Safety assessment of potential food ingredients in canine hepatocytes

Research Highlights
- An innovative in vitro method was developed to study the toxicity of pet food ingredients for dogs.
- LGO induced up-regulation of 16 and down-regulation of 24 genes with CYP450 and HSP most affected.
- Canine hepatocytes may be used to define possible hazard and toxicity of food ingredients.

This research aimed to develop in vitro methods to assess hazard of canine food ingredients. Canine hepatocytes were harvested and cell viability of clove-leaf oil (CLO), eugenol (EUG), lemongrass oil (LGO), guanosine monophosphate (GMP), inosine monophosphate (IMP), sorbose, ginger-root extract (GRE), cinnamon-bark oil (CBO), cinnamaldehyde (CINA), thymol oil (TO), thymol (THYM), and citric acid were assessed with positive controls: acetaminophen (APAP), aflatoxin B1 and xylitol. Molecular Toxicology PathwayFinder array (MTPF) analyzed toxicity mechanisms for LGO. LC50 for APAP was similar among human (3.45), rat (2.35), dog (4.26 mg/ml). Aflatoxin B1 had an LC50 of 4.43 (human), 5.78 (rat) and 6.05 (dog) µg/ml; xylitol did not decrease viability. LC50 of CLO (0.185 ± 0.075(SD)), EUG (0.165 ± 0.112), LGO (0.220 ± 0.012), GRE (1.54 ± 0.31) mg/ml; GMP (166.03 ± 41.83), GMP + IMP (208.67 ± 15.27) mM; CBO (0.08 ± 0.03), CINA (0.11 ± 0.01), TO (0.21 ± 0.03), THYM (0.05 ± 0.01), citric acid (1.58 ± 0.08) mg/ml, while sorbose was non-toxic. LGO induced upregulation of 16 and down-regulation of 24 genes, which CYP and heat shock most affected. These results suggest that in vitro assays such as this may be useful for hazard assessment of food ingredients for altered hepatic function.