绿茶多酚对帕金森大鼠神经保护作用及对PI3K/Akt信号通路的影响

Neuroprotective Effect of Green Tea Polyphenols on Rats with Parkin-son’s Disease and Its Effect on PI3K/Akt Signaling Pathway

目的 探究绿茶多酚 (GTP) 对帕金森 ( PD) 大鼠神经保护作用, 并初步探究其作用机制.方法 将大鼠分为对照组 (Control组)、 Model组、 GTP低、中、高剂量组 ( GTP-L、 GTP-M、 GTP-H)、 PI3K激活剂 (740 Y-P) 组, 每组12只, 阿普吗啡 (APO) 旋转诱导实验、悬挂实验评估大鼠神经行为学变化;免疫组化检测大鼠黑质组织中络氨酸羟化酶 (TH) 阳性表达情况;检测黑质组织中丙二醛 ( MDA)、超氧化物歧化酶 (SOD)、谷胱甘肽过氧化物酶 ( GSH-Px) 活性;免疫荧光法检测组织中CD11b阳性表达情况;Tunel染色检测神经元凋亡情况;免疫印迹 ( WB) 检测组织中磷脂酰肌醇激酶 ( PI3K)、 p-磷脂酰肌醇激酶 (PI3K)、蛋白激酶B (Akt)、 p-蛋白激酶B (Akt)、 Bcl-2、 Bax、 Caspase-3蛋白表达情况.结果与Sham组相比, Model组APO诱导圈数升高, 悬挂实验评分升高, Model组脑黑质TH阳性表达率降低,脑黑质中SOD、 GSH-PX水平降低、 MDA水平升高, CD11b阳性表达率升高, p-PI3K、 p-Akt蛋白表达降低, 神经细胞凋亡率升高, Bax、 caspase-3蛋白表达升高, Bcl-2蛋白表达降低, 差异显著 (P<0.05).与Model组相比, GTP各组、 740 Y-P组APO诱导圈数降低, 悬挂实验评分降低, 脑黑质中SOD、 GSH-PX水平升高、 MDA水平降低, CD11b阳性表达率降低, p-PI3K、 p-Akt蛋白表达升高, 神经细胞凋亡率降低, Bax、 caspase-3蛋白表达降低, Bcl-2蛋白表达升高, 差异显著 (P<0.05).结论 绿茶多酚可能通过激活PI3K/Akt信号通路, 降低解氧化应激反应, 缓解神经元损伤进而发挥神经保护作用.

Objective To investigate the neuroprotective effect of green tea polyphenols (GTP) on Parkinson’s disease ( PD) rats and its mechanism.Methods The rats were divided into Control group, Model group, GTP low, medium, and high dose groups ( GTP-L, GTP-M, GTP-H), PI3K activator group (740 Y-P), with 12 rats in each group.The neurobehavioral chan-ges of rats were evaluated by apomorphine ( APO) rotation induction test and suspension test.The positive expression of thyrosine hydroxylase ( TH) in substantia nigra of rats was detected by immu-nohistochemistry.The activities of malondialdehyde ( MDA ) , superoxide dismutase ( SOD ) and glutathione peroxidase ( GSH-Px ) in substantia nigra were detected.The positive expression of CD11b was detected by immunofluorescence.Tunel staining was used to detect neuronal apopto-sis.The expression levels of phosphatidylinositol kinase ( PI3K ) , p-phosphatidylinositol kinase ( PI3K), protein kinase B ( Akt) , P-protein kinase B ( Akt) , Bcl-2, Bax, and Caspase-3 were detected by Western blotting ( WB).Results Compared with Sham group, APO induced cycles number increased, hanging test score increased, TH positive expression rate in substantia nigra de- creased, SOD, GSH-PX levels decreased and MDA levels increased in substantia nigra, the posi-tive expression rate of CD11b increased, the expression of p-PI3K and p-Akt decreased, and the apoptotic rate of nerve cells increased, the expression of Bax and caspase-3 protein increased, the expression of Bcl-2 protein decreased in Model group, and the differences were significant ( all P<0.05).Compared with model group, APO induced cycles number decreased, hanging test score decreased, the levels of SOD and GSH-PX increased and MDA decreased in substantia nigra, the positive expression rate of CD11b decreased, the expressions of p-PI3K and p-Akt increased, and the apoptotic rate of nerve cells decreased, the expression levels of Bax and caspase-3 decreased, while the expression of Bcl-2 increased in GTP group and 740 Y-P group, and the differences were significant ( all P<0.05).Conclusion Green tea polyphenols may play a neuroprotective role by activating PI3K/Akt signaling pathway, reducing oxidative stress response, and alleviating neuronal damage.