Blunted inflammatory response to lipopolysaccharide endotracheal istallation due to thermal preconditioning

AIM: Heat shock proteins (HSPs), induced by thermal stress, make the cells more resistant to following stress. We aimed to verify if rats heating reduces the production of TNF-alpha in a model of acute respiratory distress syndrome (ARDS). METHODS: We divided 34 Wistar rats in Group A and Group B. The rats of Group A received thermal shock and tracheal instillation of lipopolysaccharide (LPS), the rats of Group B only tracheal instillation of LPS. All the rats have been then subdivided in 6 subgroups sacrificed at different times after instillation of LPS: A30 and B30 at 30 min, A90 and B90 at 90 min and A180 and B180 at 180 min. We dosed the serum concentration of TNF-alpha and the values of every subgroup have been compared with the Student t-test. RESULTS: The serum concentration of TNF-alpha in the subgroup A90 resulted significantly lower than in the subgroup B90. CONCLUSIONS: The exposure to thermal stress resulting in the production of HSPs reduced the concentration of TNF-alpha in this model of ARDS.