Mechanism Of Hypoxic Training Promoting Angiogenesis On Muscular Tissue

Objective:In order to provide a theoretical basis and applied methods for hypoxic training applied in sports practice, this thesis studied the mechanism of hypoxic training promoting angiogenesis on muscular tissue by exploring the effect of hypoxic training on regulating the hypoxic responsive genes on muscular issue, the effect of the hypoxic responsive genes on boosting angiogenesis on muscular issues, and the angiogenesis mechanism of hypoxic training muscular tissue.Material and Methods:Hypoxia cell culture and electrophoretic mobility shift assay were applied to study the protein-DNA binding activity of hypoxia induced factor-1 and vascular endothelium growth factor gene, and fms-like tyrosine kinase-1 of human umbilicus vein endothelial cell under hypoxia. 3×3 factorial experiment, progressive treadmill exercise, hypoxia and super-hypoxia increasing by degree were used to establish animal model with different training pattern and different hypoxic stimulus. Thereafter, Blood-gas analysis, in situ hybridization, immunohistochemical technology and computer image processing methods were used to study the effect of hypoxic training on the oxygen binding status of arterial blood, the effect of oxygen binding status of arterial blood on hypoxia induced factor-1αof muscular tissue, and then the promoting effect of hypoxic training on genes transcription of vascular endothelium growth factor and fms-like tyrosine kinase-1. In addition, Enzyme linked immunosorbnent assay, Stereology, immunohistochemical technology and computer image processing methods were used to study the accelerating effect of vascular endothelium growth factor and fms-like tyrosine kinase-1 on hypoxic training angiogenesis of muscular tissue. In the end, transmission electron microscope was applied to study the morphological mode of angiogenesis of hypoxic training muscular tissue.Conclusions:Different Oxygen content mixed gases were administered to culture human umbilical vein endothelium cell to found hypoxia cell culture model for ex vivo study of hypoxic training, and an animal model of hypoxic training was successfully established by progressive treadmill exercise and hypoxic stimulus with progressive hypoxia.Simple hypoxia (hypoxia content from 18.2kPa to 15.2 kPa ) and super- hypoxia (hypoxia content from 17.4 kPa to 11.3kPa ) could not increase density of micro- blood vessel. Normoxic training, hypoxic training, and hypoxic administration after training could increase density of micro- blood vessel. Interaction occurred between hypoxic administration and training pattern, and hypoxic administration and training pattern had different main effects. From the changing of micro- blood vessel, hypoxic training was found to be better than normoxic training to micro- blood vessel on muscular tissue.In vivo, hypoxia could increase binding activity of HIF-1 of culture human umbilical vein endothelium cell and VEGF,Flt-1 DNA. The binding activity was regulated by oxygen content within a certain range. Ex vivo, hypoxia could decrease arterial blood oxygen binding; hypoxic training was the most efficient stimulus to decrease arterial partial pressure of oxygen, while it could decrease arterial blood oxygen binding to a large degree. The transcription regulation mechanism of angiogenesis of hypoxic training muscular tissue was: affected by the degree of oxygen binding, hypoxic training could increase the protein expression of HIF-1 o?n muscular tissue and the increase could promote the genes transcription of VEGF and Flt-1.The mechanism of hypoxia responsive genes promoting the angiogenesis of hypoxic training muscular tissue was: hypoxic training could increase the protein of angiogenesis hypoxia responsive genes VEGF and Flt-1, and after VEGF protein was produced, it could secrete by autocrine or by paracrine, combine with Flt-1 receptor on the vascular endothelium cell membrane, and participate in the angiogenesis of muscular tissue. Hypoxia, training, and hypoxic training all could reduce the content of serum VEGF, meanwhile, the proteins of VEGF on muscular tissue increased and the Flt-1 receptors also increased. Therefore, ingestion and utilization of VEGF from circulation was increased on muscular tissue.Angiogenesis on muscular tissue could be performed by means of sprouting and no-sprouting, among which no-sprouting angiogenesis pattern, i.e. intussusceptive microvascular growth, was the major way, suggesting that muscular tissue could take faster and more economical angiogenesis pattern to satisfy the demands of energy and metabolization.