山茱萸环烯醚萜苷对局灶性脑缺血大鼠血管内皮生长因子及其受体表达的影响

Effects of cornel iridoid glycoside on the expressions of vascular endothelial growth factor and its receptor in rats with focal cerebral ischemia

目的研究山茱萸环烯醚萜苷（CIG）对局灶性脑缺血大鼠神经功能和血管内皮细胞生长因子（VEGF）及其受体FLK-1表达的影响。方法取成年雄性SD大鼠115只，随机分为假手术组、模型组及CIG治疗组。治疗组又分为20、60和180mg／kg剂量组，每组23只大鼠。采用大脑中动脉线栓法制作大鼠局灶性脑缺血模型，造模后3h开始灌胃给药。造模后7、14和28d，采用改良神经功能缺损评分（mNSS）评价大鼠的神经功能，用免疫组化法和Western Blot法检测VEGF蛋白表达。用RT—PCR方法检测VEGF及其受体FLK-1的mRNA表达。结果①造模后7、14和28d，与模型组相比，CIG 60和180mg／kg组大鼠mNSS均显著降低（F=2．832，F=4．970，F=2．661，均P〈0．05）；②造模后7d，模型组大鼠大脑皮质VEGF蛋白与假手术组相比无明显变化，14和28d时，VEGF蛋白表达降低；与模型组相比，7、14和28d时，CIG 60和180mg／kg组VEGF蛋白表达显著增加（F=1．202，F=1．705，F=2．189，均P〈0．05）；③造模后28d，CIG 60和180mg／kg组大鼠VEGF阳性细胞染色面积显著增加（F=13．249，均P〈0．05）；④造模后7d，与模型组相比，CIG 60和180mg／kg组大鼠大脑皮质VEGF-mRNA表达亦显著增加（F=2．389，均P〈0．05）；CIG 60和180mg／kg组FLK-1 mRNA的表达也显著增加（F=3．657，均P〈0．05）。结论CIG能明显改善局灶性脑缺血大鼠的神经功能，其机制可能与CIG促进VEGF蛋白的表达有关。

Objective To study the effects of cornel iridoid glycoside （CIG） on the neurological function and expression of vascular endothelial growth factor （VEGF） and its receptor in rats with focal cerebral ischemia. Methods A total of 115 adult male Sprague-Dawley rats were randomly allocated into the sham operation, model and CIG （or treatment） groups. The latter was redivided into low- （20 mg/kg）, medium- （60 mg/kg） and high- （180 mg/kg） dose groups （n =23 in each group）. A rat model of focal cerebral ischemia was induced by middle cerebral artery embolization. Three hours after the model was established, the rats began to receive intragastric administration of CIG. Seven, 14 and 28 days after model making, the neurological function of rats was evaluated by the modified neurological severity score （ mNSS）, the expression of VEGF protein was detected by immunohistochemical method and Western Blot, and the expressions of the mRNA levels of VEGF and its receptor Flk-1 were assayed by reverse-transcriptase polymerase chain reaction （RT-PCR）. Results ① Seven, 14 and 28 days after the model was established, the mNSS scores in the medium and high-dose CIG groups were decreased significantly as compared with the model group （F = 2. 832 ,F = 4. 970 ,F = 2. 661, all P 〈 0.05）. ②After seven days, there was no significant change in the expression of VEGF protein in the rat cerebral cortex between the model group and the sham-operation group ; after 7, 14 and 28 days, the expression of VEGF protein in the rat cerebral cortex was decreased in the model group, while it was increased significantly in the CIG medium and high-dose groups as compared with the model group （ F = 1. 202, F = 1. 705, F = 2. 189, all P 〈 0. 05 ）. ③wenty-eight days after the model was established, the VEGF positive cell staining areas in the CIG and highclose groups were increased significantly （F = 13.249, all P 〈 0. 05）. ④Seven days after model establishment, the expressions of the VEGF-mRNA in rat cerebral cortex were increased significantly in the CIG medium and high-dose groups as compare with the model group （F=2.389, all P〈 0.05）. The expression of FLK-1 mRNA in the rat cerebral cortex in the CIG medium and treatment groups was also increased significantly （F = 3. 657, all P 〈 0. 05）. Conclusion CIG improves the neurological function significantly in rat model with focal cerebral ischemia, and its mechanism may be associated with the expression of VEGF protein promoted by CIG.