Veterinary session

Causative agents of hepatitis-hydropericardium, runting-stunting syndrome, chicken anemia and infectious bursal disease play a major role in the poultry industry, even in vaccinated flocks. The organ damage is triggered by excessive inflammation caused by cell death and free radicals in those diseases, thus it is essential to find supplementary substances to alleviate the negative effect. Our aim of this study was to induce inflammation with a viral double-stranded RNA (dsRNA) analog polyinosinic-polycytidylic acid (poly I:C) on chicken primary hepatocyte-non-parenchymal cell co-cultures in order to investigate possible immunomodulatory effects of chicoric acid (CA) in comparison to the antioxidant and anti-inflammatory n-acetyl-cysteine (NAC). Cell cultures were treated with 50 µg/mL poly I:C and additionally with 100 and 200 µg/mL NAC or 10 and 100 µg/mL CA for 24 hours. Following treatment, metabolic activity (CCK assay), extracellular lactate dehydrogenase (LDH) activity, interleukin-6 (IL-6), interleukin-8 (IL-8) concentrations of the medium, malondialdehyde (MDA) and caspase-3 levels of the cell lysate were measured. The results reveal that NAC per se decreased the cellular metabolic activity, whereas CA was able to restore it under poly I:C-induced inflammation. LDH activity, measured to assess the level of cytotoxicity, indicated no significant alteration in NAC treatment groups. In contrast, CA treatment led to a significant reduction in cytotoxicity under inflammatory and normal conditions. Further, the measurement of IL-6 and IL-8 revealed that NAC (100 µg/mL) and CA were able to decrease the concentration of these pro-inflammatory cytokines after poly I:C application, moreover CA also reduced the cytokine production in intact cell cultures. To examine the rate of apoptosis, caspase-3 was measured and revealed no significant alterations after NAC treatment. CA in high concentration elevated the caspase-3 level in the poly I:C induced cell group to the baseline of the control group. Furthermore, the MDA concentration, indicating the amount of lipid peroxidation, was not affected by most of the treatments either with NAC or CA. Only the lower concentration of CA treatment decreased the level of this oxidative stress marker in cells which were treated with poly I:C. Hereby we first applied an inflammatory, chicken-derived primary hepatic cell co-culture model which proved to be efficient to investigate inflammation induced mild cytotoxicity to challenge NAC and CA. The results indicate, that CA, present in many plants of Asteraceae, proves to be a more beneficial supplement in vitro than NAC applied on the present culture of chicken origin. CA was able to maintain cellular metabolic activity and showed dose-dependent anti-inflammatory and hepatocytoprotective effect under physiologic and inflammatory conditions. Therefore, we suggest that CA might alleviate the damage caused by dsRNA viruses, improving poultrys’ health and production.