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

Abstract

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 8th 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.

Fig. 1

Weight progress. a The mice weights were monitored from the first experimental day to the 11th day. On 8th day mice received an intraperitoneal injection of 5-FU. b The weight loss delta was performed 72 h after mucositis induction subtracting the weight from the first experimental day to the last weight measured. Different letters indicate statistical significance at 11th day (p < 0.05), n = 10

Fig. 2

The effect of omega-3 fatty acid on intestinal permeability. a Intestinal permeability 24 h after of mucositis induction. b Intestinal permeability 72 h after mucositis induction. Different letters indicate statistical significance, measured by ANOVA (p < 0.05). Data are representative of three different experiments with 5 mice/group each

Fig. 3

Ingestion of omega-3 fatty acid inhibited ileum mucosa damage caused by 5-FU. a Normal histological aspects in the ileum mucosa were observed 24 h after 5-FU injection in all groups. b Increased cell infiltration in the lamina propria was observed in the mice that developed mucositis and mucosal architecture disruption was also observed 72 h after 5-FU injection. Bar = 100 μm. The slices were stained with H&E. 100 ×

Fig. 4

Omega-3 fatty acid is able to maintain ileum mucosal architecture in mice with mucositis. a, b and c) Morphometrical analyses of the small intestine slices from the mice treated or not with the n-3-rich diet were performed using ImageJ software 24 h after mucosittis induction. d, e and f Morphomeric analyses after mucositis induction. a and b Villus mean height (μm), (b and e) Lieberkün crypt mean height (μm) and (c and e) ratio between villus and crypt mean heights. Different letters indicate statistical significance calculated by ANOVA (p < 0.05), n = 5

Fig. 5

Omega-3 fatty acid prevents apoptosis in the ileum mucosa after 5-FU injection. Ileum fragments were subjected to TUNEL labeling and morphometric analyses. a Few apoptotic cells were labeled in the mucosa from the CTL, CTL + n-3 FA and MUC+ n-3 FA mice. Increased apoptotic cells were observed in the mice that developed mucositis (MUC). Bar = 100 μm. b Villus height and apoptotic cell number ratio. Different letters indicate statistical significance (p < 0.05) that were measured by ANOVA (n = 5/group)