Cannabidiol Differently Affects Osteoblasts and Osteocytes

Objectives: This study investigated whether cannabidiol (CBD) affects the viability and differentiation of osteoblasts (OB) and osteocytes (OCY).
Methods: Mouse bone marrow-derived OB and OCY cell lines (Ocy454) were cultured under differentiation conditions for up to 7 days to assess the temporal expression of CBD receptors, Cr1 and Cr2, by real-time PCR. The cells were then incubated with varying CBD concentrations (100, 10, 5, 1, 0.5 and 0.1 μM). Cell viability was measured by MTT assay (n=4), and osteoblast and osteocyte phenotypes were evaluated by ALP activity (Fast red, n=4) and CREB expression (western blot, n=3), respectively. Untreated cells were used as a Control. Data were analyzed using one-way ANOVA (p≤0.05).
Results: In OB, Cr1 expression increased from days 3 to 5 and 7 (p<0.01), while Cr2 expression remained unchanged (p=0.08). On day 7, CBD concentrations of 100, 10, and 5 μM reduced OB viability, whereas lower concentrations maintained viability similar to the Control (p<0.01). Additionally, 100, 10, and 5 μM concentrations decreased ALP activity, whereas lower concentrations showed no difference compared to the Control (p<0.01). In OCY, Cr1 and Cr2 expressions decreased from day 3 to 5 (p=0.01) with no difference at 7 days (p=0.5). On day 5, 100 μM CBD reduced cell viability, whereas 1 μM improved it compared to Control (p<0.01). Furthermore, CBD at 1 and 5 μM concentrations increased CREB expression compared to Control.
Conclusions: CBD receptors’ expression was time-dependent in both osteoblasts and osteocytes. Concentrations of CBD below 5 μM preserved OB viability without affecting phenotype, whereas 1–5 μM increased viability and enhanced OCY differentiation. These findings provide insights into the cellular effects of CBD in bone tissue and suggest its therapeutic potential for managing bone defects, particularly for patients with chronic CBD use.