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BACKGROUND: Insulin-like growth factor-I(IGF-1), as one of the important members of growth factor family,participants in the regulation of many physiological functions and behaviors, having very strong neuroprotective effect. However, the expression of IGF-1 following cerebral ischemia/reperfusion is still disputed.OBJ ECTIVE: To observe the expression of IGF-1 and protein of corpora striata in ischemic side at the early stage of middle cerebral artery ischemia/reperfusion in rhesus monkey.DESIGN: A completely randomized grouping design, controlled animal experimentSETTING: Institute of Cerebrovascular Disease, Affiliated Hospital of Medical College of Qingdao University.MATERIALS: ① Totally 17 rhesus monkeys , of either gender, aged 4 to 5 years, were enrolled . Seven rhesus monkeys observed with gene chip were randomly divided into 2 groups: sham operation group (n=3)and ischemia/reperfusion group (n=4). Ten rhesus monkeys observed with in situ hybridization and immunohistochemistry method were randomly divided into 2 groups: sham operation group (n=3)and ischemia/reperfusion group (n=7). Rhesus monkeys observed under microscope were divided into 2 groups: sham operation group (n=6) and ischamia/reperfusion group (n=11). ② Materials used in the experiment: cresyl violet (Sigma Company, America); immunohistochemical reagent kit ( Huamei Bio-engineering Company); In situ hybridization reagent kit (Boshide Bio-engineering Co. Ltd, Wuhan); 12 800 dots chip (Boxing Company,Shanghai).METHODS: This experiment was carried out at the Institute of Cerebrovascular Disease, Affiliated Hospital of Medical College of Qingdao University from January 2001 to December 2003. ① The onset area of middle cerebral artery was blocked for 2 hours, middle cerebral artery ischemia/reperfusion models were created.② After ischemia/reperfusion for 24 hours, cerebral tissue sections of rhesus monkeys were prepared and stained with cresyl violet. Image analysis was performed with 500IW image analysis software. Morphological change of corpora striata of operative side was observed in the rhesus monkeys between two groups. Total RNA was extracted from cerebral tissue. ③ Detection of gene chip: Cy3-duTP and Cy5-duTP were used to respectively perform reverse transcription labeling. The sample was reversely transcribed into cDNA, then hybridized with cDNA of cerebral tissue. Genes with the separate absolute value of cy3 and cy5＞800,cy3/cy5 ＞ 2(high expression) or ＜ 0.5 (Iow expression) were found out. Those were genes with differential expression. ④ The expressions of IGF-1 mRNA and protein level of corpora striata in ischemic side of rhesus monkeys were detected between sham operation group and ischemia/reperfusion group at 9 and 24 hours after ischemia/reperfusion with in situ hybridization method and immunohistochemical method. Brown granules were IGF-1 protein positive cells. ⑤ Analysis of variance was used in the difference comparison of measurement data among groups.MAIN OUTCOME MEASURES: ① Change of morphological structure of corpora striata at ischemic side in rhesus monkeys. ② Change of cerebral gene expression profiles at ischemia/reperfusion in rhesus monkeys between two groups. ③ Expression of IGF-1 mRNA and protein level of corpora striata at ischemia/reperfusion in rhesus monkeys between two groups.RESULTS: ① Pathological change: Obvious pathological change of cerebral infarction appeared in the ischemia and reperfusion group, while there was no such pathological change in the sham operation group.② Change of gene expression profile: There were 4480 genes with difference expression in the ischemia/reperfusion group and sham-operation group, in which, 260 genes had high expression and their absolute value was over 800, and 63 genes had Iow expression. Cy3/cy5 of IGF-1 was 0.379, being relative Iow expression. ③ IGF-1 mRNA and protein positive cell counts in corpora striata at cerebral ischemic side[IGF-1mRNA: (9.72±1.18),(9.11 ±0.76),(14.77±0.60) counts/field;lGF-1 protein: (15.11 ±1.83),(15.39±0.78),(34.62±0.97)counts/field, P ＜ 0.05-0.01].CONCLUSION: IGF-1 mRNA and protein are lowly expressed in middle cerebral artery of rhesus monkeys at ischemia/reperfusion.