葛根素延缓动脉粥样硬化进展的机制研究

目的:明确葛根素(Pur)对小鼠动脉粥样硬化斑块稳定性的治疗作用及其潜在机制。方法:用高脂饮食喂养成年小鼠诱导动脉粥样硬化模型,将小鼠分为Con组,ApoE~(-/-)组,ApoE~(-/-)+Pur组。采用HE染色分别检测各组小鼠中动脉粥样硬化斑块面积,免疫荧光染色检测斑块中MMP2的阳性区域面积。用50μg/mL ox-LDL干预巨噬细胞诱导动脉粥样硬化细胞模型,并用Ad-sh-Sirt3干扰Sirt3表达,将细胞分为Con组、ox-LDL组、ox-LDL+Pur组、ox-LDL+Pur+Ad-sh-Sirt3组。Western-blot检测Sirt3表达含量,TUNEL法检测巨噬细胞凋亡。结果:动物水平,与Con组相比,ApoE~(-/-)组小鼠出现了显著的动脉粥样硬化斑块,ApoE~(-/-)组小鼠MMP2阳性区域面积显著高于Con组(P0.05);Pur处理后,ApoE~(-/-)+Pur组动脉粥样硬化斑块面积明显低于ApoE~(-/-)组(P0.05),MMP2的阳性区域面积显著低于ApoE~(-/-)组(P0.05)。细胞水平,Western结果显示,与对照组相比,ox-LDL组Sirt3表达量显著降低(P0.05),ox-LDL+Pur组Sirt3表达水平显著高于ox-LDL组(P0.05)。相比于Con组,ox-LDL组巨噬细胞凋亡水平显著升高(P0.05);给予Pur处理后,相比于单纯ox-LDL组,ox-LDL+Pur组巨噬细胞的凋亡水平显著降低(P0.05)。Ad-sh-Sirt3处理消除了葛根素对于巨噬细胞凋亡的抑制作用(P0.05)。结论:外源性Pur可能通过激活Sirt3表达,进一步降低巨噬细胞凋亡水平,减少巨噬细胞的浸润,增加动脉粥样硬化斑块稳定性。     

神经鞘磷脂合成酶2基因的缺失有抗动脉粥样硬化及抗炎作用

本文以神经鞘磷脂合成酶2基因敲除(sphingomyelin synthase 2 knockout,SMS2-/-)小鼠为研究对象,旨在探讨神经鞘磷脂(sphingomyelin,SM)代谢与动脉粥样硬化(atherosclerosis,AS)发生之间的关系。雄性3月龄SMS2-/-小鼠为实验组,同性别同月龄C57BL/6J(wild-type,WT)小鼠为对照组。用高脂高胆固醇饮食喂养两组小鼠,并给予胆盐以促进AS斑块的形成。喂养3个月后解剖观察小鼠主动脉弓,剖开胸腹主动脉进行油红染色以观察AS斑块发生情况;同时收集小鼠腹腔巨噬细胞,用脂多糖刺激后,提取核蛋白用Western blot方法检测核因子κB(nuclear factor-κB,NFκB)p65含量;高脂饮食喂养前后,小鼠断尾取血,酶法测定血清SM水平,用血脂检测试剂盒检测血脂水平。结果显示,高脂饮食喂养3个月后,SMS2-/-小鼠的主动脉弓和胸腹主动脉很少形成AS斑块,而WT小鼠则产生了较多AS斑块;高脂饮食喂养前后,SMS2-/-小鼠血清SM水平均明显低于WT小鼠(P0.05),而血脂水平并无显著性差异(P0.05);高脂饮食喂养后,SMS2-/-小鼠腹腔巨噬细胞经过脂多糖刺激产生的NFκBp65含量明显低于WT小鼠。以上结果提示,SMS2基因的缺失有抗AS及抗炎作用,因而可能成为临床治疗的新策略。     

绞股蓝皂苷调控长链非编码RNA TUG1/miR-26a干扰线粒体凋亡对ApoE~(-/-)AS小鼠肝脏脂质沉积的影响及机制研究

为探讨绞股蓝皂苷通过影响长链非编码RNA TUG1/miR-26a干扰线粒体凋亡改善ApoE~(-/-)AS小鼠肝脏脂质沉积防治AS机制,本实验将10只C57BL/6J小鼠作为正常对照组,20只健康ApoE~(-/-)小鼠随机分为模型组、绞股蓝皂苷组(高脂饲料喂养12周),灌胃给药4周。HE染色观察小鼠肝脏脂质沉积情况,全自动生化分析仪检测血脂水平,实时荧光定量Q-PCR检测长链非编码TUG1、miRNA-26a表达,实时荧光定量Q-PCR及Wes全自动蛋白质印迹定量分析系统检测Bcl2、Bax、Cytc、cleaved caspase-3、cleaved caspase-9、cleaved PARP基因及蛋白表达。结果显示模型组ApoE~(-/-)小鼠血脂水平发生紊乱,肝细胞体积变大,脂肪空泡明显,小鼠肝脏Lnc-TUG1表达显著升高,miRNA-26a显著下降(P0.01);Bax、Cyt-c、cleaved caspase-3、cleaved PARP mRNA及蛋白表达显著升高,Bcl2 mRNA及蛋白显著下降(P0.01或P0.05);cleaved caspase-9蛋白表达显著升高(P0.01或P0.05),cleaved caspase-9 mRNA仅有上升趋势;绞股蓝皂苷干预后血脂紊乱得以改善,肝细胞脂肪变性程度减轻,脂肪空泡明显减少,小鼠肝脏Lnc TUG1表达有所下降,miRNA-26a表达有所上调(P0.05),小鼠肝脏Bax、Cyt-c、cleaved caspase-3、cleaved caspase-9 mRNA及蛋白表达显著下调,Bcl2 mRNA及蛋白显著上调(P0.01或P0.05),cleaved PARP蛋白表达显著下调(P0.05),cleaved PARP mRNA仅有下调趋势;研究结果提示绞股蓝皂苷可能通过影响长链非编码RNA TUG1/miR-26a干扰线粒体凋亡改善ApoE~(-/-)AS小鼠肝脏脂质沉积,进而防治动脉粥样硬化。     

黄连解毒汤通过调节性T细胞产生抗动脉粥样硬化作用

目的观察黄连解毒汤(HLJDD)对ApoE~(-/-)小鼠斑块、炎症因子及调节性T细胞(Tregs)的影响。方法高脂饲料喂养雄性ApoE~(-/-)小鼠建立动脉粥样硬化(atherosclerosis,AS)模型,40只雄性ApoE~(-/-)小鼠随机分为:模型组,辛伐他汀组,HLJDD高、中、低剂量组(n=8)。HLJDD灌胃剂量依次为:每日3.5、7.0、14.0 g/(kg·bw),辛伐他汀灌胃剂量为每日5 g/(kg·bw),另设8只同龄雄性C57BL/6J小鼠为对照组,喂以普通饲料,连续给药16周后处死小鼠。检测血脂水平,观察主动脉斑块形成情况;ELISA法检测血清炎症因子水平;流式细胞术检测Tregs数量;RT-PCR法检测Foxp3 mRNA水平。结果与对照组相比,模型组中主动脉斑块明显,TC、TG与LDLC浓度显著升高,促炎因子超敏C反应蛋白(hs-CRP)、白介素-6(IL-6)与肿瘤坏死因子-α(TNF-α)水平显著升高,而HDL-C、白介素-10(IL-10)、生长转化因子-β(TGF-β)、Foxp3 mRNA水平显著降低,Tregs数量减少,二者差异有显著性(P0.01);HLJDD能显著缩小主动脉斑块面积,降低血清TC、TG与LDL-C,并降低IL-6、hs-CRP与TNF-α水平,增加血清HDL-C、IL-10、TGF-β及Foxp3 mRNA水平,并增加Tregs数量,与模型组相比差异有显著性(P0.01)。结论 HLJDD可显著减轻ApoE~(-/-)小鼠主动脉斑块损伤,可能与增加Tregs数量,从而降低血清炎症因子水平有关。     

BET蛋白通过调控NF-κB通路参与炎症基因转录

目的:探讨特异性抑制溴结构域(bromodomain and extra-terminal,BET)蛋白对血管内皮细胞激活与早期动脉粥样硬化形成的作用及其分子机制。方法:1.原代分离培养脐静脉内皮细胞和小鼠心脏血管内皮细胞后用肿瘤坏死因α(TNFα)刺激模拟炎症过程,以小分子化合物JQ1特异性抑制BET蛋白,分组如下:(1)对照组;(2)TNFα(25 ng/m L)处理组;(3)TNFα+JQ1处理组。采用Realtime-PCR及流式细胞术检测各组细胞炎症因子m RNA及蛋白水平的表达,采用5XκB荧光素酶报告基因检测各组核转录因子kappa B(NF-κB)转录活性。2.LDL受体基因敲除(LDLR-/-)小鼠随机分为2组:JQ1组(n=8,JQ1腹腔注射,50 mg/kg,每天一次)和对照组(n=8,DMSO溶媒组),同时给予高胆固醇饮食8周,采用免疫组化方法检测主动脉弓部血管细胞黏附分子-1(VCAM-1)表达水平。结果:与对照组相比,TNFα组炎症因子m RNA、蛋白表达明显上调(P0.01),使用JQ1干预后,炎症因子E选择素(E-selectin)、P选择素(P-selectin)、VCAM-1及白细胞介素-8(IL-8)m RNA及蛋白表达均明显下调(P0.01)。LDLR-/-小鼠高脂饮食诱导8周后JQ1显著下调了主动脉弓部VCAM-1蛋白表达。5XκB荧光素酶报告基因结果显示,与TNFα(-)相比,TNFα(+)组荧光素酶报告基因活性增强,JQ1可以显著下调报告基因活性(P0.01)。结论:BET蛋白通过调控NF-κB信号通路参与了血管内皮炎症基因转录;抑制BET蛋白下调了NF-κB目的基因表达从而减轻了内皮激活及高脂诱导的早期动脉粥样硬化病理改变。     

黄连提取物对动脉硬化小鼠斑块胶原类型及MMP-9/TIMP-1 比值 的影响*

目的:探讨黄连提取物对高脂喂养ApoE-/-小鼠主动脉AS斑块内胶原类型及基质金属蛋白酶-9( MMP-9)与基质金属蛋白酶组织抑制剂( TIMP-1)比值的影响,探讨黄连提取物稳定斑块的可能作用机制.方法:33只6-8周龄的ApoE基因敲除小鼠予高脂喂养13周后,待其形成成熟的AS斑块后,随机分为3组:模型组、黄连提取物组、辛伐他汀组(阳性对照组),每组11只.继续高脂喂养,并按体重比折算给予小鼠临床推荐剂量的相应药物治疗13周,处死动物,每只小鼠取主动脉根部的4个切面,行天狼猩红染色,检测各组小鼠主动脉斑块内Ⅰ、Ⅲ型胶原含量,以及斑块内MMP-9和TIMP-1的表达,计算MMP-9/TIMP-1比值.结果:给药13周后,图像分析结果显示,黄连提取物组小鼠主动脉斑块内Ⅰ型胶原含量与模型组比较有所增加,但无显著差异(P＞0.05);辛伐他汀组和黄连提取物组小鼠主动脉斑块内Ⅲ型胶原含量与模型组比较显著降低(P＜0.01).Ⅲ型/Ⅰ型胶原比值,两给药组与模型组比较均显著降低(P＜0.01).与模型组比较,黄连提取物和辛伐他汀组小鼠主动脉斑块内MMP-9的阳性表达均明显减少(P＜0.01),黄连提取物组主动脉斑块内TIMP-1的阳性表达与模型组相比明显增加(P＜0.01),辛伐他汀组TIMP-1表达有所增加,但无统计学差异(P＞0.05),两给药组之间比较无显著差异(P＞0.05).各给药组中MMP-9/TIMP-1比值均有所降低,与模型组比较具有显著差异(P＜0.05,P＜0.01).结论:在临床推荐剂量下,黄连提取物可明显改善ApoE-/-小鼠主动脉AS斑块内胶原类型,调整斑块内MMP-9/TIMP-1比值,从而促进斑块稳定.     

缺氧诱导因子在新生儿坏死性小肠结肠炎中的作用机制研究

该文探讨了缺氧诱导因子-1α(hypoxia inducible factor-1α,HIF-1α)在新生儿坏死性小肠结肠炎(neonatal necrotizing enterocolitis,NEC)中的作用机制。收集8例NEC患儿小肠组织作为疾病组和6例胃肠道畸形患儿小肠组织作为对照组。将40只7日龄的C57BL/6新生鼠(WT)分为NEC组(WT/NEC,n=20)和对照组(WT/DF,n=20),40只7日龄C57BL/6背景的谷氧还原蛋白1(glutaredoxin1,Grx1)基因敲除鼠(Grx1~(–/–))分为NEC组(Grx1~(–/–)/NEC,n=20)和对照组(Grx1~(–/–)/DF,n=20)。Western blot检测人和小鼠肠组织HIF-1α、小鼠肠组织血管内皮生长因子A(vascular endothelial growth factor A,VEGFA);qRT-PCR检测小鼠肠道血管内皮生长因子VEGFA mRNA,免疫荧光染色检测人和小鼠肠组织HIF-1α。结果显示,NEC患儿小肠组织中HIF-1α表达量较对照组显著降低(P0.05);WT/NEC小鼠小肠组织HIF-1α和VEGFA蛋白表达量较WT/DF显著降低(P0.05);WT/NEC组小肠组织中VEGFA表达量较WT/DF组显著降低(P0.05),Grx1~(–/–)/NEC组VEGFA表达量较WT/NEC组显著升高(P0.05);HIF-1α主要表达于小肠上皮细胞,NEC患儿肠组织和NEC小鼠肠组织中HIF-1α免疫荧光染色强度均较各自对照组显著降低,而Grx1基因敲除显著提高了NEC小鼠肠组织HIF-1α免疫荧光染色强度。该研究结果表明,HIF-1α在NEC患儿和NEC小鼠中有重要作用,其机制可能与肠道微血管的发育相关。     

汉黄芩素缓解高脂饮食喂养ApoE~(-/-)小鼠的动脉粥样硬化和NF-κB介导的动脉炎症反应

为探究汉黄芩素对高脂饮食喂养ApoE~(-/-)小鼠的动脉粥样硬化和炎症的影响,本研究将ApoE~(-/-)小鼠分为正常饮食组、高脂饮食组、高脂饮食+汉黄芩素10 mg/kg组、高脂饮食+汉黄芩素20 mg/kg组,高脂饮食和药物同时给予,12周后收集动脉组织。采用RT-qPCR法检测IL-6、TNF-α、ICAM-1和VCAM-1的mRNA表达;油红O染色和HE染色检测主动脉根部油脂变化和病理变化;免疫荧光染色检测Moma-2和VCAM-1表达;生化试剂盒检测血液中的血脂水平;Western blot法检测动脉的NF-κB的磷酸化和IκB-α的表达变化。结果显示,与高脂饮食组比较,汉黄芩素治疗组动脉粥样硬化斑块面积减少(P0.05),但血脂水平无变化;汉黄芩素治疗组动脉中单核/单核巨噬细胞浸润,TNF-α、IL-6、ICAM-1和VCAM-1的mRNA表达水平,VCAM-1的蛋白表达水平和NF-κB信号通路的激活均显著降低(P0.05)。提示汉黄芩素有效缓解高脂饮食喂养诱导的小鼠动脉粥样硬化,并伴随抑制NF-κB介导的动脉炎症。     

C1型尼曼–匹克病小鼠雄性不育的睾丸病理研究

该文主要研究C1型尼曼–匹克病小鼠(Npc1~(–/–)小鼠)雄性不育的睾丸病理变化,并进一步探讨Npc1基因对雄性不育的影响。随机选取P60的Npc1~(–/–)和Npc1~(+/+)雄鼠各12只,观察隐睾发生率;然后,随机选取P20、P40和P60的Npc1~(–/–)和Npc1~(+/+)雄鼠睾丸组织,统计睾丸重量并计算睾丸指数, HE染色观察生殖细胞层数并测量生精小管直径, PAS糖原染色观察生殖细胞周期并统计精母细胞在总细胞数中的相对百分比,油红O染色观察间质细胞的脂质存储;最后,随机选择P60的Npc1~(–/–)和Npc1~(+/+)雄鼠睾丸,通过TUNEL染色观察生殖细胞凋亡,并通过Western blot检测凋亡蛋白Cleaved-caspase-3、Cleaved-caspase-9、p53、Bax和Bcl-2的表达水平。结果显示,与Npc1~(+/+)雄鼠相比, Npc1~(–/–)雄鼠均有隐睾发生,睾丸重量和睾丸指数均显著降低(P0.05, P0.001),生殖细胞层数不明显,生精小管管径显著减小(P0.001),生精周期不规律且精母细胞数量显著减少(P0.001),间质细胞的脂质存储显著减少(P0.001);生殖细胞凋亡大幅增加(P0.001), Cleaved-caspase-3、Cleaved-caspase-9、p53、Bax表达量显著升高(P0.001),Bax/Bcl-2比率显著升高(P0.001)。该文结果提示, Npc1基因突变导致隐睾、睾丸结构异常、间质细胞脂质储存减少及生殖细胞凋亡,因此, Npc1基因可能成为研究男性不育的新靶点。     

脂代谢相关基因在apoE基因缺失幼龄小鼠肝脏中的表达

本文旨在分析脂代谢相关基因在载脂蛋白E(apolipoprotein E,apoE)基因缺失(apoE-/-)幼龄小鼠肝脏中的表达特征及其与血脂紊乱和动脉粥样硬化(atherosclerosis,AS)早期病变的关系.利用半定量RT-PCR和荧光实时定量RT-PCR技术,分析14 d龄、1、2和3月龄apoE-/-小鼠及同龄野生型(wild type,WT)小鼠肝脏脂代谢相关基因的表达,并进行血生化指标及主动脉病理形态学榆测.apo-/-小鼠肝脏中apoAI、apoAIV表达在14d龄时即发生显著变化(P<0.05);在1月龄时apoB10G表达较同龄WT小鼠明显上调(P＜0.05);apoA V表达则在2月龄时较同龄WT小鼠上调(P＜0.05),此时可观察到apoE-/-小鼠主动脉内膜出现AS早期病变;Faf/CD36和Angptl 3表达在3月龄时较同龄WT小鼠上调(P＜0.05);实验中检测的其它基因的mRNA表达与同龄WT小鼠相比无显著性差异.apoE-/-小鼠血清总胆同醇、甘油三酯、低密度脂蛋白胆固醇和高密度脂蛋白胆固醇含量均高于同龄WT小鼠,并随年龄增长而升高.apoE-/-小鼠和同龄WT小鼠血清中apoB100蛋白浓度在14 d龄到3月龄问变化趋势与其在肝脏中mRNA表达及血清中低密度脂蛋白胆崮醇含量变化趋势基本一致.上述部分脂代谢相关基因表达在幼龄小鼠即发生改变,与血脂紊乱以及主动脉AS病变发生发展过程呈正相关,说明其可能在幼龄小鼠脂质代谢紊乱发生过程中起重要作用,从而引起动脉内皮细胞功能改变乃至AS早期病变的发生.     

Genetic deletion or TWEAK blocking antibody administration reduce atherosclerosis and enhance plaque stability in mice

Clinical complications associated with atherosclerotic plaques arise from luminal obstruction due to plaque growth or destabilization leading to rupture. Tumour necrosis factor ligand superfamily member 12 (TNFSF12) also known as TNF-related weak inducer of apoptosis (TWEAK) is a proinflammatory cytokine that participates in atherosclerotic plaque development, but its role in plaque stability remains unclear. Using two different approaches, genetic deletion of TNFSF12 and treatment with a TWEAK blocking mAb in atherosclerosis-prone mice, we have analysed the effect of TWEAK inhibition on atherosclerotic plaques progression and stability. Mice lacking both TNFSF12 and Apolipoprotein E (TNFSF12^−/−ApoE^−/−) exhibited a diminished atherosclerotic burden and lesion size in their aorta. Advanced atherosclerotic plaques of TNFSF12^−/−ApoE^−/− or anti-TWEAK treated mice exhibited an increase collagen/lipid and vascular smooth muscle cell/macrophage ratios compared with TNFSF12^+/+ApoE^−/− control mice, reflecting a more stable plaque phenotype. These changes are related with two different mechanisms, reduction of the inflammatory response (chemokines expression and secretion and nuclear factor kappa B activation) and decrease of metalloproteinase activity in atherosclerotic plaques of TNFSF12^−/−ApoE^−/−. A similar phenotype was observed with anti-TWEAK mAb treatment in TNFSF12^+/+ApoE^−/− mice. Brachiocephalic arteries were also examined since they exhibit additional features akin to human atherosclerotic plaques associated with instability and rupture. Features of greater plaque stability including augmented collagen/lipid ratio, reduced macrophage content, and less presence of lateral xanthomas, buried caps, medial erosion, intraplaque haemorrhage and calcium content were present in TNFSF12^−/−ApoE^−/− or anti-TWEAK treatment in TNFSF12^+/+ApoE^−/− mice. Overall, our data indicate that anti-TWEAK treatment has the capacity to diminish proinflamatory response associated with atherosclerotic plaque progression and to alter plaque morphology towards a stable phenotype.     

Adiponectin Receptor 2 Deficiency Results in Reduced Atherosclerosis in the Brachiocephalic Artery in Apolipoprotein E Deficient Mice

Adiponectin has been shown to have beneficial cardiovascular effects and to signal through the adiponectin receptors, AdipoR1 and AdipoR2. The original aim of this study was to investigate the effect of combined AdipoR1 and AdipoR2 deficiency (AdipoR1^-/-AdipoR2^-/-) on atherosclerosis. However, we made the interesting observation that AdipoR1 ^-/- AdipoR2 ^-/- leads to embryonic lethality demonstrating the critical importance of the adiponectin signalling system during development. We then investigated the effect of AdipoR2-ablation on the progression of atherosclerosis in apolipoprotein E deficient (ApoE ^-/-) mice. AdipoR2^-/-ApoE^-/- mice fed an atherogenic diet had decreased plaque area in the brachiocephalic artery compared with AdipoR2 ^+/+ApoE^-/- littermate controls as visualized in vivo using an ultrasound biomicroscope and confirmed by histological analyses. The decreased plaque area in the brachiocephalic artery could not be explained by plasma cholesterol levels or inflammatory status. However, accumulation of neutral lipids was decreased in peritoneal macrophages from AdipoR2^-/-ApoE^-/- mice after incubation with oxidized LDL. This effect was associated with lower CD36 and higher ABCA1 mRNA levels in peritoneal macrophages from AdipoR2^-/-ApoE^-/- mice compared with AdipoR2^+/+ApoE^-/- controls after incubation with oxidized LDL. In summary, we show that adiponectin receptors are crucial during embryonic development and that AdipoR2-deficiency slows down the progression of atherosclerosis in the brachiocephalic artery of ApoE-deficient mice.     

Protein deglycase DJ-1 deficiency induces phenotypic switching in vascular smooth muscle cells and exacerbates atherosclerotic plaque instability

Protein deglycase DJ-1 (DJ-1) is a multifunctional protein involved in various biological processes. However, it is unclear whether DJ-1 influences atherosclerosis development and plaque stability. Accordingly, we evaluated the influence of DJ-1 deletion on the progression of atherosclerosis and elucidate the underlying mechanisms. We examine the expression of DJ-1 in atherosclerotic plaques of human and mouse models which showed that DJ-1 expression was significantly decreased in human plaques compared with that in healthy vessels. Consistent with this, the DJ-1 levels were persistently reduced in atherosclerotic lesions of ApoE^−/− mice with the increasing time fed by western diet. Furthermore, exposure of vascular smooth muscle cells (VSMCs) to oxidized low-density lipoprotein down-regulated DJ-1 in vitro. The canonical markers of plaque stability and VSMC phenotypes were evaluated in vivo and in vitro. DJ-1 deficiency in Apoe^−/− mice promoted the progression of atherosclerosis and exaggerated plaque instability. Moreover, isolated VSMCs from Apoe^−/−DJ-1^−/− mice showed lower expression of contractile markers (α-smooth muscle actin and calponin) and higher expression of synthetic indicators (osteopontin, vimentin and tropoelastin) and Kruppel-like factor 4 (KLF4) by comparison with Apoe^−/−DJ-1^+/+ mice. Furthermore, genetic inhibition of KLF4 counteracted the adverse effects of DJ-1 deletion. Therefore, our results showed that DJ-1 deletion caused phenotype switching of VSMCs and exacerbated atherosclerotic plaque instability in a KLF4-dependent manner.     

Unique and analogous functions of aquaporin 0 for fiber cell architecture and ocular lens transparency

Aquaporin (AQP) 1 and AQP0 water channels are expressed in lens epithelial and fiber cells, respectively, facilitating fluid circulation for nourishing the avascular lens to maintain transparency. Even though AQP0 water permeability is 40-fold less than AQP1, AQP0 is selectively expressed in the fibers. Delimited AQP0 fiber expression is attributed to a unique structural role as an adhesion protein. To validate this notion, we determined if wild type (WT) lens ultrastructure and fiber cell adhesion are different in AQP0^−/−, and TgAQP1^+/+/AQP0^−/− mice that transgenically express AQP1 (TgAQP1) in fiber cells without AQP0 (AQP0^−/−). In WT, lenses were transparent with ‘Y’ sutures. Fibers contained opposite end curvature, lateral interdigitations, hexagonal shape, and were arranged as concentric growth shells. AQP0^−/− lenses were cataractous, lacked ‘Y’ sutures, ordered packing and well-defined lateral interdigitations. TgAQP1^+/+/AQP0^−/− lenses showed improvement in transparency and lateral interdigitations in the outer cortex while inner cortex and nuclear fibers were severely disintegrated. Transmission electron micrographs exhibited tightly packed fiber cells in WT whereas AQP0^−/− and TgAQP1^+/+/AQP0^−/− lenses had wide extracellular spaces. Fibers were easily separable by teasing in AQP0^−/− and TgAQP1^+/+/AQP0^−/− lenses compared to WT. Our data suggest that the increased water permeability through AQP1 does not compensate for loss of AQP0 expression in TgAQP1^+/+/AQP0^−/− mice. Fiber cell AQP0 expression is required to maintain their organization, which is a requisite for lens transparency. AQP0 appears necessary for cell-to-cell adhesion and thereby to minimize light scattering since in the AQP0^−/− and TgAQP1^+/+/AQP0^−/− lenses, fiber cell disorganization was evident.     

Adaptive changes in structure of skeletal muscles from adult <Emphasis Type="Italic">Sod1</Emphasis> homozygous knockout mice

Cu/Zn superoxide dismutase (SOD1), which is localized cytoplasmically and in the mitochondrial intermembrane space, is an enzyme that is critically important for superoxide free-radical elimination. Compared with age-matched wild-type littermates (Sod1 ^+/+ ), SOD1 homozygous knockout (Sod1 ^-/- ) mice have smaller body masses, heart and skeletal muscle masses, and muscle cross-sectional areas. At the light-microscopic level, cross sections of skeletal muscles from Sod1 ^-/- mice show no gross structural abnormalities. Following the staining of muscles of Sod1 ^-/- mice for succinate dehydrogenase (SDH) enzymatic activity, a grouping of SDH-positive fibers has been observed. Immunostaining for neural cell adhesion marker in the gastrocnemius muscle of Sod1 ^-/- mice has revealed a small number of atrophic denervated muscle fibers. No denervated fibers are observed in extensor digitorum longus (EDL), tibialis anterior, or plantaris muscles. An increase in mRNA expression levels of myogenin and acetylcholine receptor alpha has been detected in muscles in Sod1 ^-/- mice, but no changes in MyoD expression occur. Compared with fast oxidative fibers in EDL muscles of Sod1 ^+/+ mice, those of Sod1 ^-/- mice show increased accumulations of sub-sarcolemmal mitochondria. We conclude that the lack of SOD1 in adult Sod1 ^-/- mice does not result in extensive denervation of skeletal muscle fibers, although the distribution of fiber types is modified, and that fast oxidative fibers develop alterations in the amount and spatial distribution of sub-sarcolemmal mitochondria. This study was supported by NIA grant PO1-AG20591, by the Nathan Shock Center Contractility Core (NIA grant P30-AG13283), and by a Nathan Shock Center Pilot Award (to T. Kostrominova).     

葛仙米多糖对高脂小鼠血脂和肠道微生物的影响

[目的]研究葛仙米多糖对高脂饲料喂养小鼠血脂和肠道微生物的影响.[方法]将健康的8周龄雄性小鼠分成5组,每组10只:正常组C57/6CNC小鼠(N:灌胃生理盐水,喂饲标准饲料),对照组ApoE-/-小鼠(C:灌胃生理盐水,喂饲标准饲料),模型组ApoE-/-小鼠(M:灌胃生理盐水,喂饲高脂高胆固醇饲料),葛仙米多糖低剂...     

Impact of the B Cell Growth Factor APRIL on the Qualitative and Immunological Characteristics of Atherosclerotic Plaques

Studies on the role of B lymphocytes in atherosclerosis development, have yielded contradictory results. Whereas B lymphocyte-deficiency aggravates atherosclerosis in mice; depletion of mature B lymphocytes reduces atherosclerosis. These observations led to the notion that distinct B lymphocyte subsets have different roles. B1a lymphocytes exert an atheroprotective effect, which has been attributed to secretion of IgM, which can be deposited in atherosclerotic lesions thereby reducing necrotic core formation. Tumor necrosis factor (TNF)-family member ‘A Proliferation-Inducing Ligand’ (APRIL, also known as TNFSF13) was previously shown to increase serum IgM levels in a murine model. In this study, we investigated the effect of APRIL overexpression on advanced lesion formation and composition, IgM production and B cell phenotype. We crossed APRIL transgenic (APRIL-Tg) mice with ApoE knockout (ApoE^-/-) mice. After a 12-week Western Type Diet, ApoE^-/-APRIL-Tg mice and ApoE^-/- littermates showed similar increases in body weight and lipid levels. Histologic evaluation showed no differences in lesion size, stage or necrotic area. However, smooth muscle cell (α-actin stain) content was increased in ApoE^-/-APRIL-Tg mice, implying more stable lesions. In addition, increases in both plaque IgM deposition and plasma IgM levels were found in ApoE^-/-APRIL-Tg mice compared with ApoE^-/- mice. Flow cytometry revealed a concomitant increase in peritoneal B1a lymphocytes in ApoE^-/-APRIL-Tg mice. This study shows that ApoE^-/-APRIL-Tg mice have increased oxLDL-specific serum IgM levels, potentially mediated via an increase in B1a lymphocytes. Although no differences in lesion size were found, transgenic ApoE^-/-APRIL-Tg mice do show potential plaque stabilizing features in advanced atherosclerotic lesions.     

Loss of NAC1 Expression Is Associated with Defective Bony Patterning in the Murine Vertebral Axis

NAC1 encoded by NACC1 is a member of the BTB/POZ family of proteins and participates in several pathobiological processes. However, its function during tissue development has not been elucidated. In this study, we compared homozygous null mutant Nacc1^-/- and wild type Nacc1^+/+ mice to determine the consequences of diminished NAC1 expression. The most remarkable change in Nacc1^-/- mice was a vertebral patterning defect in which most knockout animals exhibited a morphological transformation of the sixth lumbar vertebra (L6) into a sacral identity; thus, the total number of pre-sacral vertebrae was decreased by one (to 25) in Nacc1^-/- mice. Heterozygous Nacc1^+/- mice had an increased tendency to adopt an intermediate phenotype in which L6 underwent partial sacralization. Nacc1^-/- mice also exhibited non-closure of the dorsal aspects of thoracic vertebrae T10-T12. Chondrocytes from Nacc1^+/+ mice expressed abundant NAC1 while Nacc1^-/- chondrocytes had undetectable levels. Loss of NAC1 in Nacc1^-/- mice was associated with significantly reduced chondrocyte migratory potential as well as decreased expression of matrilin-3 and matrilin-4, two cartilage-associated extracellular matrix proteins with roles in the development and homeostasis of cartilage and bone. These data suggest that NAC1 participates in the motility and differentiation of developing chondrocytes and cartilaginous tissues, and its expression is necessary to maintain normal axial patterning of murine skeleton.     

Chronic Internal Exposure to Low Dose 137Cs Induces Positive Impact on the Stability of Atherosclerotic Plaques by Reducing Inflammation in ApoE-/- Mice

After Chernobyl and Fukushima Daï Chi, two major nuclear accidents, large amounts of radionuclides were released in the environment, mostly caesium 137 (¹³⁷Cs). Populations living in contaminated territories are chronically exposed to radionuclides by ingestion of contaminated food. However, questions still remain regarding the effects of low dose ionizing radiation exposure on the development and progression of cardiovascular diseases. We therefore investigated the effects of a chronic internal exposure to ¹³⁷Cs on atherosclerosis in predisposed ApoE^-/- mice. Mice were exposed daily to 0, 4, 20 or 100 kBq/l ¹³⁷Cs in drinking water, corresponding to range of concentrations found in contaminated territories, for 6 or 9 months. We evaluated plaque size and phenotype, inflammatory profile, and oxidative stress status in different experimental groups. Results did not show any differences in atherosclerosis progression between mice exposed to ¹³⁷Cs and unexposed controls. However, ¹³⁷Cs exposed mice developed more stable plaques with decreased macrophage content, associated with reduced aortic expression of pro-inflammatory factors (CRP, TNFα, MCP-1, IFNγ) and adhesion molecules (ICAM-1, VCAM-1 and E-selectin). Lesions of mice exposed to ¹³⁷Cs were also characterized by enhanced collagen and smooth muscle cell content, concurrent with reduced matrix metalloproteinase MMP8 and MMP13 expression. These results suggest that low dose chronic exposure of ¹³⁷Cs in ApoE^-/- mice enhances atherosclerotic lesion stability by inhibiting pro-inflammatory cytokine and MMP production, resulting in collagen-rich plaques with greater smooth muscle cell and less macrophage content.     

Imaging decreased brain docosahexaenoic acid metabolism and signaling in iPLA2�� (VIA)-deficient mice

Ca²⁺-independent phospholipase A₂β (iPLA₂β) selectively hydrolyzes docosahexaenoic acid (DHA, 22:6n-3) in vitro from phospholipid. Mutations in the PLA2G6 gene encoding this enzyme occur in patients with idiopathic neurodegeneration plus brain iron accumulation and dystonia-parkinsonism without iron accumulation, whereas mice lacking PLA2G6 show neurological dysfunction and neuropathology after 13 months. We hypothesized that brain DHA metabolism and signaling would be reduced in 4-month-old iPLA₂β-deficient mice without overt neuropathology. Saline or the cholinergic muscarinic M_1,3,5 receptor agonist arecoline (30 mg/kg) was administered to unanesthetized iPLA₂β^−/−, iPLA₂β^+/−, and iPLA₂β^+/+ mice, and [1-¹⁴C]DHA was infused intravenously. DHA incorporation coefficients k* and rates J_in, representing DHA metabolism, were determined using quantitative autoradiography in 81 brain regions. iPLA₂β^−/− or iPLA₂β^+/− compared with iPLA₂β^+/+ mice showed widespread and significant baseline reductions in k* and J_in for DHA. Arecoline increased both parameters in brain regions of iPLA₂β^+/+ mice but quantitatively less so in iPLA₂β^−/− and iPLA₂β^+/− mice. Consistent with iPLA₂β’s reported ability to selectively hydrolyze DHA from phospholipid in vitro, iPLA₂β deficiency reduces brain DHA metabolism and signaling in vivo at baseline and following M_1,3,5 receptor activation. Positron emission tomography might be used to image disturbed brain DHA metabolism in patients with PLA2G6 mutations.