Effect of benzo(a)pyrene on dopaminergic neurons and α-synuclein in brain and its mechanism involved.
10.19723/j.issn.1671-167X.2020.03.007
- Author:
Yu Ze QI
1
;
Hui Hui QUAN
1
;
Wei Xing XU
1
;
Qing Ru LI
1
;
Hui ZHOU
1
Author Information
1. Department of Occupational and Environmental Health, Peking University School of Public Health, Beijing 100191, China.
- Publication Type:Journal Article
- Keywords:
Alpha-synuclein;
Benzo(a)pyrene;
Dopaminergic neurons;
Parkinson’s disease
- MeSH:
Animals;
Benzo(a)pyrene;
Brain;
Dopamine;
Dopaminergic Neurons;
Humans;
Mice;
alpha-Synuclein
- From:
Journal of Peking University(Health Sciences)
2020;52(3):438-443
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVE:To analyze the effect of benzopyrene on the decrease of dopaminergic neurons, and the increase and aggregation of α-synuclein, which are the pathological features of Parkinson's disease, and to explore its possible mechanisms.
METHODS:Eight-month-old transgenic mice with human SNCA gene were randomly divided into a BaP-exposed group and a control group. BaP and solvent corn oil were injected intraperitoneally to BaP-exposed group and control group respectively, once a day for 60 days. The motor dysfunction of mice was tested by rotarod test. The effects of BaP on the decrease of dopaminergic neurons and increase and aggregation of α-synuclein were observed by immunohistochemistry and Western blot experiments respectively, and the expression of related mRNA was detected by quantitative real-time PCR (qRT-PCR). Twenty genes were tested in the study, mainly related to neurotransmitter transporter (2 genes), neurotransmitter receptor function (10 genes), cellular autophagy (5 genes), and α-synuclein aggregation and degradation (3 genes).
RESULTS:After BaP exposure, the movement time of the mice in the rotarod test was significantly reduced (P<0.05). The substantia nigra dopami-nergic neurons in the mice were significantly reduced, which was 62% of the control group (P<0.05), and the expression of α-synuclein in the midbrain increased, which was 1.36 times that of the control group (P<0.05). After BaP exposure, mRNA expressions of 14 genes in the midbrain of the mice were significantly down-regulated (P<0.05). Alpha-synuclein degradation and cell autophagy (5 genes), neuron transporters (2 genes), and neurotransmitter receptor functions (5 genes) were involved. The expression of one gene, Synphilin-1, was significantly up-regulated (P<0.01), which was related to α-synuclein aggregation.
CONCLUSION:BaP exposure not only inhibited function of neurotransmitter receptor and dopamine transporter, but also interfered cell autophagy, thereby hindering the degradation of α-synuclein, which could lead to decrease of dopaminergic neurons in substantia nigra and increase and aggregation of α-synuclein in midbrain, as the significant pathology of Parkinson's disease. Therefore, BaP exposure may increase the risk of Parkinson's disease.
