Effect of an omega-3 lipid emulsion in reducing oxidative stress in a rat model of intestinal ischemia-reperfusion injury

Abstract

Objectives: The usefulness of omega-3 lipid emulsions has been extensively studied. The objectives of the present study were to examine the effect of an omega-3 lipid emulsion in reducing oxidative stress in a rat model of intestinal ischemia-reperfusion injury and the underlying mechanism.

Methods: A total of 66 rats were divided into three dietary groups (lipid-free, soybean oil, and fish oil groups). Each animal was administered total parenteral nutrition for 3 days, followed by induction of intestinal ischemia for 100 min. Animals subjected to sham surgery served as the controls. Intestinal tissue and blood were harvested 6 and 12 h after the surgery, then, assessment of the histological damage score, plasma-related parameters, and statistical evaluation were performed.

Results: The histological damage score in the intestinal tissues was significantly lower in the fish oil group than in the soybean oil group (P = 0.0121). The late-phase urinary level of 8-hydroxy-2-deoxyguanosine was also significantly lower in the fish oil group as compared with that in the other groups (P = 0.0267). Furthermore, the plasma level of high-mobility group box 1 protein was also significantly lower in the fish oil group as compared with that in the lipid-free group (P = 0.0398).

Conclusion: It appeared that intravenous administration of an omega-3 lipid emulsion prior to ischemia-reperfusion injury reduced the oxidative stress and severity of tissue damage. Modification of membrane fatty acids may serve as the mechanism underlying this reduction of tissue damage.

Fig. 1

Histological findings in sham surgery group. No mucosal damage was seen (hematoxylin−eosin staining×100)

Fig. 2

Representative findings of intestinal tissue specimens after ischemia−reperfusion injury (b, d, f) (hematoxylin−eosin staining×100). Tissue damage scores were also shown (a, c, e). The histological damage score was significantly lower in the fish oil group as compared with that in the soybean oil group (P = 0.0121)

Fig. 3

The 8-OHdG levels were significantly lower in the fish oil group than in the soybean oil group in the late phase (101.7 ± 38.1 vs. 61.7 ± 21.3 ng/mg CRE, respectively, P = 0.0267)

Fig. 4

The PGE2 score at 6 h tended to be lower in the fish oil group than in the soybean oil group (214 ± 74 vs. 416 ± 258 pg/mL, P = 0.1737)

Fig. 5

The plasma levels of HMGB1 were significantly lower in the fish oil group than in the lipid-free group (0.763 ± 0.32 vs. 1.4 ± 0.63 ng/ml, P = 0.0398)

Fig. 6

The mechanism underlying intestinal ischemia−reperfusion injury is typically described as a cascade