Abstract:

Objective To investigate the protective effects of Schisandra Chinensis lignans (SCL) on the oxidative stress injury of PC12 cells induced by hydrogen peroxide and influence in NF-κB/iNOS/NO signaling pathway, and to explore the mechanisms. Methods The PC12 cells were divided into control group, model group(H₂O₂ 200 μmol·L^-1), high dose of SCL group(SCL 30 mg·L^-1+ H₂O₂ 200 μmol·L^-1, SCL₁ group)and low dose of SCL group(SCL 10 mg·L^-1+ H₂O₂ 200 μmol·L^-1, SCL₂ group).The PC12 cells were untreated (control group) or treated with H₂O₂ (200 μmol·L^-1) for 6 h (model group).The PC12 cells in SCL₁ and SCL₂ group were firstly pretreated with different concentrations of SCL for 2 h, and then continuously with SCL and exposed to 200 μmol·L^-1 H₂O₂ for 6 h at the same time.The survival rate of PC12 cells was evaluated by MTT assay.The activities of lactate dehydrogenase (LDH), superoxide dismutase (SOD) and the levels of malondialdehyde (MDA) and nitric oxide (NO) were detected by microplate reader.The fluorescence intensity of reactive oxygen species (ROS) was assessed with flow cytometry.Immunohistochemistry and Western blotting Methods were used to detect the protein expressions of inducible nitric oxide synthase (iNOS) and nuclear factor kappa B P65 (NF-κB P65). Results Compared with control group, the survival rates of PC12 cells in model group were significantly decreased (P<0.01);the LDH activities in the supernatant were increased (P<0.01), the SOD activities were decreased(P<0.01), the MDA and NO levels were increased (P<0.01), the cell ROS level was increased (P<0.01), the number of positive cells of NF-κB were increased (P<0.01), and the expression levels of iNOS and NF-κB P65 protein were increased (P<0.01). Compared with model group, the survival rates of PC12 cells in SCL₁ and SCL₂ groups were increased (P<0.05 or P<0.01), the LDH activities in the supernatant were decreased (P<0.05 or P<0.01), the SOD activities were increased (P<0.01), the MDA and NO levels were decreased (P<0.05 or P<0.01), the cell ROS levels was decreased (P<0.01), the number of positive cells of NF-κB was decreased (P<0.05 or P<0.01), and the expression levels of iNOS and NF-κB P65 protein were decreased (P<0.05). Conclusion SCL could protect the oxidative stress injury of PC12 cells, its mechanism may be related to inhibiting the NF-κB/iNOS/NO signaling pathway, reducing the free radical generation and alleviating lipid peroxidation damage.

Key words: Schisandra Chinensis, oxidative stress, nuclear factor, nitric oxide synthase