The Transport Removals And Regulation Of Tenuigenin On Beta-Amyloid-induced PC12 Cells Function And Cell Cycle

Tenuigenin is a major component of the dried root of P. Tenuifolia, or ’yuanzhi’, which is traditional Chinese medicine. In traditional Chinese medicine clinical treatment, Polygala has been used to treat disharmony between heart and kidney cause insomnia, forgetfulness, palpitation, trance embolism. It’s used as tonic, sedative and preventing dementia agents. Recent research has shown that it can prevent nerve cell from injuring through not only resisting β-amyloid protein toxicity, regulating Tau proteins and cholinergic system, mitigating glutamate neurotoxicity, but also anti-inflammatory, antioxidant, inhibiting apoptosis and promoting neuronal regeneration, etc. However, there are less reports about more in-depth study of neuroprotective effect of tenuigenin, such as transporter-mediated apoptotic signaling pathway. And the reports, which about tenuigenin’s regulation of Aβ-induced cell cycle disorder, are even less. This paper will continue to further study the neural protective effect and its mechanism of tenuigenin. The details are as follows:1. The study of tenuigenin on Aβ-induced pc12 cells damage and apoptosis: To set up the cell model of Alzheimer disease using PC12 cells induced with Aβ_25-35. We detected Aβ-induced PC12 cell viability by MTT assay. Real time PCR to detect the effect of tenuigenin on mrna of Bcl-2, Bax, Caspase-3 and Caspase-8 in PC12 cells induced with Aβ_25-35. Spectrophotometry to detect tenuigenin on enzymatic activity of Caspase-3 and Caspase-8 in PC12 cells induced with Aβ_25-35. The results suggested that, tenuigenin can improve cell viability of PC12 cells PC12 cells induced with Aβ_25-35, and has protective effect of abnormal expression of Bcl-2, Bax, Caspase-3 and Caspase-8.2. The study of tenuigenin on Aβ-induced pc12 cells oxidative stress: detected the generation of reactive oxygen species（ROS） by DCFH-DA; detected malondialdehyde（MDA） content by thiobarbituric acid（TBA）; detect superoxide dismutase（SOD） activity by xanthine oxidation; and detect GSH-Px vitality by NADPH. The results suggested that, tenuigenin can reduce the generation of ROS and MDA content, and increase SOD and GSHPx activity on PC12 cells induced by Aβ.3. The study of tenuigenin on Aβ transporter protein expression levels of RAGE and LRP1: Western blot to detect protein expression of RAGE and LRP1. The results suggested that, tenuigenin can reverse the abnormal protein expression of RAGE and LRP1.4. The study of tenuigenin of regulation of Aβ-induced cell cycle disorder: Western blot to detected protein expression of p21, Cyclin D1 and E2F1. The results suggested that, tenuigenin can increase protein expression of p21, and reduce protein expression of Cyclin D1 and E2F1. It implies a certain cell cycle regulatory role.These results indicated there are protect effect of tenuigenin for PC12 cells injury induced by Aβ23-35. Its possible molecular mechanisms are that tenuigenin increase Aβ transport capacity through by regulating RAGE and LRP1; reducing concentration of Aβ-induced ROS and MDA, and increasing SOD and GSH-Px activity to reduce oxidative stress on cell stimulation injury; promoting the expression of p21 and decreasing expression of cyclin D1 and E2F1 to prevent nerve cell cycle disorder; upregulating anti-apoptotic gene Bcl-2 and reducing pro-apoptotic genes Bax expression, plus inhibiting the expression of caspase-3 and caspase-8 to reduce abnormal cell death, and thus play a protective effect on nerve cells.