| Background:In the middle-aged and elderly population worldwide,ischemic stroke is currently the number one cause of threat to human life and health due to its high morbidity,high disability and high mortality.The status of technology in the future basic research of cerebrovascular diseases is self-evident.By establishing various models to simulate the pathophysiological mechanism of human ischemic stroke and exploring potential treatment methods,it has become a routine experimental process for stroke research in the field of neuromedicine.Although many studies have established animal models of diseases through various methods to test potential treatment methods,and some of them have shown good results in rodent model tests,but most of these treatment methods They all ended in failure in human clinical trials.From the lessons of these clinical transformation failures,we can conclude that the current research has an urgent need for animal models that have clinical relevance that better matches humans.Animal models of various large-scale human diseases,such as non-human primates,pigs,sheep,dogs,etc.,their brain structures and physiological and pathological basis of the body are closer to humans.Among them,non-human primate models The connection with the clinic is the closest,which makes the study of cerebral ischemia model preparation and related pathophysiological mechanisms become a key step in the clinical transformation of ischemic stroke intervention measures.Objective:This study adopted a series of experimental process optimization and surgical interventions to prepare a non-human primate ischemic stroke model with concentrated ischemic areas in the cerebral cortex and high degree of experimental reproducibility.Conduct behavioral tests and imaging performance evaluation of the model to quantify the actual degree of compliance of the model,so as to provide a reliable animal detection model for subsequent neuroprotective intervention research.Methods:In this study,6 experimental cynomolgus monkeys(Rhesus macaques)with good growth and development status were selected,provided by the Primate Research Center of Guangzhou Institute of Biological Resources Application,weighing 5-7 kg,male,and randomly divided into A,Group B and 3,each group is numbered#1～6,the two groups of animals were treated with selective clamping of M1 segment of the temporary middle cerebral artery through the wing-point approach,and the operation was performed under intubation general anesthesia Among them,the animals in group A were temporarily blocked for 45 minutes,and the animals in group B were temporarily blocked for 90 minutes.Give analgesic drugs and take various routine care within 24 hours after surgery to ensure the animal’s vital signs are stable.The non-human primate stroke model scale(NHPSS)was used to track and record the neurobehavioral performance of experimental animals on the first,second,fourth,and seventh days after surgery.At 6 hours,48 hours,7 days,and 20 days,MRI scans were performed on the experimental animals,and the scan results were recorded;the data was analyzed and processed using statistical software SPSS.Results:Group A(45tMACO):Cynomolgus monkeys numbered#1,#2,#3 underwent 45 minutes of selective clamping of the middle cerebral artery M1 segment;Group B(45tMACO):numbered#4,#5,#6 Cynomolgus monkeys underwent 90-minute selective clamping of the middle cerebral artery M1 segment;6 experimental animals underwent magnetic resonance scanning before operation,and MRA showed no obvious vascular-related lesions;postoperative 6h,48h,7d,and 20d At the time node,MR scans of 6 experimental animals were performed.The DWI sequence showed that during the ischemic hyperacute period(6h,48h),the distribution of infarcts gradually expanded with time.The average volume of the experimental animal infarct volume in Group A was 2.18ml,9.75ml,9.31ml,1.93ml;the average volume of the experimental animal infarct volume in Group B was 8.40ml,18.21ml,14.75ml,7.11ml,respectively.In group A,within 6 minutes after 45 minutes of unilateral middle cerebral artery occlusion,cerebral infarcts surrounded part of the frontal lobe,parietal lobe,and insular lobe motor cortex,while in group B,the range of infarcts expanded 6 hours after 90 minutes of ischemia To include the midline structure,such as the cingulate gyrus;at 48h,the experimental animal cerebral infarction area reached the largest in the DWI images of the two groups A and B;the infarcts on the 7th scan of the two groups began to decrease earlier than before Small until the 20th day reaches the minimum area.DWI imaging of all cynomolgus monkeys in Group A and Group B revealed that the entire cerebral hemisphere in the same direction had obvious cortical damage.At the same time,the average score of the non-human primate neurobehavioral scoring table on the four-day sampling statistics was Group A:17.3,15.6,14.7,12.3;Group B:22.3,25.7,20.0,18.7;Animals all survive for a long time.This result indicates that the cerebral hemispheric infarcts of experimental animals have limitations and small variability,and the volume of cerebral infarctions has a good correlation with the neurobehavioral prognosis.Conclusion:In this study,a microsurgical craniotomy technique was used to temporarily block the M1 segment of the middle cerebral artery of cynomolgus monkeys using an aneurysm clip.A replicable and highly clinically relevant model of cynomolgus monkey cortical infarction was created.It is confirmed that the variability of this model is small,and the animals have obtained a good survival rate.In addition,the results of neurobehavioral scoring of experimental animals showed that the degree of brain tissue damage of experimental animals had a good correlation with the degree of prognosis,and the unexpected damage of subcortical(basal ganglia)was minimized,and the variation was reduced as much as possible.MR images show that the white matter in the deep brain of the experimental animals in this study is largely intact.The use of neuroprotective agents to protect the ischemic penumbra and cortical areas has good expectations in future clinical studies,and Due to the moderate cortical infarct volume of the model,the calculated volume of the DWI images of the two groups of animals at 48h is about 25%and 33%,respectively.Therefore,the model was used to adjust the size of the infarct and the subsequent examination of the negative or positive effects of candidate neuroprotective drugs Provides more room for adjustment.This non-human primate ischemic stroke model has the advantage of being more accurate and more similar to humans when evaluating hypothetical treatment methods than rodent models,thereby reducing the probability of failure of human clinical trials,And provides more possibilities for preclinical screening of neuroprotective agents aimed at reducing cortical infarction in human large vessels. |
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