Institute of Animal Nutrition, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
Food Funct. 2016 May 18;7(5):2303-11. doi: 10.1039/c5fo01194a. Epub 2016 Apr 25.
N-Carbamylglutamate (NCG), an effective precursor of arginine (ARG), can enhance ARG synthesis, increase intestinal growth, and improve reproductive performance. However, the antioxidant effect of NCG remains largely unknown. This study aims to survey the effects of ARG and NCG supplementation on the antioxidant statuses of the liver and plasma in rats under oxidative stress. Rats were fed for 30 days with one of the three iso-nitrogenous diets: basal diet (BD), BD plus 1% ARG, and BD plus 0.1% NCG. On day 28, half of the rats fed with BD were intraperitoneally injected with 12 mg per kg body weight of diquat (diquat group) and the other half was injected intraperitoneally with sterile 0.9% NaCl solution (control group). The other diet groups also received an intraperitoneal injection of 12 mg per kg body weight of diquat, as follows: diquat + 1% ARG (DT + ARG), and diquat + 0.1% NCG (DT + NCG). Rat liver and plasma samples obtained 48 h after diquat injection were analyzed. Results indicated that diquat significantly affected the plasma conventional biochemical components (relative to the controls), which were partially alleviated in both the DT + ARG and DT + NCG groups (P < 0.05). Diquat also significantly decreased the glutathione (GSH) content (by 30.0%), and decreased anti-superoxide anion (ASA; by 13.8%) and anti-hydroxyl radical (AHR; by 38.9%) abilities in the plasma, and also decreased catalase (CAT) activity both in the liver (by 17.5%) and plasma (by 33.4%) compared with the control group. By contrast, diquat increased the malondialdehyde (MDA) content (by 23.0%) in the plasma (P < 0.05) compared with the control group. Relative to those of the diquat group, higher CAT activity and GSH content were noted in the plasma of the DT + ARG group and in the liver of both DT + ARG and DT + NCG groups (P < 0.05). Furthermore, the DT + ARG group exhibited significantly enhanced plasma ASA activity (P < 0.05). The DT + NCG group showed significantly improved total antioxidant capacity (T-AOC) in the liver and plasma (P < 0.05). Increased GSH content and elevated ASA and AHR activities were also found, but the MDA content in the plasma was depleted (P < 0.05). Compared with the DT + ARG group, the DT + NCG group showed increased liver and plasma T-AOC, enhanced plasma AHR activity, increased liver ASA activity, and decreased plasma MDA content (P < 0.05). Overall, supplementation of 1% ARG and 0.1% NCG can partially protect the liver and plasma from oxidative stress. Furthermore, compared with 1% ARG, 0.1% NCG more effectively alleviated oxidative stress.
N- 氨甲酰谷氨酸（NCG），精氨酸（ARG）的有效前体，可以增强 ARG 的合成，促进肠道生长，改善生殖性能。然而，NCG 的抗氧化作用在很大程度上仍然未知。本研究旨在调查 ARG 和 NCG 补充剂对氧化应激大鼠肝和血浆抗氧化状态的影响。大鼠连续 30 天喂食三种等氮饮食之一：基础饮食（BD）、BD 加 1%ARG 和 BD 加 0.1%NCG。第 28 天，一半喂食 BD 的大鼠经腹腔注射 12mg/kg 体重的百草枯（百草枯组），另一半大鼠经腹腔注射无菌 0.9%NaCl 溶液（对照组）。其他饮食组也接受了 12mg/kg 体重的百草枯腹腔注射，如下：百草枯+1%ARG（DT+ARG）和百草枯+0.1%NCG（DT+NCG）。百草枯注射后 48 小时采集大鼠肝和血浆样本。结果表明，百草枯显著影响了血浆常规生化成分（与对照组相比），而 DT+ARG 和 DT+NCG 组部分缓解了这些影响（P<0.05）。百草枯还显著降低了血浆中的谷胱甘肽（GSH）含量（减少 30.0%），降低了抗超氧阴离子（ASA；减少 13.8%）和抗羟自由基（AHR；减少 38.9%）能力，还降低了肝（减少 17.5%）和血浆（减少 33.4%）中的过氧化氢酶（CAT）活性，与对照组相比。相比之下，与对照组相比，百草枯组血浆中丙二醛（MDA）含量增加了 23.0%（P<0.05）。与百草枯组相比，DT+ARG 组血浆和 DT+ARG 和 DT+NCG 组肝中的 CAT 活性和 GSH 含量更高（P<0.05）。此外，DT+ARG 组血浆 ASA 活性显著增强（P<0.05）。DT+NCG 组肝和血浆中的总抗氧化能力（T-AOC）显著提高（P<0.05）。GSH 含量增加，ASA 和 AHR 活性升高，但血浆 MDA 含量减少（P<0.05）。与 DT+ARG 组相比，DT+NCG 组肝和血浆 T-AOC 增加，血浆 AHR 活性增强，肝 ASA 活性升高，血浆 MDA 含量减少（P<0.05）。总的来说，补充 1%ARG 和 0.1%NCG 可以部分保护肝和血浆免受氧化应激。此外，与 1%ARG 相比，0.1%NCG 更有效地缓解氧化应激。
