Toll样受体2和4在小鼠肺炎链球菌中耳急性感染中的作用

目的 探讨Toll样受体2(Toll-like receptor 2,TLR2)和Toll样受体4(Toll-like receptor 4,TLR4)在小鼠肺炎链球菌中耳感染中的作用.方法 野生型(wild type,WT)C57BL/6J小鼠、TLR2缺陷(TLR2-/-)和TLR4缺陷(TLR4-/-)小鼠分别通过中耳鼓膜接种肺炎链球菌悬液[1×106菌落形成单位(colony forming unit,CFU)].在细菌接种前、接种后第3天和第7天分别进行听性脑干反应(ABR)和鼓室声导抗测试,血液及中耳积液中细菌滴度测定,颞骨病理切片形态学观察,反转录聚合酶链反应(RT-PCR)检测不同基因型小鼠炎性细胞因子IκB激酶β(IκB kinase β,IKKβ)、核因子κB(NF-κB)、肿瘤坏死因子α(TNF-α)、白细胞介素-1β(interleukin-1β,IL-1β)、巨噬细胞炎性蛋白1α(MIP-1α)、黏蛋白/黏液素5AC和5B(MUC5AC和MUC5B)mRNA的表达.结果 中耳接种肺炎链球菌3d后,TLR2-/-小鼠死亡率为58.8％(40/68),TLR4-/-小鼠死亡率为35.6％(21/59),而WT小鼠的死亡率仅为17.3％(9/52).接种7d后,TUR2-/-小鼠死亡率为82.4％(54/68),TLR4-/-小鼠死亡率为54.2％(32/59),而WT小鼠的死亡率仅为23％(12/52),三组之间差异具有统计学意义(P＜0.01).ABR测试结果显示,接种后存活3d及7d的TLR2-/-和TLR4-/-小鼠ABR阈值高于WT小鼠,三组之间的差异具有统计学意义(P＜0.01).颞骨病理发现,TLR2-/-和TLR4-/-小鼠接种肺炎链球菌后第3天中耳出现积液和组织破坏,接种后第7天感染极为严重.TLR2-/-鼠出现严重的耳蜗炎性细胞浸润,内外毛细胞破坏、盖膜肿大和血管纹退变,以及螺旋神经节细胞的损伤;TLR4-/-鼠可见耳蜗内外毛细胞和螺旋神经节细胞的损伤;而WT鼠的耳蜗未见炎性细胞浸润和组织破坏,内外毛细胞基本正常.在接种细菌3d和7d的TLR2-/-鼠中耳黏膜未发现肥大细胞,但在TLR4-/-和WT鼠中耳黏膜发现较多的肥大细胞并有脱颗粒现象.接种肺炎链球菌后3d和7d的TLR2-/-和TLR4-/-小鼠血液中细菌滴度均高于WT小鼠,差异具有统计学意义(P值均＜0.05).接种肺炎链球菌3d后,TLR2-/-小鼠听泡组织中NF-κB、TNFα、IL-1β、MIP-1α、MUC5AC、MUC5B等因子的mRNA表达水平低于TLR4-/-和WT小鼠,差异具有统计学意义(P值均＜0.05).结论 TLR2-/-鼠在肺炎链球菌激惹后产生相对低水平的致炎性细胞因子,中耳清除细菌能力下降,引发脓毒血症,导致高死亡率.TLR2和TLR4是2种重要的小鼠中耳炎性反应的受体和信号转导分子.     

家兔实验性慢性鼻窦炎窦腔粘膜血流测定

人类鼻窦炎窦腔粘膜血流量是否有改变尚无定论。本研究旨在建立慢性鼻窦炎的动物模型以测定窦腔粘膜血流量。作者用家兔作实验,麻醉后按下列三种方法建立实验性鼻窦炎:(1)皮下注射卵清蛋白,每周4次,共2周。窦腔内留置导管注射卵清蛋白,每周3次共2周,并接种肺炎链球菌(10~8个);(2)鼻背部皮肤作切口,鼻窦骨壁钻孔,切开窦腔粘膜放入一块带肺炎球菌的棉绒。(3)与第2种方法相同,但不接种细菌,用异丁稀酸封闭窦口。从实验性鼻窦炎产生到测鼻窦粘膜血流的时间为5周至9个月。部分家兔鼻窦粘膜进行光镜和扫描电镜组织学检查。结果:15只家兔中6只实验失败,其余家兔实验性鼻窦炎的表现是打喷嚏、流涕;鼻窦粘膜     

实验性鼻炎的早期粘膜改变

急性鼻窦炎乃常见病,其发生与窦口阻塞(解剖变异和/或粘膜异常)后窦腔内氧张力降低、出现渗液、构成相对缺氧环境、有利于细菌繁殖等有关。呼吸道的粘纤系统是重要的防御机制,正常清除功能的障碍会促成炎症的发生。患急性鼻窦炎常分离到肺炎链球菌、流感嗜血杆菌和绿脓杆菌,这类细菌感染时的许多生化产物(如纤毛毒素、类脂寡糖、白细胞酶等)都能降低纤毛活力,使纤毛摆动频率(CBF)降低,从而抑制窦粘膜的清除功能,促成细菌感染。因兔上颌窦大,对感染的反应类似人类,故选用无感染的新西兰大白兔20只,分为4组,每组5只,氯胺酮麻醉下,剃毛消毒后,在面     

家兔急性鼻窦炎鼻源性模型的建立

目的探讨在家兔鼻腔填塞膨胀海绵并植入细菌以制备急性鼻窦炎鼻源性动物模型的方法。方法健康成年雄性新西兰白兔30只,随机抽取5只处死,测量其右侧鼻腔前鼻孔上下径、内外径以及前鼻孔至上颌窦自然开口的距离,余25只分成模型组(10只)、单纯堵塞组(10只)和空白对照组(5只)。将2.5 mm×5 mm×28 mm大小Merocel高分子膨胀海绵置入模型组、单纯堵塞组兔右侧鼻腔,同时向模型组兔鼻腔内高分子膨胀海绵中注射植入1 mlⅢ型肺炎链球菌悬液,单纯堵塞组注射等量生理盐水。第10天行鼻窦CT扫描后将兔处死,分别取右上颌窦、筛窦窦腔分泌物行细菌培养,并将右上颌窦、筛窦完整取出,全组织包埋行组织病理学检查。结果除模型组1只于第4天死亡外,其余均存活。模型组家兔CT检查均示右上颌窦、筛窦腔不同程度浑浊化,鼻窦腔内分泌物细菌培养阳性率为100%,光镜观察可见窦腔大量中性粒细胞聚积,上皮变性,局部溃疡形成,黏膜内及黏膜下大量炎性细胞浸润。单纯堵塞组8只家兔可见类似的影像学改变,但病理学改变程度较轻,与模型组相比,差别有统计学意义。结论成功建立了家兔急性鼻窦炎的鼻源性动物模型,为进一步研究鼻源性鼻窦炎的发病机制及治疗干预奠定基础。     

120dB白噪声对C57BL/6J小鼠听力损失的观察研究

目的观察120d B宽频带白噪声对C57BL/6J小鼠听阈阈值、耳蜗基底膜毛细胞形态与带状突触数量的影响。方法:20只听力正常的5-6周龄C57BL/6J小鼠随机分为四组,3组实验组,分别为给予白噪声后立即测量组(0d)、噪声暴露后7天测量组(7d)、噪声暴露后14天组(14d);1组对照组。每组5只小鼠(n=10),实验组小鼠120d B白噪声暴露2h,0d组立即测量小鼠听阈,7天和14天应用相同方法测量小鼠听阈值,并计算出每只小鼠噪声暴露前后的阈移值。各组测量阈值后立即处死取耳蜗用4%多聚甲醛固定后进行免疫荧光染色和扫描电镜检查,观察小鼠带状突触与内外毛细胞形态变化并计数。结果噪声暴露2h后即刻组其各个频率5只小鼠(n=10)阈值均未引出,暴露后七天小鼠听阈部分恢复(P<0.01)。暴露后第14天,14天组各频率的听阈继续恢复,但与暴露前的差异较第7天比有所减小,但仍有统计学差异(所有P<0.01)。并且观察到带状突触明显减少,扫描电镜观察外毛细胞纤毛有倒伏粘连。结论 120d B白噪声噪声暴露2小时能够造成小鼠听力永久性阈移,外毛细胞明显损伤,带状突触数量明显减少。     

小鼠变应性鼻炎合并急性细菌性鼻窦炎的初步研究

目的 探讨变应性鼻炎动物模型合并急性细菌性鼻窦炎的方法.方法 清洁级C57BL6/J小鼠40只,随机分为4组:A组(卵清蛋白+肺炎链球菌);B组(卵清蛋白+生理盐水);C组[磷酸盐缓冲溶液(phosphate buffered solution,PBS)+肺炎链球菌];D组(PBS+生理盐水),每组各10只.①实验第1～9天,A组和B组每天腹腔注射200μl 10%卵清蛋白,第10～17天A、B组用6%卵清蛋白鼻腔局部激发建立变应性鼻炎模型,C组和D组用等量PBS替代,步骤同前;②于实验第13天A组和C组鼻腔接种肺炎链球菌ATCC 49619 200μl;B组和D组用等量生理盐水代替.接种后第6天处死动物,处死前各组动物行内眦静脉采血,以间接酶联免疫吸附试验检测血清白介素5水平.取鼻面骨,石蜡包埋,连续切片,行HE染色和0.5%甲苯胺蓝染色,计算机辅助显微镜下观察肥大细胞脱颗粒情况,并计算每平方毫米鼻窦黏膜中多形核中性粒细胞和嗜酸粒细胞的数量.结果 A组和B组分别有9只和8只动物变应性鼻炎建模成功,鼻部症状、黏膜水肿和黏膜下微血管明显扩张,C组症状轻微,D组无任何症状.A组鼻窦黏膜多形核中性粒细胞密度(-x±s)为(139.3±26.5)个/mm2,高于B组(70.7±16.7)个/mm2、C组(63.0±14.7)个/mm2和D组(40.2±14.1)个/mm2(P值均＜0.01);A组和B组嗜酸粒细胞密度和白介素5水平(-x±s)分别为(134.6±25.5)个/mm2、(48.2±13.9)pg/ml和(116.2±25.2)个/mm2、(40.8±7.8)pg/ml,均高于C组(16.7±2.7)个/mm2、(23.9±8.7)pg/ml(P值均＜0.05)和D组(13.4±4.9)个/mm2、(24.6±6.5)pg/ml(P值均＜0.05).结论 变应性鼻炎合并细菌性鼻窦炎造模成功.     

家兔急性鼻窦炎上颌窦黏膜病理改变

目的 观察家兔实验性鼻源性急性鼻窦炎上颌窦黏膜超微结构及黏液纤毛传输功能的改变.方法 健康成年雄性新西兰白兔15只,随机分为实验组(10只)和空白对照组(5只).将3 mm×5 mm×25 mm大小Merocel(R)高分子膨胀海绵置入实验组兔右侧鼻腔,并向高分子膨胀海绵中注射植入1 mlⅢ型肺炎链球菌悬液.2周后,用印度墨汁法测定上颌窦黏液纤毛传输速度.然后处死动物,取右上颌窦黏膜通过透射电镜观察其超微结构改变.结果 实验组家兔上颌窦黏液纤毛传输速度明显低于空白对照组,有极显著统计学差异(P＜0.01).实验组上颌窦黏膜在透射电镜下观察到纤毛变性、脱落,排列紊乱,可见复合纤毛、微管动力臂缺陷、胞质突起、内质网扩张、线粒体肿胀、胞浆水肿及黏膜下层淋巴细胞浸润等超微的结构改变.结论 急性鼻窦炎上颌窦黏膜超微结构明显改变,黏液纤毛传输速度减慢,结构改变导致功能下降.     

兔慢性鼻窦炎模型建模方法的比较与优化改良

目的探讨改进慢性鼻窦炎动物模型的制备方法。方法将66只新西兰大白兔制成动物模型，随机分成空白对照组(6只)、假手术Ⅰ、Ⅱ组(各10只)、单纯细菌组(10只)、单纯窦口堵塞组(10只)、窦口堵塞 金黄色葡萄球菌组(10只)、窦口不完全堵塞 窦腔留置棉絮组(10只)，术后42d取上颌窦黏膜标本分别进行形态学观察及细菌学检查。结果各实验组建立慢性鼻窦炎模型成功率：窦口堵塞组为80％，窦口堵塞 金黄色葡萄球菌组为100％，窦口不完全堵寒 窦腔留置棉絮组为100％，单纯细菌组、空白对照组及假手术对照组均为0％。感染鼻窦均表现为中重度慢性炎症，培养的细菌以机会致病菌为主。采用窦口堵塞 金黄色葡萄球菌方法并发上颌窦积脓概率高。结论相对其他建模方法，窦口不完全堵塞 窦腔留置棉絮的建模方法是一种更理想的慢性鼻窦炎动物模型的制备方法。     

家兔实验性急性化脓性鼻窦炎模型的建立

目的探讨应用金黄色葡萄球菌建立家兔急性化脓性鼻窦炎模型的方法. 方法家兔40只,其中空白组10只,单纯手术组10只,余为模型组,在全麻下行上颌窦造口术,塞入棉绒,注入金黄色葡萄球菌0.3ml.造模后7天时观察其炎症反应和鼻黏液纤毛输送功能的变化. 结果实验性急性化脓性鼻窦炎家兔7天病程时白细胞(WBC)计数及中性粒细胞(N)百分比增加,血清C-反应蛋白浓度显著升高,窦腔分泌物细菌分离培养阳性,鼻黏液纤毛传输时间延长,光镜、电镜下窦腔及窦口黏膜充血、水肿、纤毛脱落等. 结论应用金黄色葡萄球菌,采取上颌窦造口术可以建立稳定的家兔急性化脓性鼻窦炎模型.     

急性中耳炎时中耳对绿脓杆菌感染的易感性

为研究慢性化脓性中耳炎的发病机理，把中耳正常的粟鼠随机分成三组，各18只。二个组双中耳接种7F型肺炎链球菌，诱发肺炎链球菌性中耳炎（POM），其中一组在肺炎链球菌接种后三天，一耳接种绿脓杆菌，并每天肌注普鲁卡因青霉素50000u共5天，该组称为“早接种组”。另一组在肺炎链球菌接种后三天先青霉素治疗5天（量同），于第7天一耳接种绿脓杆菌，称为“晚接种组”。第三组作对照，仅一耳接种绿脓杆菌，未诱发肺炎链球菌性中耳炎，亦不给青霉素治疗。结果：36只接种脑炎链球菌动物的中耳液标本，接种后三天肺炎链球菌培养均阳性，用青霉…     

A comparative experimental study between recombinant active gene 1-deficient mice and C57BL/6 mice model of acute bacterial rhinosinusitis]

OBJECTIVE: To explore the infective course of acute bacterial rhinosinusitis in recombinent active gene 1 (Rag 1)-defecient mice (Rag1) and C57BL/6 mice (C57) and the difference between them after intranasal streptococcus pneumoniae inoculation. METHODS: Ten mice of each strain (Rag1 and C57) received Streptococcus pneumoniae strain T59, ATCC 49,619 suspended in trypticase soy broth, and controls (two mice for each strain) received trypticase soy broth alone. After 2, 5, 10 and 14 days, nasal lavage cultures were obtained and then the mice were killed. The heads were embedded with paraffin and serial sections were made for histological analysis. The percentage of sinus cavity occupied by neutrophil cluster (% cluster) and the number of polymorphonuclear leukocytes per square millimeter of sinus mucosa (PMN/mm2) were calculated by the use of a computer-aided microscope in conjunction with a reconstruction and image analysis system. RESULTS: % Cluster and PMN/mm2 in infected mice both of Rag1 and C57 appeared to peak on five and ten days separately, which were significantly heavier than those in controls(P < 0.05). The infection in C57 decreased by two weeks. But in contrast to C57, the infection in Rag1 had not been controlled and Streptococcus pneumoniae were still seen in the nasal lavage culture by two weeks. This difference between infected Rag1 and infected C57 was significant at P < 0.05. CONCLUSION: Acute bacterial rhinosinusitis in Rag1 and C57 mice were successfully induced by intranasal inoculation of streptococcus pneunoniae. This bacterial infection in C57 could be controlled completely and rapidly. In contrast, Rag1 failed to control rhinosinusitis and had a tendency to chronic inflammation, suggesting that T- and B-cell-dependent immunity was important for clearance of bacteria from rhinosinus and gene knockout mice was a convenient tool for investigation of the pathogenesis of experimental rhinosinusitis.     

Bactrim reduces the inflammatory response in a murine model of acute rhinosinusitis

OBJECTIVE: To determine whether treatment with an antibiotic (trimethoprim-sulfamethoxazole) reduced the inflammatory response in a murine form of Streptococcus pneumoniae-induced rhinosinusitis. DESIGN: We randomized 18 C57BL/6 mice to either treatment with intraperitoneal trimethoprim-sulfamethoxazole (Bactrim, 30 mg/kg) or no treatment (control). After 2 days, we inoculated all C57BL/6 mice intranasally with a Bactrim-susceptible strain of Streptococcus pneumoniae, ATCC 49619, suspended in Trypticase soy broth. At day 5 after bacterial inoculation, we sacrificed the mice and prepared histopathologic sections of their sinuses after culturing their nasal cavities by lavage. SETTING: Animal care facility at a tertiary, academic institution. METHODS: The histopathologic sections of the sinuses were examined in a blind manner for the percent of sinus cavity area occupied by neutrophil clusters, and for the number of neutrophils per square millimeter of sinus mucosa. RESULTS: The Bactrim group had a significantly smaller sinus area occupied by neutrophil clusters (1.58% +/- 1.13 vs 4.38% +/- 3.41; P < 0.05), significantly fewer neutrophils infiltrating the mucosa (58.81 +/- 29.63/mm2 vs 105.85 +/- 48.49/mm2; P < 0.05), and significantly less growth of Streptococcus pneumoniae colonies in the intranasal cultures (8 few and 1 moderate vs 3 few, 3 moderate, and 1 many; P = 0.05) compared to the control group. CONCLUSION: In our murine model of acute rhinosinusitis, Bactrim decreased the number of neutrophil clusters in the sinus cavities, the number of neutrophils infiltrating the sinus mucosa, and the growth of Streptococcus pneumoniae. We propose that our murine model can be used for the study of the pathophysiology and treatment of acute rhinosinusitis.     

Effect of genetic background on the response to bacterial sinusitis in mice

OBJECTIVE: To study the importance of ongoing allergen exposure and TH1/TH2 genetic background in augmented bacterial and inflammatory responses in allergic and infected mice. DESIGN: BALB/c and C57BL/6 mice were made allergic to ovalbumin. After 1 day of intranasal allergen exposure, they were inoculated intranasally with Streptococcus pneumoniae. The numbers of bacteria and inflammatory cells in the sinuses were determined, and nasal responsiveness to histamine was assessed. RESULTS: Infected BALB/c and C57BL/6 mice that received ongoing ovalbumin challenge following intraperitoneal sensitization showed significantly greater bacterial load and phagocyte level compared with the infected-only mice. Differences were diminished after the allergen challenge was stopped. Allergic and infected C57BL/6 mice showed fewer bacteria and phagocytes compared with the allergic and infected BALB/c mice. Surprisingly, in contrast to the nonallergenic C57BL/6 mice, the infected BALB/c mice showed a larger number of bacteria 28 days after infection. CONCLUSIONS: Ongoing allergic reaction augments bacterial load in both BALB/c and C57BL/6 mice and induces nasal hyperreactivity to histamine. Allergic and infected C57BL/6 mice show less allergic inflammation and bacterial load compared with allergic and infected BALB/c mice. Stopping allergen exposure reduces the response. Infected BALB/c mice, which favor a TH2 response, were less able to clear infection than C57BL/6 mice, which favor a TH1 response. Inflammation and bacterial load are affected by genetic background of mice and ongoing allergen stimulation.     

C57Bl/6 and BALB/c mice have similar neutrophil response to acute Streptococcus pneumoniae sinus infections

BACKGROUND: Previous investigations have shown that mice with a tendency toward a T(H)1 or T(H)2 lymphocyte response manifest different reactions to inoculation with the parasite Leishmania major. BALB/c mice (with a tendency for a T(H)2 response) showed evidence of systemic infection, whereas C57Bl/6 mice (with a tendency for a T(H)1 response) showed only a local reaction. OBJECTIVE: To investigate whether BALB/c and C57Bl/6 mice respond differently to acute bacterial infection of the sinuses. METHODS: We inoculated the nasal cavities of C57Bl/6 and BALB/c mice with Streptococcus pneumoniae (type ATCC59), or with broth as a control. The mice were humanely killed 2, 5, 10, and 14 days after inoculation. Their heads were fixed, decalcified, and embedded in paraffin blocks. Sections were stained with hematoxylin and eosin, and the degree of inflammation was quantified by the number of neutrophils per square millimeter of the sinus mucosa and the percentage of the sinus cavity occupied by neutrophil clusters. RESULTS: Both groups of mice showed evidence of inflammation that was significantly greater than controls (P =.01), with no difference between groups. There was a correlation between the number of neutrophils per square millimeter in the sinus mucosa and the percentage of neutrophil clusters (C57Bl/6 mice, r = 0.37, P<.001; BALB/c mice, r = 0.20, P<.001). In the infected mice, the number of infiltrating neutrophils was significantly greater (P<.001) in anatomically lower (dependent) areas of the sinuses compared with the upper areas. CONCLUSION: Unlike leishmaniasis, acute bacterial sinusitis is not affected by the tendency of the host to favor either a T(H)1 or T(H)2 response.     

Evaluation of importance of Toll-like receptor 4 in acute Streptococcus pneumoniae sinusitis in mice

OBJECTIVES: To investigate the effect of RC-527, a synthetic toll-like receptor 4 (TLR4) agonist, on stimulating the immune response before acute Streptococcus pneumoniae sinusitis in a mouse model, and to determine the importance of TLR4 in modulating the response to S. pneumoniae. Toll-like receptor 4 agonists have been shown to induce protective innate immune responses when administered before some bacterial or viral challenges in mice. DESIGN: We intranasally inoculated BALB/c, TLR4 complex-deficient C3H/HeJ, and wild-type C3H/HeOuJ mice with S. pneumoniae 24 hours after treatment with 10 or 1 microg of RC-527 or vehicle. Bacterial counts from nasal lavage culture and the cell markers GR1, CD11b, CD3, CD4, and CD8 in sinus tissue were quantified at postinoculation days 2, 5, and 14. MAIN OUTCOME MEASURE: Immune response induced by RC-527. RESULTS: Treatment with RC-527 induced an immune response through TLR4, as demonstrated by recruitment of phagocytes in uninfected wild-type C3H/HeOuJ mice, but not in TLR4 complex-deficient C3H/HeJ mice. The immune response was also demonstrated by a significant increase of CD3+, CD4+, and CD8+ T cells in infected and uninfected wild-type C3H/HeOuJ mice, but not in TLR4 complex-deficient C3H/HeJ mice. However, the enhancement of the immune response induced by the TLR4 agonist showed a limited effect on bacterial clearance. CONCLUSIONS: Our studies in mice suggest that stimulation of TLR4 plays a minor role in the overall response to S. pneumoniae infection of the upper airway, and stimulating this receptor before infection does not significantly enhance the immune response of immunocompetent mice to clear S. pneumoniae infection.     

Acute bacterial rhinosinusitis causes hyperresponsiveness to histamine challenge in mice

OBJECTIVES: To develop a physiologic test of nasal responsiveness in mice and to evaluate whether mice with acute bacterial sinusitis develop nasal hyperresponsiveness. DESIGN: Several experimental studies will be described. The first was a titration pilot study. The second was a randomized, placebo-controlled study. The remainder were before-and-after trials. SPECIES: BALB/c or C57BL/6 mice. INTERVENTIONS: For these experiments, we exposed mice to histamine intranasally, then counted the number of sneezes and nose rubs as the primary outcome measure of nasal responsiveness. First, we constructed a dose-response curve. Second, we treated the mice with desloratadine, a histamine 1 receptor antagonist, prior to histamine exposure. Third, we challenged, with intranasal histamine, mice made allergic using 2 techniques. Fourth, we infected mice with Streptococcus pneumoniae to determine whether acute sinusitis causes nasal hyperresponsiveness to histamine exposure. RESULTS: Nasal histamine challenge led to a reproducible, dose-dependent increase in sneezing and nose rubs. The response to histamine exposure was blocked by desloratadine (P < or = .05). Allergic mice had a significant increase in responsiveness (P < or = .05) over baseline after exposure to antigen. Mice with acute sinusitis had a sustained increase in responsiveness, although less severe than after allergy, compared with baseline values that lasted 12 days after infection (P < or = .05). CONCLUSIONS: Nasal challenge with histamine is a physiologic test of nasal responsiveness. The hyperresponsiveness of allergic mice to histamine exposure parallels the response to nonspecific stimuli during the human allergic reaction. In addition, we showed that acute bacterial sinusitis causes nasal hyperresponsiveness in mice.     

Histological and immunological observations of bacterial and allergic chronic rhinosinusitis in the mouse

BACKGROUND: The purpose of this study was to elucidate histological and immunologic features of mouse models of bacterial chronic rhinosinusitis (BCRS) and allergic chronic rhinosinusitis (ACRS). METHODS: A BCRS mouse model was established using Streptococcus pneumoniae inoculation plus Merocel (Medtronic, Jacksonville, FL) ostiomeatal obstruction for 12 weeks. An ACRS mouse model was developed by means of ovalbumin (OVA) i.p. injection and subsequent repeated OVA intranasal challenge for 12 weeks. Histological changes of sinonasal mucosa of both models were examined by means of hematoxylin and eosin staining for general morphology and inflammatory cell, periodic acid-Schiff staining for goblet cell, and Masson-trichrome staining for collagen. Enzyme-linked immunosorbent assay was used to detect the concentrations of various cytokines in nasal lavage fluid. RESULTS: Polymorphonuclear neutrophil infiltration in lamina propria was more obvious in the BCRS model, whereas eosinophil infiltration was more apparent in the ACRS model. Significant goblet cell and subepithelial gland hyperplasia, subepithelial fibrosis, epithelial thickening, and mononuclear cell infiltration were shown in both models with more severe extent found in the ACRS model. Interleukin (IL)-6 and tumor necrosis factor alpha levels in NLF from both models were increased and peaked at 1 week. Interferon gamma levels were also up-regulated in both models but reached maximum at 1 week in the BCRS model and 4 weeks in the ACRS model. IL-8 (CXCL8) levels were only increased in BCRS mice and peaked at 1 week, whereas IL-5, IL-13, and eotaxin (CCL11) levels were only enhanced in ACRS mice and peaked at 1 week. The Th1/Th2 ratio in BCRS mice was significantly higher than that in ACRS mice (6.68 +/- 2.33 versus 1.37 +/- 0.86; p < 0.01). CONCLUSION: Histological and immunologic features of BCRS and ACRS mouse models were similar to those of human noneosinophilic and eosinophilic CRS, respectively. BCRS and ACRS mouse models have distinct immunologic characteristics and are applicable for CRS research.     

Developing a mouse model of acute bacterial rhinosinusitis

The objective of this study is to establish a mouse model of acute bacterial rhinosinusitis. 179 healthy male BALB/c mice were divided into four groups in this randomized and controlled study. Sponge slivers impregnated with methicillin-resistant Staphylococcus aureus (MRSA COL) suspension were inserted into the right nasal cavities for group A; sponge slivers impregnated with sterile saline were inserted into the right nasal cavities for group B; group C mice were inoculated with MRSA COL suspension in right nasal cavities; group D was control group without any treatment. Mice were killed on days 1, 4, 7 and 14, respectively. Nasal lavage fluid was prepared for microbiological culture. Histological examinations of nasal specimens were performed to observe the severity of inflammatory reaction. Acute bacterial rhinosinusitis was induced in all group A mice. Less severe inflammation was seen in partial group B mice compared with that in group A mice (P ≤ 0.05). No inflammatory reaction was found in group C and D mice. In conclusion, a mouse model of acute bacterial rhinosinusitis has been developed successfully using an easier, less invasive and potentially more reversible technique than those used in previous studies.     

Intranasal infection of ICR mice with herpes simplex virus type 1

Intranasal inoculation of mice with herpes simplex virus (HSV) provides a model of human herpetic infection through a natural route of inoculation. Five-week-old male ICR mice were infected intranasally with various strains of herpes simplex virus type 1 (HSV-1), and the fundamental aspects of the pathogenicity of this virus were studied. Six virus strains examined showed variance in their virulence determined by lethal dose 50 (LD50) for mice. Four of the strains were revealed to be virulent, and two were shown to be attenuated. The relative degree of virulence among these strains corresponded well to that shown by intraperitoneal inoculation. When mice were inoculated with a virulent virus strain (F), virus multiplication was shown clearly in several organs tested, such as the lung, brain, olfactory bulb, trigeminal ganglion, spinal cord and adrenal gland. Viremia was also demonstrated. On the other hand, in mice inoculated with an attenuated virus strain (-GCr), virus was recovered only from the lung and adrenal gland and in much less amount than in the respective organs of mice infected with the virulent strain. No viremia was demonstrated. These data strongly suggest that the lethal effect of HSV-1 on mice is dependent upon whether or not significant virus multiplication occurs in the central nervous system, which is the critical target organ of HSV. Preinoculation of mice with an attenuated strain via the intranasal route suppressed the lethal effect of subsequent infection with any of the virulent strains by the same route of inoculation, although this protection phenomenon was not so pronounced when the virulent UNO-1A strain was used.(ABSTRACT TRUNCATED AT 250 WORDS)