缺氧缺血新生鼠脑组织谷氨酸及脑细胞内钙改变和降钙素基因相关肽的保护作用

Protective function of calcitonin gene-related peptide and the changes of glutamic acid and free calcium in hypoxic-ischemic brain cells of neonatal rats

目的:探讨新生鼠缺氧缺血性脑损伤(hypoxic-ischemic,HIE)脑组织谷氨酸、脑细胞内钙的改变及降钙素基因相关肽(calciumgene-relatedpeptide,CGRP)的神经保护作用,为临床治疗和早期康复提供理论依据。方法:实验于2003-05/09在广东医学院儿科实验室完成。选择45只7d龄SD大鼠,分为正常对照组、药物治疗组、生理盐水组。药物治疗组于HIE后给予CGRP3μg/(kg·d),腹腔内注射,连续3d,而生理盐水组每天给予同剂量生理盐水腹腔内注射。各组分别在规定时间内断头取脑。采用全自动氨基酸分析仪检测脑组织谷氨酸的浓度,应用钙荧光指示剂Fura-ZAM法测定脑细胞胞浆游离钙离子浓度。结果:新生鼠缺氧缺血后生理盐水组脑组织谷氨酸及细胞内钙浓度最高犤(2.83±1.39)μmol/L,(129.47±17.21)nmol/L犦,与正常对照组犤(1.45±0.56)μmol/L,(93.72±24.16)nmol/L犦比较差异有显著性意义(P<0.01),而药物治疗组犤(1.77±0.60)μmol/L,(103.35±12.46)nmol/L犦与正常对照组比较差异无显著性意义(P>0.05)。结论:CGRP能抑制缺氧缺血新生鼠脑组织谷氨酸的释放,从而阻止谷氨酸介导的钙内流,提示CGRP具有神经保护作用。

AIM: To study the protective role of calcium gene- related peptide (CGRP) in nerve and the changes of glutamic acid and free calcium in cells of hypoxic- ischemic (HIE) brain in neonatal rats to provide academic foundation for clinical treatment and early rehabilitation.METHODS: The experiment was finished in the Department of Pediatrics of Guangdong Medical College from May to September 2003. Forty- five SD rats of 7 days old were randomly divided into three groups: normal control group, CGRP group and saline group. In CGRP group, the rats were given CGRP intraperitoneal injection for 3 days in doses of 3 μ g/kg per day soon after the HIE model was performed. In saline group, the rats were given saline in same doses intraperitoneal injection for 3 days. All the rats were decapitated and the content of glutamic acid in cerebral tissue were detected with a full- automatic biochemical analyzer, and the concentration of dissociative calcium ion was measured with calcium fluorescence indicator in Fura- ZA.RESULTS: The contents of glutamic acid and free calcium ion in saline group [(2.83± 1.39)μ mol/L,(129.47± 17.21) nmol/L] were obviously higher than those in control group[(1.45± 0.56)μ mol/L,(93.72 ± 24.16)nmol/L] and there was significant difference(P< 0.01). But there was no significant difference in the content between control and CGRP groups[(1.77± 0.60) μ mol/L,(103.35± 12.46) nmol/L](P > 0.05).CONCLUSION: CGRP can inhibit the release of glutamic acid in hypoxic- ischemia cerebral cell and prevent calcium influx induced by glutamic acid, which may reveal CGRP has neural protective function.