A new method for focal transient cerebral ischaemia by distal compression of the middle cerebral artery

Aims: Rodent experimental models are essential for in vivo study of stroke. Our aim was to develop a reproducible method of mouse transient focal cerebral ischaemia by distal artery compression. Methods: The distal middle cerebral artery (dMCA) was occluded by compression with a blunted needle, and cerebral blood flow was monitored by laser Doppler flowmetry to ensure appropriate occlusion and reperfusion in Balb/c mice. The ischaemic lesion was evaluated 24h after occlusion by TTC staining and immunolabelling (NeuN, CD31, GFAP and Iba-1) while the established permanent dMCA occlusion (dMCAO) model was used as a control. The corner test was performed to evaluate neurological behaviour. Results: Laser Doppler flowmetry register showed a homogenous arterial occlusion among animals. Forty-five minutes of arterial occlusion did not lead brain infarction when evaluated by TTC staining 24h after occlusion. Extending the cerebral ischaemia period to 60min induced a cortically localized homogeneous brain infarct. No differences in infarct volume were detected between animals submitted to permanent or 60-min transient dMCAO (42.33±9.88mm3 and 37.63±12.09mm3 respectively). The ischaemic injury was confirmed by immunohistochemistry in the 60-min transient dMCAO model but not in the 45-min model. Neurological deficits assessed with the corner test were significant only during the first 48h but not at long term. Conclusions: This work shows an easy-to-perform method for the induction of brain ischaemia and reperfusion to assess stroke repair and treatment screening, with cortically localized ischaemic cell damage, low mortality and neurological impairment in the acute phase. © 2012 British Neuropathological Society.