Effects of Maternal Linseed Oil Supplementation on Metabolic Parameters in Cafeteria Diet-induced Obese Rats

Because linseed oil may influence maternal and fetal metabolisms, we investigated its role in the modulation of lipid metabolism in cafeteria diet-induced obese rats and their offspring. Female Wistar rats were fed control or cafeteria food, which were either supplemented or not supplemented with linseed oil （5%） for I month before and during gestation. At parturition, serum and tissue lipids and enzyme activities were analyzed. Cafeteria diet induced adverse metabolic alterations in both mothers and offspring. Linseed oil improved metabolic status. In conclusion, linseed oil displayed health benefits by modulating tissue enzyme activities in both obese mothers and their newborns.

Changes of Neuronal Activities after Gut Electrical Stimulation with Different Parameters and Locations in Lateral Hypothalamus Area of Obese Rats

This study tested the effects of the gastrointestinal pulse train electrical stimulation with different parameters and at different locations on the neuronal activities of the lateral hypothalamus area（LHA） in obese rats in order to find the optimal stimulation parameter and location. Eight gastric electrical stimulations（GES） with different parameters were performed and the neuronal activities of gastric-distension responsive（GD-R） neurons in LHA were observed. The effects of stimulations with 8 parameters were compared to find the optimal parameter. Then the optimal parameter was used to perform electrical stimulation at duodenum and ileum, and the effects of the duodenal and ileac stimulation on the GD-R neurons in LHA were compared with the gastric stimulation of optimal parameter. The results showed that GES with the lowest energy parameter（0.3 ms, 3 mA, 20 Hz, 2 s on, 3 s off） activated the least neurons. The effects of GES with other parameters whose pulse width was 0.3 ms were not significantly different from those of the lowest energy parameter. Most gastric stimulations whose pulse width was 3 ms activated more LHA neurons than the smallest energy parameter stimulation, and the effects of those 3 ms gastric stimulations were similar. Accordingly, the lowest energy parameter was recognized as the optimal parameter. The effects of stimulations with the optimal parameter at stomach, duodenum and ileum on the LHA neuronal activities were not different. Collectively, gastrointestinal electrical stimulation（GIES） with relatively large pulse width might have stronger effects to the neuronal activities of GD-R neurons in LHA of obese rats. The effects of the GIES at different locations（stomach, duodenum and ileum） on those neurons are similar, and GES is preferential because of its easy clinical performance and safety.

Calorie control increased vaspin levels of serum and periepididymal adipose tissue in diet-induced obese rats in association with serum free fatty acid and tumor necrosis factor alpha

Background Vaspin was recently identified as a novel adipokine that is predominantly secreted from adipose tissue and exerts insulin-sensitizing effects. This study was undertaken to elucidate the regulative effects of calorie control on the expression of vaspin and its potential mechanism.Methods Diet-induced obese Sprague Dawley （SD） rats were adopted as experimental models and accepted interventions of various ingestions and pioglitazone. Various differentiated stages of cultured 3T3-L1 cells were dealt with pioglitazone or TNFα in vitro for 48 hours to further verify findings in animal experiments.Results The rats were successfully induced into an obese experimental model with hyperinsulinemia, hyperlipidemia, and increased serum free fatty acid and TNFa by 12-week high-fat diet. It was found that depending on whether the rats were fed by a high-fat diet or a basal diet, there was extremely higher vaspin in the periepididymal fat pad than in subcutaneous adipose tissues by 16 weeks. Vaspin in sera and the periepididymal fat pad was much lower in rats with a high-fat diet than those with a basal diet （all P 〈0.05）, but vaspin in subcutaneous fat tissues was prone to increase in rats with a high-fat diet. A 4-week calorie restriction or pioglitazone on the obese rats resulted in a partial recovery of vaspin levels in sera and periepididymal adipose tissues, especially the latter revealed a more obvious superiority and increased vaspin levels of subcutaneous adipose. Surprisingly, the treatment of 4-week high-fat diet on non-obese rats did not significantly depress vaspin of sera and periepididymal adipose tissues. However, it is unknown if re-feeding generated the effect on vaspin levels of obese and non-obese rats on sera or adipose tissues. The correlation analysis showed that vaspin levels of serum and periepididymal fat tissues were negatively correlated with serum FFA, TNFα and insulin; meanwhile, there was a positive correlation between serum vaspin and vaspin of periepididymal fat tissues. Pioglitazone enhanced vaspin levels in cultured 3T3-L1 cells and supernatant in various differentiated stages, and this effect became more and more obvious along with the change of preadipocytes into mature fat cells. Administration of TNFα caused suppression on vaspin expression in differentiated stages of 3T3-L1 cells.Conclusions The present data indicated that a long-term high-fat diet could induce obesity metabolic syndrome in SD rats and finally lead to lower vaspin of sera and periepididymal fat, while pioglitazone and chronic calorie-control ingestion could enhance the production of vaspin. It was undoubtedly demonstrated that vaspin expression was strongly associated with insulin sensitivity, serum FFA, and TNFα.

Effects of hypoxic exercise training on microRNA expression and lipid metabolism in obese rat livers

To investigate the effects of hypoxic exercise training on microRNA （miRNA） expression and the role of miRNA expression in regulating lipid metabolism, 20 dietary-induced obese SD rats were divided into a normoxic sedentary group （N, n=10） and a hypoxic exercise training group （H, n=10）. After four weeks, measurements were taken of body weight, body length, fat mass, serum lipid concentration, miRNAs differentially expressed in rat liver, and gene and protein expression levels of perexisome proliferator activated receptor a （PPARα）, fatty acid synthetase （FAS）, and carnitine palmitoyl transferase 1A （CPTIA） in rat liver. Body weight, Lee＇s index, fat mass, fat/weight ratio, and serum levels of total cholesterol （TC） and high density lipoprotein cholesterol （HDL-C） were all significantly lower in the H group than in the N group （P〈0.01）. Six miRNAs expressed significantly differently in the liver （P〈0.05）. Specifically, expression levels of miR-378b were significantly lower in the H group than in the N group （P〈0.05）. Compared with the normoxic sedentary group, hypoxic exercise training resulted in a lower ratio of FAS mRNA to CPTIA mRNA （P〈0.05）, as well as lower CPT1A protein levels （P〈0.01）, while a higher ratio of FAS to CPT1A protein levels （P〈0.01） was observed. In conclusion, hypoxic training may elevate the resistance of high fat diet induced obesity in rats by reducing the expression of miR-378b, and decrease the fatty acid mitochondrial oxidation in obese rat livers by decreasing the protein expression of CPTIA and increasing the protein expression ratio of FAS/CPTIA.

Bitter Melon Powder Protects against Obesity-associated Fatty Liver Disease by Improving Colonic Microenvironment in Rats with High-fat Diet-induced Obesity

This study explored how bitter melon powder （BMP） alters the colonic microenvironment during the development of obesity-associated fatty liver in rats. We observed that BMP effectively inhibited the body weight gain and lipid accumulation in the liver, ameliorated glucose intolerance, and increased the colon weight after an 8-week treatment compared to that in the high-fat diet （HFD） group. BMP significantly decreased fecal water toxicity towards HT-29 cells, as revealed by the cell counting kit （CCK）-8 assay results, and the mRNA expression of Toll-like receptor 4 （TLR4） in colon mucosa. Additionally, gut permeability in the BMP group was restored to normal levels. Finally, BMP alleviated the inflammatory state of the rat colon mucosa and liver tissues as well as the systemic inflammation.