Tetramethylpyrazine prevents ethanol-induced hepatocyte injury via activation of nuclear factor erythroid 2-related factor 2.
OBJECTIVE
Inhibiting the major features of alcoholic liver disease (ALD) such as lipid accumulation and oxidative stress is a promising strategy of treating ALD. Tetramethylpyrazine (TMP) has curative effects on various diseases. However, the effects of TMP on ethanol-induced hepatocyte injury and the related mechanisms remain unclear. The aim of this study is to elucidate the effects of TMP and the potential mechanisms in vitro.


METHODS
Ethanol-stimulated LO2 cells were used as an in vitro model of ALD. Several biomarkers related to cell injury, lipid accumulation, and oxidative stress were determined to evaluate the effects of TMP. Nuclear factor erythroid 2-related factor 2 (Nrf2) expression plasmids and Nrf2 small interfering RNA (siRNA) were used to establish the role of Nrf2.


RESULTS
TMP increased Nrf2 expression and nuclear translocation. TMP prevented ethanol-induced hepatocyte injury, as indicated by the enhanced cell viability, reduced activities of aspartate transaminase and alanine aminotransferase in the culture medium, and inhibition of cell apoptosis. Furthermore, TMP reduced the levels of lipid droplets, triglyceride, and total cholesterol, probably by regulating genes related to lipid metabolism. Besides, TMP alleviated ethanol-induced oxidative stress by increasing superoxide dismutase activity and the glutathione level and by reducing the levels of reactive oxygen species and malondialdehyde. In addition, overexpression of Nrf2 enhanced the effects of TMP on cell injury, lipid accumulation, and oxidative stress, whereas Nrf2 siRNA eliminated the effects of TMP.


CONCLUSIONS
TMP prevents ethanol-induced hepatocyte injury by inhibiting lipid accumulation and oxidative stress, and via an Nrf2 activation-dependent mechanism.
Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
Chunfeng
C
Lu
Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
Yuanyuan
Y
Jiang
Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China; Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
Feng
F
Zhang
Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
Jiangjuan
J
Shao
Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
Li
L
Wu
Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
Xiafei
X
Wu
Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
Naqi
N
Lian
Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
Lianyun
L
Chen
Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
Huanhuan
H
Jin
Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
Qin
Q
Chen
Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China; Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
Yin
Y
Lu
Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China; Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China. Electronic address: nytws@163.com.
Shizhong
S
Zheng
D000410:Alanine Transaminase / Q000378:metabolism; D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001219:Aspartate Aminotransferases / Q000378:metabolism; D015415:Biomarkers; D002478:Cells, Cultured; D002492:Central Nervous System Depressants / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D000431:Ethanol / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D022781:Hepatocytes / Q000187:drug effects*; D006801:Humans; D050356:Lipid Metabolism / Q000187:drug effects; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D010957:Plasmids / Q000235:genetics; D011719:Pyrazines / Q000494:pharmacology*; D034741:RNA, Small Interfering / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000378:metabolism
D000975:Antioxidants; D015415:Biomarkers; D002492:Central Nervous System Depressants; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D011719:Pyrazines; D034741:RNA, Small Interfering; D000431:Ethanol; D013482:Superoxide Dismutase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; C017953:tetramethylpyrazine
Alcoholic liver disease; Hepatocyte; Lipid accumulation; Oxidative stress