Description: Introduction/purpose: Recovery from muscle damage involves a type of programmed cell death known as apoptosis. Damage Associated Molecular Patterns (DAMPs) are released after muscle damage and may cause premature apoptosis in monocytes infiltrating the damaged site. This may alter the time course of events towards recovery. Therefore, the purpose of this study was to investigate if downhill running causes a change in the susceptibility of monocytes to apoptosis. Methods: Participants (5 male, 6 female) completed a downhill running protocol consisting of 6-5 minute bouts at a speed of 6-9mph on a -15% grade treadmill. Venous blood samples were collected immediately pre-exercise (PRE), in addition to 4 -h, 24 -h and 48 -h post-exercise. Creatine kinase (CK) was measured to give an indication of muscle damage. Monocytes were analyzed by flow cytometry for expression of multicaspase and annexin v reagent was used to detect changes in the plasma membrane. A MILLIPLEX MAP human early apoptosis magnetic bead 7-plex kit (EMD Millipore, Billerica, MA) was used to assess the relative concentration of phosphorylated protein kinase B (Akt), Bcl-2 associated death promoter (BAD), B cell lymphoma-2 (Bcl-2), active caspase-8, active caspase-9, c jun N terminal kinase (JNK) and tumor protein p53 by Luminex multiplex assay. Results: CK peaked at 24- h. Monocytes showed greater expression of multicaspase at 24 –h and 48 -h than at PRE. Bcl-2, p53 and caspase-8 were all significantly greater at 24 –h than at PRE. Conclusion: Downhill running did alter the apoptotic response of monocytes and therefore may be important in the recovery process from muscle damage.
Date: August 2016
Creator: Pennel, Kathryn Ann Foster