Role of interleukin 10 in murine postoperative ileus.

BACKGROUND AND AIMS: Intestinal manipulation triggers an inflammatory cascade within the muscularis causing postoperative ileus (POI). The aim of this study was to investigate the recovery and therapeutic potential of interleukin 10 (IL10) for POI. METHODS: POI was induced by bowel surgical manipulation (SM) in wild-type, IL10(-/-) and recombinant murine IL10 (rmIL10)-treated mice. Immunohistochemistry localised IL10 in the muscularis externa, histochemistry quantified neutrophil recruitment, and quantitative PCR quantified alterations in mRNA. Luminex multiplex analysis, Griess reaction and ELISA measured proteins, nitric oxide (NO) and prostanoid release from the muscularis externa, respectively, in 24 h organ culture. Gastrointestinal transit and jejunal circular muscle organ bath techniques assessed gastrointestinal function. RESULTS: In IL10 knockouts compared with the wild type, the expression of numerous proinflammatory mRNAs (IL6, IL1 beta, chemokine C-C motif ligand 2 (CCL2) and haem oxygenase-1) and proteins (IL6, IL1 alpha, IL12, IL17, interferon gamma, tumour necrosis factor alpha, CCL2, interferon-inducible protein-10 and granulocyte-macrophage colony-stimulating factor (GM-CSF)) were accentuated, and release of muscle inhibitors NO and prostanoids was increased; motility never recovered from manipulation and mortality rate was 87.5%. In wild types, complete functional recovery occurred in 7 days with no mortality. SM delay in transit and suppression in jejunal circular muscle contractions were significantly improved by rmIL10 treatment. Upregulation in IL1 beta, IL6 and CCL2 mRNAs and inflammatory mediators (IL1 alpha, IL6, CCL2, macrophage inflammatory protein-1 alpha, GM-CSF, NO and prostaglandin) after SM were significantly less with rmIL10 treatment, which resulted in a decrease in neutrophil recruitment compared with SM controls. CONCLUSION: IL10 plays an obligatory role in postoperative intestinal recovery, and exogenous IL10 prevents its development. Pre-emptive exogenous recombinant human IL10 could be a treatment for the prevention of clinical POI.

IL-10 administration attenuates pulmonary neutrophil infiltration and alters pulmonary iNOS activation following hemorrhagic shock.

OBJECTIVE AND DESIGN: Several studies report immuno-modulatory effects of endogenous IL-10 after trauma. This study investigates the effect of IL-10 administration on systemic and pulmonary inflammation in hemorrhagic shock. MATERIAL AND METHODS: Male C57/BL6 mice (4-6 animals per group) were subjected to volume controlled hemorrhagic shock for 3 hrs followed by resuscitation. Animals were either subcutaneously injected with 0.9 % saline (Shock group) or with recombinant mouse IL-10 (Shock+IL-10 group) 1 h before and 1 h after the induction of hemorrhagic shock. Serum TNF-alpha, IL-6, and keratinocyte (KC) concentrations were measured with the Luminex multiplexing platform. Acute pulmonary inflammation was assessed by pulmonary myeloperoxidase (MPO) and inducible nitric oxide synthase (iNOS) activity. RESULTS: IL-10 administration significantly decreased serum TNF-alpha (10.30 +/- 1.68 vs 37.42 +/- 10.64; p < 0.05), IL-6 (44.22 +/- 6.65 vs 85.24 +/- 7.94; p < 0.05), and KC (276.74 +/- 52.67 vs 465.61 +/- 58.98; p < 0.05) levels following hemorrhagic shock. Further, pulmonary MPO activity was significantly lower (2698.85 +/- 431.10 vs 4580.67 +/- 294.38; p < 0.05) and pulmonary iNOS activity upregulated. CONCLUSION: These findings suggest that administration of IL-10 modulates the degree of hemorrhage-induced systemic and pulmonary inflammation and support the notion of a central role for iNOS in acute lung injury.

Role of interleukin-6 in hemopoietic and non-hemopoietic synergy mediating TLR4-triggered late murine ileus and endotoxic shock.

BACKGROUND: Early murine endotoxin-induced ileus at 6 h is exclusively mediated by non-hemopoietic TLR4/MyD88 signaling despite molecular activation of hemopoietic cells which included a significant IL-6 mRNA induction. Our objective was to define the role of hemopoietic cells in LPS/TLR4-triggered ileus and inflammation over time, and identify mechanisms of ileus. METHODS: CSF-1(-/-) , TLR4 non-chimera and TLR4 chimera mice were single-shot intraperitoneal injected with ultrapure lipopolysaccharide (UP-LPS) and studied up to 4 days. Subgroups of TLR4(WT) mice were additionally intravenously injected with exogenous recombinant IL-6 (rmIL-6) or murine soluble IL-6 receptor blocking antibody (anti-sIL-6R mAB). KEY RESULTS: Hemopoietic TLR4 signaling independently mediated UP-LPS-induced ileus at 24 h, but chemotactic muscularis neutrophil extravasation was not causatively involved and mice lacking CSF-1-dependent macrophages died prematurely. Synergy of hemopoietic and non-hemopoietic cells determined ileus severity and mortality which correlated with synergistic cell lineage specific transcription of inflammatory mediators like IL-6 within the intestinal muscularis. Circulating IL-6 levels were LPS dose dependent, but exogenous rmIL-6 did not spark off a self-perpetuating inflammatory response triggering ileus. Sustained therapeutic inhibition of functional IL-6 signaling efficiently ameliorated late ileus while preemptive antibody-mediated IL-6R blockade was marginally effective in mitigating ileus. However, IL-6R blockade did not prevent endotoxin-associated mortality nor did it alter circulating IL-6 levels. CONCLUSIONS & INFERENCES: A time-delayed bone marrow-driven mechanism of murine endotoxin-induced ileus exists, and hemopoietic cells synergize with non-hemopoietic cells thereby prolonging ileus and fueling intestinal inflammation. Importantly, IL-6 signaling via IL-6R/gp130 drives late ileus, yet it did not regulate mortality in endotoxic shock.

The effect of the transplanted pineal gland on the sympathetic innervation of the rat sublingual gland.

We investigated the effect of the pineal on sympathetic neurons that normally innervate the sublingual gland of the rat. When the pineal gland was transplanted into the sublingual gland, it remained as a distinct mass that was innervated by sympathetic axons. Injection of the retrograde tracer, Fast Blue, into the sublingual gland labelled sympathetic neurons in the ipsilateral superior cervical ganglion (SCG). Thirty per cent of all neurons labelled retrogradely by Fast Blue injection into transplanted pineal glands were immunoreactive for both neuropeptide Y (NPY) and calbindin. This combination is characteristic of sympathetic neurons innervating the pineal gland in its normal location, but not the sympathetic vasoconstrictor neurons normally innervating the sublingual gland. This, and our previous study in which the pineal gland was shown to similarly influence the phenotype of salivary secretomotor neurons, suggests that a range of different functional classes of sympathetic neuron are able to change their phenotype in response to signals released by the pineal gland.