Splenectomy attenuates severe thermal trauma-induced intestinal barrier breakdown in rats.

The severe local thermal trauma activates a number of systemic inflammatory mediators, such as TNF-α, NF-κB, resulting in a disruption of gut barrier. The gastrointestinal tight junction (TJ) is highly regulated by membrane-associated proteins including zonula occludens protein-1 (ZO-1) and occludin, which can be modulated by inflammatory cytokines. As splenectomy has been shown to reduce secretion of cytokines, we hypothesized that (1) severe scald injury up-regulates TNF-α and NF-κB, meanwhile down-regulates expression of ZO-1 and occludin, leading to the increased intestinal permeability, and (2) splenectomy can prevent the burn-induced decrease in ZO-1 and occludin expression, resulting in improved intestinal barrier. Wistar rats undergoing a 30% total body surface area (TBSA) thermal trauma were randomized to receive an accessorial splenectomy meanwhile or not. Intestinal injury was assessed by histological morphological analysis, and serum endotoxin levels, TNF-α, NF-κB, ZO-1 and occludin levels were detected by Western blotting in the terminal ileum mucosal tissue. 30% TBSA burn caused a significant increase in serum endotoxin levels, but NF-κB, and TNF-α, and the average intestinal villus height and mucosal thickness were decreased significantly. Burn injury could also markedly decrease the levels of ZO-1 and occludin in terminal ileum mucosal tissue (all P<0.01). Splenectomy at 7th day after burn significantly reversed the burn-induced breakdown of ZO-1 and occludin (all P<0.01). The results of this study suggest that severe thermal injury damages the intestinal mucosal barrier. Splenectomy may provide a therapeutic benefit in restoring burn-induced intestinal barrier by decreasing the release of inflammatory cytokines and recovering TJ proteins.

Three-dimensional metal azide coordination polymers with amino carboxylate coligands: synthesis, structure, and magnetic properties.

The reaction of M(II) ions with azido ligands in the presence of different amino carboxylic acids gave four three-dimensional metal-azido coordination polymers, [Mn(3,5-daba)(N(3))](n) (1), [Cd(3,5-daba)(N(3))](n) (2; 3,5-daba = 3,5-diaminobenzoate), [Mn(4-aba)(N(3))](n) (3; 4-aba = 4-aminobenzoate), and [Cu(2)(gly)(2)(N(3))(2)](n) (4; gly = glycinate), which display different topological structures. Polymers 1 and 2 present 4,6-connected 3D networks with different Schlafli symbols. However, 3 and 4 feature an unprecedented trinodal 3,6-connected network with the Schlafli symbol (4(2).6)(4.6(2))(4(3).6(6).8(6)) and an unusual 4-connected 3D net with the Lonsdaleite (hexagonal diamond) topology, respectively. Magnetic susceptibility measurements revealed dominant antiferromagnetic couplings for 1 and 3 and an overall dominant ferromagnetic coupling for 4, which presents metamagnetic behavior with a magnetic phase transition at a critical temperature of 6 K and a transition field of ca. 6030 Oe. The results demonstrate that the EE azido and syn-anti carboxylato bridges in our cases induce an antiferomagnetic interaction, and the anti-anti carboxylato bridge in 4 mediates a ferromagnetic interaction. The magnetic interaction through the EO azido bridge in 3 and 4 has a dependence on the value of the M-N-M bond angle.

Endogenous danger signals trigger hepatic ischemia/reperfusion injury through toll-like receptor 4/nuclear factor-kappa B pathway.

BACKGROUND: Restoration of blood flow to the ischemic liver lobes may paradoxically exacerbate tissue injury, which is called hepatic ischemia/reperfusion injury (IRI). Toll-like receptor 4 (TLR4), expressed on several liver cell types, and the nuclear factor-kappa B (NF-kappaB) signaling pathway are crucial to mediating hepatic inflammatory response. Because IRI is essentially a kind of profound acute inflammatory reaction evoked by many kinds of danger signals, we investigated TLR4/NF-kappaB signaling pathway activation in a murine model of partial hepatic IRI. METHODS: Wild-type mice (WT, C3H/HeN) or TLR4 mutant mice (C3H/HeJ) were subjected to 45 minutes of partial hepatic ischemia followed by 1 hour, 3 hours of reperfusion. Sham group accepted the same procedure without the obstruction of blood supply. At the end of reperfusion, the compromise of liver function and the histological change of liver sections were measured as the severity of liver injury. The level of endotoxin in the portal vein was measured by limulus assay. NF-kappaB activation was determined by electrophoretic mobility shift assay (EMSA). The levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) in systemic blood after hepatic IRI were assessed by enzyme-linked immunosorbent assay (ELISA). RESULTS: The compromise of liver function and the morphological injuries in mutant mice were relieved more markedly than those in WT mice after partial hepatic IRI. NF-kappaB activation in WT mice was stronger than that in TLR4 mutant mice, and both were stronger than those in the sham operated mice (P < 0.01). Endotoxin in each group was undetectable. The levels of TNF-alpha and IL-1beta in systemic blood were elevated in both strains, but lower in the sham operated group. These mediators were significantly decreased in TLR4 mutant mice compared with those in WT mice (P < 0.01). CONCLUSIONS: The TLR4/NF-kappaB signaling pathway may mediate hepatic IRI triggered by endogenous danger signals. Inhibition of the TLR4/NF-kappaB pathway may be a potential therapeutic target for attenuating ischemia/reperfusion-induced tissue damage in some clinical settings.

[Adult intestinal heterotopic gastric mucosa resulting in alimentary tract hemorrhage: a report of 11 cases].

OBJECTIVE: To investigate the clinical characteristics,diagnosis and treatment of intestinal heterotopic gastric mucosa resulting in alimentary tract hemorrhage. METHODS: Eleven cases of intestinal heterotopic gastric mucosa with alimentary tract hemorrhage during the past 24 years in our hospital were reviewed and the clinical data were analyzed retrospectively. RESULTS: The median age was 29 years old. Nine cases had abdominal pain, and radionuclide (99m)Tc-pertechnetate scan revealed bleeding lesion in 6 cases preoperatively. Segmental resection of the intestine with bleeding lesion were performed in all patients, postoperative pathology confirmed heterotopic gastric mucosa. The lesion was located in the jejunum in five cases and in the ileum in six cases. All lesions were complicated with diverticulum, or inflammatory mass on the intestinal wall, or abnormity of intestinal duplication. CONCLUSIONS: Intestinal heterotopic gastric mucosa is difficult to be diagnosed preoperatively, and radionuclide (99m)Tc-pertechnetate scan plays a role in preoperative diagnosis.

[Inhibition of rat RAW264.7 macrophage inflammatory cytokines release by small hairpin RNAi targeting Toll-like receptor].

OBJECTIVE: To construct a eukaryotic expression vector carrying the small hairpin RNA (shRNA) for Toll-like receptor 4 (TLR4) mRNA and a reporter gene of enhanced green fluorescence protein (EGFP) and study the inhibition of cytokine release by rat RAW264.7 macrophages induced by lipopolysaccharide (LPS) stimulation through transfection and expression of shRNA targeting TLR4 gene via the RNAi mechanism. METHODS: The H1 promotor and double BbsIrestrict endoenzyme site from the plasmid psiRNA-hH1neo were cloned into the reporter gene plasmid pEGFP-C1 at the MluIrestrict endoenzymic site, thus forming the plasmid pEGFP-H1/siRNA containing Bbs site and reporter EGFP gene. Then an oligo nuclear hairpin sequence targeting TLR4 gene was designed by the internet tool siRNA Wizard and then inserted into the plasmid pEGFP-H1/siRNA so as to form the plasmid pEGFP-H1/TLR4-siRNA. Rat macrophages of the line RAW264.7 were cultured and transfected with pEGFP-H1/TLR4-siRNA mediated by lipofectamine 2000. Another RAW264.7 cells were transfected with pEGFP-H1/control sequence-siRNA or blank plasmid. Lipopolysaccharide was added into the 3 kinds of culture fluid for 2 and 68 hours respectively. ELSA was used to detect the levels of tumor necrosis factor-alpha (TNF-alpha) in the supernatants. RESULTS: Restriction endonuclease analysis showed that the construction pEGFP-H1/TLR4-siRNA carrying hairpin RNA for TLR4 gene and reporter EGFP gene was successful. The expression of EGFP gene was 50% +/- 8%. The TNF-alpha level of the TLR4-siRNA transfection group 2 hours and after transfection was 825 pg/ml +/- 136 pg/ml, significantly lower than those of the pEGFP-H1/control sequence-siRNA and blank plasmid groups (2190 pg/ml +/- 359 pg/ml and 1265 pg/ml +/- 283 pg/ml respectively, both P < 0.01). The TNF-alpha level of the TLR4-siRNA transfection group 8 hours and after transfection was 1179 pg/ml +/- 240 pg/ml, significantly lower than those of the pEGFP-H1/control sequence-siRNA and blank plasmid groups (4720 pg/ml +/- 227 pg/ml and 4689 pg/ml +/- 310 pg/ml respectively, both P < 0.01). CONCLUSION: shRNA targeting TLR4 gene can inhibit the TNF-alpha release by RAW264.7 cells evoked by LPS.