Effects of Cannabidiol on RAW 264.7 Macrophage Viability and Inflammatory Markers

Abstract

Cannabidiol (CBD) is a non‐psychoactive derivative from the marijuana plant. There has been an explosion of readily available commercial products infused with and marketing CBD contents, and yet there is a paucity of information regarding the specific effects of CBD on immunity. Our laboratory is interested in examining the effects of CBD on innate immunity, using the immortalized murine macrophage cell line, RAW 264.7. The objective of this research was to determine the effects of CBD on the proliferation, activation, and inflammatory cytokine production in lipopolysaccharide (LPS)‐activated murine macrophages. Additionally, we wanted to determine if maintaining the murine macrophages in serum‐free media during CBD incubation would have an effect on cell viability. RAW 264.7 cells were incubated with either 0.2 or 20 μM of CBD for 24 hours in serum‐free media (SFM) or complete media (CM), followed by a 6 hour, 0.01 μg/ml LPS challenge in SFM. Cell viability was determined via cell counts with Trypan blue exclusion and MTS assay. Macrophages cultured in CM tended to have higher percentages of live cells (Trypan blue exclusion method) compared to those cultured in SFM (54.7+5.4% vs 31.8+5.4% live; ANOVA, p=0.07). Additionally, culturing macrophages in CM also resulted in significantly higher viability (MTS assay) compared to macrophages in SFM (0.58+0.06 vs 0.29+0.06 490nm absorbance; ANOVA, p=0.03). There was no significant effect of CBD concentration (ANOVA; p=0.4) or CBD concentration*media (ANOVA; p=0.2) type on cell viability. These results suggest that concentrations of 0.2 and 20 μM CBD have no detrimental effects on murine macrophage viability and proliferation and that CBD pre‐incubation of macrophages should be performed in complete media. Additionally, data will be presented on the effects of CBD on macrophage activation, including nitric oxide (NO) and interleukin (IL)‐6 production.Support or Funding InformationDenison University Biology Department and Denison Lisska Center for Scholarly Engagement