Effect of conjugated linoleic acid type, treatment period, and dosage on differentiation of 3T3 cells

Antiadipogenic Effects of Different Molecular Forms of Conjugated Linoleic Acid on 3T3-L1 Cells: Comparison between Free Fatty Acid and Phosphatidylcholine Forms

The antiadipogenic activity of conjugated linoleic acids (CLA) in the form of phosphatidylcholine-bound (CLA-PC) or free fatty acids (FFA; CLA-FFA) was evaluated using 3T3-L1 adipocytes. Phosphatidylcholine from soya (soy-PC) was used as the comparison of PC form. Both the lipid accumulation and activity of glycerol-3-phosphate dehydrogenase were measured to determine lipogenesis, whereas the glycerol content was measured to evaluate lipolysis. The CLA uptake also measured to find out the utilization of CLA by the cells. As a results, lipid accumulation in 3T3-L1 adipocytes was inhibited in a dose-dependent manner following treatment with CLA-PC (50-400 μM). Both CLA-PC and soy-PC significantly suppressed lipid accumulation compared with CLA-FFA, even though the amount of CLA in CLA-PC was a half than CLA-FFA. The CLA uptake of PC form was superior to FFA form, however, no difference was noted between CLA-PC and soy-PC. These forms exerted their antiadipogenic activity via the suppression of lipogenesis, and not by increasing lipolysis. Short-term treatment, especially in the middle stage of differentiation, was more effective than long-term treatment; especially for CLA-FFA. The antiadipogenic effect of CLA-PC was partially attributed to the chemical structure of the PC molecule. These results provide important information for the utilization of physiologically functional fatty acids and particularly CLA in the food and medical fields.

The Inhibitory Effects of Djulis (Chenopodium formosanum) and Its Bioactive Compounds on Adipogenesis in 3T3-L1 Adipocytes

The aim of this study was to provide new insights into the role of the ethanolic extracts of Djulis (Chenopodium formosanum, EECF) and its bioactive compounds in preventing adipogenesis in 3T3-L1 adipocytes. The results demonstrated EECF significantly inhibited oil red O-stained material (OROSM), triglyceride levels and glycerol-3-phosphate dehydrogenase (GPDH) activity in 3T3-L1 adipocytes. The expression of the critical molecules involved in lipid synthesis such as PPARγ, C/EBPα and SREBP-1c was attenuated in EECF-treated cells. According to HPLC-DAD and HPLC-MS/MS analysis, rutin, kaempferol, betanin and another nine compounds were present in EECF. The suppression of lipid accumulation by rutin, kaempferol and betanin occurred by decreasing the gene expression of PPARγ, C/EBPα and SREBP-1c. Taken together, these findings suggest the presence of bioactive compounds in EECF may partly account for the anti-adipogenesis of EECF and EECF is therefore a potentially lipid lowering functional food.

Carnosic Acid Inhibits Lipid Accumulation in 3T3-L1 Adipocytes Through Attenuation of Fatty Acid Desaturation

Background:

Excess body fat accumulation contributes to the development of metabolic disorders that can cause adverse health effects. Carnosic acid (CA), a major bioactive component of rosemary (Rosemarinus officinalis), has been suggested to possess anti-adipogenic properties. The present study was conducted to elucidate the mechanism underlying the anti-adipogenic effects of CA.

Methods:

3T3-L1 pre-adipocytes were treated with CA (0.1, 1, and 10 μM) from day 0 to day 8 of differentiation. On day 8, biochemical markers of lipid accumulation and the degree of fatty acid desaturation were measured.

Results:

Oil Red O staining results, triglyceride (TG) accumulation, and glycerol 3-phosphate dehydrogenase activity suggested that CA significantly inhibited lipid accumulation in 3T3-L1 adipocytes. CA significantly decreased mRNA expression of peroxisome proliferator-activated receptor-γ, sterol regulatory element-binding protein 1, and CCAAT/enhancer binding protein-α in a dose-dependent manner. Moreover, it decreased the ratio of both C16:1/C16:0 and C18:1/C18:0, with reduced expression of stearoyl CoA desaturase 1 mRNA and protein.

Conclusions:

These results suggest that CA efficiently suppressed adipogenesis in 3T3-L1 adipocytes and its action, at least in part, is associated with the downregulation of adipogenesis-related genes and the fatty acid composition of TG accumulated in adipocytes.

Adipocyte membrane glycerol permeability is involved in the anti-adipogenic effect of conjugated linoleic acid

Conjugated linoleic acid (CLA), a group of minor fatty acids from ruminant origin, has long been recognized as a body fat lowering agent. Given the trans(t)10,cis(c)12-CLA well documented interference on lipolysis, we hypothesized for adipocytes altered permeation to glycerol when supplemented with this isomer. 3T3-L1 murine differentiated adipocytes were medium supplemented with linoleic acid (LA) and individual or combined c9,t11 and t10,c12-CLA isomers. Adipocytes treated with the t10,c12-CLA isomer and CLA mixture showed reduced triacylglycerols content (p < 0.001), re-enforcing the t10,c12-CLA as the anti-adipogenic CLA isomer. This finding was supported by decreased Δ9-desaturase index and adipocyte differentiation markers for the t10,c12-CLA group (p < 0.001), which suggest reduced lipogenesis and differentiation, respectively. The glycerol permeability was higher in all CLA treated cells compared to control and LA groups (p < 0.05). The increase in glycerol permeability agrees with both reduced triacylglycerols and non-osmotic cellular volume in the t10,c12-CLA and CLA mixture groups. Taken together, our data suggest that the increased adipocyte plasma membrane glycerol fluxes may be part of the anti-adipogenic response to CLA treatments.

Effects of Panicum miliaceum L. extract on adipogenic transcription factors and fatty acid accumulation in 3T3-L1 adipocytes

The dietary intake of whole grains is known to reduce the incidence of chronic diseases such as obesity, diabetes, cardiovascular disease, and cancer. To investigate whether there are anti-adipogenic activities in various Korean cereals, we assessed water extracts of nine cereals. The results showed that treatment of 3T3-L1 adipocytes with Sorghum bicolor L. Moench, Setaria italica Beauvois, or Panicum miliaceum L. extract significantly inhibited adipocyte differentiation, as determined by measuring oil red-O staining, triglyceride accumulation, and glycerol 3-phosphate dehydrogenase activity. Among the nine cereals, P. miliaceum L. showed the highest anti-adipogenic activity. The effects of P. miliaceum L. on mRNA expression of peroxisome proliferator-activated receptor-γ, sterol regulatory element-binding protein 1, and the CCAAT/enhancer binding protein-α were evaluated, revealing that the extract significantly decreased the expression of these genes in a dose-dependent manner. Moreover, P. miliaceum L. extract changed the ratio of monounsaturated fatty acids to saturated fatty acids in adipocytes, which is related to biological activity and cell characteristics. These results suggest that some cereals efficiently suppress adipogenesis in 3T3-L1 adipocytes. In particular, the effect of P. miliaceum L. on adipocyte differentiation is associated with the downregulation of adipogenic genes and fatty acid accumulation in adipocytes.

Effect of conjugated linoleic acids from beef or industrial hydrogenation on growth and adipose tissue characteristics of rats

BACKGROUND

The conjugated linoleic acid (CLA) content of beef can be increased by supplementing appropriate beef cattle diets with vegetable oil or oil seed. Yet the effect of consumption of such beef on adipose tissue characteristics is unclear, thus the study was conducted to compare adipose tissue responses of rats to diets containing beef from steers either not provided or provided the oil supplements to alter CLA composition of the fat in muscle.

METHODS

Effects of feeding synthetic (industrial hydrogenation) CLA or CLA from beef on growth and adipose tissue responses of weanling, male, Wistar rats (n = 56; 14 per treatment diet) were investigated in a completely randomized design experiment. Diets were: control (CON) diet containing casein and soybean oil, synthetic CLA (SCLA) diet; where 1.69% synthetic CLA replaced soybean oil, two beef-diets; CONM and CLAM, containing freeze dried beef from steers either not fed or fed 14% sunflower seeds to increase CLA content of beef. Diets were isonitrogenous (20% protein) and isocaloric. Rat weights and ad libitum intakes were recorded every 2 wk. After 9 wk, rats were fasted for 24 h, blood sampled by heart puncture, sacrificed, tissue and organs were harvested and weights recorded. The adipose tissue responses with regard to cellularity and fatty acid compositions of retroperitoneal and inguinal adipose tissue were determined.

RESULTS

Body weights and gains were comparable, but organ weights as percent of body weight were greater for rats fed SCLA than CONM. Fasting blood glucose concentration was lower (p < 0.01) in rats fed SCLA than those fed CONM or CLAM. Retroperitoneal and inguinal fat weights, as percent of body weight were greater (p < 0.01) in rats fed CONM or CLAM than those fed CON or SCLA diets. Adipocyte numbers were least in retroperitoneal tissue of rats fed SCLA, while inguinal tissue cell density and total number were lower (p = 0.02) in rats fed CLAM (7.26 x 10⁷ cells/g and 8.03 x 10⁸ cells) than those fed CONM (28.88 x 10⁷ cells/g and 32.05 x 10⁸ cells, respectively).

CONCLUSION

Study suggests that dietary CLA either as synthetic or high CLA-beef may alter adipose tissue characteristics by decreasing the number of adipocytes and by decreasing the size of the tissue.

Effect of a seaweed extract on fatty acid accumulation and glycerol-3-phosphate dehydrogenase activity in 3T3-L1 adipocytes

This study was to determine the effect of a seaweed Ascophyllum nodosum extract (SE) containing 220 mg g(-1) phlorotannins on differentiation and fatty acid accumulation in differentiating 3T3-L1 adipocytes. 3T3-L1 cells (2 x 10(4) mL(-1)) were seeded to 24-well plates and proliferated to reach confluence and then were treated with media containing 0, 12.5, 25, 50, 75 and 100 mug mL(-1) SE for 8 days. Dexamethasone, methyl-isobutylxanthine and insulin (DMI) were added to the media in the first 2 days to induce cell differentiation. On day 8 the adipocytes were harvested for measuring cellular fatty acid concentration and the activity of glycerol-3-phosphate dehydrogenase (GPDH). It was found that treatment with SE increased (P < 0.01, n = 6) cellular myristoleic acid (C14:1), palmitoleic acid (C16:1) and oleic acid (C18:1) and total monounsaturated fatty acids (MUFA) without significantly affecting the cell number and saturated fatty acid (SFA). Ratios of MUFA/SFA, C14:1/C14:0, C16:1/C16:0 and C18:1/C18:0 in cellular lipids increased (P < 0.05, n = 6) with the SE treatment in a dose dependent manner (P < 0.001). Treatment with 75 microg mL(-1) SE depressed (P < 0.05) cellular GPDH activity. The results indicate that the biological factors in the SE may be involved in differentiation and MUFA accumulation in adipocytes.