Abstract:

Objective To explore the protective effect and mechanism of flavones from vitis vinifera L（VTF） on motor behavior disorders in mice induced by rotenone. Method Totally 40 C57BL/6 male mice were randomly divided into four groups，with 10 mice in each group：control（Con） group，Rot group，Rot+VTF group，and VTF group. Rot group：rotenone was injected intraperitoneally for 3 consecutive weeks at a dose of 1.5 mg/（kg·d）. Rot+VTF group：mice were gavaged with VTF at a dose of 420 mg/（kg·d） first，and then injected with rotenone at a dose of 1.5 mg/（kg·d） after 1 hour. VTF group：VTF was administered by gavage at 420 mg/（kg·d）. The Con group：mice were injected with equal amounts of solvent. After 3 weeks，the motor behavior ability of mice was detected through suspension experiments，pole climbing experiments，and gait detection. The damage of dopaminergic neurons in mice were detected through immunohistochemical staining. Western blot and q-RTPCR were used to detect the microglia activation and M1 polarization levels in the midbrain. Results Compared with the Con group，the suspension test scores of mice in the Rot group decreased and the pole climbing test time was prolonged. Compared with the Rot group，the Rot+VTF group showed an increase in suspension test scores and a decrease in pole climbing test time，with statistically significant differences（all P<0.05）. The gait detection results showed that compared with the Con group，the stride length of the Rot group mice was shortened and the stride distance was increased. Compared with the Rot group，the mice in the Rot+VTF group showed an increase in stride length and a decrease in stride distance，with statistically significant differences（all P<0.05）. The immunohistochemical staining results showed that compared with the Con group，the number of tyrosine hydroxylase-positive dopaminergic neurons（TH+ cells） in the Rot group mice was significantly reduced，and the ionized calcium-binding adapter molecule1（IBA1） optical density value was increased in the midbrain. Compared with the Rot group，the number of TH+ cells increased and the IBA1 optical density value decreased in the Rot+VTF group，with statistically significant differences（all P<0.05）. The results of Western blot and q-RTPCR detection showed that compared with the Con group，the expression levels of IBA1，inducible nitric oxide synthase（iNOS），tumor necrosis factor-α（TNF-α），interleukin（IL）-1β and IL-6 in the midbrain of mice in the Rot group were increased. Compared with the Rot group，the expression levels of IBA1，iNOS，TNF-α，IL-1β and IL-6 in Rot+VTF group were decreased，with statistically significant differences（all P<0.05）. Conclusion VTF may alleviate the damage to dopaminergic neurons in the midbrain of mice induced by rotenone by inhibiting the microglia activation and M1 polarization-mediated inflammatory response，thereby improving dyskinesia in mice.

Key words: Vitis vinifera L, Flavone, Rotenone, Dopaminergic neurons, Dyskinesia, Microglia