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Although changes in airway responsiveness in pulmonary inflammation are commonly related to the action of infiltrated leukocytes, our previous report suggested a direct role of inflammatory cytokines in LPS-induced lung hyporesponsiveness. The aim of this study was to define if cytokines detected in the BALF (bronchoalveolar lavage fluid) of intratracheal LPS-treated mice could be, at least in part, responsible for 5-HT (5-hydroxytryptamine) lung hyporeactivity. Our results show that intratracheal instillation of LPS induced a time-dependent increase in IL-(interleukin-)1β, IL-6, and TNF (tumor necrosis factor)α in the BALF. Cytokine production was paralleled by 5-HT lung hyporesponsiveness, and intratracheal administration of TNFα proved to be very efficient in inhibiting 5-HT responsiveness. In addition, systemic treatment with rolipram, an inhibitor of TNFα production, was paralleled by a significant recovery of lung responsiveness. On the contrary, IL-1β and IL-6 were not demonstrated to play a relevant role in 5-HT hyporesponsiveness. It is concluded that TNFα could be a crucial mediator of LPS-induced lung hyporesponsiveness.

Although it is commonly accepted that the anti-inflammatory effect of nonsteroidal anti-inflammatory drugs (NSAIDs) is mainly associated to their ability to inhibit the cyclooxygenase (COX) enzyme system, several results indicate that non-COX mechanisms could be important in the therapeutical effect of these drugs. The aim of this study was to define if NSAIDs could exert, at least in part, their anti-inflammatory effect by inhibiting the activities of human polymorphonuclear leukocytes (PMNs) triggered by chemotactic stimuli and, if so, to understand the relationship of this effect with COX inhibition. A unique opportunity to dissociate the inhibition of prostaglandin (PG) synthesis from other therapeutical properties of NSAIDs is constituted by ketoprofen isomers being the S-isomer 100 time more potent than R-isomer on COX inhibition. Our results show that R- and S-ketoprofen, independently of their potency as PG inhibitors, proved very efficacious in selective inhibition of interleukin-8 (IL-8) chemotaxis. Inhibition of IL-8 chemotaxis was not restricted to ketoprofen isomer as it could be observed also with drugs belonging to different classes of NSAIDs and it was obtained at drug concentration superimposable to plasma levels after therapeutic administration in patients. Reduction of IL-8 migration by ketoprofen isomers was paralleled by selective inhibition of PMN response in terms of intracellular calcium concentration ([Ca 2+ ] i ) increase and extracellular signal regulated kinase(ERK)-2 activation, two intracellular mediators reported to be critical for PMN activities. It is concluded that inhibition of IL-8 chemotaxis could represent a new clinical target for ketoprofen isomers and, in fact, contribute to the anti-inflammatory activity of NSAIDs.