Relative Expression of Apoptotic and Vascular Epithelial Growth Factor Receptor Genes in Gamma-Irradiated Rat Kidney

Biological process of wound healing, which occurs in three phases of revascularization (inflammatory, proliferative, and maturation) is an important essential step in regulating this process. Blood vessels serve as carriers for various cells, cytokines, and growth factors that are needed for tissue repair. The formation of new blood vessels is a necessary event during embryogenesis, but it occurs rarely in the adult with few exceptions, such as in the female reproductive system and wound healing. Angiogenesis is controlled by a variety of mitogenic, chemotactic, and inhibitory peptide and lipid factors that act on invading endothelial and smooth muscle cells. One of the most important angiogenic factors is the vascular endothelial growth factor (VEGF), a glycosylated protein of 46-48 kD composed of two disulphide linked subunits. The VEGF family consists of six members, five splicing forms of VEGF and the placenta-derived growth factor (PDGF). In normal, VEGF is expressed during embryogenesis and in a limited number of sites in adults. In disease states, VEGF can be detected in various tumor cells, the synovial pannus in rheumatoid arthritis, and in keratinocytes during wound healing. Five different VEGF isoforms, with 121, 145, 165, 189, and 106 amino acids, can be generated as a result of an alternative splicing from the single VEGF gene. The VEGF molecules bind to receptors known as VEFGR- 1 (FLT-1, fms-like tyrosine kinase 1), VEGFR-2 (KDR, kinase domain region/FLK-1, fetal liver kinase 1), VEGFR-2 (FLT-4), neurophilin-1, neurophilin-2, and heparan sulfate proteoglycans. Ionizing radiation can affect the angiogenesis and neovascularization on normal tissues in radiotherapy or by background radiation surrounding living beings. Kidney belongs to the urinary system and classified to the radio-resistant organ according to the previous studies. Therefore, the present study tested the effect of gamma irradiation and mercury chloride (MgCl2) to the renal region by confirming the apoptosis and the expression of renewal receptors to signals for angiogenesis-related growth factors after irradiation