| IntroductionCerebral ischemia - reperfusion is a frequent consequence during cardiac and neurologic surgery. Many surgical procedures such as cardiopulmonary bypass , coronary artery bypass graft, carotid endarterectomy, aneurysmectomy, and resection of arterio - venous malformations , are associated with a substantial risk of global or focal cerebral ischemia. It is well known that intracellular Ca 2+ overload , excitotoxic activity of glutamate and concomitant generation of free radicals are thought to play the prominent role as triggering factors in the pathogenesis of brain ischemia - reperfusion injury. Although anesthesia - linked neuroprotection has been extensively investigated in transient focal and global ischemia in variety of animal model, the underlying mechanisms remains unclear until now.Propofol, a widely used intravenous anesthetics, has cerebral vascular and metabolic effects similar to barbiturates. And it is used for maintenance of neuro-surgical anesthesia because it reduces the cerebral metabolic rate, cerebral blood flow,and intracranial pressure. Although the use of propofol as a cerebral pro-tectant during certain neurosurgical procedures has been advocated, consensus has not been reached as to a protective effect of propofol on cerebral ischemia. Both positve and negative results have been reported with different experimental materials and different methods of ischemia. The neuronal protective property of anesthetics has been frequently attributed to their ability to reduce cerebral metabolism and to suppress brain electrical activity. However, recent reports suggest that cerebral metabolic reduction is riot sufficient to provide neuronal protection and that alternative mechanisms supporting this effect could be related to the cascade of biochemical events triggered by ischemia - reperfusion . However, mechanism remains to be established.Prophylactic pharmacologic neuroprotection interventions could be of great benefit in patients undergoing cardiovascular or neurosurgical procedures. In this study we observed the neuroprotective effects of propofol and explore the possible mechanism during global cerebral ischemia - reperfusion injury by the use of four - vessel occlusion method in a rat model. We selected the hippocampus of rats as our research material because the sensitivity of them to ischemia stimulus is more severe than other parts of the brain. Our experiment consists of four parts as followings: (l)The effects of propofol on ATP content, ATPase activity, lipid peroxidation and ultrastructure in hippocampus mitochondrial in rats during global ischemia - reperfusion. (2)The effects of propofol on levels of amino acids and neuronal apoptosis of hippocampus after global ischemia - reperfusion in rats. (3) The effects of propofol on the expression of c - fos and heat shock protein 70 genes during ischemia - reperfusion in rats. (3)The effects of propofol on the expression of ICAM - 1 and NF - KB genes during global ischemia - reperfusion in rats.Materials and Methods1. Animals: 180 male Wistar rats weighing between 250 - 300g were provided by The Experimental Animal Center of China Medical University.2. Main Apparatus;A set of WATERS HPLC ( 510 chromatograph pump, 486 electrochemical detector ) , MILLENNIVM32 data disposed system, Biometra PCR amplification device,Kodak ID gel imaging analytical system,S500P ultraviolet, DuBan T21 low temperature and high speed centrifuger. H -600 transmission electron microscope, FACSCan flow cytometry, CELL QUEST data disposed system, OLYMPUS AX 70 photomicrography system, Metamorph microscope image analyzer.3. Main Reagent:DEPC( Sigma) ,Trizol Total RNA Isolation Reagent (Gib-co) ,Taq DNA polymerase ( TaKaRa) , Reverse Transcription Kits (TaKaRa) , Primers of c - fos, HSP70, ICAM - 1 , NF - KB, internal reference (3 - actin and - actin, c - fos, HSP70, ICAM - 1, NF - KB Immunohistochemical Detection Kit(Boster) ,ATP,ADP,AMP standard product (Sigma) ,Amino acid standardproduct ( Sigma), ATP enzyme test kit, SOD,...
|
PDF Full Text Request