ABSTRACT
ObjectiveTo investigate the effects of Gandou decoction （GDD） on the mitophagy of hippocampal neurons in toxic milk （TX） mouse model of Wilson disease and explore the protective mechanism of GDD against neuron injury through the PTEN induced kinase 1 （Pink1） /E3 ubiquitin ligase （Parkin） pathway. MethodSixty mice were randomly divided into a blank group， a model group， a penicillamine group （0.09 g·kg-1）， and low- （5.5 g·kg-1）， medium- （11 g·kg-1）， and high-dose （22 g·kg-1） GDD groups， and treated correspondingly by gavage for 8 weeks. Morris water maze， traction test， and pole test were used for the evaluation of animal behaviors. Hematoxylin-eosin （HE） staining and transmission electron microscopy were used to observe cell apoptosis， ultrastructure， autophagy， and mitochondrial structure. The levels of superoxide dismutase （SOD）， reactive oxygen species （ROS）， and malondialdehyde （MDA） were detected by enzyme-linked immunosorbent assay （ELISA）. Real-time fluorescence-based quantitative polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression of Pink1， Parkin， autophagy-associated protein Beclin-1， microtubule-associated protein 1 light chain 3Ⅱ （LC3Ⅱ）， and p62. Western blot was conducted to detect the protein expression of Pink1， Parkin， Beclin-1， LC3Ⅱ/Ⅰ， and p62. ResultCompared with the blank group， the model group showed prolonged escape latency， decreased times of platform crossing， lower score in the traction test， and longer pole climbing time （P<0.01）. Compared with the model group， the medium- and high-dose GDD groups and the penicillamine group showed shortened escape latencies， increased times of platform crossing， higher scores in the traction test， and shortened pole climbing time （P<0.01）. Compared with the blank group， the model group displayed severely damaged neurons and increased autophagosomes. Compared with the model group， the medium- and high-dose GDD groups and the penicillamine group showed improved neuron damage and reduced autophagosomes. The levels of ROS and MDA were higher and SOD was lower in the model group than those in the blank group （P<0.01）， while the levels of the above indicators were reversed by GDD intervention as compared with the model group （P<0.01）. Compared with the blank group， the model group exhibited up-regulated mRNA and protein expression of Pink1， Parkin， LC3Ⅱ， and Beclin-1 and down-regulated p62 （P<0.05）. Compared with the model group， the medium- and high-dose GDD groups showed reduced mRNA and protein expression of Pink1， Parkin， LC3Ⅱ， and Beclin-1 and increased p62 （P<0.05， P<0.01）. ConclusionGDD can significantly inhibit the excessive mitophagy in neurons of TX mice and protect neurons from damage. The mechanism may be related to the regulation of the Pink1/Parkin pathway.
ABSTRACT
BACKGROUND: Gandou decoction (GDD) has been widely used in the treatment of Wilson disease (WD) for decades. It is optimized from the Dahuanghuanglianxiexin decoction, Yinchenhao decoction, and Huanglianjiedu decoction. It was first reported in the Treatise on Febrile and Miscellaneous Diseases and A Handbook of Prescriptions for Emergencies published in the Eastern Han Dynasty and the Eastern Jin Dynasty respectively. Hepatic injury is one of the most severe complications of WD. The current study aimed to explore the hepatic-protection effects of GDD and its exact therapeutic target, with a particular focus on the expression of oxidative stress and the Wnt/ß-catenin pathway. METHODS: Hepatic injury was induced in a copper-loaded rat model using the intragastric administration of copper(II) sulfate pentahydrate (CuSO4·5H2O). The water extract of GDD (0.4 g/kg/d) was administered twice a day for 4 weeks. Copper content and alanine aminotransferase (ALT) level, structural observation under the microscope, and immunohistochemical analysis of liver tissue were performed after the final administration. Moreover, the expression of ß-catenin, GSK3ß, Dishevelled-3, c-Myc, and p-GSK3ß of liver tissue were detected to explore the relationship between the hepatic protection of GDD and the Wnt/ ß-catenin signal pathway of GDD. We also stimulated the rat hepatic cell line BRL-3A with CuSO4·5H2O to establish a hepatic injury cytomodel. GDD serum at a concentration of 20% was administered into the model cell for 24 h. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and flow cytometry were performed to detect cell viability, mitochondrial membrane potential (MMP), and the expression of reactive oxygen species (ROS). Meanwhile, the expression of the Wnt/ß-catenin signal pathway-related proteins was evaluated. RESULTS: GDD reduced copper and ALT while inhibiting oxidative stress and the degeneration and necrosis of liver tissue and hepatocytes. Treatment with GDD improved cell viability and MMP while suppressing the ROS level. Furthermore, GDD rectified the expression of Wnt/ß-catenin signal pathway-related proteins in both livers of the copper-loaded and copper-stimulated BRL-3A cell lines. CONCLUSIONS: GDD had apparent therapeutic effects on the hepatic injury of copper-loaded rats and copper-stimulated BRL-3A cells. Its mechanism is related to its regulatory effect on the Wnt/ß-catenin pathway rectification and oxidative stress antagonism.