Comparative evaluation of silicone-coated, non-coated nylon, and micro guide wire filaments for middle cerebral artery occlusion in rats: implications for reliability and reproducibility of experimental stroke models

Animal models of ischemic stroke are essential tools in studying experimental stroke. Different types of occlusion threads are used in experimental middle cerebral artery occlusion which could result in infarct size variation. In the present study, three different types of threads were used and compared with each another. Male Wistar rats were randomly and blindly assigned in three groups using heat rounded tip non silicon-coated nylon thread, commercial silicon-coated thread and micro guide wire catheter for ischemia induction. One hour ischemic stroke was followed by 23 h reperfusion. Cerebral blood flow of middle cerebral artery territory, behavioral evaluation and infarct volume calculation were done to evaluate the model. Silicon-coated thread gave a significantly more successful results than the other two threads. Around 70% of animals died by Non silicon-coated nylon thread and Micro guide wire catheter threads from subarachnoid hemorrhage. Triphenyltetrazolium chloride monohydrate staining results showed that Silicon-coated thread tended to have larger infarct volume compared to other two filaments although behavioral evaluation showed no significant different between groups. Our findings demonstrated that coating the occlusion thread with silicon provided better and more acceptable artery occlusion than nylon filament or steel guide wire catheter