银杏叶提取物对慢性脑缺血模型大鼠脑组织突触后致密物-95蛋白及递质氨基酸的影响

目的：观察银杏叶提取物对慢性脑缺血大鼠突触后致密物(postsynaptic density, PSD)-95蛋白及递质氨基酸的影响。方法采用随机数字表法将42只大鼠随机分为假手术组12只、模型组14只、银杏叶提取物组14只。除假手术组外，其余大鼠采用双侧颈总动脉永久性结扎法制备慢性脑缺血大鼠模型。造模后2 h开始灌胃给药。银杏叶提取物组灌胃银杏叶提取物混悬液28 mg/kg，假手术组、模型组灌胃等体积生理盐水，1次/d，连续给药40 d后取材检测。采用免疫组化结合图像分析技术观察大鼠脑组织 PSD-95蛋白的表达；采用邻苯二甲醛-柱前衍生高效液相色谱荧光检测法测定丘脑谷氨酸(glutamic acid, Glu)及γ-氨基丁酸(gamma aminobutyric acid, GABA)含量。结果与假手术组比较，模型组大鼠皮层、丘脑 PSD-95蛋白皮层为(212.58±45.02)比(244.20±34.28)，丘脑为(132.33±28.32)比(272.00±62.14)]表达降低(P＜0.01)，丘脑GABA含量(6081.46±2388.91)mmol/L比(8280.45±3388.49)mmol/L]下降(P＜0.05)；与模型组比较，银杏叶提取物组大鼠皮层、丘脑组织 PSD-95蛋白皮层为(237.89±34.41)比(212.58±45.02)，丘脑为(226.18±75.80)比(132.33±28.32)]表达升高(P＜0.01)，丘脑中Glu(10523.78±3639.72)mmol/L比(6081.46±2388.91)mmol/L]及GABA(18440.93±7476.88)mmol/L比(11239.83±4411.79)mmol/L]含量升高(P＜0.01)。结论银杏叶提取物可选择性调控脑缺血大鼠皮层和丘脑PSD-95的表达，提高丘脑递质氨基酸Glu、GABA含量。

Effect of ginkgo biloba extract on the expression of postsynaptic density-95 and content of neurotransmitter amino acid in chronic cerebral ischemic rats

Objective To observe the impact of ginkgo biloba extract in rats with chronic cerebral ischemia on the expression of PSD-95 protein and the content of amino acid neurotransmitter.Methods A total of 42 SD rats were divided into the sham group (n=12), the model group (n=14) and the ginkgo biloba extract group (n=14) by random number table method. Cerebral ischemia rats were produced by permanent ligation of bilateral common carotid arteries . The rats in the ginkgo biloba group were intrgastric administrated with ginkgo biloba extract suspension 28 mg/kg daily for 40 days, since 2 hours later after the surgery. The rats in the sham and model groups were intragastric administrated with equal-volumn nomal saline daily for 40 days, since 2 hours later after the surgery. The expression of PSD-95 protein was detected by immunohistochemistry techniques with image analysis. The content of Glu and GABA in the thalamus was determinated by OPA-pre-column derivatization and HPLC fluorescence detection method.Results The expression of PSD-95 protein (cortex was 212.58 ± 45.02vs.244.20 ± 34.28, thalamus was 132.33 ± 28.32 vs.272.00 ± 62.14) were significantly lower in the cortex and thalamus of the model group than those of the sham group (P<0.01). The content of GABA (6 081.46 ± 2 388.91 mmol/Lvs.8 280.45 ± 3 388.49 mmol/L) in the thalamus of the model group rats was significantly lower than the sham group (P<0.05). Ginkgo biloba extract could significantly improve the expression of PSD-95 protein (cortex was 237.89 ± 34.41 vs.212.58 ± 45.02, thalamus was 226.18 ± 75.80 vs. 132.33 ± 28.32) in the cortex and thalamus of chronic cerebral ischemia rats (P<0.01), and significantly improve the content of Glu and GABA (Glu was 10 523.78 ± 3 639.72 mmol/L vs.6 081.46 ± 2 388.91 mmol/L, and GABA was 18 440.93 ± 7 476.88 mmol/Lvs.11 239.83 ± 4 411.79 mmol/L) in thalamus with chronic cerebral ischemic rats compared with the model group rats (P<0.01).Conclusion Ginkgo biloba extract could regulate the levels of Glu, GABA and selectly regulate the PSD-95 experssion in the cortex and thalamus of cerebral ischemia rats.