Physiology and Endocrinology 1

摘要

The objective of the current study was to investigate the effects of acetoaceticacid (ACAC) on mRNA and protein abundance related to the tolllikereceptor 2/4-nuclear factor-κB (TLR2/4-NF-κB) signaling pathway inneutrophils (PMN) during the induction of inflammatory response in dairycows. Nonketotic (n = 8) and ketotic (n = 8) Holstein cows were selectedbased on serum concentrations of β-hydroxybutyrate (BHBA), nonesterifiedfatty acids (NEFA), ACAC and glucose. PMN were treated with 0.6,1.2 and 1.8 mM ACAC using 0 mM ACAC as control group, with or withoutammonium pyrrolidinedithiocarbamate (PDTC, 10 μM, 30 min), andN-acetylcysteine (NAC, 10 mM, 30 min). Total RNA and protein wereused for quantitative real-time polymerase chain reaction and Westernblotting, respectively. One-way ANOVA was performed by StatisticalPackage for the Social Science (SPSS) 17.0 and multiple comparisons ofdata were done using the Duncan test. Compared with nonketotic cows,serum concentrations of BHBA, NEFA, ACAC, hydrogen peroxide,malondialdehyde (MDA), glutathione peroxidase and tumor necrosis factorα (TNF-α) increased (P < 0.05) while glucose and catalase decreased(P < 0.01). Compared with control group, IKKβ activity, the protein abundanceof TLR2 and phosphorylated-NF-κB p65 (p-NF-κB p65) in PMNincreased in response to ACAC (P < 0.01). Additionally, ACAC increasedtranscription activity of p65. Moreover, ACAC treatment led to greaterprotein abundance of TNF-α (P < 0.01), while decrease after NAC treatment.ACAC could increase MDA (P < 0.01), where decrease the concentrationsof CAT and Cu/Zn SOD (P < 0.05) in PMN. However, abundanceof p-NF-κB p65, transcription activity of p65 and target TNF-α were decreasedin PDTC + ACAC group compared with ACAC (1.2 mM) group.In conclusion, inflammation and oxidative stress existed in the ketoticdairy cows and ACAC caused inflammatory damage and immune dysfunctionin PMN by activating the TLR2/4-NF-κB inflammatory signalingtransduction pathway, moreover, which could be alleviated by NAC.