胡黄连苷Ⅱ对大鼠脑缺血损伤后髓鞘碱性蛋白表达的影响

摘要

AIM: To verify the neuroprotective effect and optimize the therapeutic dose and time window of picroside Ⅱon cerebral ischemic injury in rats .METHODS:The forebrain ischemia model was established by the method of bilateral common carotid artery occlusion ( BCCAO ) .The successful model rats were randomly divided into 16 groups according to orthogonal design and treated by intraperitoneal injection of picroside Ⅱat different ischemic time poinis and different doses .The changes of the nerve fiber myelin were observed by fast green staining .The immunohistochemical assay and Western blotting were used to quantitatively and qualitatively determine the expression of myelin basic protein (MBP). The mRNA level of MBP in the brain tissues was tested by reverse transcription polymerase chain reaction (RT-PCR).RE-SULTS:Picroside Ⅱ increased the expression of MBP and decreased demyelination after cerebral ischemic injury .The best therapeutic time window and dose were:(1) ischemia for 2.0 h with picrosideⅡat dose of 10 mg/kg according to the results of fast green staining;(2) ischemia for 2.0 h with the dose of 10 mg/kg according to the results of immunohisto-chemical assay;(3) ischemia for 2.0 h with the dose of 10 mg/kg according to the analysis of Western blotting;(4) is-chemia for 1.5 h with the dose of 20 mg/kg according to the detection of RT-PCR.CONCLUSION:Given the principle of the lowest therapeutic dose with the longest time window , the optimized therapeutic dose and time window for rat cerebral ischemic injury is intraperitoneal injection of picroside Ⅱat the doses of 10~20 mg/kg and the time window of ischemia for 1.5~2.0 h.%目的：用正交试验法验证胡黄连苷Ⅱ对大鼠脑缺血损伤的神经保护作用并优化其最佳治疗剂量及时间窗。方法：应用双侧颈总动脉结扎法建立大鼠前脑缺血模型，按照正交试验设计分组，经腹腔注射胡黄连苷Ⅱ干预治疗。固绿髓鞘染色法观察神经纤维髓鞘变化；免疫组织化学法和Western blotting 定性、定量检测髓鞘碱性蛋白（ MBP）的表达；RT-PCR检测MBP mRNA水平。结果：胡黄连苷Ⅱ可上调大鼠脑缺血损伤后MBP表达，减少脱髓鞘；其最佳治疗时间和剂量，根据固绿髓鞘染色显示为脑缺血2．0 h腹腔注射胡黄连苷Ⅱ10 mg/kg；免疫组织化学法分析为脑缺血2．0 h腹腔注射10 mg/kg；Western blotting分析为脑缺血2．0 h给予10 mg/kg；RT-PCR显示为脑缺血1．5 h给予20 mg/kg。结论：根据用药剂量最小化和治疗时间窗最大化的原则综合评价，胡黄连苷Ⅱ对大鼠脑缺血损伤的最佳治疗时间窗为脑缺血1．5～2．0 h，最佳治疗剂量为腹腔注射10～20 mg/kg。