Investigations into the impact of and mechanisms behind age-associated impaired healing following peripheral nerve injury

Peripheral nerve injuries (PNI) present a challenging and debilitating problem to both patients and the healthcare industry . Elderly patients in particular demonstrate a significantly reduced rate of recovery after PNI, prolonging the time they are in pain and immobile. Research into the mechanisms behind these age-associated healing impairments has the potential to unlock new ways to reverse this process and possibly accelerate the rate of recovery for all patients after PNI. Since macrophages and Schwann cells have been shown to be important in peripheral nerve repair, I sought to determine whether age had an effect on their recruitment to the site of a nerve injury. To do this, I first affirmed the impact that age has on both the rate of recovery and extent of full recovery after PNI through the use of hock angle analysis, peak tetanic force (PTF) measurements, and gastrocnemius (gastroc) muscle harvests. I then used novel nerve graft techniques to determine the impact the age of the nerve tissue has on macrophage and Schwann cell recruitment after PNI. While unable to detect age-related differences in rate of recovery after PNI, I found that recovery was similarly incomplete in both old and young animals. My new assay for quantifying macrophage and Schwann cell migration into the injured nerve proved a more convenient, cost-effective method that yielded results challenging previous conceptions by showing macrophage and Schwann cell recruitment was the same between young and old mice