Thesis (PhD (Physiological Sciences))--University of Stellenbosch, 2011. / Includes bibliography. / ENGLISH ABSTRACT: Muscle injuries are associated with changes in skeletal muscle as well as the immune
system. All studies investigating possible treatment modalities have found both positive and
negative effects on muscle recovery. Since no universally accepted treatment modality
exists, this thesis aims to determine whether a plant-derived antioxidant, proanthocyanidolic
oligomer (PCO), might prove beneficial as treatment for sports injuries in order for athletes to
return to the sports field quicker. The difference in recovery of muscle following both chronic
(supplementation started 14 days prior to injury and continued thereafter) and acute
supplementation (supplementation started two hours after injury) were also investigated.
Both chronic and acute PCO supplementation in a rat hindlimb contusion injury model
resulted in earlier muscle recovery, verified by an earlier satellite cell response compared to
the placebo group. This effect was most prominent already at the four hour time point
following injury, compared to day seven and three after chronic and acute placebo treatment
respectively. PCO supplementation also resulted in quicker foetal myosin heavy chain
(MHCf) expression compared to placebo treatment. Chronic supplementation specifically
resulted in a blunted circulatory pro-inflammatory cytokine response, whilst allowing for a
significant increase in IL-10, an anti-inflammatory cytokine, on day three (in the PCO group
only). At tissue level, the response of the muscle pro-inflammatory cytokines, TNF- and IL-
6, coincided with the satellite cell response. Macrophage infiltration into the injured muscle
also followed a similar pattern to that seen for the pro-inflammatory cytokines. Macrophages
invaded the injured area quicker when supplemented with PCO chronically, however,
macrophage infiltration could not explain the cytokine response seen with acute
supplementation. Both chronic and acute supplementation with PCO was responsible for a
severely blunted neutrophil response, a novel finding of this particular antioxidant.
The main findings of the in vivo rodent study were that PCO was able to blunt the neutrophil
response, whilst allowing for earlier macrophage infiltration. To establish possible
mechanisms by which PCO might exert these beneficial effects, further analysis included determining macrophage phenotypes and neutrophil numbers in circulation. An in vitro
neutrophil migration assay was also employed to further elucidate PCO’s ability to blunt
neutrophil infiltration into the injured area. For this study, conditioned plasma were harvested
from experimental animals and added together with neutrophils from control rats and
granulocyte colony stimulating factor (G-CSF) to the insert of the migration chamber. A
chemotactic factor, N-formyl methionine-leucine-phenylalanine (fMLP), was added to the
bottom well and neutrophils were allowed to migrate for two hours. Results from this study
indicated that neutrophil migration was attenuated in vitro in the presence of conditioned
plasma from PCO supplemented rats only.
The studies in this thesis on the effect of PCO on parameters of muscle and the immune
system led to the following main conclusions: a) PCO supplementation resulted in earlier
muscle recovery as a result of earlier satellite cell activation and MHCf synthesis; b) PCO
favours an anti-inflammatory cytokine reaction, whilst blunting the pro-inflammatory cytokine
response; and c) PCO blunted the neutrophil response whilst facilitating earlier macrophage
infiltration into the injured area. The specific mechanism of action of PCO to blunt the
neutrophil response specifically, possibly includes the ability to suppress adhesion molecule
expression on the neutrophils themselves. However, this warrants further investigation. / AFRIKAANSE OPSOMMING: Spier beserings word geassosiëer met veranderinge in skeletspier sowel as die
immuunstelsel. Meeste studies wat moontlike behandelingsopsies ondersoek, het beide
positiewe en negatiewe spierherstel gerapporteer. Omrede daar geen universele
behandelingsmoontlikheid bestaan nie, is die doel van hierdie tesis om die effek van ‘n
plantgebaseerde anti-oksidant, pro-antosianiedoliese oligomeer (PSO), as ‘n voordelige
behandelingstrategie vir sportbeserings te toets. Die verskil in spierherstel na beide kroniese
(supplementering wat 14 dae voor besering begin is, en volgehou is daarna) en akute
supplementering (supplementering het twee uur na besering begin), is ook ondersoek.
Beide kroniese en akute PSO supplementering, in ‘n rot agterbeen-kneusbeseringmodel, het
gelei tot vroeë spierherstel. Die bevindinge is geverifiëer deur ‘n vroeë satelietselrespons in
vergelyking met die plasebo groep. Hierdie effek was reeds opvallend vier uur na besering,
in vergelyking met die dag sewe en dag drie tydpunt tydens kroniese en acute plasebo
behandeling onderskeidelik. In vergelyking met die kontrole groep, het PSO
supplementering ook gelei to vininger uitdrukking van miosienswaarketting (MHCf). Kroniese
supplementering het spesifiek gelei to ‘n onderdrukte sirkulatoriese pro-inflammatoriese
sitokien response, terwyl ‘n betekenisvolle toename in IL-10 op dag drie (in die PSO groep
alleenlik) waargeneem is.
Op weefselvlak, het die pro-inflammatoriese sitokiene, IL-6 en TNF- , dieselfde patron
gevolg as die van satelietselle. Makrofaaginfiltrasie binne die beseerde spier het ook ‘n
soorgelyke patroon gevolg. Makrofage het die beseerde area vinniger geïnfiltreer in die
kronies PSO-gesupplementeerde groep, maar kon nie die sitokienrespons, wat waargeneem
is met akute supplementasie, verklaar nie. Beide kroniese en akute PSO supplementering
was verantwoordelik vir ‘n onderdrukte neutrofiel respons, wat ‘n nuwe bevinding is vir
hierdie spesifieke anti-oksidant. Die hoof bevindinge in die in vivo rotstudies, is dat PSO instaat is om die neutrofielrespons te
onderdruk, en sodoende vroeë makrofaaginfiltrasie teweeg te bring. Om meganismes
waarby PSO hierdie voordelige effekte veroorsaak te ondersoek, is verdere analises gedoen
om makrofaagfenotipe en neutrofielgetalle in die sirkulasie te bepaal. ‘n In vitro
neutrofielmigrasie studie is ook aangewend om PSO se vermoë om neutrofielinfiltrasie in die
beseerde area te onderdruk, te ondersoek. Neutrofiele van kontrole rotte, tesame met
gekondisioneerde plasma van eksperimentele diere en granulosiet-kolonie stimulerende
faktor (G-KSF), is toegelaat om vir twee ure in die teenwoordigheid van ‘n chemotaktiese
faktor, N-formiel metionien-leusien-fenielalanien (fMLP) te migreer. Resultate van hierdie
studie het aangetoon dat neutrofielmigrasie, in vitro, alleenlik onderdruk word in die
teenwoordigheid van gekondisioneerde plasma van PSO-gesupplementeerde rotte.
Die studies in hierdie tesis oor die effek van PSO op parameters van spier en die
immuunsisteem, het tot die volgende hoofgevolgtrekkings gelei: a) PSO supplementering
het vroeë spierherstel, as gevolge van vroeë satelietselaktivering en MHCf sintese, teweeg
gebring; b) PSO verkies ‘n anti-inflammatoriese sitokien reaksie, terwyl dit die proinflammatoriese
sitokienrespons onderdruk; en c) PSO onderdruk die neutrofielrespons,
terwyl vroeë makrofaaginfiltrasie in die beseerde area gefasiliteer word. Die spesifieke
meganisme van aksie van PSO, om die neutrofielrespons te onderdruk, kan moontlik die
vermoë van neutrofiele om adhesie molekule uit te druk, insluit. Hierdie aanname moet egter
verder ondersoek word.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/6509 |
| Date | 03 1900 |
| Creators | Kruger, Maria Jacoba |
| Contributors | Smith, Carine, Myburgh, Kathryn H., University of Stellenbosch. Faculty of Science. Dept. of Physiological Sciences. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 292 p. : ill. |
| Rights | University of Stellenbosch |
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