Introduction: Selective cooling infusion (SCI) of Lactated Ringer’s solution into ischemic territory supplied by the middle cerebral artery (MCA) has been demonstrated as a safe procedure in stroke patients (Chen et al., Stroke, 2016). In order to conduct clinical trials for this therapy, this novel method should be tested in non-human primate (NHP) ischemic stroke models as suggested by the Stroke Therapy Academic Industry Roundtable (STAIR) committee. In the present study, we first developed a realizable thrombus-thrombolysis ischemic model in rhesus monkeys and then we determined whether a SCI of Lactated Ringer’s solution effectively provided a neuroprotection in the NHP with ischemic stroke.
Methods: An autologous clot was made and injected via a micro-catheter (Prowler -10) into the main trunk of MCA to induce focal ischemia in 24 rhesus monkeys. MCA occlusions were confirmed by DSA. Thrombolysis with rt-PA (0.9mg/kg) was completed 3 h after the onset of ischemia. Twelve ischemic animals, in a randomized manner, received SCI at 10 minutes following rt-PA administration. MRI images, NHPSS, Spetzler scores and modified movement assessment panel were used to evaluate brain infarction, neurological deficits and functional outcome through 30 days.
Results: Complete, partial, or no recanalization of MCA were found in eight animals in each ischemic group with or without SCI. SCI significantly reduced infarct volume and neurological deficits, as well as improved motor function when complete or partial reperfusion were established. However, SCI did not protect ischemic brain if reperfusion was not achieved.
Conclusion: Clot embolism and different status of thrombolytic outcomes with rt-PA were developed in rhesus monkeys. SCI is a feasible and practicable neuroprotectant in high-order brains. Reperfusion is a prerequisite for neuroprotection induced by SCI.