Étude de médicaments botaniques de la médecine traditionnelle chinoise pour la croissance des cellules endothéliales et l'angiogenèse
|Advisor:||Zhang, Ze; Mighri, Frej|
|Abstract:||Botanic drugs including those used in traditional Chinese medicine (TCM) have a long history of treating cardiovascular diseases, of which endothelial dysfunction is well established as a risk factor. In literature there exist extensive reports about the clinic and healthy benefits of botanic drugs or preparations to the cardiovascular system. Botanic drugs particularly those with potent antioxidative capacity have also been reported to protect endothelial cells (EC) in culture against free radicals and oxidants. However, there is little research about botanic drugs in the context of wound healing and tissue regeneration. This thesis studied four botanic drugs recorded in TCM to explore their effects on vascular EC growth and angiogenesis, two events actively involved in wound healing and tissue regeneration. In the first part of the thesis, human umbilical endothelial cells (HUVEC) were cultured in the presence of different doses of astragalus powder extract, astragalus injection, puerarin injection, and proanthocyanidin. Among the four drugs, proanthocyanidin showed a potent effect on cell viability and stimulated cell growth in a dose dependent manner. Outside the effective dose range proanthocyanidin was either ineffective or cytotoxic. Importantly, the proanthocyanidin under test was able to maintain a cell viability comparable with the cells supplemented with the commercially available EC growth medium at both low and normal serum conditions, which suggests the potential of proanthocyanidin as an EC growth stimulator and an angiogenic reagent. In the second part of the thesis, mechanistic studies were performed by blocking both endothelial cell growth factor receptors (VEGFR) and epithelial cell growth factor receptors (EGFR). However, the blockers were ineffective in reducing the stimulatory effect of proanthocyanidin on EC. Therefore it is concluded that proanthocyanidin stimulates EC growth through membrane receptors other than VEGFR and EGFR. In the third part of the thesis, it was shown that proanthocyanidin could be loaded into polyvinyl alcohol cryogel and then released from the gel at a concentration within the effective dose window. This demonstrated the feasibility of drug releasing of proanthocyanidin. Finally, the angiogenic property of proanthocyanidin was tested in chick embryo chorioallantoic membrane (CAM) model, showing that this botanic drug was capable of stimulating vasculature development. Preliminary data in rat subcutaneous model also support the angiogenic potential of proanthocyanidin. This thesis therefore demonstrated for the first time that proanthocyanidin was capable of modulating the activity of human EC and in particular upregulating EC activity and growth in the absence of growth factors, and that proanthocyanidin may be used as an angiogenic reagent and released from a synthetic drug carrier. Consequently, this thesis has demonstrated that botanic drugs in traditional medicine may be used as substitutes of protein products to maintain cells in culture and to induce angiogenesis for wound healing and tissue regeneration.|
|Document Type:||Thèse de doctorat|
|Open Access Date:||5 July 2018|
|Collection:||Thèses et mémoires|
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