A Comparative Study on Antioxidant System in Fish Hepatopancreas and Intestine Affected by Choline Deficiency: Different Change Patterns of Varied Antioxidant Enzyme Genes and Nrf2 Signaling Factors

Abstract

The liver and intestine are susceptible to the oxidative damage which could result in several diseases. Choline deficiency induced oxidative damage in rat liver cells. Thus, this study aimed to investigate the potential molecular mechanisms responsible for choline deficiency-induced oxidative damage. Juvenile Jian carp were fed diets differing in choline content [165 (deficient group), 310, 607, 896, 1167 and 1820 mg/kg diet] respectively for 65 days. Oxidative damage, antioxidant enzyme activities and related gene expressions in the hepatopancreas and intestine were measured. Choline deficiency decreased choline and phosphatidylcholine contents, and induced oxidative damage in both organs, as evidenced by increased levels of oxidative-stress markers (malondialdehyde, protein carbonyl and 8-hydroxydeoxyguanosine), coupled with decreased activities of antioxidant enzymes [Copper-zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD), glutathione peroxidase (GPx) and glutathione-S-transferase (GST)]. However, choline deficiency increased glutathione contents in the hepatopancreas and intestine. Furthermore, dietary choline deficiency downregulated mRNA levels of MnSOD, GPx1b, GST-rho, mGST3 and Kelch-like ECH associating protein 1 (Keap1b) in the hepatopancreas, MnSOD, GPx1b, GPx4a, GPx4b, GST-rho, GST-theta, GST-mu, GST-alpha, GST-pi and GST-kappa in the intestine, as well as intestinal Nrf2 protein levels. In contrast, choline deficiency upregulated the mRNA levels of GPx4a, GPx4b, mGST1, mGST2, GST-theta, GST-mu, Keap1a and PKC in the hepatopancreas, mGST3, nuclear factor erythoid 2-related factor 2 (Nrf2) and Keap1a in the intestine, as well as hepatopancreatic Nrf2 protein levels. This study provides new evidence that choline deficiency-induced oxidative damage is associated with changes in the transcription of antioxidant enzyme and Nrf2/Keap1 signaling molecules in the hepatopancreas and intestine. Additionally, this study firstly indicated that choline deficiency induced varied change patterns of different GPx and GST isoforms. Meanwhile, the changes of some GPx and GST isoforms caused by choline deficiency in the intestine were contrary to those in the hepatopancreas.

Modulation of growth, immunity and antioxidant‐related gene expressions in the liver and intestine of juvenileSillago sihamaby dietary vitamin C

“…In the present study, the mRNA levels of CuZnSOD, MnSOD, CAT, GST, GR and GPx were all up‐regulated by certain VC supplement, reinforcing the enhanced enzyme activities to some extent. Although performance of gene expression might be inconsistent in different tissues responded to the same nutrient (Wu et al, , ), the present results in liver and intestine were in agreement with the results in gill, spleen and head kidney of grass carp (Xu et al, , ). However, in rat liver, VC did not regulate CuZnSOD and CAT genes expression, but increased activities of CuZnSOD and CAT (Sadi, Yilmaz, & Güray, ).…”

“…SOD, CAT, GPx and GST are endogenous antioxidants, virtually distributed in all tissues of vertebrates and were widely detected to reflect resistance to oxidation (Wu et al, ; Xu et al, ; Zhang, Shen, Wang, Wu, & Xue, ). The liver and intestine play important roles in metabolism and absorption and are closely related to organism health.…”

“…It has been reported that appropriate vitamin C concentration in diets up‐regulated mRNA levels of antioxidant enzymes including copper–zinc superoxide dismutase (CuZnSOD), Mn superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S‐transferase (GST) and glutathione reductase (GR) in the skin, spleen and head kidney (Xu et al, ). However, the antioxidant enzyme gene expressions responded to the same nutrient element varied with different tissues in the same fish (Wu et al, , ). It was necessary to investigate antioxidant enzyme gene expressions in different tissue.…”

“…It was necessary to investigate antioxidant enzyme gene expressions in different tissue. The present study focused on the liver and intestine, which were important metabolic and absorptive organs, respectively, and usually exposed to free radicals, similar to Wu et al (2017).…”

The Increase in Temperature Overwhelms Silver Nanoparticle Effects on the Aquatic Invertebrate Limnephilus sp.

“…In the feeding experiment, CAT and SOD were stimulated in animals feeding on leaves treated with a high concentration of AgNPs at 10 °C (Figure 2A, C), suggesting increased intracellular accumulation of ROS. The raised GST activity observed in the animals feeding on leaves treated with the higher AgNP concentration at 16 °C (Figure 2E) further indicated that animals were under oxidative stress (Wu et al 2017). A higher GST activity implies a greater detoxification capacity or conjugation of oxidative products.…”