Endothelially Derived Nitric Oxide Affects the Severity of Early Acetaminophen-induced Hepatic Injury in Mice

Objectives: The precise mechanism of hepatocellular toxicity following acetaminophen (APAP) poisoning remains unclear. Nitric oxide is implicated in APAP toxicity as an inflammatory signaling molecule and as a precursor to the free radical peroxynitrate. The effects of inducible nitric oxide synthase (iNOS)‐derived NO in APAP toxicity are known; however, the role of endothelial nitric oxide synthase (eNOS)‐derived NO is unknown. The authors sought to evaluate the effect of eNOS‐derived NO during APAP toxicity. Methods: C57BL6/J mice deficient in eNOS (eNOS KO) or iNOS (iNOS KO) and wild‐type mice (WT) were treated with 300 mg/kg APAP. Alanine aminotransferase levels and plasma nitrate and nitrite levels were measured. Hypoxia inducible factor (HIF)‐1α and Glucose Transporter 1 (Glut‐1) levels were determined by Western blot. Results: Alanine aminotransferase levels were significantly elevated in all treated animals. Alanine aminotransferase levels were significantly lower in eNOS KO and iNOS KO than in treated WT animals. Plasma nitrate/nitrite levels were significantly higher in WT animals than in iNOS KO and eNOS KO animals. HIF‐1α expression was increased in WT mice and decreased in iNOS KO mice. Glut‐1 is a downstream, indirect marker of HIF function. Glut‐1 expression was increased in WT and eNOS KO mice. Conclusions: Deficiency of either iNOS or eNOS results in decreased NO production and is associated with reduced hepatocellular injury following APAP poisoning. HIF‐1α and Glut‐1 levels are increased following APAP poisoning, implying that HIF‐1α is functional during the pathogenic response to APAP poisoning.     

敲除巨噬细胞移动抑制因子基因可减轻小鼠重症急性胰腺炎相关肺损伤

目的:探讨巨噬细胞移动抑制因子（macrophage migration inhibitory factor, MIF）在小鼠重症急性胰腺炎（severe acute pancreatitis, SAP）相关肺损伤中的作用。方法:32只小鼠随机（随机数字法）分为4组（每组8只）：野生型对照组（WT+CON组）、野生型S...     

Ligustrazine alleviates acute pancreatitis by accelerating acinar cell apoptosis at early phase via the suppression of p38 and Erk MAPK pathways

ObjectiveThis study aimed to investigate the role of ligustrazine on apoptosis and inflammatory reaction in acute pancreatitis.MethodsRats and acinar cells were treated with caerulein to induce acute pancreatitis models. Cell models were treated with saline, p38 inhibitor, Erk inhibitor and ligustrazine. Then, the levels of TNF-α, IL-1β and IL-6 were determined by ELISA assay, the protein levels of p38, Erk1/2, p53 and cleaved caspase3 were determined by western blotting, and apoptosis were measured by flow cytometry. Rat models were treated with saline and ligustrazine. Plasma amylase and pancreatic myeloperoxidase activity and the levels of TNF-α, IL-1β and IL-6 in rats were determined. The protein levels of p38, Erk1/2, p53 and cleaved caspase3 in pancreas tissues were determined by western blotting, and pancreas tissues were also performed TUNEL staining to observe apoptosis status.ResultsLigustrazine downregulated the levels of TNF-α, IL-1β, IL-6. The protein levels of p38 and Erk were reduced by p38 inhibitor, Erk inhibitor and ligustrazine, while the levels of p53 and cleaved caspase 3 were upregulated. Apoptosis of AP acinar cells and cells in AP rat models was promoted after treated with ligustrazine. Plasma amylase and pancreatic myeloperoxidase activity in AP rat models were reduced by ligustrazine.ConclusionLigustrazine alleviates acute pancreatitis by accelerating acinar cell apoptosis at early phase via the suppression on p38 and Erk MAPK pathways. It is capable of attenuating the severity of acute pancreatitis and may have a therapeutic effect on patients with acute pancreatitis.     

Aberrant acute-phase response in aged interleukin-6 knockout mice

This study was designed to determine whether the acute-phase response in aged mice is altered by interleukin (IL) 6 deficiency. Young and aged wild-type (WT) and IL-6 knockout (KO) BALB/C female mice were injected with lipopolysaccharide (LPS; 1.5 microg/g body weight). After 24 h, aged IL-6 KO mice had an improved survival when compared with aged WT mice. Serum levels of IL-6 in aged WT animals given LPS were determined and, as expected, were significantly higher when compared with young LPS-treated WT animals (P<0.05). Serum levels of the acute-phase protein, serum amyloid A, were 50% lower in aged LPS-treated IL-6 KO mice relative to aged WT mice given LPS (P<0.001). In contrast, the induction of LPS-binding protein was not affected by age or IL-6 deficiency in LPS-treated animals. Circulating levels of corticosterone were markedly reduced in aged LPS-treated IL-6 KO mice relative to aged WT mice given LPS. These data indicate that IL-6 is an important contributor to the outcome of the acute-phase response of aged individuals challenged with endotoxin. We conclude that the absence of IL-6, a cytokine that contributes to the elevated basal proinflammatory state observed in aging, can improve the ability of aged mice to withstand an otherwise lethal challenge of bacterial endotoxin.     

Cytokine-induced injury of the lacrimal and salivary glands

Damages to the lacrimal and salivary glands that accompany various autoimmune diseases are categorized as secondary Sj?gren syndrome. Cytokines and free radicals are thought to be responsible for the pathologic changes, but the precise mechanisms are not clear. We evaluated whether cytokines alone can cause the damages in these exocrine tissues, and whether gaseous molecules such as nitric oxide (NO) play a role in these injuries. Various knockout (KO) mice as well as wild-type mice were injected intraperitoneally (i.p.) with the proinflammatory cytokines, IL-12 and IL-18, singly or in combination. Concurrent administration of IL-12 and IL-18 to mice caused serious atrophy in the lacrimal and salivary glands, which was spared when each cytokine was singly administered. Microscopically, there were apparently no infiltrating cells; nonetheless, numerous apoptotic cells were observed in the epithelium, which was confirmed by DNA ladder formation on gel electrophoresis. Serum levels of IFN-gamma and NO2/NO3 were markedly elevated. Combined injections of IL-12 and IL-18 caused the same changes in Fas-deficient and Fas-ligand deficient mice, as well as in perforin-KO mice, but the same changes were not detected in inducible NO synthase-KO mice or IFN-gamma KO mice. Thus, the synergistic effect of IL-12 and IL-18 was dependent on production of IFN-gamma and NO, but independent of Fas/Fas ligand system and perforin-dependent cytotoxic T cells. IL-18 together with IL-12 caused destructive changes in the glandular tissues without apparent lymphocyte infiltration. It is suggested that these cytokines can mediate apoptosis in glandular epithelial cells and that the elevated NO production is responsible for the change.     

Hypothermia during endotoxemic shock in female mice lacking inducible nitric oxide synthase

The present study was undertaken to evaluate: (1) whether lipopolysaccharide LPS-induced hypothermic responses may be altered during two estrous cycle phases, proestrus and diestrus, and after ovariectomy, followed by hormonal supplementation and (2) whether nitric oxide (NO) plays a role on LPS-induced hypothermia responses in female mice. Experiments were performed on adult female wild-type (WT) C57BL and inducible NO synthase knockout (KO) mice weighing 18 to 30 g. Endotoxemia was induced by intraperitoneal LPS administration from Escherichia coli at a nonlethal dose of 10 mg/kg, and body temperature was measured by biotelemetry. Hormonal replacement was performed in ovariectomized mice through 17beta-estradiol Silastic capsules (100 mug) and s.c. injection of progesterone (0.5 mg per animal). We observed that during the diestrus phase, mice presented more intensive hypothermia than during proestrus phase, and hormonal supplementation with 17beta-estradiol and progesterone attenuated hypothermia in ovariectomized mice. During diestrus and ovariectomy, KO mice had higher hypothermic response when compared with the WT group. During proestrus, the lack of statistical difference between KO and WT mice could be consequent of lower ovarian hormones plasma levels. After hormonal replacement, hypothermia was reverted in KO groups probably because of higher ovarian hormonal levels. In summary, the results demonstrated that NO release by inducible NO synthase has an important thermoregulatory role in LPS-induced hypothermia in female mice. Besides, this involvement is directly dependent on the presence of ovarian hormones and their respective levels.     

Recombinant human interleukin-1 receptor antagonist (rhIL-1Ra) attenuates caerulein-induced chronic pancreatitis in mice

Chronic pancreatitis is a progressive inflammatory disease featuring irreversible irregular scarring of the exocrine parenchyma characterized by acinar destruction and fibrosis subsequent to inflammation in the pancreas. Despite decades of research, the knowledge is limited to the treatment of this disease. After finding a connection between interleukin-1β (IL-1β) and interleukin-1 receptor antagonist (IL-1Ra) in caerulein-induced chronic pancreatitis, we assumed that recombinant human IL-1Ra (rhIL-1Ra), the natural antagonist of IL-1β, might have a protective role in chronic pancreatitis in mice. Chronic pancreatitis was induced by repetitive intraperitoneal injections of caerulein in C57/BL mice followed by a consecutive administration of rhIL-1Ra (10 mg/kg). Collagen content and histological changes in the pancreas as well as serum amylase and lipase were measured. We found that rhIL-1Ra significantly decreased the hydroxyproline and the fibrotic area in the pancreas after the caerulein challenge. Caerulein-induced serum amylase elevation and tissue damage were also attenuated in rhIL-1Ra treated mice. Our results reveal a potential role of rhIL-1Ra in protecting mice against caerulein-induced chronic pancreatitis and lead to a conclusion that this protein may be a potential candidate agent for the treatment of chronic pancreatitis in humans.     

Endogenous interleukin-12 improves the early antimicrobial host response to murine Escherichia coli peritonitis

Interleukin (IL)-12 is a heterodimeric proinflammatory cytokine formed by a p35 and a p40 subunit. To determine the role of IL-12 in abdominal sepsis, p35 gene-deficient (IL-12 knockout, KO) mice and normal wild-type (WT) mice were injected intraperitoneally with Escherichia coli. Peritonitis was associated with a bacterial dose-dependent increase in IL-12 p40 and IL-12 p75 concentrations in peritoneal fluid and plasma. Whereas at 6 h postinfection, IL-12 KO and WT mice displayed similar bacterial counts, at 20 hours IL-12 KO mice had significantly more bacteria in liver homogenates and were more susceptible to progressing to systemic infection. In addition, IL-12 KO mice demonstrated higher levels of proinflammatory cytokines in peritoneal fluid and increased lung and liver injury. IL-12 deficiency did not influence the recruitment of cells to the site of the infection. These data suggest that endogenous IL-12 is involved in the early antibacterial host response during abdominal sepsis.     

Nobiletin protects against murine l-arginine-induced acute pancreatitis in association with downregulating p38MAPK and AKT

Acute pancreatitis (AP) is an inflammatory disease characterized by acinar cell damage, oxidative stress, and inflammation of the pancreas. Nobiletin (3′,4′,5,6,7,8-hexamethoxyflavone), a major polymethoxy flavone, has shown health-promoting properties in previous studies. Therefore, in this study, we investigated whether nobiletin protects against experimental AP induced with l-arginine. C57BL/6 mice were treated with 25 or 50 mg/kg nobiletin by intraperitoneal injection once daily for 14 consecutive days. AP was then induced in the mice with two intraperitoneal injections of l-arginine (4 g/kg). The nobiletin treatment significantly reduced the plasma amylase levels, pancreatic myeloperoxidase activity, percentage of pancreatic necrosis, plasma proinflammatory factors, the generation of reactive oxygen species, cell apoptosis, tissue damage, and the expression of phosphorylated p38MAPK (p-p38MAPK) and p-AKT. These results suggest that nobiletin is a new therapeutic method for l-arginine-induced AP in mice.     

Immune Suppression by Recombinant Interleukin (rIL)-12 Involves Interferon γ Induction of Nitric Oxide Synthase 2 (iNOS) Activity: Inhibitors of NO Generation Reveal the Extent of rIL-12 Vaccine Adjuvant Effect

Recombinant interleukin 12 (IL-12) can profoundly suppress cellular immune responses in mice. To define the underlying mechanism, recombinant murine (rm)IL-12 was given to C57BL/6 mice undergoing alloimmunization and found to transiently but profoundly suppress in vivo and in vitro allogeneic responses and in vitro splenocyte mitogenic responses. Use of neutralizing antibodies and genetically deficient mice showed that IFN-γ (but not TNF-α) mediated rmIL-12–induced immune suppression. Splenocyte fractionation studies revealed that adherent cells from rmIL-12–treated mice suppressed the mitogenic response of normal nonadherent cells to concanavalin A and IL-2. Addition of an inhibitor of nitric oxide synthase (NOS) restored mitogenic responses, and inducible (i)NOS^−/− mice were not immunosuppressed by rmIL-12. These results support the view that suppression of T cell responses is due to NO produced by macrophages responding to the high levels of IFN-γ induced by rmIL-12. When a NOS inhibitor was given with rmIL-12 during vaccination of A/J mice with irradiated SCK tumor cells, immunosuppression was averted and the extent of rmIL-12''s ability to enhance induction of protective antitumor immunity was revealed. This demonstrates that rmIL-12 is an effective vaccine adjuvant whose efficacy may be masked by its transient immunosuppressive effect.     

Interleukin-12-deficient mice are at greater risk of UV radiation-induced skin tumors and malignant transformation of papillomas to carcinomas

Solar UV radiation-induced immunosuppression is a risk factor for nonmelanoma skin cancer. Interleukin (IL)-12 has been shown to possess antitumor activity and inhibit the immunosuppressive effects of UV radiation in mice. In this study, we generated IL-12 knockout (KO) mice on a C3H/HeN background to characterize the role of IL-12 in photocarcinogenesis. After exposure of the mice to UVB (180 mJ/cm2) radiation thrice a week for 35 weeks, the development of UV-induced tumors was more rapid and the tumor multiplicity and tumor size were significantly higher in IL-12 KO mice than their wild-type (WT) counterparts (P < 0.05-0.001). Moreover, the malignant transformation of UVB-induced papillomas to carcinomas was higher in IL-12 KO mice in terms of carcinoma incidence (55%, P < 0.001), carcinoma multiplicity (77%, P < 0.001), and carcinoma size (81%, P < 0.001). As IL-12 has the ability to repair UV-induced DNA damage, we determined this effect in our in vivo IL-12 KO mouse model. We found that UVB-induced DNA damage in the form of cyclobutane pyrimidine dimers was removed or repaired more rapidly in WT mice than IL-12 KO mice. Similarly, the UVB-induced sunburn cell formation is primarily a consequence of DNA damage. It was observed that UVB-induced sunburn cells were repaired rapidly in WT mice compared with IL-12 KO mice. The rapid removal or repair of UV-induced cyclobutane pyrimidine dimers or sunburn cells will result in reduced risk of photocarcinogenesis. Taken together, our data show that IL-12 deficiency is associated with the greater risk of photocarcinogenesis in mice, and this may be due to reduction in damaged DNA repair ability.     

Bacteria-triggered CD4(+) T regulatory cells suppress Helicobacter hepaticus-induced colitis

We have previously demonstrated that interleukin (IL)-10-deficient (IL-10 knockout [KO]) but not wild-type (WT) mice develop colitis after infection with Helicobacter hepaticus. Here, we show that infected recombination activating gene (RAG) KO mice develop intestinal inflammation after reconstitution with CD4(+) T cells from IL-10 KO animals and that the cotransfer of CD4(+) T cells from H. hepaticus-infected but not uninfected WT mice prevents this colitis. The disease-protective WT CD4(+) cells are contained within the CD45RB(low) fraction and unexpectedly were found in both the CD25(+) and the CD25(-) subpopulations of these cells, their frequency being higher in the latter. The mechanism by which CD25(+) and CD25(-) CD45RB(low) CD4(+) cells block colitis involves IL-10 and not transforming growth factor (TGF)-beta, as treatment with anti-IL-10R but not anti-TGF-beta monoclonal antibody abrogated their protective effect. In vitro, CD45RB(low) CD4(+) cells from infected WT mice were shown to produce IL-10 and suppress interferon-gamma production by IL-10 KO CD4(+) cells in an H. hepaticus antigen-specific manner. Together, our data support the concept that H. hepaticus infection results in the induction in WT mice of regulatory T cells that prevent bacteria-induced colitis. The induction of such cells in response to gut flora may be a mechanism protecting normal individuals against inflammatory bowel disease.     

Interleukin-1 mediates thermal injury-induced lung damage through C-Jun NH2-terminal kinase signaling

OBJECTIVE: The molecular mechanisms of lung damage following thermal injury are not clear. The purpose of this study was to determine whether interleukin (IL)-1 mediates burn-induced inducible nitric oxide synthase (iNOS) expression, peroxynitrite production, and lung damage through c-Jun NH2-terminal kinase (JNK) signaling. DESIGN: Prospective, experimental study. SETTING: Research laboratory at a university hospital. SUBJECTS: Thermal injury models in the mice. INTERVENTIONS: IL-1 receptor type 1 (IL-1R1) mice, Tnfrsf1a mice, and wild-type (WT) mice were subjected to 30% total body surface area third-degree burn. The JNK inhibitor, SP600125, was given to mice to study the involvement of the JNK pathway in thermal injury-induced lung damage. WT --> WT, WT --> IL-1R1, and IL-1R1 --> WT chimeric mice were generated to determine the role of hematopoietic cells in IL-1-mediated lung damage. Neutrophils were harvested and treated in vitro with N-formyl-methionyl-leucyl-phenylalanine (fMLP). MEASUREMENTS AND MAIN RESULTS: IL-1R1 mice rather than Tnfrsf1a mice showed less thermal injury-induced lung damage. IL-1R1 mice displayed less lung JNK activity; intercellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM), chemokine receptor 2 (CXCR2), and macrophage inflammatory protein-2 (MIP2), messenger RNA expression; myeloperoxidase activity; and neutrophil p38 mitogen-activated protein kinase (MAPK) phosphorylation after thermal injury. SP600125 significantly reduced thermal injury-induced blood dihydrorhodamine (DHR) 123 oxidation, iNOS expression, and lung permeability in WT mice but not in IL-1R1 mice. IL-1R1 --> WT chimeric mice rather than WT --> IL-1R1 chimeric mice showed less thermal injury-induced lung damage. fMLP increased reactive oxygen species (ROS) production of neutrophils in WT mice but not in IL-1R1 mice. SP600125 decreased ROS production of neutrophils in WT mice but not in IL-1R1 mice. CONCLUSIONS: Thermal injury-induced lung JNK activation; lung ICAM, VCAM, CXCR2, and MIP2 expression; and DHR 123 oxidation are IL-1 dependent. JNK inhibition decreases IL-1-mediated thermal injury-induced lung damage. Given that the IL-1 receptor is critical in thermal injury-induced p38 MAPK phosphorylation and ROS production of neutrophils, we conclude that IL-1 mediates thermal injury-induced iNOS expression and lung damage through the JNK signaling pathway.     

Regulation of murine intestinal inflammation by reactive metabolites of oxygen and nitrogen: divergent roles of superoxide and nitric oxide.

Several reports have implicated reactive oxygen and nitrogen metabolites (RONS) in the initiation and/or progression of inflammatory bowel diseases (IBDs). We have investigated the role of three key RONS-metabolizing enzymes (inducible nitric oxide synthase [iNOS], superoxide dismutase [SOD], nicotinamide adenine dinucleotide phosphate [NADPH] oxidase) in a murine model of IBD. Mice genetically deficient ((-/-)) in either iNOS or the p47phox subunit of NADPH oxidase, transgenic (Tg) mice that overexpress SOD, and their respective wild-type (WT) littermates were fed dextran sulfate sodium (DSS) in drinking water for 7 days to induce colitis. In addition, the specific iNOS inhibitor 1400W was used in DSS-treated WT and p47phox(-/-) mice. WT mice responded to DSS feeding with progressive weight loss, bloody stools, elevated serum NO(X) and colonic mucosal injury with neutrophil infiltration. Both the onset and severity of colitis were significantly attenuated in iNOS(-/-) and 1400W-treated WT mice. While the responses to DSS did not differ between WT and p47phox(-/-) mice, enhanced protection was noted in 1400W-treated p47phox(-/-) mice. Interestingly, SOD(Tg) mice exhibited more severe colitis than their WT littermates. These findings reveal divergent roles for superoxide and iNOS-derived NO in intestinal inflammation.     

腹腔内注射骨髓间充质干细胞对急性胰腺炎小鼠相关肺损伤的影响及相关机制研究

目的研究腹腔内注射骨髓间充质干细胞(BMSC)对雨蛙素诱导的急性胰腺炎(AP)小鼠肺损伤的影响,并进一步探讨其可能的机制。方法选取Balb/c小鼠作为研究对象,分为Sham组(注射0.9%氯化钠溶液),AP组(腹腔注射雨蛙素诱导AP模型)和AP+BMSC组(经BMSC治疗的AP模型),每组各8只。分别在AP诱导成功后12、24、48 h,收集小鼠血液并处死小鼠,测定不同组小鼠肺组织湿/干重比值,并用苏木精-伊红染色法评估小鼠肺组织病理变化,并检测3组小鼠肺组织髓过氧化物酶(MPO)活性和血清肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)、白细胞介素-10(IL-10)、淀粉酶(AMY)以及丙二醛(MDA)含量。结果与Sham组相比,AP组和AP+BMSC组小鼠在诱导建立AP模型后12、24、48 h肺组织湿/干重比值、血清淀粉酶、肺组织MPO以及血清TNF-α、IL-6、IL-10和丙二醛均显著升高,差异均有统计学意义(P<0.05);与AP组小鼠相比,AP+BMSC组小鼠在诱导建立AP模型后12、24、48 h肺组织湿/干重比值、血清淀粉酶、肺组织MPO以及血清TNF-α、IL-6、IL-10和丙二醛均显著降低,血清IL-10含量显著升高,差异均有统计学意义(P<0.05)。结论腹腔内注射骨髓间充质干细胞可显著减弱AP引起的肺损伤,其作用机制可能与改善AP小鼠氧化应激及炎症反应水平有关。     

Erythropoietin requires endothelial nitric oxide synthase to counteract TNF-[alpha]-induced microcirculatory dysfunction in murine striated muscle

In the present study, we aimed to evaluate whether erythropoietin (EPO) treatment may exert nonhematopoietic endothelial protection against TNF-[alpha]-induced microvascular inflammation and to determine the involvement of the nitric oxide (NO)-producing enzyme isoforms endothelial NO synthase (eNOS) and inducible NO synthase (iNOS). Murine dorsal skinfold chambers of wild-type (WT) animals were topically stimulated with TNF-[alpha] after pretreatment with epoetin beta (1,000 IU/kg body weight i.p.) or physiological saline. Leukocyte behavior, microvascular perfusion, and apoptosis were assessed by in vivo fluorescence microscopy. To study the involvement of NO, we compared eNOS-deficient (eNOS-/-) and iNOS-deficient (iNOS-/-) mice with WT animals. TNF-[alpha]-associated leukocyte activation, perfusion failure, and apoptosis were substantially attenuated in EPO-pretreated WT mice, which was accompanied by marked reduction of perivascular infiltration with F4/80-stained macrophages. The anti-inflammatory protective effects of EPO were abolished in eNOS-/-, but not in iNOS-/- mice, both with unaffected intercellular adhesion molecule 1 expression. However, the antiapoptotic effect of EPO was maintained in both eNOS-/- and iNOS-/- mice, indicating that this mechanism might rather be independent of NO. We conclude that EPO treatment elicits protection against TNF-[alpha]-induced microcirculatory dysfunction, depending on NO derived from endothelial cells, but not on the inducible isoform.     

白细胞介素-6/糖蛋白130/转录激活因子3通路在百草枯诱导小鼠急性肺损伤中的作用机制

目的基于肺特异性白细胞介素-6(IL-6)敲除小鼠研究IL-6/糖蛋白130(gp130)/转录激活因子3(STAT3)通路在百草枯(PQ)诱导急性肺损伤(ALI)中的作用。方法野生型C57BL/6J小鼠分为IL-6野生型(IL-6 WT)组、IL-6 WT+PQ组,采用Sftpc(肺表面活性蛋白C基因)-Cre⁺小鼠与IL-6^FLOX/FLOX小鼠交配的方式得到肺特异性IL-6敲除小鼠并分为IL-6 KO组、IL-6 KO+PQ组,单次腹腔注射PQ诱导ALI,比较四组小鼠肺组织病理改变、肺泡动脉氧分压差(PA-aO₂)、肺组织湿/干质量比值(W/D)、IL-6/gp130/STAT3通路、核转录因子-κB(NF-κB) p65、肿瘤坏死因子-α(TNF-α)及白细胞介素-1β(IL-1β)的差异。结果与IL-6 WT组比较,IL-6 WT+PQ组小鼠肺组织出现了典型的ALI病理改变,肺组织胞浆蛋白中IL-6、gp130、p-STAT3、TNF-α、IL-1β表达水平及胞核蛋白中NF-κB p65的表达水平、PA-aO₂、W/D明显增加(P <0.05);与IL-6 WT+PQ组比较,IL-6 KO+PQ组小鼠肺组织病理改变明显改善,肺组织胞浆蛋白中IL-6、gp130、p-STAT3、TNF-α、IL-1β的表达水平及胞核蛋白中NF-κB p65的表达水平、PA-aO₂、W/D明显降低(P <0.05)。结论 IL-6/gp130/STAT3通路激活与PQ诱导ALI有关。     

Up-regulated PAR-2-mediated salivary secretion in mice deficient in muscarinic acetylcholine receptor subtypes

Protease-activated receptor-2 (PAR-2) is expressed in the salivary glands and is expected to be a new target for the treatment of exocrine dysfunctions, such as dry mouth; however, the salivary secretory mechanism mediated by PAR-2 remains to be elucidated. Therefore, mechanism of the PAR-2-mediated salivary secretion was investigated in this study. We found that a PAR-2 agonist peptide, SLIGRL-OH, induced salivary flow in vivo and dose-dependent increase in [Ca(2+)](i) submandibular gland (SMG) acinar cells in wild-type (WT) mice and mice lacking M(3) or both M(1) and M(3) muscarinic acetylcholine receptors (mAChRs), whereas secretions in PAR-2 knockout (PAR-2KO) mice were completely abolished. The saliva composition secreted by SLIGRL-OH was similar to that secreted by mAChR stimulation. Ca(2+) imaging in WT acinar cells and beta-galactosidase staining in PAR-2KO mice, in which the beta-galactosidase gene (LacZ) was incorporated into the disrupted gene, revealed a nonubiquitous, sporadic distribution of PAR-2 in the SMG. Furthermore, compared with the secretion in WT mice, PAR-2-mediated salivary secretion and Ca(2+) response were enhanced in mice lacking M(3) or both M(1) and M(3) mAChRs, in which mAChR-stimulated secretion and Ca(2+) response in acinar cells were severely impaired. Although the mechanism underlying the enhanced PAR-2-mediated salivary secretion in M(3)-deficient mice is not clear, the result suggests the presence of some compensatory mechanism involving PAR-2 in the salivary glands deficient in cholinergic activation. These results indicate that PAR-2 present in the salivary glands mediates Ca(2+)-dependent fluid secretion, demonstrating potential usefulness of PAR-2 as a target for dry mouth treatment.