Cannabidiol improves memory and decreases IL-1β serum levels in rats with lipopolysaccharide-induced inflammation

Abstract

Aim: Memory improving and anti-inflammatory properties of cannabidiol (CBD) were investigated in an experimental model of lipopolysaccharide (LPS)-induced inflammation. Materials and methods: Male Wistar rats were randomly divided into 4 groups: control, LPS control, LPS + CBD 5 mg/kg bw, and LPS + CBD 10 mg/kg bw. Animals were treated with CBD 14 days before LPS administration and throughout the experiment. Step-through passive avoidance task, Y-maze, and novel object recognition test (NORT) were used to assess the memory functions. The following parameters were recorded: latency time, spontaneous alternations percentage (SA%) and recognition index (RI). IL-10, IL-6, TNF-α, and IL-1β serum levels were measured to evaluate the immunomodulatory properties of CBD. Results: LPS led to significant decrease of the recorded parameters in all memory tasks. This demonstrated the memory-impairing effect of LPS-induced inflammation. In the Y-maze and NORT tests, both doses of CBD increased SA% and RI, respectively. Significant difference was found in comparison with the LPS controls. Rats from the CBD treated groups showed increased latency in the step-through passive avoidance task. In the short-term memory test, both CBD doses significantly increased this parameter when compared with both control groups (p<0.05 and p<0.001, respectively), whereas in the long-term memory test, statistical significance was reached only in comparison with the LPS controls (p<0.01). CBD treatment failed to reduce TNF-α and IL-6 serum levels. The lower studied dose significantly decreased IL-10 and IL-1β concentrations compared to LPS controls (p<0.01 and p<0.05, respectively). Conclusions: CBD improved spatial working and recognition memory in rats with LPS-induced inflammation. Suppression of IL-1β production could be attributed to the observed effect.