Effects of nitrite and oxygen on angiogenesis in vascular networks of the chicken embryo

摘要: EFFECTS OF NITRITE AND OXYGEN ON ANGIOGENESIS IN VASCULAR NETWORKS THE CHICKEN EMBRYO By Michael D. Connery, PhD A dissertation submitted in partial fulfillment of the requirements for degree Doctor Philosophy at Virginia Commonwealth University. University, 2013. Director: Dr. Roland N. Pittman, Professor, Department Physiology and Biophysics Nitric oxide (NO) is an important mediator angiogenesis primarily produced endogenously through action nitric synthase (NOS). An alternate pathway NO production conversion nitrite to NO, which depends on presence hemoglobin (Hb) hypoxic conditions. The angiogenic effects topically applied sodium two vascular beds ex ovo chicken embryonic model were assessed. Gas barrier films used modulate local oxygen levels chorioallantoic membrane (CAM), a respiratory network, area vasculosa (AV) yolk sac, typical peripheral network. low-permeable film polyvinylidene chloride (PVDC) highly permeable regenerated cellulose (RC) surface vasculature alter diffusion transport produce environment low or high oxygen, respectively. Phosphorescence Quenching Microscopy (PQM) was verify membranes underneath films. Following 48 hours continuous application (330 μg/kg/day), saline, + cPTIO (a scavenger) (1mg/kg/day), response quantified by measuring density network complexity. PVDC reduced CAM PO2 17.9±5.5 mmHg AV 29.5±3.6 while RC maintained 115 mmHg. At edge film, there found be small transition between nearby regions. After application, significant increases vascularity observed under conditions, but not normoxic conditions (p<0.03). inhibited nitrite-induced returned with saline application. No changes CAM, trend after compared saline+cPTIO. These results indicate that diffusible gases, O2, play roles growth new blood vessels, way appears depend gas exchange function