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Gamma-tocotrienol reduces the triacylglycerol level in rat primary hepatocytes through regulation of fatty acid metabolism.

ABSTRACT: The present study was carried out to investigate the effect of vitamin E analogs, especially gamma-tocotrienol (?-T3), on hepatic TG accumulation and enzymes related to fatty acid metabolism in three types of rat primary hepatocytes: (1) normal hepatocytes, (2) hepatocytes incubated in the presence of palmitic acid (PA), and (3) hepatocytes with fat accumulation. Our results showed that ?-T3 significantly reduced the TG content of normal hepatocytes. ?-T3 also increased the expression of carnitine palmitoyltransferase 1 (CPT1A) mRNA, and tended to reduce that of sterol regulatory element binding protein 1c (SREBP-1c) mRNA. In addition, ?-T3 markedly suppressed the gene expression of both C/EBP homologous protein (CHOP) and SREBP-1c induced by PA. As these two genes are located downstream of endoplasmic reticulum (ER) stress, their suppression by ?-T3 might result from a decrease of ER stress. Moreover, ?-T3 suppressed the expression of interleukin 1? (IL-1?), which lies downstream of CHOP signaling. Taken together, our data suggest that ?-T3 might prevent hepatic steatosis and ameliorate ER stress and subsequent inflammation in the liver.

SUBMITTER: Muto C

PROVIDER: S-EPMC3541416 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature

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Gamma-tocotrienol reduces the triacylglycerol level in rat primary hepatocytes through regulation of fatty acid metabolism.

Muto Chie C Yachi Rieko R Aoki Yoshinori Y Koike Taisuke T Igarashi Osamu O Kiyose Chikako C

Journal of clinical biochemistry and nutrition 20121130 1

The present study was carried out to investigate the effect of vitamin E analogs, especially gamma-tocotrienol (γ-T3), on hepatic TG accumulation and enzymes related to fatty acid metabolism in three types of rat primary hepatocytes: (1) normal hepatocytes, (2) hepatocytes incubated in the presence of palmitic acid (PA), and (3) hepatocytes with fat accumulation. Our results showed that γ-T3 significantly reduced the TG content of normal hepatocytes. γ-T3 also increased the expression of carniti ...[more]

PMID: 23341695

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Project description:AIM:To investigate the effects of electroporation on primary rat hepatocyte and to optimize the electroporation conditions introducing foreign genes into primary hepatocytes. METHODS:A single-pulse procedure was performed at low voltage (220-400 V) but with high capacitance (500-950 microF). Hepatocytes were divided into 4 groups according to the electroporation conditions: group I, 220 V and 500 microF; group II, 220 V and 950 microF; group III, 400 V and 950 microF,and group IV. The control group was freshly isolated hepatocytes and directly cultured under the same conditions as those of electroporation groups. The effects of electroporation on primary rat hepatocytes were detected by trypan blue exclusion (TBE) and MTT analysis. Besides, albumin (Alb), alanine transaminase (ALT) and lactate dehydrogenase (LDH) in the supernatants of cultured hepatocytes were measured by biochemical assay. RESULTS:Between day 1 and day 15 after incubation, primary rat hepatocytes of each electroporation group appeared normal, being the same with those of control group. TBE staining showed that slight hepatocyte damage and high survival rate were found in the electroporation groups and the control group. Cultured for 3, 7, 11 and 15 days, hepatocyte viability was approximately 92.6+/-2.5 %, 89.5+/-3.3 %, 82.0+/-3.5 % and 74.3+/-1.2 %, respectively. MTT analysis indicated that the viabilities of hepatocytes had no significant difference between each electroporation group, and those were similar to that of control group. At the 36th hour after electroporation, Alb, ALT and LDH in the supernatants of control group were 5.3+/-0.1 g x L(-1), 183.7+/-8.4 nkat x L(-1) and 896.8+/-58.5 nkat x L(-1); those of group II were 5.7+/-0.1 g x L(-1), 215.4+/-16.7 nkat x L(-1) and 1063.8+/-51.8 nkat x L(-1); and those of group III were 5.8+/-0.2 g x L(-1), 217.1+/-8.4 nkat x L(-1) and 1063.8+/-10.0 nkat x L(-1). Statistically, the proteins of group II and group III were significantly higher than those of control group (P<0.05), whereas the protein production of group I, Alb, ALT and LDH were 5.3+/-0.2 g x L(-1), 205.4+/-3.3 nkat x L(-1) and 1035.4+/-116.9 nkat x L(-1), were similar to those of control group. At the same time, TBE and MTT analysis indicated that there was no significant cell viability difference between electroporation groups and control group. CONCLUSION:This single-pulse electroporation procedure performed at low voltage (220-400 V) but with high capacitance (950 microF) is one of the optimal choices to introduce foreign genes into primary rat hepatocyte.

Project description:BackgroundLipid abnormalities, enhanced inflammation and oxidative stress seem to represent a vicious circle in atherogenesis, and therapeutic options directed against these processes seems like a reasonable approach in the management of atherosclerotic disorders. Krill oil (RIMFROST Sublime®) is a phospholipid-rich oil with eicosapentaenoic acid (EPA): docosahexaenoic acid (DHA) ratio of 1.8:1. In this pilot study we determined if krill oil could favourable affect plasma lipid parameters and parameters involved in the initiation and progression of atherosclerosis.MethodsThe study was conducted as a 28 days intervention study examining effect-parameters of dietary supplementation with krill oil (832.5 mg EPA and DHA per day). 17 healthy volunteers in the age group 18-36 (mean age 23 ± 4 years) participated. Plasma lipids, lipoprotein particle sizes, fatty acid composition in plasma and red blood cells (RBCs), plasma cytokines, antioxidant capacity, acylcarntines, carnitine, choline, betaine, and trimethylamine-N-oxide (TMAO) were measured before and after supplementation.ResultsPlasma triacylglycerol (TAG) and large very-low density lipoprotein (VLDL) & chylomicron particle concentrations decreased after 28 days of krill oil intake. A significant reduction in the TAG/HDL cholesterol resulted. Krill oil supplementation decreased n-6/n-3 polyunsaturated fatty acids (PUFA) ratio both in plasma and RBCs. This was due to increased EPA, DHA and docosapentaenoic acid (DPA) and reduced amount of arachidonic acid (AA). The increase of n-3 fatty acids and wt % of EPA and DHA in RBC was of smaller magnitude than found in plasma. Krill oil intake increased the antioxidant capacity, double bond index (DBI) and the fatty acid anti-inflammatory index. The plasma atherogenicity index remained constant whereas the thrombogenicity index decreased. Plasma choline, betaine and the carnitine precursor, γ-butyrobetaine were increased after krill oil supplementation whereas the TMAO and carnitine concentrations remained unchanged.ConclusionKrill oil consumption is considered health beneficial as it decreases cardiovascular disease risk parameters through effects on plasma TAGs, lipoprotein particles, fatty acid profile, redox status and possible inflammation. Noteworthy, no adverse effects on plasma levels of TMAO and carnitine were found.

Project description:1. Various aspects of triacylglycerol metabolism were compared in rats given phenobarbital at a dose of 100mg/kg body wt. per day by intraperitoneal injection; controls were injected with an equal volume of 0.15m-NaCl by the same route. Animals were killed after 5 days of treatment. 2. Rats injected with phenobarbital demonstrated increased liver weight, and increased microsomal protein per g of liver. Other evidence of microsomal enzyme induction was provided by increased activity of aminopyrine N-demethylase and cytochrome P-450 content. Increased hepatic activity of gamma-glutamyltransferase (EC 2.3.2.2) occurred in male rats, but not in females, and was not accompanied by any detectable change in the activity of this enzyme in serum. 3. Phenobarbital treatment increased the hepatic content of triacylglycerol after 5 days in starved male and female rats, as well as in non-starved male rats; non-starved females were not tested in this regard. At 5 days after withdrawal of the drug, there was no difference in hepatic triacylglycerol content or in hepatic functions of microsomal enzyme induction between the treated and control rats. 4. After 5 days, phenobarbital increased the synthesis in vitro of glycerolipids in cell-free liver fractions fortified with optimal concentrations of substrates and co-substrates when results were expressed per whole liver. The drug caused a significant increment in the activity of hepatic diacylglycerol acyltransferase (EC 2.3.1.20), but did not affect the activity per liver of phosphatidate phosphohydrolase (EC 3.1.3.4) in cytosolic or washed microsomal fractions. A remarkable sex-dependent difference was observed for this latter enzyme. In female rats, the activity of the microsomal enzyme per liver was 10-fold greater than that of the cytosolic enzyme, whereas in males, the activities of phosphohydrolases per liver from both subcellular fractions were similar. 5. The phenobarbital-mediated increase in hepatic triacylglycerol content could not be explained by a decrease in the hepatic triacylglycerol secretion rate as measured by the Triton WR1339 technique. Since the hepatic triacylglycerol showed significant correlation with microsomal enzyme induction functions, with hepatic glycerolipid synthesis in vitro and with diacylglycerol acyltransferase activity, it is likely to be due to enhanced triacylglycerol synthesis consequent on hepatic microsomal enzyme induction. 6. In contrast with rabbits and guinea pigs, rats injected with phenobarbital showed a decrease in serum triacylglycerol concentration in the starved state; this decrease persisted for up to 5 days after drug administration stopped, and did not occur in non-starved animals. It seems to be independent of the microsomal enzyme-inducing properties of the drug, and may be due to the action of phenobarbital at an extrahepatic site.

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Gamma-tocotrienol reduces the triacylglycerol level in rat primary hepatocytes through regulation of fatty acid metabolism.

Publications

Gamma-tocotrienol reduces the triacylglycerol level in rat primary hepatocytes through regulation of fatty acid metabolism.

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