Influence of chronic administration of zearalenone on the processes of apoptosis in the porcine ovary

Abstract

Zearalenone (ZEA), a micotoxin produced by Fusarium sp. is regarded as a phytoestrogen. Although cytotoxic and genotoxic activity of ZEA was detected, the majority of its toxic influence is related to the ability of binding to estrogen receptors and disrupting the endocrine regulation of the reproductory functions in females. It was previously found that ZEA inhibits proliferation of cells in porcine ovaries, as detected with immunostaining for proliferating cells nuclear antigen (PCNA). The number of PCNA-positive cells was inversely proportional to the dose of ZEA. We decided to answer the question of whether ZEA induces apoptosis in porcine ovaries. Experimental gilts (before first estrus) were fed ZEA in a dosage of 20 (group II) or 40 (group III) µg/kg of body weight/day for 63 days. Control animals (group I) were fed a placebo. After that period animals were sacrificed, ovaries were extirpated, fixed in paraformaldehyde solution, cut into sections with a cryostat and studied for apoptosis with TUNEL kit, and for the presence of apoptosis-promoting protein Bax with immunohistochemistry. It was found that apoptosis was detected with TUNEL only in medium-sized antral ovarian follicles in animals of groups I and II. No apoptosis signal was found in the ovaries of animals in group III. No differences in the distribution and intensity of staining for Bax were found between animals of all investigated groups. The results indicate that ZEA do not induce apoptosis in porcine ovaries, and the inhibition of proliferation must be associated with other mechanisms.

Use of modified halloysite nanotubes in the feed reduces the toxic effects of zearalenone on sow reproduction and piglet development

“…The P53, Bax, Cyto C, caspase 9, and caspase 3 gene expressions were decreased and the Bcl-2 gene expression was increased in the ZEN treatment groups in the ovary of the sows and piglets. In previous studies on gilts [17,31] and pregnant rats [27], with the ZEN stimulation, the normal ovarian tissues were replaced by connective tissue, which led to an increase in weight. These conclusions may explain the results of our study.…”

“…In addition to the reproductive disorders, ZEN is frequently implicated in several genotoxic effects [13,14]. Zearalenone has been reported to induce apoptosis in vivo and in vitro [15][16][17][18]. However, available results concerning the induction of apoptosis after ZEN exposure are controversial [19,20].…”

Toxic Effects of Maternal Zearalenone Exposure on Uterine Capacity and Fetal Development in Gestation Rats

“…These conclusions were consistent with the results of previous studies in gilts. 30,51 Zearalenone is known to be rapidly absorbed after oral administration. The risk assessment, which is based on the exposure and hazard evaluation, needs to take into account the transfer of ZEN in the organism and should evaluate all contamination sources.…”

Scientific Opinion on the risks for public health related to the presence of zearalenone in food

“…In a study on apoptosis in the ovaries (Wasowicz et al, 2005), gilts before first oestrus were given zearalenone in gelatine capsules at doses of 0, 20 or 40 μg/kg b.w. per day for 63 days.…”