Heat shock proteins, Mice-Muscles, Mice-Exercise-Physiological aspects, Stress (Psychology), HSPs, Exercise, Muscle fiber type
Heat Shock Proteins, HSPs, are a critical part of a cell's ability to mediate stress. This study looks at a particular stressor, exercise, and compared HSP localization by muscle cell type to time points after exercise. Exercise-naïve female mice, ran on a treadmill for 15 min at -15°, and then their biceps brachii was excised at -1 hour (control), 0 hours, 24 hours, and 48 hours post exercise. Serial cryosections were then cut and stained, using immunofluorescence, for HSP 25, 60, 70, 90, and HSC 90. All the HSPs showed different patterns of staining following the exercise. The control HSP 25 and 60 showed all-over staining. HSP 70 showed very little to no staining. HSC 70 showed a strong, non-fiber specific, peripheral staining. HSP 90 showed preferential staining in slow fibers. At 0 hours, HSP 25 and HSC 70 are up-regulated in all cells. HSP 60 stained more brightly in all cells but even more in fast fibers. HSP 70 is up-regulated primarily in a subset of slow fibers. HSP 90 mainly stains the slow fibers. At the 24 hours, HSP 25 and 70 are very specifically up-regulated in slow fibers. HSP 60 shows a stippled up-regulation in slow fibers but, overall, the section shows lower staining than the previous time point. HSC 70 shows a stippled, more peripheral staining that is lower than at 0 hours. HSP 90 shows a more even staining between fiber types than previously but still more staining in slow fibers. Then at 48 hours, HSP 90 has fluorescence levels similar to the control. HSP 25 levels rose, but more so in the slow fibers. HSP 60 levels look lower than the control but also the staining is more peripheral. HSP 70 level is lower than at 24 hours but not as low as the control and HSC 70 level is slightly viii brighter than the 24 hours but it is increase in fluorescence is very peripheral. The pattern of expression seen could be due to increased mechanical and oxidative stress on the slow fibers, mitigation and repair of damage to the fibers, and/or a fiber specific expression patter of HSPs.
Rothenheber, Nicole Christine, "Heat shock protein localization after exercise based on muscle fiber type in mouse biceps brachii" (2010). Honors Project, Smith College, Northampton, MA.
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