects of strain and exercise. Although exercise treatment was not found to cause significant differences in gene expression, important suggestive differences included expression of the leptin receptor gene (Lepr) in B6 tower climbing and non-exercising controls. Approximately 450 genes were differentially expressed as a result of strain. The identification of genes that are differentially expressed in the hypothalamus of B6 and D2 mice may provide insight into central nervous system control of known differences in activity level and skeletal quality and lead to new pathways for research in the prevention and treatment of osteoporosis.