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The purpose of this work was to evaluate the effect of the nanosized or microsized zinc (Zn) particles on fatty acid profile, enzyme activity and the level of cholesterol, squalene and oxysterols in rats with breast cancer. Rats (female, n = 24) were divided into the following groups: control, and two test groups, whose diets were enriched with either Zn microparticles (342 nm) or Zn nanoparticles (99 nm). All rats were treated twice with the carcinogenic agent; 7,12-dimethylbenz[a]anthracene. In rats whose diet was enriched with zinc (especially in the form of nanoparticles), the number and sizes of tumors were lower. Diet supplementation also significantly reduced the cholesterol (P = 0.027) and COPs (cholesterol oxidation products) levels (P = 0.011) in rats serum. Enriching the diet with Zn microparticles decreased the Δ6-desaturase activity (P < 0.001). Zn influences fatty acids’ profile in rats’ serum as well as inhibiting desaturating enzymes. A reduced amount of pro-inflammatory arachidonic acid derivatives may be the expected effect.

Fatty acids, especially polyunsaturated, and their metabolites (eicosanoids) play many pivotal roles in human body, influencing various physiological and pathological processes. The aim of the study was to evaluate the effect of supplementation with edible oils diverse in terms of fatty acid composition on fatty acid contents, activities of converting their enzymes, and on lipoxygenase metabolites of arachidonic and linoleic acids (eicosanoids) in rat serum. Female Sprague-Dawley rats divided into seven groups were used in the study. Animals from six groups were fed one of oils daily (carotino oil, made up by combining of red palm oil and canola oil, linseed oil, olive oil, rice oil, sesame oil, or sunflower oil). One group received a standard diet only. Fatty acids were determined using gas chromatography with flame ionization detection. Eicosanoids—hydroxyeicosatetraenoic (HETE) and hydroxyoctadecadienoic acids (HODE) were extracted using a solid-phase extraction method and analyzed with HPLC. Vegetable oils given daily to rats caused significant changes in serum fatty acid profile and eicosanoid concentrations. Significant differences were also found in desaturases’ activity, with the linseed and olive oil supplemented groups characterized by the highest D6D and D5D activity. These findings may play a significant role in various pathological states.

The aim of the present research was to examine the effect of conjugated linoleic acids (CLA) supplementation on the activity of enzymes that take part in the synthesis of arachidonic acid (AA) and also to investigate the relation between their activity and the neoplastic process. The enzyme activities were established indirectly, because their measure was the amount of AA formed in vitro, being developed from linoleic acid as determined in liver microsomes of Spraque-Dawley rats. In addition, the indices of Δ⁶-desaturase (D6D) and Δ⁵-desaturase (D5D) were determined. To this aim, the method of high per-formance liquid chromatography with UV/VIS detection was used. Between the examined groups, statistically significant differences were observed in the activities of enzymes as well as D6D. The carcinogenic agent applied (DMBA) was found to significantly increase the activity of the examined enzymes. Negative correlation was found between the activities of desaturases and CLA supplementation, whereas the activity of those enzymes was a little higher in the group of rats with chemically induced cancer process. The neoplastic process has a stimulating effect on the activity of D6D. The decrease of D6D activity, resulting from the presence of CLA in the animals' diet, may confirm the anticancer properties of these isomers.