Presenter: Darsh Patel

Faculty Sponsor: Mark S. Miller

School: UMass Amherst

Research Area: Kinesiology

Session: Poster Session 4, 2:15 PM - 3:00 PM, 163, C18

ABSTRACT

The exercise approach that optimally improves skeletal muscle function and prevents disability in older adults is currently unknown. What is known is that alterations with exercise may be due to the relative distribution of myosin heavy chain (MHC) isoforms, which dictate single fiber force production and contractile velocity. To visualize these MHC isoforms, immunohistochemistry (IHC) is a common method, but prior image analysis techniques required large amounts of time and were subject to investigator bias. So, the purpose of this project was to automate the IHC analysis, which required (1) the implementation of a new IHC technique to define the borders of the muscle fibers and (2) adapting available software to our needs. The borders were defined by using a primary antibody to laminin, a component of the membrane basal lamina, in addition to antibodies illuminating the three human MHC isoforms (MHC I or slow-contracting, MHC IIA or fast-contracting, and MHC IIX or very fast-contracting). Fluorescent images were collected and submitted to a computer program, MyoVision 2.0. After modification for our needs, the program identified all fibers in each image, then determined fiber size and the isoform(s) expressed. Now, I am currently analyzing 30 pre- and post-exercise IHC images of older volunteers who underwent resistance (high-load, low-velocity) and power (low-low, high-velocity) exercise training. I hypothesize that resistance training will increase fiber size more than power training and that a change to faster MHC isoforms will be greater in power training than in resistance training.