Animal Models of Focal Cerebral Ischaemia and Haemorrhagic Transformation: Considerations in Experimental Stroke Study Design

Background: Ischaemic stroke is often complicated with haemorrhage within the infarct zone or in a remote location especially when treated with intravenous thrombolysis and/or thrombectomy. While these early recanalisation treatments are highly effective, some of the benefit is lost because of haemorrhagic complications and consequential neurological deterioration of the patients. A number of mechanisms have been described that mediate the haemorrhagic changes and several agents have been tested in experimental models for inhibiting post-stroke haemorrhage. Methods: Here, we review and discuss the small animal models of focal cerebral ischaemia and postischaemic stroke haemorrhagic transformation and how these models can best be utilised for developing further insights as well as potential treatment approaches for this serious clinical complication. Results: The need to use appropriate animal models with relevant stroke risk factors to improve the clinical relevance and applicability of findings is becoming ever more apparent. Current focal ischaemia models can be adapted for the study of haemorrhagic transformation post-stroke. Conclusion: A number of factors can be added to the animal model design to increase the incidence and/or severity of haemorrhagic transformation post-ischaemic stroke, which can improve clinical relevance, aid the study of the pathophysiology and the future development of novel interventions.