Pattern of cytokines and pharmacomodulation in sepsis induced by cecal ligation and puncture compared with that induced by endotoxin.

The production of tumor necrosis factor alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and IL-6 and their pharmacomodulation were evaluated in a model of polymicrobial sepsis induced in mice by cecal ligation and puncture (CLP) and were compared with the effects of endotoxin (lipopolysaccharide [LPS]) treatment. LPS levels rose as early as 1 h after CLP and increased further after 2 and 21 h. TNF-alpha was detectable in serum, spleen, liver, and lungs during the first 4 h, with a peak 2 h after CLP. IL-1 beta was measurable in serum after 24 h, and levels increased significantly in spleen and liver 4 and 8 h after CLP. IL-6 levels increased significantly in serum throughout the first 16 h after CLP. These cytokines were detectable after LPS injection, with kinetics similar to those after CLP but at a significantly higher level. To cast more light on the differences between these two animal models of septic shock, we studied the effects of different reference drugs. Pretreatment with dexamethasone (DEX); ibuprofen (IBU), an inhibitor of cyclooxygenase; and NG-nitro-L-arginine, an inhibitor of nitric oxide synthase, significantly reduced survival, while chlorpromazine (CPZ) and TNF did not affect it. Only the antibiotics and pentoxifylline significantly increased survival in mice with CLP. However, CPZ and DEX protected the mice from LPS mortality. On inhibiting TNF-alpha with DEX, CPZ, or pentoxifylline, survival was reduced, unchanged, and increased, respectively, and on increasing TNF-alpha with IBU and TNF, survival was decreased or unchanged, respectively, suggesting that the modulation of this cytokine does not play a significant role in sepsis induced by CLP, unlike treatment with LPS. The negative effects of IBU and N(G)-nitro-L-arginine suggest a protective role by prostaglandins and nitric oxide in sepsis induced by CLP.     

LPS pretreatment by the oral route protects against sepsis induced by cecal ligation and puncture. Regulation of proinflammatory response and IgM anti-LPS antibody production as associated mechanisms

Objective: To explore the efficacy of prophylactic oral lipopolysaccharide (LPS) in sepsis induced by cecal ligation and puncture (CLP). Material: Male Balb/c mice. LPS serotype O55: B5 Treatment: Mice were treated every 4 days for a total of 5 times with 50 μg of LPS by intraperitoneal (IP) or oral (O) routes. Treatment was stopped one week prior to CLP. Control (C) groups received the vehicle orally, and sham (S) groups were used as reference. Methods: Histopathology was performed to determine inflammation in liver and lung. Serum cytokines were measured by ELISA, and TNFα tissue expression by RTPCR. Antibodies against LPS were measured by ELISA. Results: Administration of LPS by the oral route significantly increased survival (p<0.05) of mice in association with a reduction of Kupffer cells in liver, pulmonary edema in lung, shorter or delayed TNFα expression in target organs, a trend to decreased IFNγ and increased IL-10 serum levels, and a notable increase in the production of specific IgM anti-LPS antibodies. Conclusions: LPS by oral route protected against CLP. The underlying mechanisms could be the modulation of the proinflammatory response and an increased production of IgM anti-LPS antibodies. Received 12 July 2006; returned for revision 16 November 2006; returned for final revision 14 April 2007; accepted by I. Ahnfelt-R?nne 16 May 2007     

Febrile response induced by cecal ligation and puncture (CLP) in rats: involvement of prostaglandin E<Subscript>2</Subscript> and cytokines

The purpose of the present study was to better understand the events involved in the febrile response induced by cecal ligation and puncture (CLP), a complex infectious process. To this end, we conducted in vivo experiments in rats examining (1) fever development, (2) bacterial number in the infection focus and in blood, (3) peripheral and hypothalamic synthesis of cytokines, (4) hypothalamic and cerebrospinal fluid (CSF) synthesis of prostaglandin E₂ (PGE₂), (5) the effect of anti-IL-6 antibody on fever, and (6) the effect of celecoxib on fever and hypothalamic synthesis of PGE₂ after CLP induction. We found that CLP promotes fever and animal death depending on the number of punctures. The peak of CLP-induced fever overlapped with the maximal increase in the number of bacteria in the infectious focus and blood, which occurred at 6 and 12 h. The peak of the febrile response also coincided with increased amounts of interleukin (IL)-1β, IL-6 and IL-10 in the peritoneal exudate and serum; IL-6 in the hypothalamus and PGE₂ in the CSF and predominantly in the hypothalamus. Moreover, intracerebroventricularly injected anti-IL-6 antibody reduced the febrile response while celecoxib reduced the fever and PGE₂ amount in the hypothalamus induced by CLP. Tumor necrosis factor (TNF)-α peaked at 3 h at all sites studied. Conversely, IL-10 concentration decreased in the hypothalamus. These findings show that the peak of CLP-induced fever is accompanied by an increase of bacteria in peritoneal fluid (local infection) and blood; local synthesis of pyrogenic (IL-1β, IL-6) and antipyretic (IL-10) cytokines and central production of IL-6 and PGE₂, suggesting that these last are the central mediators of this response.