In vivo injury paradigms

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Recent progress in the area of stroke research suggests that a number of molecular mechanisms are intimately involved in the evolution of ischemic brain injury. Gene induction has been observed following ischemia, but the exact roles of many are not yet well known. Some gene products are known to be detrimental to the cell while others are felt to be neuroprotective. The goals of this project are to define more precisely the roles of three classes of genes which may play neuroprotective roles. They are: the proto oncogene, bcl-2, antioxidant genes (sod-1 and gspx) and the stress protein, hsp70. In Project 2, we will utilize genetically normal animals and study 3 different in vivo models of ischemia (2 focal and one global models of cerebral ischemia). We will alter gene expression via gene transfer using defective herpes simplex and adenoviral vectors. We will study the limits and conditions under which gene over-expression may improve neuron survival. We hypothesize that injury due to some, but not other kinds of insults will be attenuated with gene product over-expression, and that these observations will offer insight into the pathophysiology of cell death. We will examine whether gene transfer after the onset of injury is neuroprotective, and whether over-expression of Bcl-2 and antioxidant genes are protective against permanent as well as transient focal cerebral ischemia. We will also examine mechanisms underlying neuroprotection, or lack of neuroprotection, by examining the participation of other gene products such as the stress proteins, caspases and Bcl-2 family proteins in response to gene over-expression and cerebral injury. We will also study whether gene over-expression alters generation of superoxide and apoptosis. These novel approaches will hopefully add insight into the complex molecular processes involved in cerebral ischemia and may lead to the development of treatments for stroke and other degenerative disorders.