| Aims The main pathophysiological character of cerebrovascular disease (CBD) is complex injury induced by brain aging and ischemia. Previous pathogensis studies about CBD were always undertaken with single factor, cerebral ischemia or brain aging. However epidemiological survey indicated CBD often occured in aged, implicating that cerebral ischemia based on brain aging should not be neglected. The manifestation of brain aging such as decline of learning and memory is already seen during prophase (45-59 old). Multiple cerebral embolism and other types of CBD often happen in human over 60. It shows that CBD occurrence is based on brain aging. So it is one of our main objectives to investigate the underlying mechanism of brain aging and ischemia complex injury, which is also the premise and background of experimental therapeutics.Pituitary adenylate cyclase -activating polypeptide (PACAP) is a neuropeptide with multiple biological activitis. It can modulate cell development, growth, proliferation, differentiation, etc. It was reported recently that PACAP had a high neuroprotective role, indicating a promising prospect in the treatment of brain aging and ischemia. But systemic study about its protection is scarce, especially lack in brain ischemia based on aging.Our research is to investigate the common pathophysiological character of complex injury- neuronal apoptosis at molecular and cellular level,observe antagonistic effects of PACAP on them, and the relationship between these changes and synaptic circulation (LTP), to provide instruction for treatment of CBD in clinics.Part I. Investigation of neuronal apoptosis in complex injury of brain aging and ischemia and effect of PACAP on them.To study the regularity of oxygen stress and apoptosis during complete cerebral ischemia-reperfusion model in aging rats and the underlying mechanism of PACAP.The amount of survival and apoptotic neurons stained by HE and TUNEL was measured in hippocampal CA1 region and cortex at interval 6h, Id, 3d, 5d and 7d following complete cerebral ischemia ten minutes by four-vessles ligation method. The ultrastructures and themalondialdehyde(MDA), suoeroxide dismutase (SOD) , glutathionc peroxidase (GSH-Px) were assayed. In addition, the change of Caspasc-3 and TrkA gene expression was also observed using SABC immunohistochemistry method. Meantime, effect of PACAP by intracere -broventricular injection on previous parameters was also analysized.The results showed number of survival neurons reduced remarkably, apoptotic neurons increased in hippocampus CA1 region and cortex. Electron microscope in CA1 region also indicated apoptotic occurrence, such as chromatin edging, nuclei pycnosis, etc. Neuronal damage happened the most severely in reperfusion 3d. Furthermore, MDA contents inreased, SOD and GSH-Px activity decreased significantly, especially 3d following ischemia. Caspase-3 and TrKA expression were activated during reperfusion and the variation was closely correlated with apoptotic change11at almost the same interval. The increase of TrKA implicated neuronal endogenous protection. The apoptotic mechanism was related to the increase of oxygen free radicals and decrease of antioxidantase activity.The MDA content was reduced, SOD and GSH-Px were increased in rats brain after PACAP treatment, which were remarkably different from those in the group without PACAP treatment. Survival neurons were increased and apoptotic neurons were attenuated remarkably. Ultrastrctures in CA1 region were also attenuated. Caspase-3 expression was inhibited and TrKA was increased in cortex which indicated that PACAP might play a neuroprotective role by expanding the effect of NGF.Part II. Injury of reactive oxygen species (ROS) on hippocampal cells and protection of PACAP.To further investigate the mechanism of neuronal injury caused by the common virulence factor-ROS and protection of PACAP on apoptosis signal transduction in vitro.ROS model was set up by hypoxan...
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