TDK conference 2017

Broiler chickens are commonly exposed to immunsuppressive factors, which can deteriorate their health and productivity. The dietary uptake of mycotoxins, often contaminating cereals used in poultry nutrition, cannot be avoided in most cases, thus investigations on the effects of mycotoxins as stressors are of high importance.

The suggested deteriorative effects of T-2 toxin were studied on primary intestinal epithelial cell cultures, hepatocyte and Kupffer cell mono-cultures as well as on hepatocyte – Kupffer cell co-cultures, originated from chicken. Cells were freshly isolated from 20-24-day-old broiler chicks. Intestinal epithelial cell cultures were prepared from tissue explants and from cells isolated by enzymatic digestion with collagenase and dispase. Confluent monolayers were characterized by the binding of concanavalin A lectin to enterocytes and by the immunocytochemical detection of cytokeratins. Since the majority of cultured cells were proven to be enterocytes, intestinal cell cultures were exposed to various concentrations (10, 100 and 1000 nM) of T-2 toxin for 24 h. Hepatocytes and Kupffer cells were isolated by differential centrifugation following a multi-step perfusion of the liver, and they were subsequently co-cultured in the ratio of 6:1. After 24 h culturing, confluent hepatic cell cultures were incubated with different T-2 toxin concentrations (10, 100 and 1000 nM) for 1, 8 and 24 h. The viability of cultured cells was assessed by CCK-8 assay; H2O2 concentration of culture media was measured by Amplex Red method.

The viability of intestinal epithelial cells gained by collagenase-dispase digestion was significantly decreased by 100 and 1000 nM T-2 toxin exposures, while H2O2 production of tissue explants was remarkably increased by these treatments. All toxin concentrations diminished the viability of hepatic co-cultures after 8 h incubation, but no significant differences were observed on mono-cultures. Further, cellular H2O2 production of co-cultures was significantly stimulated by 100 nM T-2 toxin exposure for 24 h, while 1000 nM concentration caused an increase on both hepatocyte mono- and co-cultures.

Since the viability of intestinal epithelial cells was decreased and their H2O2 release was increased by the T-2 toxin exposure, the toxin-triggered cellular deteriorative alterations are supposed to be (partly) in connection with the oxidative stress. Viability of liver cells was reduced only by the 8 h toxin incubation, which was not coupled to increased H2O2 production. A longer, 24 h lasting toxin exposure highly elevated the H2O2 concentration of culture media, but did not affect cell viability. Based on these data, it can be assumed that enterocytes seem to be more sensitive to T-2 toxin exposures than liver cells, because the viability of the latter cells could not be diminished by a prolonged, 24 h long toxin incubation, in spite of the toxin-evoked elevation in cellular H2O2 production.