l-Arginine Protects Ovine Intestinal Epithelial Cells from Lipopolysaccharide-Induced Apoptosis through Alleviating Oxidative Stress

Abstract

This research aims to explore the effect of L-arginine (Arg) upon lipopolysaccharide (LPS)-induced induction of the oxidative stress as well as subsequent apoptosis within ovine intestinal epithelial cells (IOECs). Through a 16 h incubation, cells were divided into four groups and the medium was replaced with different medium as follows: (1) control (Con), Arg-free Dulbecco's modified Eagle's F12 Ham medium (DMEM); (2) Arg treatment, Arg-free DMEM supplemented with 100 μM Arg;(3) LPS treatment, Arg-free DMEM supplemented with 10 μg/mL LPS; (4) LPS with Arg treatment, Arg-free DMEM supplemented with both 10 μg/mL LPS and 100 μM Arg. After culturing for 24 h in different mediums, some characteristics of cells in the four groups were measured. Addition of Arg increased cell viability induced with LPS compared with the LPS group (p < 0.05). Arg significantly decreased the release of dehydrogenase (LDH) and the production of malonaldehyde (MDA) (p < 0.05) within IOECs challenged by the LPS. Compared with the LPS group, cells treated with Arg and Arg + LPS increased (p < 0.05) mRNA as well as protein expression of glutathione peroxidase 1 (GPx1), catalase (CAT), superoxide dismutase 2 (SOD2), B-cell lymphoma 2 (Bcl2), quinone oxidoreductase 1 (NQO1), heme oxygenase (HO-1), and nuclear factor erythroid 2-related factor 2 (Nrf2). IOEC treatment with Arg reduced significantly (p < 0.05) apoptosis induced by the LPS (12.58 ± 0.79%). The results showed that Arg promoted the protein expression of Nrf2, up-regulated expression of the phase II metabolizing enzymes (NQO1 and HO-1), as well as antioxidative enzymes (GPx1, CAT, and SOD2) for alleviating oxidative injury and protected IOECs from LPS-induced apoptosis.

Dietary Supplementation of L-Arginine and N-Carbamylglutamate Attenuated the Hepatic Inflammatory Response and Apoptosis in Suckling Lambs with Intrauterine Growth Retardation

“…Two pathways are mainly responsible for activating caspases, including the death receptor-regulated pathway (like Fas/FasL) to activate procaspase-8 and the mitochondrioncontrolled pathway to activate procaspase-9 [54]. Moreover, the dysfunction of mitochondria, together with the production of mitochondrial cytochrome C in the cytoplasm, marks a vital link to activate caspase-9; subsequently, caspase-3 can implement the apoptotic process [56]; such mechanism is different from that of Bcl-2, the mitochondrial membrane protein [57,58]. In our study, L-Arg or NCG reversed the Bax, Fas, Bcl-2, caspase-9, caspase-8, and caspase-3 gene levels in IUGR lambs.…”

N-Carbamylglutamate and l-arginine supplementation improve hepatic antioxidant status in intrauterine growth-retarded suckling lambs

“…Protein content was quantied by the bicinchoninic acid protein assay kit (Nanjing Jiancheng Bioengineering Institute, Nanjing, Jiangsu, China). 14…”

L-Arginine Inhibited Inflammatory Response and Oxidative Stress Induced by Lipopolysaccharide via Arginase-1 Signaling in IPEC-J2 Cells

“…L-arginine also showed an inhibitory effect on IL-1β-mediated NF-κB-activation in Caco-2 cells [25]. In addition, Zhang et al, demonstrated that L-arginine protected ovine intestinal epithelial cells from LPS-induced apoptosis through attenuating oxidative stress [26]. However, the precise molecular mechanism of L-arginine alleviated inflammatory response as well as decreased oxidative injury induced by LPS still remains unexplored.…”