Date of Award

1-1-2013

Document Type

Open Access Dissertation

Department

Exercise Science

First Advisor

James A Carson

Abstract

Radiotherapy has been proven as an effective and necessary treatment for cancer. The dose given is dependent on cancer type and location. It has been previously established that skeletal muscle is the most radiation tolerant tissue in the body. With that being said there is a current gap in the literature that is missing the effect of radiation doses on the histological properties of skeletal muscle. The overall purpose of this study is to determine the effect that a single unfractionated dose of 16Gy radiation has on histological properties of myofibers when compared to 4 fractionated doses of 4Gy . 24 C57/BL6 female mice under went hind limb irradiation procedures at UNC Chapel HIll under Dr. Ted Bateman and were sacrificed two weeks later. Tissues were then shipped to USC where serial sectioning was done on a cryostat, MHC and SDH staining procedures were all conducted. Upon analysis the fiber type specific myosin heavy chain isoforms IIA and IIB CSA both decreased significantly (p=. 04, p=.002). The SDH activity of each treatment group showed a significant decrease in glycolytic fibers and an upward trend in small oxidative fibers in regards to mean CSA but in terms of distribution showed an increase of smaller oxidative fibers (p=.03) and a loss of larger glycolytic fibers (p=.02) in the un-fractionated 16Gy group (n=7). The findings of this study show that unfractionated radiation dosing has atrophic effects on individual myofiber histological properties when compared with 4 fractionated 4Gy treatments.

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