Circadian Rhythms: Using a Non-insulin-dependent Type 2 Diabetes Mellitus Mouse Model (TALLYHO/JngJ)
Type 2 diabetes mellitus is a chronic disease that affects the lives of millions. A type 2 diabetic is unable to properly produce insulin, a hormone that helps glucose enter the cells. As a result, there are high levels of glucose in the bloodstream, which can lead to heart disease, kidney, and nerve damage, and loss of eyesight. It is well known that some individuals are genetically prone to the disease, but a disrupted sleep/wake cycle can increase an individual’s chance of developing diabetes. Insulin is secreted in a daily (i.e., circadian) pattern from the pancreas, and a functional biological clock is necessary for proper insulin release. In addition, studies have shown that diabetes affects the genes which regulate the circadian rhythm, such as period, clock, and bmal1. Given that there is a relationship between circadian rhythms and diabetes, this study investigates TALLYHO/Jng (TH) mice which mimic human diabetes symptoms such as hyperglycemia, hyperinsulinemia, obesity, and enlargement of the islets of Langerhans in the pancreas. Eight male TH mice running wheel turn activity was observed under constant darkness for the course of several weeks. Their free running periods were observed pre and post the onset of diabetes. TH displayed less activity but more frequent bouts per day than the wild type mouse C57BL/6J. TH mice with access to a running wheel were significantly lighter when compared to studies done by Kim et al, 2006 and Steward et al, 2010, in which TH mice did not have access to running wheels. Since there is such a weight difference among the different studies, future experiments will examine blood glucose levels between mice with and without access to running wheels.
Danielle Holt, Mentor: Dr. Joe Seggio (Biology)
Adrian Tinsley Program for Undergraduate Research 2013 Summer Symposium
Bridgewater State University
TVSBSC / Team TVS