A Review on the Experimental Animal Models of Cerebral Ischemia

Stroke is the third leading cause of death and the major cause of adult physical disability in the world. Despite advances in understanding the pathophysiological mechanisms of cerebral ischemia over the past few decades, the available therapies have not been effective for these patients. Nowadays, various animal models are used to study pathophysiology as well as risk factors, and to find therapeutic strategies for cerebral ischemia. These models divide into two forms: global cerebral ischemia and focal cerebral ischemia. Global ischemia models are divided into complete and incomplete models of ischemia, which are produced by occluding the cerebral blood flow completely or incompletely. Several focal cerebral ischemic stroke models have been developed in a variety of species that interrupt the blood flow to the brain in one or more areas of the brain. The vast majority of cerebral stroke cases are caused by transient or permanent occlusion of a cerebral blood vessel (ischemic stroke) eventually leading to brain infarction. The infarct size and the neurological outcome depend on a multitude of factors such as the duration and severity of ischemia, the existence of collateral systems, age, sex, and genetic background.

Thus, ischemic stroke is a highly complex and heterogeneous disorder. It is obvious that experimental models of stroke cannot cover all the specific aspects of this disease. Therefore, the success of preclinical stroke research in developing new therapeutics for these patients might rely on the selection of the appropriate animal stroke model. This review deals with the most common stroke models and also discusses the advantages and limitations of each model.