视黄醇对试验性乳腺炎大鼠炎性细胞因子释放的影响

为研究视黄醇对脂多糖(LPS)诱发的乳腺炎大鼠炎性细胞因子释放的影响,40只清洁级SD孕鼠自怀孕第10天起,3个试验组(每组8只)分别为低(L)、中(M)、高(H)剂量组,分别灌胃视黄醇(溶解于大豆油)4 000、8 000和16 000 U/kg·d,对照组灌胃等量的大豆油,连续灌胃1 d。产后72 h分别灌注灭菌生理盐水和10μg/侧LPS到大鼠第4对乳腺(两侧)内,12 h处死大鼠。LPS灌注乳腺12 h后,乳腺组织中肿瘤坏死因子-α(TNF-α)、白细胞介素-8(IL-8)均显著升高,白细胞介素-2(IL-2)水平显著降低。与阳性对照组相比,灌胃中、高剂量的视黄醇显著降低乳腺组织中TNF-α水平,低、中、高剂量视黄醇能显著降低血清中TNF-α水平,显著提高血清中IL-2水平。结果证实:视黄醇能抑制炎性细胞因子过度释放,提高机体免疫力,对LPS诱发的试验性乳腺炎大鼠有一定的保护作用。     

视黄醇对大肠杆菌诱发的急性乳腺炎大鼠氧化应激的作用研究

本文探讨视黄醇对大鼠大肠杆菌乳腺炎氧化应激的调节作用.选用72只清洁级SD大鼠,随机分成实验组和对照组(n=36).怀孕后10d起,灌胃视黄醇(溶剂为大豆油)8000I.U/kg·d,连续灌注10d;对照组灌胃等体积的大豆油.产后72h,经乳头管灌注LPS 10μɡ/侧到第四对乳腺内.分别于灌注前(0h)及灌注后2、4、8、16和24h(n=6)颈静脉放血处死大鼠后采样.髓过氧化物酶活力检测结果与组织病理学观察显示,视黄醇降低了LPS诱发炎症过程中中性粒细胞在组织中的积聚与持续激活,有效控制了细胞损伤,并加快了组织修复;同时,视黄醇处理显著降低LPS灌注后IL-8及外周血PMN活性氧的释放.实验结果表明,灌胃视黄醇对LPS诱导的实验性乳腺炎大鼠PMN引起的氧化应激具有一定的保护作用.     

金黄色葡萄球菌诱导大鼠乳腺炎模型的建立

妊娠Wistar大鼠84只,随机分为试验组和对照组(n=42)。产后第4天,试验组经第4对乳腺的乳导管灌注金黄色葡萄球菌0.1 m L(2×107CFU/m L),对照组注射同量的生理盐水。动态观察和记录大鼠的临床症状、病理组织学变化、胸腺和脾脏指数、乳腺组织内细菌数和血液学变化。结果显示,注菌后,试验组胸腺和脾脏指数显著或极显著升高(P0.05或P0.01);乳腺组织内细菌量在接种后6 h迅速升高,之后开始下降,直至96 h,乳腺组织仍可以检测到金黄色葡萄球菌,高于300 CFU/mg乳腺组织;外周血中的嗜中性粒细胞在接种后6 h,12 h,极显著升高(P0.01),之后差异不显著;病理组织学检查显示,接种细菌后可导致明显的炎症反应。表明本研究建立了经乳腺导管灌注金黄色葡萄球菌诱发大鼠乳腺炎的动物模型。     

脂多糖对小鼠乳腺组织中Toll-like Receptor4表达的影响

将40只雌性ICR小鼠,受孕后随机分为试验组和对照组。雌鼠产后10-11d,试验组经第4对乳头灌注LPS,对照组灌注生理盐水,分别于灌注后不同时间采集样本,组织学分析乳腺病理变化;分析对各组乳腺组织中TLR4和TNF-α mRNA表达变化。组织学结果显示,灌注1．5h后乳腺组织中炎性细胞增多,6、12h乳腺腺泡内有大量的炎性细胞浸润,腺泡结构崩解;6h TLR4 mRNA表达极显著高于对照组（P〈0．01）;4个试验组中TNF-αmRNA表达极显著高于对照组（P〈0．01）。试验结果表明LPS能够增强TLR4和TNF-α mRNA表达。     

LPS对小鼠乳腺组织中NF—KB、ACCa和β-CaseinmRNA表达的影晌

为探讨灌注不同质量浓度LPS对小鼠乳腺组织中NF-xB、ACCa和pCaseinmRNA表达的影响，选择30只雌性ICR小鼠为试验动物，受孕后随机分为试验组和对照组，试验组经第4对乳头灌注不同质量浓度LPS（0．1，5，10，50，100mg／L），对照组灌注生理盐水，于灌注后6h采集乳腺组织样品，组织学方法分析乳腺组织的病理变化；采用RT—PCR方法分析乳腺组织中NF_KB、ACCa和B—CaseinmRNA表达的变化。病理切片结果显示，随着LPS灌注浓度的增加，乳腺小叶间炎性细胞数量逐步增加，乳腺小叶内腺泡结构破坏程度也变大；对乳腺组织中NF-xB、ACCa和pCasein的mRNA表达水平进行分析时，发现灌注LPS小鼠乳腺组织中NF-KBmRNA的表达水平随着LPS灌注浓度的增加而逐步增加，而ACCa和pCaseinmRNA的表达水平则随着LPS灌注浓度的增加而逐步降低。结果表明，灌注LPS能够上调N-KBmRNA的表达，下调ACCa和肛CaseinmRNA的表达。     

CpG-DNA对金黄色葡萄球菌诱导的大鼠实验性乳腺炎的作用

72只泌乳期SD雌性大鼠随机均分成对照组和试验组(n=36),对照组于产后0h左后腿胫骨前肌内注射0.01mol/L、pH7.2 PBS100μL/只;试验组肌注CpG-DNA 200μg/只。产后72h经乳头管灌注2×1012CFU/mL金黄色葡萄球菌各100μL/侧到第4对乳腺(两侧)内。分别于灌注前0h,灌注后8、16、24、48和72h(n=6)颈静脉放血处死。结果显示,乳腺组织细菌数在灌注后24h上升至最高,CpG-DNA能显著降低8、16和72h的细菌数。IL-2在不同时间点有显著下降,对照和试验组乳腺组织IL-2分别在16和24h下降至最低。TNF-α在24h达最高,CpG-DNA能显著提高0、24和72h乳腺组织TNF-α水平。CpG-DNA能显著提高血清感染后各时间点及乳腺组织0和16h MPO水平。乳腺组织NAGase和白蛋白在24h上升至最高,血清中24h下降至最低。CpG-DNA能显著降低48和72h乳腺组织NAGase活力,并极显著降低8和72h乳腺白蛋白浓度。上述结果显示,CpG-DNA可促进细胞因子的产生,减少乳腺组织细菌数量,减轻炎症介质对细胞和血-乳屏障完整性的损伤,提示CpG-DNA对金黄色葡萄球菌感染诱发的大鼠乳腺炎有一定的保护作用。     

复合抗氧化剂对脂多糖诱导的大鼠肠道损伤的修复作用

本试验旨在通过脂多糖(LPS)诱导自由基建立大鼠肠道损伤模型,研究复合抗氧化剂对肠道损伤的修复作用.36只42日龄的SD大鼠随机分成3组,每组12只.对照组和诱导组饲喂基础饲粮,修复组在基础饲粮中添加复合抗氧化剂.诱导组和修复组大鼠在试验的第5、9、13和17天每千克体重腹腔注射0.8 mg LPS,对照组注射等量生理...     

LPS对小鼠乳腺组织中NF-κB、ACCα和β-Casein mRNA表达的影响

为探讨灌注不同质量浓度LPS对小鼠乳腺组织中NF-κB、ACCα和β-Casein mRNA表达的影响,选择30只雌性ICR小鼠为试验动物,受孕后随机分为试验组和对照组,试验组经第4对乳头灌注不同质量浓度LPS(0.1,5,10,50,100mg/L),对照组灌注生理盐水,于灌注后6h采集乳腺组织样品,组织学方法分析乳腺组织的病理变化;采用RT-PCR方法分析乳腺组织中NF-κB、ACCα和β-Casein mRNA表达的变化。病理切片结果显示,随着LPS灌注浓度的增加,乳腺小叶间炎性细胞数量逐步增加,乳腺小叶内腺泡结构破坏程度也变大;对乳腺组织中NF-κB、ACCα和β-Casein的mRNA表达水平进行分析时,发现灌注LPS小鼠乳腺组织中NF-κB mRNA的表达水平随着LPS灌注浓度的增加而逐步增加,而ACCα和β-Casein mRNA的表达水平则随着LPS灌注浓度的增加而逐步降低。结果表明,灌注LPS能够上调NF-κB mRNA的表达,下调ACCα和β-Casein mRNA的表达。     

移植骨髓间充质干细胞对乳腺炎模型大鼠乳腺组织及血清中酶活性变化的影响

旨在研究乳腺基部移植骨髓间充质干细胞(BMSC)对试验性乳腺炎大鼠模型血清中N-乙酰基-β-D-氨基葡萄糖苷酶(NAGase)、碱性磷酸酶(ALP)、乳酸脱氢酶(LDH)、髓过氧化物酶(MPO)的影响,70只产后SD雌性大鼠,其中5只于产后72h(试验前1d)处死,作为空白对照组;另外65只大鼠乳头管灌注内毒素制作乳腺炎动物模型。造模处理1d后(试验0d),随机选取5只模型大鼠处死,作为试验对照组;其余60只随机分为生理盐水组,抗生素组和BMSC移植组,每组20只,并于试验1、3、5、7d各组分别处死5只,所有屠宰大鼠心脏采血,制备血清,检测血清中NAGase、ALP、LDH、MPO水平;同时采集乳腺组织,制作石蜡切片,进行病理组织学检测。结果表明,空白对照大鼠乳腺组织无异常,腺泡上皮细胞排列整齐;灌注内毒素的试验对照大鼠,在注射内毒素24h后乳腺腺泡结构破坏严重,腺上皮细胞脱落、坏死,腺泡腔内有大量中性粒细胞和脱落上皮细胞浸润,间隔增宽。血清中ALP、LDH、NAGase、MPO活性与灌注前相比显著升高(P0.05)。治疗后各组乳腺组织逐渐恢复;试验7d时移植BMSC组已恢复到正常水平;灌注内毒素后血清中NAGase、ALP、LDH、MPO活性与灌注前相比显著升高(P0.05),治疗后,移植BMSC组血清中ALP、NAGase活性于1、3、7d时、MPO活性于1、3、5、7d时、LDH活性于7d时与对照组差异显著(P0.05)。研究结果说明,BMSC能修复受损乳腺组织,降低血清中ALP、LDH、NAGase、MPO等乳腺炎相关酶的活性。     

胆酸对LPS诱导小鼠乳腺炎的保护作用及其机制

乳腺炎是危害奶牛养殖业最为主要的疾病之一,严重制约着奶业的健康发展。抗生素作为乳腺炎的主要治疗药物,易造成细菌耐药性等问题。因此,寻找安全有效的方法或制剂替代抗生素对于乳腺炎的防治具有重要意义。胆酸(cholic acid, CA)作为机体的天然代谢产物,报道具有抑菌抗炎功能。本研究旨在探讨CA对脂多糖(LPS)诱导小鼠乳腺炎的保护作用及机制。将40只分娩后的BALB/c母鼠随机分为5组,包括空白对照组、LPS造模组、LPS+CA(10 mg/kg)组、LPS+CA(20 mg/kg)组和LPS+CA(30 mg/kg)组。通过对小鼠乳腺组织进行病理学观察、炎性细胞因子及相关信号通路检测等方法探究CA对LPS诱导小鼠乳腺炎的保护作用及机制。结果显示,CA呈剂量依赖性地改善LPS诱导小鼠乳腺组织病理损伤,显著降低髓过氧化物酶(MPO)活性和炎性细胞因子TNF-α和IL-1β的表达。进一步研究表明,CA显著抑制了LPS诱导的NF-κB信号通路激活,增加了法尼醇X受体(FXR)的表达。结果表明,CA通过上调FXR受体表达,进而抑制LPS诱导的NF-κB信号通路及炎性细胞因子产生,发挥对乳腺炎...     

Estabishment of Mastitis Model in Mouse by Artificial Infection of Staphylococcus aureus Small Colony Variants

In order to establish the mouse mastitis model induced by Staphylococcus aureus small colony variants (SCVs),40 BALB/c mice 6 to 8 days postpartum were randomly divided into eight groups,negative control group,physiologic saline group and six treated groups with different doses (1.0×10³,1.0×10⁴ and 1.0×10⁵ CFU/mL) of Staphylococcus aureus SCVs or Staphylococcus aureus quality control strains.50 μL physiologic saline and Staphylococcus aureus liquid were injected into the forth mammary glands in physiologic saline group and the six treated groups,respectively.All the mice were sacrificed 24 h after treatment.One side of the forth mammary glands was used to make pathological section,the other side was used to detect the concentration of TNF-α in the supernatant.The results showed that mice had different degrees of clinical symptoms in the treated groups,their mammary glands appeared different degrees of inflammatory symptoms and pathological changes.Under the same injected dose,the Staphylococcus aureus quality control strains group pathologic changed more severe than the Staphylococcus aureus SCVs group.The experimental data had been statistically analyzed by using SPSS software,the result showed that the expression of TNF-α of the Staphylococcus aureus quality control strains group were extremely significantly higher than that of Staphylococcus aureus SCVs group with high dose (P<0.01).The results indicated that Staphylococcus aureus and its SCVs could be used to establish the mice mastitis model,and Staphylococcus aureus SCVs caused relatively minor inflammation than the normal strains.The results provided a new research materials and meaningful exploration to research the prevention and control of chronic mastitis cows and its pathogenic mechanism caused by Staphylococcus aureus SCVs,and laid the foundation for studying the deeper relationship between Staphylococcus aureus SCVs and chronic mastitis.     

金黄色葡萄球菌小菌落突变株感染小鼠乳房炎模型的建立

为了建立由金黄色葡萄球菌小菌落突变株(small colony variants,SCVs)诱发感染乳房炎动物模型,本试验取40只分娩6~8 d的BALB/c小鼠,随机分成8组(n=5),分别为阴性对照、生理盐水组和不同剂量金黄色葡萄球菌SCVs及金黄色葡萄球菌质控菌株(1.0×10³、1.0×10⁴、1.0×10⁵ CFU/mL)试验组,对生理盐水组及各试验组小鼠第4对乳腺注射生理盐水和对应剂量的菌液(50 mL/只),注射后24 h解剖观察病理变化,一侧乳头制作石蜡切片,另一侧研磨后用ELISA检测试剂盒检测组织匀浆上清中的TNF-α含量。结果显示,注射菌液的试验组,小鼠均出现不同程度的临床症状,乳腺出现不同程度的炎性症状和病理变化。同一注射剂量下,金黄色葡萄球菌质控菌株较金黄色葡萄球菌 SCVs病理变化严重,通过SPSS等软件对试验数据进行统计分析后得出,高浓度处理组金黄色葡萄球菌质控菌株的TNF-α表达量极显著高于金黄色葡萄球菌SCVs(P<0.01)。结果表明,金黄色葡萄球菌及其SCVs均可用来建立小鼠乳房炎模型,且金黄色葡萄球菌SCVs引起的情况较其正常株轻微,这一结果为由金黄色葡萄球菌SCVs引起的奶牛慢性乳房炎的预防和控制及其致病机制的研究提供了新的材料和有益的探索,为SCVs与慢性乳房炎更深层次关系的研究奠定基础。     

荔蒲煎液对脂多糖诱导的大鼠乳腺炎的防治作用

本试验利用脂多糖（LPS）诱发试验性大鼠乳腺炎，探讨中药荔蒲煎液对试验性乳腺炎的防治作用。24只SD孕鼠随机分成阴性对照纽（NC）、阳性对照组（PC）、药物预防纽（Pre）和治疗纽（Tre）。Pre组大鼠灌服荔蒲煎液，持续4d。随后，PC组和Pre组大鼠乳房注入LPS，NC组乳管注入等量生理盐水；Tre组大鼠乳管注入LPS24h后灌服荔蒲煎液，连续灌胃4d。对所有大鼠乳腺组织切片进行组织病理学观察、测定胸腺指数和脾脏指数，并进行白细胞计数以及碱性磷酸酶（ALP）和谷胱甘肽过氧化物酶（GSH—Px）的活性检测。结果表明，Pre和Tre组胸腺、脾脏指数以及GSH-Px活性均明显高于PC组（P〈0．05），而白细胞数与ALP活性则低于PC组，Pre和Tre组之间无明显差异。病理组织学检查显示荔蒲煎液能减轻LPS引起的炎症反应。上述结果提示荔蒲煎液有利于维持机体的氧化-还原平衡，对LPS诱发的试验性大鼠乳腺炎有较好的防治效果。     

Growth of Staphylococcus aureus and Streptococcus species in bovine mammary secretions during the nonlactating and peripartum periods following intramammary infusion of lipopolysaccharide at cessation of milking.

The objective was to determine if induced mammary inflammation at cessation of milking influenced growth of gram-positive mastitis pathogens in mammary secretions, particularly during early involution. Growth of all mastitis pathogens evaluated was similar in cell-free fat-free mammary secretions from LPS-infused and control glands. These data indicate that intramammary infusion of LPS at cessation of milking did not alter growth of gram-positive mastitis pathogens in mammary secretion during the nonlactating period. Stage of lactation and the nonlactating period influenced bacterial growth and marked differences between bacteria and among strains of a bacterial species were observed. Staphylococcus aureus grew well in secretions collected during late lactation, but growth decreased during early- and mid-involution and increased again in secretions obtained near parturition. Streptococcus agalactiae and Strep. uberis grew better in mammary secretion obtained during involution than in secretions collected during late or early lactation. Streptococcus dysgalactiae grew well in mammary secretions at all time periods. These data demonstrate the variability of mastitis pathogen growth during physiologic transitions of the bovine udder.     

Experimental staphylococcal mastitis in the mouse: the persistence of chronic infection from one lactation to the next.

Chronic staphylococcal mastitis was established in 50 mammary glands of 25 mice. The mice were mated and in the subsequent lactation there was alveolar mastitis in one of 50 glands. A further five glands had abscesses that contained staphylococci but there was no alveolar mastitis. The results are discussed in relation to the large number of infections that persist from one lactation to the next in cows not subjected to mastitis control measures.     

Protective effect of CpG-DNA against mastitis induced by Escherichia coli infection in a rat model

A mastitis model in rats, induced by Escherichia coli infection, was established and the protective effect of Cytosine-phosphate-Guanosine (CpG)-DNA was determined. An E. coli suspension containing either 2 x 10(3) colony forming units (CFU)mL(-1)(EL group), 2 x 10(5)CFU mL(-1) (EH group), or (as controls) 100 microL phosphate buffer saline (CON group), was inoculated into the mammary glands 72 h after parturition. The rats were euthanased 24 h post-infection. The histopathological changes in mammary tissue in the EL group were mild, whereas the structural changes in the EH group were severe and polymorphonuclear leukocytes (PMNs) had accumulated in the mammary alveoli. Interleukin (IL)-6 and tumour necrosis factor (TNF)-alpha and N-acetyl-beta-d-glucosaminidase (NAGase) were significantly increased in the mammary tissue from the EH group but not significantly changed in the EL group. On the basis of these findings, the potential protective effect of CpG-DNA on mammary glands was tested using a 2 x 10(5)CFU mL(-1) suspension. An intramuscular injection of either CpG-DNA (200 microg) or PBS (100 microL) was given immediately after parturition. At 72 h post-partum, 2 x 10(5)CFU mL(-1)E. coli (100 microL) were inoculated into the mammary glands of all rats. At pre-infection (0 h), and 8, 16, 24, 48 and 72 h after inoculation six rats were euthanased. CpG-DNA induced more rapid migration of PMNs from the blood to mammary tissue at the initial stage of infection, stimulated the secretion of IL-6 and TNF-alpha at different time points, reduced viable E. coli in mammary tissues and decreased the activity of NAGase. CpG-DNA also promoted the expression of its specific receptor TLR-9 mRNA in mammary tissue. The study showed that CpG-DNA protected against E. coli mastitis in this rat model.     

β-防御素在荷斯坦奶牛正常和炎性乳腺上皮细胞中的差异表达

为探讨荷斯坦奶牛乳腺上皮细胞在正常和炎性2种情况下β-防御素（BNBD5）的表达量是否存在差异,本研究通过添加内毒素（LPS）建立了实验性乳房炎的乳腺上皮细胞模型,并采用实时荧光定量RT-PCR方法检测了乳腺上皮细胞中BNBD5mRNA表达水平的变化。结果显示,添加LPS后乳腺上皮细胞中炎性因子IL-6、IL-12和TNF-α的mRNA表达量与空白对照组相比显著增加（P〈0.01）,并且α-酪蛋白mRNA表达量显著降低（P〈0.01）,说明添加LPS诱发上皮细胞产生了一定的炎性反应;并且当添加LPS终质量浓度为300μg/L并培养48h之后BNBD5的表达量最高,与空白对照组存在极显著差异（P〈0.01）;推测BNBD5基因可能参与了由LPS诱发的奶牛乳房炎的防御机制。     

Induced staphylococcal infections in the bovine mammary gland

In a study to develop and define a practical model of bovine mastitis caused by Staphylococcus aureus, induced infections were attempted in 203 bovine mammary glands of 41 cows, using 12 strains of S aureus. Approximately 100 colony-forming units of S aureus in saline solution were injected after milking, and milk samples were collected daily from test glands for 14 days to monitor the progress of infections and inflammatory responses. Relationships were examined for cow-related factors and for various characteristics of the strains of S aureus used to the development of a persistent intramammary infection. A dairy cow that was useful in this model was defined as follows: (1) the 2nd to 7th month in the 1st to 5th lactation; (2) producing milk from all mammary glands that contained less than 6 x 10(5) somatic cells/ml; and (3) having mammary glands that were free of any primary mastitis pathogen, as well as micrococci and Corynebacterium bovis. From the present study, it was not possible to define clearly a strain of S aureus which would be useful in the model, but 5 strains of S aureus were identified as being capable of producing persistent subacute infections with a high degree of repeatability.