Protective Effect of D-Methionine on Body Weight Loss, Anorexia, and Nephrotoxicity in Cisplatin-Induced Chronic Toxicity in Rats.

D-methionine is a sulfur-containing amino acid that can act as a potent antioxidant. Anorexia and nephrotoxicity are side effects of cisplatin. The protective effects of D-methionine on cisplatin-induced anorexia and renal injury were investigated. The model of chronic cisplatin administration (5 mg/kg body weight) involved intraperitoneal injection on days 1, 8, and 15 and oral D-methionine (300 mg/kg body weight) coadministration daily for 20 days. On the 21st day of treatment, food intake and body weight in the cisplatin-treated group significantly decreased by 52% and 31%, respectively, when compared with a control group. D-methionine coadministration with cisplatin decreased food intake and body weight by 29% and 8%, respectively. In cisplatin-treated rats, white blood cell, mean corpuscular volume, and platelet values significantly decreased, while mean corpuscular hemoglobin concentration significantly increased by 8.6% when compared with control rats. Cisplatin administration resulted in significantly decreased feeding efficiency, elevated renal oxidative stress, and reduced antioxidative activity. Leukocyte infiltration, tubule vacuolization, tubular expansion, and swelling were observed in the kidneys of cisplatin-treated rats. Oral D-methionine exhibited an antianorexic effect, with improvement in food intake, feeding efficiency, and hematological toxicities, as well as a protective effect against nephrotoxicity by elevated antioxidative activity. D-methionine may serve as a chemoprotectant in patients receiving cisplatin as part of a chemotherapy regimen.

18-carbon polyunsaturated fatty acids ameliorate palmitate-induced inflammation and insulin resistance in mouse C2C12 myotubes.

Skeletal muscle is a major site of insulin action. Intramuscular lipid accumulation results in inflammation, which has a strong correlation with skeletal muscle insulin resistance (IR). The aim of this study was to explore the effects of linoleic acid, alpha-linolenic acid, and gamma-linolenic acid (GLA), 18-carbon polyunsaturated fatty acids (PUFAs), on palmitic acid (PA)-induced inflammatory responses and IR in C2C12 myotubes. Our data demonstrated that these three test 18-carbon PUFAs can inhibit PA-induced interleukin-6 and tumor necrosis factor-α messenger RNA (mRNA) expression and IR as evidenced by increases in phosphorylated AKT and the 160-kD AKT substrate, mRNA and plasma membrane protein expression of glucose transporter 4, and glucose uptake. Moreover, the 18-carbon PUFAs blocked the effects of PA on activation of mitogen-activated protein kinases (MAPKs), protein kinase C-θ (PKC-θ), AMP-activated protein kinase (AMPK) and nuclear factor-κB (NF-κB). Of note, supplementation with GLA-rich borage oil decreased proinflammatory cytokine production and hindered the activation of MAPKs, PKC-θ and NF-κB in the skeletal muscles of diabetic mice. The 18-carbon PUFAs did not reverse PA-induced inflammation or IR in C2C12 myotubes transfected with a constitutively active mutant IκB kinase-ß plasmid, which suggests the importance of the inhibition of NF-κB activation by the 18-carbon PUFAs. Moreover, blockade of AMPK activation by short hairpin RNA annulled the inhibitory effects of the 18-carbon PUFAs on PA-induced IR but not inflammation. Our findings suggest that the 18-carbon PUFAs may be useful in the management of PA-induced inflammation and IR in myotubes.

Indigofera suffruticosa Mill extracts up-regulate the expression of the π class of glutathione S-transferase and NAD(P)H: quinone oxidoreductase 1 in rat Clone 9 liver cells.

Because induction of phase II detoxification enzyme is important for chemoprevention, we study the effects of Indigofera suffruticosa Mill, a medicinal herb, on the expression of π class of glutathione S-transferase (GSTP) and NAD(P)H: quinone oxidoreductase 1 (NQO1) in rat Clone 9 liver cells. Both water and ethanolic extracts of I. suffruticosa significantly increased the expression and enzyme activities of GSTP and NQO1. I. suffruticosa extracts up-regulated GSTP promoter activity and the binding affinity of nuclear factor erythroid 2-related factor 2 (Nrf2) with the GSTP enhancer I oligonucleotide. Moreover, I. suffruticosa extracts increased nuclear Nrf2 accumulation as well as ARE transcriptional activity. The level of phospho-ERK was augmented by I. suffruticosa extracts, and the ERK inhibitor PD98059 abolished the I. suffruticosa extract-induced ERK activation and GSTP and NQO-1 expression. Moreover, I. suffruticosa extracts, especially the ethanolic extract increased the glutathione level in mouse liver and red blood cells as well as Clone 9 liver cells. The efficacy of I. suffruticosa extracts in induction of phase II detoxification enzymes and glutathione content implies that I. suffruticosa could be considered as a potential chemopreventive agent.

Beneficial effects of histidine and carnosine on ethanol-induced chronic liver injury.

Alleviative effects of histidine and carnosine in mice against ethanol-induced oxidative and inflammatory was examined. After chronic alcoholic liver injury was induced, histidine and carnosine at 0.5, 1, 2g/L were added to the drinking water for 3 weeks. Results showed that the post-intake of histidine or carnosine markedly decreased alanine aminotransferase and aspartate aminotransferase activities (P<0.05). Ethanol treatment increased malondialdehyde (MDA) level, decreased glutathione (GSH) content and catalase and glutathione peroxidase (GPX) activities, and increased cytochrome P450 2E1 (CYP2E1) activity in liver (P<0.05). The post-intake of histidine and carnosine significantly decreased MDA formations, increased GSH content, enhanced catalase and GPX activities, and suppressed CYP2E1 activity (P<0.05), in which the effects on catalase and CYP2E1 activities were dose-dependent (P<0.05). Ethanol treatment elevated hepatic levels of c-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) (P<0.05), the post-intake of histidine and carnosine significantly and dose-dependently diminished the release of CRP, IL-6, and TNF-alpha (P<0.05). Ethanol treatment caused down-regulation in both catalase and GPX mRNA expression, and up-regulated both IL-6 and TNF-alpha mRNA expression (P<0.05). Histidine and carnosine post-treatments significantly and dose-dependently upregulated catalase mRNA, and down-regulated mRNA expression of IL-6 and TNF-alpha (P<0.05). Based on the observed anti-oxidative and anti-inflammatory effects, the supplement of histidine or carnosine might be helpful for the treatment of chronic alcoholic liver injury.