Effects of idebenone on behavior and mitochondrial autophagy of brain tissue in Parkinson disease model mice / 中华行为医学与脑科学杂志

ABSTRACT

Objective:To investigate whether idebenone can improve behavioral disorders in mice with Parkinson disease (PD) by increasing PHB2 mediated mitophagy.Methods:In the first small experiment, thirty mice were randomly divided into normal control group, model group and treatment group according to the random number table method, with 10 animals in each group.The aim of this study was to observe the effect of idebenone on the behavior of Parkinson disease model mice. In the second experiment, 20 mice were randomly divided into blank control group, MPTP group, shRNA-PHB2 group and shRNA-PHB2+ MPTP group, with 5 mice in each group. The changes of tyrosine dehydrogenase (TH) in brain tissue were detected by immunofluorescence assay. In the third experiment, 30 mice were randomly divided into blank control group, shRNA-PHB2 group, MPTP+ idebenone group, shRNA-PHB2+ MPTP group, shRNA-PHB2+ idebenone group and shRNA-PHB2+ MPTP+ idebenone group, with 5 animals in each group. The aim of this study was to investigate the effect of idebenone on mitochondrial autophagy in mouse brain.C57BL-6 mice were intraperitoneally injected with MPTP to establish the animal model of chronic PD. Then 200 mg / kg idebenone was given by gavage for 21 days. And the expression of PHB2 in brain was inhibited by microinjection of adeno-associated virus 9 (AAV9) shRNA inhibin 2(PHB2) into lateral ventricle. The behavioral changes of the PD mice were detected by Morris water maze, and the changes of tyrosine dehydrogenase (TH) induced by inhibiting PHB2 were detected by immunohistochemistry. The protein expression of LC3 and PHB2 in substantia nigra of midbrain was detected by Western blot.The data were analyzed by GraphPad 7.0 and SPSS 22.0.Results:(1) In the water maze test data of the first small experiment, the repeated measurement ANOVA showed that the group-time interaction effects of latency of mice from 1 to 7 days were significant ( Ftime×group=20.51, P<0.05). Simple effect analysis showed that on the 5th, 6th and 7th day, the incubation period of the treatment group was significantly shortened (all P<0.05). Univariate analysis of variance showed that on the 7th day of the test, the differences between the control group and the model group, the model group and the treatment group, the control group and the treatment group were all statistically significant( t=-49.95, -21.81, 28.14; all P<0.01). In the third small experiment, repeated measurement analysis of variance showed that the interaction between time and group was significant ( Ftime×group=42.11, P<0.01). Simple effect analysis showed that compared with MPTP+ idebenone group, the latency of shRNA-PHB2+ MPTP+ idebenone group was significantly prolonged (all P<0.05). There were no significant difference between shRNA-PHB2+ MPTP+ idebenone group and shRNA-PHB2+ MPTP group except the 4th day ( P<0.05). On the 7th day, compared with MPTP+ idebenone group, the residence time of shRNA-PHB2+ MPTP+ idebenone group was significantly increased ( t=-34.36, P<0.001), but there was no significant difference between shRNA-PHB2+ MPTP group and shRNA-PHB2+ MPTP+ idebenone group ( t=2.94, P>0.05). (2)The results of immunofluorescence experiment showed that the relative expression of TH in the control group, model group, shRNA-PHB2 group and shRNA-PHB2+ MPTP group were (41.03±3.01), (24.20±4.18), (38.39±3.31) and (13.12±2.65), respectively. Compared with the control group, the expression of TH in the midbrain of the MPTP group was significantly down-regulated, the difference was statistically significant( t=7.98, P<0.01). Compared with the MPTP group, the expression of TH in shRNA-PHB2 group was down regulated ( t=-6.73, P<0.05). (3) Western blot results showed that the relative expression of LC3 in midbrain tissue of control group, shRNA-PHB2 group, MPTP+ idebenone group, shRNA-PHB2+ MPTP group, shRNA-PHB2+ idebenone group and shRNA-PHB2+ MPTP+ idebenone group were (0.86±0.07), (0.77±0.08), (0.42±0.05), (0.21±0.05), (0.66±0.09) and (0.27±0.07). The relative expression of PHB2 were (1.13±0.14), (0.56±0.11), (1.08±0.14), (0.27±0.07), (0.68±0.14) and (0.24±0.10). Compared with MPTP+ idebenone group, the relative expression of LC3 and PHB2 in shRNA-PHB2+ MPTP+ idebenone group was significantly decreased ( F=1.96, P<0.01). Conclusion:Idebenone can increase the level of mitophagy in PD mice through PHB2, thus improving the behavioral disorder.