Attenuating effects of omega-3 fatty acids (Omegaven) on irradiation-induced intestinal injury in mice

Effect of Dietary Supplementation with Omega-3 Fatty Acid on the Generation of Regulatory T Lymphocytes and on Antioxidant Parameters and Markers of Oxidative Stress in the Liver Tissue of IL-10 Knockout Mice

INTRODUCTION

chronic low-grade inflammation, or inflammaging, emerges as a crucial element in the aging process and is associated with cardiovascular and neurological diseases, sarcopenia, and malnutrition. Evidence suggests that omega-3 fatty acids present a potential therapeutic agent in the prevention and treatment of inflammatory diseases, mitigating oxidative stress, and improving muscle mass, attributes that are particularly relevant in the context of aging. The objective of the present study was to evaluate the effectiveness of supplementation with omega-3 fish oil in improving the immune response and oxidative stress in knockout mice for interleukin IL-10 (IL-10-/-).

MATERIAL AND METHODS

female C57BL/6 wild-type (WT) and interleukin IL-10 knockout (IL-10-/-) mice were fed during 90 days with a standard diet (control groups), or they were fed/supplemented with 10% of the omega-3 polyunsaturated fatty acid diet (omega-3 groups). Muscle, liver, intestinal, and mesenteric lymph node tissue were collected for analysis.

RESULTS

the IL-10-/-+O3 group showed greater weight gain compared to the WT+O3 (p = 0.001) group. The IL-10-/-+O3 group exhibited a higher frequency of regulatory T cells than the IL-10-/- group (p = 0.001). It was found that animals in the IL-10-/-+O3 group had lower levels of steatosis when compared to the IL-10-/- group (p = 0.017). There was even greater vitamin E activity in the WT group compared to the IL-10-/-+O3 group (p = 0.001) and WT+O3 compared to IL-10-/-+O3 (p = 0.002), and when analyzing the marker of oxidative stress, MDA, an increase in lipid peroxidation was found in the IL-10-/-+O3 group when compared to the IL-10-/- group (p = 0.03). Muscle tissue histology showed decreased muscle fibers in the IL-10-/-+O3, IL-10-/-, and WT+O3 groups.

CONCLUSION

the findings show a decrease in inflammation, an increase in oxidative stress markers, and a decrease in antioxidant markers in the IL-10-/-+O3 group, suggesting that supplementation with omega-3 fish oil might be a potential intervention for inflammaging that characterizes the aging process and age-related diseases.

Omega-3 fatty acids impair miR-1-3p-dependent Notch3 down-regulation and alleviate sepsis-induced intestinal injury

Background

Sepsis is a troublesome syndrome that can cause intestinal injury and even high mortality rates. Omega-3 fatty acids (FAs) are known to protect against intestinal damage. Accordingly, the current study set out to explore if omega-3 FAs could affect sepsis-induced intestinal injury with the involvement of the microRNA (miR)-1-3p/Notch3-Smad axis.

Methods

First, cecal ligation and perforation (CLP) was performed to establish septic mouse models in C57BL/6J mice, and mouse intestinal epithelial MODE-K cells were induced by lipopolysaccharide (LPS) to establish sepsis cell models. The CLP-induced septic mice or LPS-exposed cells were subjected to treatment with Omega-3 FAs and activin (Smad signaling activator), miR-1-3p inhibitor and over-expressed/short hairpin RNA (oe-/sh)-Notch3 to explore their roles in inflammation, intestinal oxidative stress and cell apoptosis. A dual-luciferase reporter gene assay was further performed to verify the regulatory relationship between miR-1-3p and Notch3.

Results

Omega-3 FAs inhibited CLP-induced intestinal injury and ameliorated LPS-induced intestinal epithelial cell injury by down-regulating miR-1-3p, as evidenced by decreased levels of tumor necrosis factor-α, interleukin-1β (IL-1β) and IL-6, in addition to diminished levels of reactive oxygen species, malondialdehyde levels and superoxide dismutase activity. Furthermore, miR-1-3p could down-regulate Notch3, which inactivated the Smad pathway.

Conclusion

Collectively, our findings indicated that omega-3 FAs elevate the expression of Notch3 by down-regulating miR-1-3p, and then blocking the Smad pathway to alleviate intestinal epithelial inflammation and oxidative stress injury caused by sepsis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00425-w.

Dietary supplementation with omega-3 fatty acid attenuates 5-fluorouracil induced mucositis in mice

Background

Studies showed the positive effects of omega-3 fatty acid (n-3 FA) for the treatment of inflammatory bowel disease as it alleviated the symptoms and promoted better mucosal integrity. The objective of this study was to determine whether a diet with the addition of n-3 FA helps control the inflammation observed in 5-fluorouracil (5-FU) induced mucositis.

Methods

BALB/c mice were randomly divided into four groups as follows: 1: control (CTL), fed a standard chow diet; 2: CTL + n-3 FA – n-3 FA, fed a diet with n-3; 3: mucositis (MUC), fed a standard chow diet and subjected to mucositis; and 4: MUC+ n-3 FA, fed a diet with n-3 FA and subjected to mucositis. On the 8^th day, the animals of the MUC and MUC + n-3 FA groups received an intraperitoneal injection of 300 mg/kg 5-FU for mucositis induction. After 24 h or 72 h, all mice were euthanized and evaluated for intestinal permeability, bacterial translocation, intestinal histology and apoptosis.

Results

Mice that received the diet with n-3 FA and a 5-FU injection showed less weight loss compared to the animals of the MUC group (p < 0.005). Decreased intestinal permeability and bacterial translocation were also observed in animals fed n-3 FA, and these mice underwent mucositis compared to the MUC group (p < 0.005). These data were associated with mucosal integrity and a reduced number of apoptotic cells in the ileum mucosa compared to the mice that received the control diet and 5-FU injection.

Conclusion

Together, these results show that omega-3 fatty acid decreases the mucosal damage caused by 5-FU-induced mucositis.