β-Hydroxybutyrate activates the NF-κB signaling pathway to promote the expression of pro-inflammatory factors in calf hepatocytes.
OBJECTIVE
β-hydroxybutyrate (BHBA) is the major component of ketone bodies in ketosis. Dairy cows with ketosis often undergo oxidative stress. BHBA is related to the inflammation involved in other diseases of dairy cattle. However, whether BHBA can induce inflammatory injury in dairy cow hepatocytes and the potential mechanism of this induction are not clear. The NF-κB pathway plays a vital role in the inflammatory response.


METHODS
Therefore, this study evaluated the oxidative stress, pro-inflammatory factors and NF-κB pathway in cultured calf hepatocytes treated with different concentrations of BHBA, pyrrolidine dithiocarbamate (PDTC, an NF-κB pathway inhibitor) and N-acetylcysteine (NAC, antioxidant).


RESULTS
The results showed that BHBA could significantly increase the levels of oxidation indicators (MDA, NO and iNOS), whereas the levels of antioxidation indicators (GSH-Px, CAT and SOD) were markedly decreased in hepatocytes. The IKKβ activity and phospho-IκBα (p-IκBα) contents were increased in BHBA-treated hepatocytes. This increase was accompanied by the increased expression level and transcription activity of p65. The expression levels of NF-κB-regulated inflammatory cytokines, namely TNF-α, IL-6 and IL-1β, were markedly increased after BHBA treatment, while significantly decreased after NAC treatment. However, the p-IκBα level and the expression and activity of p65 and its target genes were markedly decreased in the PDTC + BHBA group compared with the BHBA (1.8 mM) group. Moreover, immunocytofluorescence of p65 showed a similar trend.


CONCLUSIONS
The present data indicate that higher concentrations of BHBA can induce cattle hepatocyte inflammatory injury through the NF-κB signaling pathway, which may be activated by oxidative stress.
College of Veterinary Medicine, Jilin University, Changchun, China.
Xiaoxia
X
Shi
Xinwei
X
Li
Dangdang
D
Li
Yu
Y
Li
Yuxiang
Y
Song
Qinghua
Q
Deng
Jianguo
J
Wang
Yuhang
Y
Zhang
Hongyan
H
Ding
Liheng
L
Yin
Yuming
Y
Zhang
Zhe
Z
Wang
Xiaobing
X
Li
Guowen
G
Liu
D020155:3-Hydroxybutyric Acid / Q000494:pharmacology*; D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D005979:Glutathione Peroxidase / Q000378:metabolism; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051550:I-kappa B Kinase / Q000378:metabolism; D020672:I-kappa B Proteins / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011759:Pyrrolidines / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*; D013482:Superoxide Dismutase / Q000378:metabolism; D013859:Thiocarbamates / Q000494:pharmacology; D051996:Transcription Factor RelA / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D020672:I-kappa B Proteins; D053583:Interleukin-1beta; D015850:Interleukin-6; D016328:NF-kappa B; D011759:Pyrrolidines; D013859:Thiocarbamates; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha; C020972:pyrrolidine dithiocarbamic acid; D009569:Nitric Oxide; D008315:Malondialdehyde; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D051550:I-kappa B Kinase; D020155:3-Hydroxybutyric Acid; D000111:Acetylcysteine