Researcher(s)
- Hailey Bonelli, Biomedical Engineering, University of Delaware
Faculty Mentor(s)
- Dawn Elliott, Biomedical Engineering, University of Delaware
Abstract
Introduction: Tendon degeneration can consist of tendon rupture (quick and painful injury) or tendinopathy (chronic pain). As aging occurs, there are notable cellular, structural, and functional changes. Aging effects on the tendon response to overload are unknown. Therefore, the first objective was to assess changes in activity and tendon mechanics due to normal aging. The second objective was to assess the effect of increased loading on rat activity and tendon mechanics 8-weeks post in a surgical rodent model of tendon overload called synergistic ablation (SynAb). We hypothesize that rodent activity will not change with age, however, mechanical properties will decrease with age. We further hypothesize that we will see a more degenerative change in tendon mechanics due to overload with increased age.
Materials and Methods: To evaluate aging on activity and mechanics, rats at 3-months, 5-months, 7-months, 12-months, and 14-months old were observed. To evaluate age on tendon overload, younger rats (3-months at surgery) and older rats (12-months at surgery) were assigned to two groups, a bilateral hind limb surgery to resect the Achilles tendon created the SynAb group and the Intact control group that had no surgery performed. Activity was monitored bi-weekly to obtain the total distance traveled (m) in the cage and the total number of times the rat stood on their hind legs (rearings) over 12 hours. After 8-weeks the rats were euthanized, and plantaris tendons were used for mechanical testing.
Results and Discussion: Our results showed that aging did not have an effect on activity but had a greater effect on the mechanical response to load in older rats. This may be due to a decreased ability of older rats to adapt to the SynAb treatment. In conclusion, rat activity stays consistent throughout aging, and tendon overload leads to a greater degenerative mechanical properties with aging.