Cortisol Content in Hair Measured by LC-MS/MS: A Noninvasive Marker of Chronic Stress in Companion Animals
Serum and saliva cortisol levels are often reliable measures of the acute stress response in companion animals. However, there is scarce knowledge regarding cortisol hair content as a measure of chronic stress in pets. This study investigated baseline hair cortisol levels from healthy dogs, atopic dogs, healthy cats or cats suffering from feline idiopathic cystitis (FIC).
Hair cortisol measures could help better monitor stressrelated chronic illnesses such as atopy in dogs and FIC in cats. Measuring the cortisol hair content using liquid chromatography-tandem mass spectrometry (LC-MS/MS) technique could offer such a noninvasive method.
Hair was collected from 23 atopic dogs, from 13 healthy dogs, also from 8 FIC cats and from 25 healthy cats. For each animal, approximatively 150 mg of hair was collected from three body sites. LC-MS/MS was performed on samples to quantify hair cortisol concentration. Statistical analyses were run to compare cortisol levels from healthy and atopic dogs (Mann-Whitney U test), also from healthy and FIC cats (Student t-test).
The baseline hair cortisol levels were significantly higher (p=0.0321) in atopic [med: 4.49, min: 1.49, max: 500] than in healthy [med: 2.63, min: 1.34, max: 4.20] dogs. The baseline hair cortisol levels were not significantly different in healthy [mean: 2.3970, SD: 0.5225] and FIC cats [mean: 2.7386, SD: 0.8078].
Hair cortisol content evaluated by LC-MS/MS appears to reflect the dog’s chronic stress status when suffering from atopy. Unanticipated findings in cats suffering from FIC suggest that this cannot be established yet for feline subjects.