Fish oil supplementation during adolescence attenuates metabolic programming of perinatal maternal high-fat diet in adult offspring

Perinatal maternal high-fat diet (HFD) increases susceptibility to obesity and fatty liver diseases in adult offspring, which can be attenuated by the potent hypolipidaemic action of fish oil (FO), an n-3 PUFA source, during adult life. Previously, we described that adolescent HFD offspring showed resistance to FO hypolipidaemic effects, although FO promoted hepatic molecular changes suggestive of reduced lipid accumulation. Here, we investigated whether this FO intervention only during the adolescence period could affect offspring metabolism in adulthood. Then, female Wistar rats received isoenergetic, standard (STD: 9 % fat) or high-fat (HFD: 28·6 % fat) diet before mating, and throughout pregnancy and lactation. After weaning, male offspring received the standard diet; and from 25 to 45 d old they received oral administration of soyabean oil or FO. At 150 d old, serum and hepatic metabolic parameters were evaluated. Maternal HFD adult offspring showed increased body weight, visceral adiposity, hyperleptinaemia and decreased hepatic pSTAT3/STAT3 ratio, suggestive of hepatic leptin resistance. FO intake only during the adolescence period reduced visceral adiposity and serum leptin, regardless of maternal diet. Maternal HFD promoted dyslipidaemia and hepatic TAG accumulation, which was correlated with reduced hepatic carnitine palmitoyl transferase-1a content, suggesting lipid oxidation impairment. FO intake did not change serum lipids; however, it restored hepatic TAG content and hepatic markers of lipid oxidation to STD offspring levels. Therefore, we concluded that FO intake exclusively during adolescence programmed STD offspring and reprogrammed HFD offspring male rats to a healthier metabolic phenotype in adult life, reducing visceral adiposity, serum leptin and hepatic TAG content in offspring adulthood.

Dietary curcumin supplementation attenuates inflammation, hepatic injury and oxidative damage in a rat model of intra-uterine growth retardation

Rats with a normal birth weight (NBW) or intra-uterine growth retardation (IUGR) were fed basic diets (NBW and IUGR groups) or basic diets supplemented with curcumin (NC and IC groups) from 6 to 12 weeks. The body weight of IUGR rats was lower (P<0·05) than that of the controls. Rats with IUGR showed higher (P<0·05) concentrations of TNF-α, IL-1β and IL-6; higher (P<0·05) activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in their serum; and increased (P<0·05) concentrations of malondialdehyde (MDA), protein carbonyl (PC) and 8-hydroxy-2'-deoxyguanosine (8-OHDG) in the liver compared with the NBW rats. The livers of IUGR rats exhibited a lower (P<0·05) superoxide dismutase activity and decreased (P<0·05) metabolic efficiency of the hepatic glutathione redox cycle compared with those of the NBW rats. In response to dietary curcumin supplementation, concentrations of inflammatory cytokines and activities of AST and ALT in the serum and MDA, PC and 8-OHDG in the liver were lower (P<0·05), and the hepatic glutathione redox cycle in the liver was improved (P<0·05) in the IC group than in the IUGR group. These results were associated with lower (P<0·05) phosphorylated levels of the NF-κB pathway and Janus kinase 2 (JAK2) and higher (P<0·05) mRNA expression of genes involved in the nuclear factor, erythroid 2-like 2 (Nfe2l2)/antioxidant response element (ARE) pathway in the liver of the IC rats than that of the IUGR rats. Maternal undernutrition decreased birth weight and led to inflammation, oxidative damage and injury in rats. Curcumin appeared to be beneficial in preventing IUGR-induced inflammation, oxidative damage and injury by activating the expression of the NF-κB, JAK/STAT and Nfe2l2/ARE pathways in the liver.

Curcumin attenuates hepatic fibrosis and insulin resistance induced by bile duct ligation in rats

Recent studies have strongly indicated the hepatoprotective effect of curcumin; however, the precise mechanisms are not well understood. This study aimed to determine the protective effect of curcumin on hepatic damage and hepatic insulin resistance in biliary duct ligated (BDL) fibrotic rat model. To accomplish this, male Wistar rats were divided into four groups (eight for each): sham group, BDL group, sham+Cur group and BDL+Cur group. The last two groups received curcumin at a dose of 100 mg/kg daily for 4 weeks. The mRNA/protein expression levels of Ras-related C3 botulinum toxin substrate 1 (Rac1), Rac1-GTP, dinucleotide phosphate oxidase 1 (NOX1), signal transducer and activator of transcription 3 (STAT3), suppressor of cytokine signalling 3 (SOCS3), insulin receptor substrate 1 (IRS1), extracellular signal-regulated kinase 1 (ERK1), specific protein 1 (Sp1) and hypoxia-inducible factor-1α (HIF-1α) were measured by real-time PCR and Western blotting, respectively. Fasting blood glucose, insulin and Leptin levels were determined and homoeostasis model assessment-estimated insulin resistance, as an index of insulin resistance, was calculated. Curcumin significantly attenuated liver injury and fibrosis, including amelioration of liver histological changes, reduction of hepatic enzymes, as well as decreased expression of liver fibrogenesis-associated variables, including Rac1, Rac1-GTP, NOX1, ERK1, HIF-1α and Sp1. Curcumin also attenuated leptin level and insulin resistance, which had increased in BDL rats (P<0·05). Furthermore, compared with the BDL group, we observed an increase in IRS1 and a decrease in SOCS3 and STAT3 expression in the curcumin-treated BDL group (P<0·05), indicating return of these parameters towards normalcy. In conclusion, Curcumin showed hepatoprotective activity against BDL-induced liver injury and hepatic insulin resistance by influencing the expression of some genes/proteins involved in these processes, and the results suggest that it can be used as a therapeutic option.