Hunan International Joint Laboratory of Animal Intestinal Ecology and Health, Laboratory of Animal Nutrition and Human Health, College of Life Sciences , Hunan Normal University , Changsha 410081 , PR China.
Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process , National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production , Changsha 410125 , PR China.
J Agric Food Chem. 2018 Oct 31;66(43):11273-11283. doi: 10.1021/acs.jafc.8b04470. Epub 2018 Oct 22.
α-Ketoglutarate (AKG) can act as an antioxidant both in vitro and in vivo. However, the mechanisms of the protective effects of AKG are still not well understood. We evaluated the effects of AKG supplementation on the regulation of the constitutive-androstane-receptor (CAR) pathway in porcine intestinal cells and piglets exposed to HO. Our data showed that AKG treatment significantly increased not only the intra- and extracellular levels of AKG (26.9 ± 1.31 μmol/g protein, 1064.4 ± 39.80 μmol/L medium) but also those of Asp (29.3 ± 0.21 μmol/g, 4.20 ± 0.11 μmol/L), Gln (24.82 ± 1.50 μmol/g, 1087.80 ± 16.10 μmol/L), and Glu (91.90 ± 3.6 μmol/g, 19.76 ± 1.00 μmol/L). There was approximately a 4-fold increase in α-ketoglutarate dehydrogenase mRNA levels in enterocytes and a simultaneous reduction in ROS levels ( P < 0.05). Moreover, AKG treatment increased the activities of the antioxidant enzymes and the efficiency of cellular respiration ( P < 0.05). AKG also regulated the mRNA levels of the target genes involved in antioxidant responses and xenobiotic detoxification in enterocytes. Increases in the protein levels of SOD1, SOD2, CAR, RXRα, and UCP2 and marked reductions in the expression levels of Nrf2 and Keap1 proteins ( P < 0.05) were observed after AKG administration in the HO-induced piglets. Our results indicated that AKG may protect against oxidative stress by activating CAR signaling and modulating the expression of key antioxidant-related targets, which improves cellular respiration and antioxidant capacity. The in vivo and in vitro effects of AKG suggest that it may prove to be useful in the reduction of oxidative stress in animal and human trials and subsequent prevention of gastrointestinal pathologies.
α-酮戊二酸（AKG）在体外和体内均可作为抗氧化剂。然而，AKG 保护作用的机制尚不清楚。我们评估了 AKG 补充对猪肠细胞中组成型雄烷受体（CAR）途径的调节作用，以及对接触 HO 的仔猪的影响。我们的数据表明，AKG 处理不仅显著增加了 AKG 的细胞内和细胞外水平（26.9±1.31μmol/g 蛋白，1064.4±39.80μmol/L 培养基），还增加了 Asp（29.3±0.21μmol/g，4.20±0.11μmol/L）、Gln（24.82±1.50μmol/g，1087.80±16.10μmol/L）和 Glu（91.90±3.6μmol/g，19.76±1.00μmol/L）的水平。肠细胞中α-酮戊二酸脱氢酶 mRNA 水平增加了约 4 倍，同时 ROS 水平降低（P<0.05）。此外，AKG 处理增加了抗氧化酶的活性和细胞呼吸效率（P<0.05）。AKG 还调节了肠细胞中参与抗氧化反应和外来物解毒的靶基因的 mRNA 水平。在 HO 诱导的仔猪中，AKG 给药后，SOD1、SOD2、CAR、RXRα和 UCP2 的蛋白水平增加，Nrf2 和 Keap1 蛋白的表达水平显著降低（P<0.05）。我们的结果表明，AKG 通过激活 CAR 信号通路和调节关键抗氧化相关靶基因的表达，可能有助于防止氧化应激，从而改善细胞呼吸和抗氧化能力。AKG 的体内和体外作用表明，它可能有助于减少动物和人类试验中的氧化应激，并随后预防胃肠道疾病。
