Anandamide enhances expression of heat shock proteins Hsp70 and Hsp25 in rat lungs

Anandamide (AEA), an endogenous cannabinoid and vanilloid receptor ligand, possesses anti-inflammatory properties. Transport of AEA through cytoplasm is facilitated by heat shock protein (HSP) Hsp70, which enhances the rate of cellular AEA uptake, possibly via direct interactions. In lungs, increased HSP expression is an endogenous, protective mechanism against acute lung inflammation. We hypothesised that AEA could enhance the expression of cytoprotective Hsp70 and Hsp25. Anaesthetised rats were injected intravenously with 1 mg/kg AEA or saline. Lungs were removed 2 and 24 h after injection for evaluation of HSP expression. Hsp70 and Hsp25 expression in lungs was evaluated by immunohistochemistry. The relative levels of these HSPs in lung sections were determined through optical density measurements and western blotting of lung homogenates. Western blot and immunohistochemistry analyses indicated that expression of both proteins was significantly higher in AEA-injected animals than in control animals 2 and 24 h after treatment. AEA administration enhanced Hsp70 and Hsp25 expression in lungs. Therefore, AEA-HSP interactions could be involved in mechanisms protecting against lung inflammation, indicating a possible use of AEA as a treatment for lung inflammation. (C) 2011 Elsevier B.V. All rights reserved.