Enhanced anti‐inflammatory potency of a nitric oxide‐releasing prednisolone derivative in the rat

Abstract

1 Derivatization of nonsteroidal anti-inflammatory drugs, such that they release nitric oxide (NO) in small amounts, has been shown to significantly increase their anti-inflammatory activity and analgesic potency. In this study, we compared the anti-inflammatory potency of prednisolone to a nitric oxidereleasing derivative of prednisolone (NCX-1015). 2 Carrageenan-induced inflammation of an airpouch in the rat was used. The rats were pretreated with equimolar doses of prednisolone or NCX-1015 and the effects on leukocyte infiltration into the airpouch and exudates levels of prostaglandin E 2 (PGE 2 ), leukotriene B 4 (LTB 4 ) and nitrite (as an index of NO production) were measured 6 h later. 3 Injection of carrageenan into the airpouch resulted in a progressive increase in leukocyte infiltration, and accumulation of PGE 2 , LTB 4 and nitrite. Carrageenan also induced elevated expression of cyclooxygenase-1 and -2, inducible nitric oxide synthase and 5-lipoxygenase in the inflammatory exudate. 4 Prednisolone dose dependently reduced the numbers of leukocytes within the airpouch exudates, as well as reducing PGE 2 , LTB 4 and nitrite levels. NCX-1015 also reduced leukocyte numbers and inflammatory mediator levels. However, the doses of NCX-1015 required to produce a maximal reduction of each of these parameters was one-third to one-tenth the dose of prednisolone that produced a comparable effect. 5 The reduction of PGE 2 and NO production was likely to be at least in part due to reduced expression of the key enzymes responsible for their synthesis (cyclooxygenase-2, inducible NO synthase), with NCX-1015 producing greater suppression than prednisolone at an equimolar dose. 6 Coadministration of prednisolone with a nitric oxide donor (DETA-NONOate) resulted in a greater reduction of leukocyte infiltration and inflammatory mediator production than was observed with either drug alone. 7 These results support the notion that delivery of NO to a site of inflammation can markedly enhance the anti-inflammatory activity of a glucocorticoid.

Enhanced Anti-Inflammatory Potency of a Nitric Oxide-Releasing Derivative of Flunisolide: Role of Nuclear Factor-κB

“…In the present study, we demonstrated that the anti-inflammatory potency of flunisolide could be markedly increased (ϳ40-fold) by addition, through an ester linkage, of a NO-releasing moiety. This increase in potency is consistent with previous studies in which NOreleasing derivatives of prednisolone have been examined in experimental inflammation models (Paul-Clark et al, 2000Fiorucci et al, 2002a;Turesin et al, 2003). NCX-1024 was found to be more active in suppressing endotoxin-induced up-regulation of COX-2 mRNA expression and NF-B activation, which may contribute to the observed increase in anti-inflammatory potency.…”

“…They further showed that a similar derivatization of prednisolone, but without the NO-releasing (ONO 2 ) group, did not affect antiinflammatory potency. Turesin et al (2003) demonstrated that coadministration of prednisolone with a DETA-NONOate, an NO donor, resulted in a significantly greater reduction of leukocyte infiltration and inflammatory mediator production in a rat airpouch model than was observed with either drug alone. NO can exert many anti-inflammatory effects, including reduction of leukocyte adherence to the vascular endothelium (Gauthier et al, 1994) and suppression of production of various chemotactic factors (Walford and Loscalzo, 2003).…”

“…One hour before the carrageenan injection, one of the test drugs (flunisolide or NCX-1024) at doses ranging from 0.007 to 23 mol/kg, or the vehicle (1% dimethyl sulfoxide; DMSO), was injected directly into the airpouch (1 ml/kg). We have previously demonstrated that this amount of DMSO does not significantly affect the recruitment of leukocytes or the generation of inflammatory mediators in the airpouch (Turesin et al, 2003). The direct injection of the test drugs into the airpouch was selected as the route of administration to eliminate the possibility of different bioavailability within the airpouch if delivered via another route, which would confound direct comparisons of drug potency.…”

“…Finally, the rest of the exudate was centrifuged at 1000g for 10 min. The supernatants were also collected and stored at -80°C for subsequent measurement of prostaglandin E 2 (PGE 2 ) using a specific, commercially available enzyme-linked immunosorbent assay (Turesin et al, 2003).…”

Gastric Tolerability and Prolonged Prostaglandin Inhibition in the Brain with a Nitric Oxide-Releasing Flurbiprofen Derivative, NCX-2216 [3-[4-(2-Fluoro-α-methyl-[1,1′-biphenyl]-4-acetyloxy)-3-methoxyphenyl]-2-propenoic acid 4-nitrooxy butyl ester]

“…The samples were reconstituted in 200 l of phosphate-buffered saline (pH 7.4) and stored at Ϫ70°C until measurement of PGE 2 content by ELISA was performed (Wallace et al, 2000). In some experiments, the right hemisphere of the brain from each rat was excised and processed for detection of COX-1 and COX-2 expression by Western blotting, as described in detail previously (Turesin et al, 2003).…”