Effect of dietary fish oil supplementation on cellular adhesion molecule expression and tissue myeloperoxidase activity in diabetic mice with sepsis

Effects of dietary adjustment of n-3:n-6 fatty-acid ratio to 1:2 on anti-inflammatory and insulin-signaling pathways in ovariectomized mice with high fat diet-induced obesity

Estrogen deficiency increases the secretion of inflammatory mediators and can lead to obesity. Consequently, estrogen deficiency can cause metabolic syndrome, particularly insulin resistance during menopause. Both fish oil and perilla oil contain n-3 fatty acids, which may regulate several inflammatory cytokines. Additionally, adjusting the dietary n-3:n-6 fatty-acid ratio to 1:2 may help treat or prevent chronic diseases. Therefore, we investigated the effect of anti-inflammatory and insulin-signaling pathways, not solely in relation to the (n-3:n-6 fatty-acid ratio at 1:2), but also considering the origin of n-3 fatty acids found in fish oil and perilla oil, in a mouse model of estrogen deficiency induced by ovariectomy and obesity induced by a high-fat diet (HFD). Female C57BL/6J mice were divided into five groups: sham mice on a normal diet; ovariectomized (OVX) mice on a normal diet (OC); OVX mice on a HFD plus lard oil (OL), fish oil (OF), or perilla oil (OP). The dietary n-3:n-6 ratio in the OF and OP groups was adjusted to 1:2. The results showed OF group exhibited significantly lower abdominal adipose tissue weight, fewer liver lipid droplets, and smaller uterine adipocytes, compared with the OL group. Compared with the OL group, the OF and OP groups exhibited higher oral glucose tolerance and lower serum alanine aminotransferase activity, triacylglycerol levels, and total cholesterol levels. Hepatic JAK2, STAT3, and SOCS3 mRNA expression and p-NF-κB p65 and IL-6 levels were significantly lower in the OF and OP groups than in the OL group. Only the OF group exhibited an increase in PI3K and Akt mRNA expression, decrease in GLUT2 mRNA expression, and considerable elevation of p-Akt. Both fish and perilla oil reduced inflammatory signaling markers. However, only fish oil improved insulin signaling (PI3K, Akt, and GLUT2). Our data suggest that fish oil can alleviate insulin signaling through activating the PI3K-Akt-GLUT2 cascade signaling pathway.

Medicinal Plants with Multiple Effects on Diabetes Mellitus and Its Complications: a Systematic Review

PURPOSE OF REVIEW

This systematic review describes evidence concerning medicinal plants that, in addition to exerting hypoglycemic effects, decrease accompanying complications such as nephropathy, neuropathy, retinopathy, hypertension, and/or hyperlipidemia among individuals with diabetes mellitus (DM).

RECENT FINDINGS

Studies on the antidiabetic mechanisms of medicinal plants have shown that most of them produce hypoglycemic activity by stimulating insulin secretion, augmenting peroxisome proliferator-activated receptors (PPARs), inhibiting α-amylase or α-glucosidase, glucagon-like peptide-1 (GLP-1) secretion, advanced glycation end product (AGE) formation, free radical scavenging plus antioxidant activity (against reactive oxygen or nitrogen species (ROS/RNS)), up-regulating or elevating translocation of glucose transporter type 4 (GLUT-4), and preventing development of insulin resistance. Not only are medicinal plants effective in DM, but many of them also possess a variety of effects on other disease states, including the complications of DM. Such plants may be appropriate alternatives or adjuncts to available antidiabetic medications.

A soybean and fish oil mixture with different n-6/n-3 PUFA ratios modulates the inflammatory reaction in mice with dextran sulfate sodium-induced acute colitis

BACKGROUND & AIMS

Inflammatory bowel disease is a recurrent disease of the gastrointestinal tract. n-3 polyunsaturated fatty acids (PUFAs) are proved to have anti-inflammatory and immunomodulatory properties. This study evaluated the effects of different dietary n-6/n-3 PUFA ratios on the mechanism of alleviating the inflammatory response in mice with dextran sulfate sodium (DSS)-induced colitis.

METHODS

Mice were randomly assigned to 6 groups including 3 non-colitis groups (C, LF, and HF) and 3 colitis groups (DC, DLF, and DHF). Mice in the C and DC groups were fed a common semipurified diet with soybean oil as the fat source. The other groups received an identical component except that part of the soybean oil was replaced by different amounts of fish oil. The n-6/n-3 PUFA ratio of the LF and DLF groups was 4:1, the ratio of the HF and DHF groups was 2:1. After feeding the respective diets for 2 weeks, the colitis groups were given distilled water containing 2% DSS, while the non-colitis groups were given distilled water for 5 days. After that, all mice were sacrificed at the recovery phase after drinking distilled water for another 5 days.

RESULTS

Colitis resulted in higher expressions of colonic inflammatory mediators in colon tissues and colon lavage fluid. Also, colonic peroxisome proliferator-activated receptor (PPAR)-γ and the IκBα/nuclear factor (NF)-κB p65 ratio were lower than those of the non-colitis groups. Compared to the DC group, fish oil-enriched colitis groups had lower inflammatory mediator expressions and higher PPAR-γ protein levels and IκBα/NF-κB p65 ratios in colon tissues. The DHF group had even lower colonic inflammatory gene and higher PPAR-γ protein expressions than did the DLF group.

CONCLUSIONS

These findings suggest that diets enriched with fish oil upregulated PPAR-γ and decreased NF-κB activation that may consequently have reduced luminal inflammatory mediator production. Compared to a n-6/n-3 PUFA ratio 4:1, a ratio of 2:1 was more effective in reducing inflammatory reactions in DSS-induced colitis.

Dietary fish oil reduces systemic inflammation and ameliorates sepsis-induced liver injury by up-regulating the peroxisome proliferator-activated receptor gamma-mediated pathway in septic mice

This study investigated the effect of dietary fish oil on systemic inflammation and hepatic injury in mice with polymicrobial sepsis. Male ICR mice were assigned to a control group (C, n=30) and a fish oil group (FO, n=30). Mice in the C group were fed a semi-purified diet with 10% soybean oil, and those in the FO group were fed a fish oil diet (2.5% fish oil+7.5% soybean oil; w/w). Three weeks later, sepsis was induced by cecal ligation and puncture (CLP), and mice were sacrificed at 0, 6 and 24 h after CLP, respectively. Results showed that compared with C group, the FO group had lower plasma levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and nitrite at 6 and 24 h after CLP. Also, peritoneal lavage fluid concentrations of TNF-α and prostaglandin (PG) E2 were significantly lower at 24 h in the FO than in the C group. The FO group had lower myeloperoxidase activities at 6 h after CLP in various organs. Plasma aminotransferase and alanine aminotransferase activities revealed significantly decreased in the FO group. The DNA-binding activity of peroxisome proliferators-activated receptor gamma (PPARγ) and mRNA expression of I kappaB alpha (IκBα) were up-regulated while nuclear factor (NF)-κB p65 DNA-binding activity, inducible nitric oxide synthase protein expression and the concentration of nitrotyrosine were significantly decreased in the FO group in liver after CLP. These results indicate that dietary fish oil administration may attenuate systemic inflammation and up-regulate hepatic PPARγ DNA-binding activity, which may consequently have ameliorated liver injury in these septic mice.

Polysaccharides from extracts of Antrodia camphorata mycelia and fruiting bodies modulate inflammatory mediator expression in mice with polymicrobial sepsis

OBJECTIVES

Antrodia camphorata (AC) is a traditional Chinese medicine, and the polysaccharides contained within AC (AC-PSs) are reported to possess various biological functions. This study extracted AC-PSs from mycelia and fruiting bodies and evaluated their influences on inflammatory mediator expressions in septic mice.

METHODS

There were one normal control (NC) and three experimental groups. The normal control group underwent a sham operation, whereas the experimental groups underwent cecal ligation and puncture (CLP) to induce sepsis. Mice in the experimental groups were further divided into saline, mycelia, and fruiting body treatment groups. Saline or AC-PSs were injected intraperitoneally twice at 0.5 and 1 h after CLP and the mice were sacrificed at 6 or 16 h after sepsis for further analysis.

RESULTS

Compared with the normal control group, interleukin (IL)-6, tumor necrosis factor-α, IL-10, and monocyte chemotactic protein-1 levels in plasma and/or peritoneal lavage fluid in the septic mice dramatically increased after CLP. The increased levels of these inflammatory mediators in the two AC-PS-treated groups had decreased by 16 h after CLP. Messenger RNA expressions of tumor necrosis factor-α, IL-6, and IL-10 in the splenocytes were lower in the 2 AC-PS-treated groups than in the saline group. Consistent with the results, lung nuclear factor-κB expressions decreased and less severe interstitial inflammation was observed in the histologic finding after CLP in mice that had received AC-PSs. The fruiting body group had higher white blood cell counts and lower IL-6 levels in the peritoneal lavage fluid 6 h after CLP, whereas the interferon-γ level was higher 16 h after CLP than in the saline group. These alterations were not found in mice injected with the mycelia extract.

CONCLUSION

The administration of AC-PSs from mycelia or fruiting bodies decreased the inflammatory mediator expressions at the location of injury and in the circulation, especially in the late stage of sepsis. AC-PSs from fruiting bodies seemed to be more effective in decreasing the inflammatory response than those from mycelia. These findings suggest that AC-PSs from mycelia and fruiting bodies have potential protective effects against polymicrobial sepsis.

Insights into modeling streptozotocin-induced diabetes in ICR mice

Streptozotocin (STZ)-induced diabetes in ICR mice is often used to model diabetes mellitus and its complications, as well as other pathologies. In studies of diabetes progression and effects of newly developed treatments, experimental results may be difficult to interpret because blood glucose levels (BGLs) of untreated diabetic control animals tend to decline substantially during typical experimental time spans of 8-11 h. To address this problem, the authors examined several experimental conditions that might affect BGL stability, including STZ dose, initial mouse weight, fasting regimen and light:dark cycle. The authors found that diabetes severity was dependent on initial mouse weight and that weight loss after diabetes induction was less severe in heavier mice. Furthermore, a dose of 150 mg STZ per kg body weight was sufficient to induce stabilized acute diabetes without causing many complications. Finally, BGL could be stabilized in diabetic mice that were not treated with insulin by avoiding pre-fasting before an 8-h experiment and by allowing mice limited access to food during the experiment.

Effect of dietary omega-3 polyunsaturated fatty acids on experimental periodontitis in the mouse

BACKGROUND AND OBJECTIVE

Periodontitis is an infective disease caused predominantly by gram-negative anerobes. The host inflammatory response to these bacteria causes alveolar bone loss, which characterizes periodontitis. Omega-3 polyunsaturated fatty acids have recognized anti-inflammatory effects; their oxygenated derivatives are key mediators in reducing inflammation. In this study we tested the hypothesis that dietary supplementation with tuna fish oil rich in the n-3 polyunsaturated fatty acid, docosahexaenoic acid, would reduce alveolar bone loss in mice inoculated with periodontopathic bacteria.

MATERIAL AND METHODS

Adult mice were fed experimental diets containing either 10% tuna oil or Sunola oil for 57 d. After 14 d, 35 mice on each diet were inoculated orally with Porphyromonas gingivalis, with a mixture of P. gingivalis and Fusobacterium nucleatum, with carboxymethylcellulose or remained untreated. The mice were killed, and soft tissue biopsies from the oral cavity of treated mice were used to determine the polyunsaturated fatty acid concentrations. The maxilla was removed, stained and digitally imaged to assess bone loss around the upper molars.

RESULTS

n-3 polyunsaturated fatty acid levels were significantly higher in oral soft tissues of mice fed tuna oil compared with the control group. Mice fed tuna oil and inoculated with P. gingivalis or with the combination of F. nucleatum and P. gingivalis exhibited 72% and 54% less alveolar bone loss respectively, compared with the treatment control group.

CONCLUSION

Alveolar bone loss was inversely related to n-3 polyunsaturated fatty acid tissue levels. In conclusion, fish oil dietary supplementation may have potential benefits as a host modulatory agent in the prevention and/or adjunctive management of periodontitis.