Study On The Angiogenesis Mode In Wound Healing Process

Capillaries are the only place for metabolism and material exchange.Capillaries provide nutrients,oxygen,and replace metabolites such as CO₂,and transmit them outside the body.When the local tissue were cut,angiogenesis is not only part of the integrity of self-repair,but also the basic conditions for the further repair of tissue.The development of new capillaries is necessary in supporting the new organization. Angiogenesis can reduce the diffusion distanc for oxygen from the capillary to the cells and increase the oxygen supply in cell,and improve cell function under hypoxic conditions and thus improve the overall supply for trauma tissue.Sprouting angiogenesis and intussusception angiogenesis are the main forms of angiogenesis in the process of wound healing.The study of angiogenesis in the wound healing has achieved much progress.The specific process and the basic mechanism of sprouting and intussusception angiogenesis have been understood more deeply.The detailed mechanism about angiogenesis in wound healing is still not dear.In order to find the answers to these questions,based on the model of endothelial cell factor diffusion to surrounding tissue, we attempt to introduce a series of assumptions about capillary network construction. The responses of endothelial cells to different concentration of endothelial growth factor are studied in order to explore angiogenesis mode.In this thesis,the study is done through the following aspects mainly.In the first part,the background of angiogenesis in wound healing and the related current situation and basic knowledge are summarized.Because angiogenesis is associated with the whole process of wound healing,the basic skin wound healing processes are introduced.The study of the relationship between angiogenesis and wound healing are illustrated in detail.At the same time,angiogenesis modes in wound healing in recent years are summarized,the questions of existence for these models are put forward,as well as the purpose and significance of the thesis.In the second part,the basic process and respective regulatory mechanism of sprouting and intussusception angiogenesis are analyzed and explored.On the basis of sprouting and intussusception angiogenesis,angiogenesis mechanisms and modes in wound healing are concerned.In the third part,the models of angiogenesis mode in wound healing are observed through experiment.Make a deep full-thickness wound in adult SD rat skin,draw materials from skin at different time points of post-trauma,Observe capillary and endothelial cells by TEM and estimate the angiogenesis mode by the ultrastructure of endothelial cells and the continuity of basement membrane.Through experiments it is found that sprouting mainly exists in acute hypoxia of early trauma and intussusception occurs in the slow hypoxic conditions,along with VEGF concentration decreasing.In the fourth part,based on a series of facts including that cells in trauma or hypoxic conditions express VEGF abundantly,the endothelial cell receptors increase,VEGF and endothelial receptor Flk-1 and Flt-1 are bound specificly to proliferate for endothelial cell, the responses of endothelial cells are different with different VEGF concentration,some assumptions of capillary network construction is introduced,the model of endothelial growth factor diffusion to surrounding tissue is constructed and the influencing factors of endothelial growth factor are analyzed.Based on the responses of endothelial cells to different concentrations of endothelial growth factor,the modes of angiogenesis are judged.And in accordance with the characteristics of capillary development,the capillary network in wound is constructed.Through these studies,The version and model about relationship between angiogenesis modes in wound healing and the response of endothelial cell to different concentrations of the endothelial growth factor is drew off,which provides evidence for judging the angiogenesis mode in wound healing process.