Fish oil increases the release of tumour necrosis factor and interleukin-6, and has no effect on the incidence of multiple organ failure in rats with peritonitis

Abstract

Objective: To find out if fish oil given intraperitoneally would cause a reduction in the release of tumour necrosis factor and interleukin-6 in abdominal exudate and blood (experiment A), and if it reduces the incidence of organ failure in rats with peritonitis (experiment B).

Design: Laboratory experiment.

Setting: University animal laboratory.

Material: Thirty-six selectively decontaminated rats in each experiment.

Interventions: All rats were pretreated with 2 ml fish oil, lecithin, or saline, intraperitoneally for one or six weeks before intraperitoneal injection of zymosan. Experiment A: Samples of abdominal exudate and plasma were taken regularly for 24 hours after the zymosan had been given. Experiment B: Clinical, biochemical, and histological variables were measured over a 12-day period after the zymosan had been given.

Main outcome measures: Experiment A: Concentrations of tumour necrosis factor and interleukin-6 in abdominal exudate and plasma. Experiment B: Incidence of multiple organ failure.

Results: Experiment A: Concentrations of tumour necrosis factor and interleukin-6 in abdominal exudate and plasma were significantly higher in rats pretreated with fish oil, compared with control rats. This effect was more pronounced after six weeks of pretreatment. Experiment B: There were no significant differences between the groups for any variable.

Conclusion: Fish oil given intraperitoneally increased rather than reduced local and systemic release of tumour necrosis factor and interleukin-6, and did not reduce the incidence of organ failure in rats with sterile peritonitis.