Effects of 15d-PGJ(2)-loaded poly(D,L-lactide-co-glycolide) nanocapsules on inflammation

BACKGROUND and PURPOSEThe PPAR-gamma agonist 15d-PGJ(2) is a potent anti-inflammatory agent but only at high doses. To improve the efficiency of 15d-PGJ(2), we used poly(D,L-lactide-co-glycolide) nanocapsules to encapsulate it, and function as a drug carrier system. The effects of these loaded nanocapsules (15d-PGJ(2)-NC) on inflammation induced by different stimuli were compared with those of free 15d-PGJ(2).EXPERIMENTAL APPROACHMice were pretreated (s.c.) with either 15d-PGJ(2)-NC or unloaded 15d-PGJ(2) (3, 10 or 30 mu g center dot kg-1), before induction of an inflammatory response by i.p. injection of either endotoxin (LPS), carrageenan (Cg) or mBSA (immune response).KEY RESULTSThe 15d-PGJ(2)-NC complex did not display changes in physico-chemical parameters or drug association efficiency over time, and was stable for up to 60 days of storage. Neutrophil migration induced by i.p. administration of LPS, Cg or mBSA was inhibited by 15d-PGJ(2)-NC, but not by unloaded 15d-PGJ(2). In the Cg model, 15d-PGJ(2)-NC markedly inhibited serum levels of the pro-inflammatory cytokines TNF-alpha, IL-1 beta and IL-12p70. Importantly, 15d-PGJ(2)-NC released high amounts of 15d-PGJ(2), reaching a peak between 2 and 8 h after administration. 15d-PGJ(2) was detected in mouse serum after 24 h, indicating sustained release from the carrier. When the same concentration of unloaded 15d-PGJ(2) was administered, only small amounts of 15d-PGJ(2) were found in the serum after a few hours.CONCLUSIONS and IMPLICATIONSThe present findings clearly indicate the potential of the novel anti-inflammatory 15d-PGJ(2) carrier formulation, administered systemically. The formulation enables the use of a much smaller drug dose, and is significantly more effective compared with unloaded 15d-PGJ(2).

Anti-Helicobacter pylori activity and oxidative burst inhibition by the naphthoquinone 5-methoxy-3,4-dehydroxanthomegnin from Paepalanthus latipes

Helicobacter pylori is a bacterium recognized as the major cause of chronic gastritis and peptic ulcers. Infection by H. pylori induces inflammatory responses and pathological changes in the gastric microenvironment. The host Keywords: immune cells (especially neutrophils) release inflammatory mediators and large 5-methoxy-3,4-dehydroxanthomegnin amounts of reactive oxygen species (ROS), which are associated with an increased Helicobacter pyloririsk of developing gastric cancer. In this study, we evaluated the anti-H. pylori and oxidative burst antioxidantactivitiesofa1,4-naphthoquinone-5-methoxy-3,4-dehydroxanthomegnin. Paepalanthus latipes The antimicrobial activity was assessed using a spectrophotometric microdilution technique, and antioxidant activity was assessed by noting the effect of 5-methoxy3,4-dehydroxanthomegnin on the neutrophil oxidative burst using luminol-and lucigenin-amplified chemiluminescence. The results showed that 5-methoxy-3,4dehydroxanthomegnin is a potent anti-H. pylori compound (MIC 64 µg/mL and MBC 128 µg/mL) and a strong antioxidant. 5-Methoxy-3,4-dehydroxanthomegnin decreased luminol- and lucigenin-amplified chemiluminescence, with ED50 values of 1.58±0.09 µg/mL and 5.4±0.15 µg/mL, respectively, reflecting an inhibitory effect on the oxidative burst. These results indicate that 5-methoxy-3,4-dehydroxanthomegnin is a promising compound for the prevention and treatment of diseases caused by H. pylori infection, such as gastritis, peptic ulceration, and gastric cancer, because reactive oxygen intermediates are involved in the pathogenesis of gastric mucosal injury induced by H. pylori infections.

Abdominal hyperalgesia in secretory phospholipase A(2)-induced rat pancreatitis: Distinct roles of NK1 receptors

We investigated the potential of secretory phospholipase A(2) (sPLA(2))-induced pancreatitis to promote abdominal hyperalgesia, as well as to depolarize sensory fibres in vitro using a grease-gap technique. Pancreatitis was induced by the injection of sPLA(2) from Crotalus durissus terrificus (sPLA(2) Cdt, 300 mu g kg(-1)) venom into the common bile duct of rats. Pancreatic inflammatory signs, serum amylase levels and abdominal hyperalgesia were evaluated in rats treated or not with SR140333, a tachykinin NK1 receptor antagonist. Injection of sPLA(2) Cdt caused pancreatic oedema formation and increased pancreatic neutrophil infiltration and serum amylase at 4 h, which returned to normality by 24 h, except for the neutrophil infiltration, which was still increased at this time point. Animals injected with sPLA(2) exhibited a lower withdrawal threshold to electronic von Frey stimulation in the upper abdominal region at 4 h, but not 24 h, post-injection when compared with saline-injected rats. Pre-treatment of animals with SR140333 significantly reduced the sPLA(2) Cdt-induced abdominal hyperalgesia, without affecting the other parameters. Neither sPLA(2) Cdt nor sPLA(2) from Naja mocambique mocambique venom depolarized capsaicin-sensitive sensory fibres from rat vagus nerve, but they decreased the propagated compound action potentials in both A and C fibres. These data show for the first time that NK1 receptors play an important role in the early abdominal hyperalgesia in a rat model of sPLA(2)-induced pancreatitis, suggesting that these receptors are of importance in the development of pain in the pancreatitis condition. We also provide evidence that sPLA(2)s do not directly depolarize sensory fibres in vitro. (C) 2011 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved.