Investigation of the in vitro effects of cannabidiol, cannabidiolic acid, and the terpene β-caryophyllene on lymphocytes harvested from atopic and healthy dogs: A preliminary study

Cannabidiol (CBD) has been shown to have anti-inflammatory and antipruritic properties without the significant psychoactive effects. This study aims to evaluate the cytotoxic effects of, and the production of cytokines after exposure to CBD, cannabidiolic acid (CBDA), and β-caryophyllene (BCP), alone and in combination, by peripheral blood mononuclear cells (PBMC) from healthy and atopic dogs. Six healthy and five atopic, privately-owned dogs were enrolled. Peripheral blood mononuclear cells were harvested and incubated for 24 h with different concentrations of CBD, CBDA, and BCP alone or in combination. Cell viability and inflammatory cytokines were assessed. There was no difference in cell viability between baseline and tested concentrations of CBD, CBDA, or BCP in either healthy or in atopic PBMC. There was no effect of CBD, CBDA and BCP on the secretion of cytokines compared to baseline in healthy or atopic PMBC. The only exception was interleukin (IL)-10, increased in healthy PMBC exposed to CBD 100 ng/mL (p = 0.031) or CBDA 600 ng/mL (p = 0.017). Tumor necrosis factor (TNF)-α, monocyte chemoattractant protein (MCP-1), IL-2, and IL-18 were higher in atopic PBMC exposed to combinations of CBD, CBDA, and BCP compared to healthy post-exposure PBMC. This is the first study that tested the effect of CBD, CBDA, and BCP at different concentrations on atopic and healthy canine PBMC. The results of this study show that CBD, CBDA and BCP, at the tested concentrations, are safe for canine PBMC. However, CBD, CBDA and BCP did not show any direct anti-inflammatory effect under these experimental conditions. Further research is needed to confirm these results in a larger canine population.