Effect of the qualitative composition of a high-fat diet in rats with systemic inflammatory response syndrome upon myocardial resistance to ischemic-reperfusion injury and cytokine levels

Overweight and obesity are among the main factors of cardiovascular risk, but the prospective studies on the dependence between high-fat diets and weight gain yielded contradictory results. Different types of fats exert varying metabolic effects, and this fact leads to a difference in the risk associated with increasing body weight. The effects of fat quality in the daily diet on immunological status and resistance of myocardium to ischemic-reperfusion damage should be studied experimentally in biomedical models. The purpose of this work was to assess the effect of the qualitative composition of a high-fat diet used for induction of primary visceral obesity (PVO) in rats with systemic inflammatory response syndrome (SIRS) upon myocardial resistance to ischemic-reperfusion injury, and levels of pro- and anti-inflammatory cytokines. The experiments were performed on adult male Wistar rats with PVO caused by 28-day consumption of any fat types: hydrogenated fats (HF), vegetable oils (VO), animal fats (AF) or milk fat (MF). The SIRS model included a combination of chemically induced colitis (CIC) and intragastric injection of a broad-spectrum antimicrobial agent (AMA) for three days. Five days later, immunological and biochemical studies were conducted, as well as composition of intestinal microbiota in faecal samples, morphological changes in the structure of the large intestine, hemodynamic parameters and myocardial resistance to ischemic-reperfusion injury were studied in the model of isolated heart perfusion, by Langendorff technique. There was a significant increase in the concentration of anti-inflammatory cytokines in animals with SIRS, i.e., TNFα, IL-1α, IL-2, IL-8, as well as a decrease in TGF-1β, an anti-inflammatory cytokine. SIRS was accompanied by severe dietary disorders and evacuatory function of the gastrointestinal tract. Minimal changes in the intestinal microbiota composition, as well as the most pronounced regeneration signs of intestinal epithelium was observed in rats in the group with MF injection. There was a trend for increasing size of infarction in all the groups as compared with control, directly correlating with increase in BDNF and IL-2 production. However, a significant increase in the infarction size was found only in the group receiving milkfat, thus suggesting a decrease in myocardial resistance to ischemic reperfusion injury (IRI). Thus, the presence of SIRS in the primary obesity model is characterized by controllable change of inflammation markers and depends on the quality of dietary fats. The degree of morphofunctional deterioration of isolated heart, including a decrease in resistance to ischemia-reperfusion injury, correlates with the concentration of BDNF and IL-2 during the studied observation terms.