长期酒精暴露诱导胰岛素抵抗对视网膜胶质细胞的影响

目的:本文旨在探讨长期酒精暴露诱导胰岛素抵抗对小鼠视网膜胶质细胞的损伤以及IGF-1可能的作用。方法:选取野生型(wild type,WT)小鼠48只,酒精暴露建立动物模型,用血糖仪测定血糖浓度,用ELISA测定血胰岛素和IGF-1浓度,并计算胰岛素抵抗指数(homeostasis model assessment of insulin resistance,HOMAIR),利用免疫荧光染色观察视网膜胶质细胞的变化。结果:长期酒精暴露引起小鼠胰岛素抵抗(P<0.05),酒精暴露后出现视网膜胶质细胞的损伤如星形胶质细胞数量减少,Müller细胞GS染色减弱,呈剂量依赖性(P<0.05)。结论:长期酒精暴露可以诱导小鼠胰岛素抵抗和视网膜胶质细胞损伤,IGF-1浓度和胰岛素抵抗指数呈负相关,提示IGF-1可以作为胰岛素抵抗综合征的标志物。     

谷氨酰胺对高脂饮食诱导C57BL/6J小鼠肥胖和胰岛素抵抗的影响

目的:探讨谷氨酰胺(L-glutamine,Gln)对高脂饮食(high-fat diet,HFD)诱导小鼠肥胖和胰岛素抵抗的影响。方法:60只雄性C57BL/6J小鼠随机分为正常对照(normal control,NC)组、HFD组、HFD+丙氨酸(Lalanine,Ala)组和HFD+Gln组,每组15只。每周记录小鼠体重,给药16周后禁食不禁水12 h测定空腹血糖(fasting blood glucose,FBG),处死后剖腹取附睾脂肪垫并称重。采用酶联免疫法检测小鼠胰岛素(insulin,INS)、瘦素(leptin,LEP)、脂联素(adiponectin,APN)和胰高血糖素样肽1(glucagon-like peptide-1,GLP-1)的水平,并计算胰岛素抵抗指数(insulin resistance index,IRI)和胰岛素敏感指数(insulin sensitivity index,ISI)。结果:与NC组比较,HFD组小鼠体重和附睾脂肪垫重量明显升高,FBG、INS、IRI和LEP水平均明显升高,ISI和APN水平明显降低(P0.05);与HFD组比较,HFD+Gln组小鼠体重明显下降,FBG和LEP水平明显降低,IRI明显减小(P0.05)。4组小鼠血清的GLP-1水平差异无统计学显著性。结论:谷氨酰胺减轻高脂饮食诱导的肥胖小鼠体重和胰岛素抵抗。     

长期酒精暴露引起小鼠胰岛素抵抗：神经酰胺的可能作用

目的 探讨长期酒精暴露与胰岛素敏感性之间的关系并探讨其相关的分子机制;观察神经酰胺在酒精引起胰岛素抵抗过程中的可能作用。 方法 建立C57BL/6J野生型（WT）小鼠和神经鞘磷脂合成酶2基因敲除（SMS₂^-/-）3月龄小鼠的长期酒精暴露模型,两基因型小鼠又分为对照组、中剂量酒精组和高剂量酒精组,共计90只。建模5个月后,用血糖仪测定小鼠空腹血糖值,用酶学法检测血清胰岛素浓度,并计算胰岛素抵抗指数。利用免疫荧光染色法观察各组小鼠海马CA1区胰岛素受体底物2（IRS2）阳性细胞表达情况,免疫印迹法检测小鼠海马组织IRS2蛋白的相对表达量。 结果 1.长期酒精暴露导致WT和SMS-/-2小鼠空腹血糖值和胰岛素抵抗指数升高,且具有剂量依赖性（P<0.05）;但SMS₂^-/-小鼠随着酒精剂量的增加胰岛素抵抗指数升高幅度较小。 2.免疫组织化学染色显示,酒精暴露诱导WT和SMS₂^-/-小鼠海马IRS2阳性细胞数降低,有剂量依赖性（P<0.05）;与相同处理条件的WT小鼠相比,酒精诱导SMS₂^-/-小鼠海马IRS2阳性细胞数降低增多（P<0.05）。 3.免疫印迹法检测各组间小鼠海马组织IRS2蛋白相对表达量与上述结果一致。 结论 长期酒精暴露可引起胰岛素抵抗,IRS2蛋白表达降低,且存在剂量依赖性,因此酒精导致IRS2表达下降可能是胰岛素抵抗的分子机制之一;神经酰胺可能参与酒精暴露诱导IRS2表达下降的过程,且有促进胰岛素抵抗形成的作用。     

避光饲养对小鼠视网膜视杆细胞和双极细胞发育的影响

目的:探讨避光饲养对小鼠视网膜视杆细胞和双极细胞发育的影响。方法:选取健康C57BL/6小鼠,按2∶1雌雄比例进行合笼饲养,仔鼠出生后,随机分成2组。对照组自然光照下饲养,避光组采取完全暗室饲养;分别收集生后P28、P42、P56子鼠视网膜进行免疫荧光染色,比较两组各时间点视杆细胞和双极细胞数量的差异。结果:避光饲养28 d后,与对照组相比,2组小鼠外网层突触带至视杆细胞层的厚度无明显差异,而P56时,避光组外网层突触带至视杆细胞层的厚度和双极细胞的数量明显少于对照组(P0.05)。结论:避光饲养可引起视杆细胞和双极细胞的丢失,并且影响双极细胞树突的发育。     

高脂饮食诱导胰岛素抵抗小鼠胰岛IRc/IRS-1低表达

目的:观察高脂饮食诱导的胰岛素抵抗模型小鼠胰岛上胰岛素受体(IRc)/胰岛素受体底物-1(IRS-1)表达的变化。方法:20只雄性昆明小鼠随机分为高脂饲料模型组和普通饲料对照组,每组各10只。喂养20周后,观察两组小鼠大体情况,称量体重(BW),酶法测空腹血糖(FBG),酶联免疫法测空腹胰岛素(FIns)浓度,计算胰岛素抵抗指数(HOMA-IR);HE染色观察胰岛组织学变化;免疫组织化学染色分析胰岛IRc/IRS-1的表达。比较两组各检测指标的统计学差异。结果:模型组FBG、HOMA-IR明显高于对照组(P均0.01);胰岛边界欠完整,内部结构紊乱,伴炎性细胞浸润;IRc/IRS-1的表达较对照组明显降低(P均0.05)。结论:高脂饮食可成功诱导小鼠外周胰岛素抵抗,且胰岛上IRc/IRS-1的表达降低。     

2型糖尿病神经病理性痛C57BL/6J小鼠模型的建立

目的利用胃饲酒精和腹腔注射链脲佐菌素(streptozotocin,STZ)建立2型糖尿病神经病理性痛C57BL/6J小鼠模型。方法 80只C57BL/6J小鼠随机分为:对照组(n=15)和实验组(n=65)。对照组每日胃饲生理盐水,12周后单次空腹腹腔注射柠檬酸缓冲液;实验组每日胃饲酒精12周诱导胰岛素抵抗,继以不同剂量链脲佐菌素(40 mg/kg、50 mg/kg、60 mg/kg)腹腔注射1次,于不同时间点分别测体重、血糖、血胰岛素浓度,计算胰岛素抵抗指数、机械缩足阈值和热缩足潜伏期的变化。结果连续胃饲酒精12周后,实验组小鼠体重明显增加,空腹胰岛素浓度升高,胰岛素抵抗指数升高,血糖未升高,机械缩足阈值和热缩足潜伏期无变化。注射STZ后,40 mg/kg剂量组血糖升高但不能长期维持,60 mg/kg剂量组血糖较高,死亡率高;50 mg/kg剂量组血糖中度升高且相对稳定,胰岛素浓度和胰岛素敏感性均降低,其机械缩足阈值和热缩足潜伏期均低于基础值和对照组(P0.05)。结论连续酒精胃饲12周后联合腹腔注射STZ50 mg/kg可以建立理想的2型糖尿病神经病理性痛小鼠模型。     

近交系C57BL/6J小鼠的脱毛特征

目的了解近交系C57BL/6J小鼠脱毛的性质和脱毛的特征。方法在各代鼠详细观察记录脱毛出现的时间、状况和缓解情况;利用对照组2对来自不同父母鼠的F1雌雄鼠进行交配实验和回盒饲养实验,观察脱毛和脱毛缓解的特征,在F2小鼠观察脱毛特征的遗传性,对脱毛区域皮肤进行病理分析。结果脱毛(头、颈或背部)多出现在3～6只同养的雌性鼠中(对照组32.4%,实验组16.3%),脱毛-新毛生长的过程交替进行,交配有缓解脱毛的作用并能维持新毛的生长状态,脱毛的特征可以遗传。皮肤病理显示皮肤各层结构、毛囊和毛囊球上皮无明显病理性改变。结论脱毛可能是本品系在特定饲养条件下适应环境压力失败及缺乏生理活动的一种表现,具有经过良性、可缓解、特征可遗传等特点。     

孕期酒精暴露对子鼠视网膜双极细胞和水平细胞发育的影响

目的 探讨孕期酒精暴露对子鼠视网膜双极细胞和水平细胞发育的影响.方法 建立孕期酒精暴露小鼠模型;采用免疫荧光染色和DiI散射技术,观察酒精对日龄7d(P7)、P14和P30子鼠视网膜双极细胞和水平细胞的影响.结果 各年龄组中,酒精组视网膜双极细胞的密度明显低于对照组,且呈剂量依赖性和长时程效应;水平细胞的树突野及树突数也明显低于对照组,呈剂量依赖性和长时程效应(P<0.01).结论 孕期酒精暴露影响子鼠视网膜双极细胞和水平细胞的发育.     

肺炎衣原体对C57BL/6J小鼠腹膜巨噬细胞泡沫化的影响

目的:探讨肺炎衣原体在C57BL/6J小鼠腹膜巨噬细胞泡沫化过程中的作用。方法:将肺炎衣原体与C57BL/6J小鼠腹膜巨噬细胞培养72h后用油红O方法染色观察细胞的形态变化并测定细胞内胆固醇的含量。结果:肺炎衣原体能使C57BL/6J小鼠腹膜巨噬细胞胞浆内脂质颗粒增多,胆固醇酯占总胆固醇的比例增加。结论:肺炎衣原体能促进C57BL/6J小鼠腹膜巨噬细胞泡沫化。     

C57BL/6J×129/J杂交小鼠ES细胞系的建株(英)

 目的：建立C57BL/6J×129/J杂交小鼠ES细胞系。 方法： 收集3.5 d.p.c.的囊胚，培养在预先铺有小鼠成纤维细胞（MEFs）的高糖DMEM培养液中。3-4 d后，挑出内细胞团（ICM），消化后重新种到新鲜的有MEFS培养液中。等到有典型的ES样集落长出，即传代以得到永久ES细胞系。通过分析碱性磷酸酶活性，SSEA-1，Oct-4的表达和形成畸胎瘤的能力来鉴定ES细胞的多向分化能力。 结果： 获得的两个C57BL/6J×129/J杂交小鼠ES细胞系绝大多数细胞具有正常的核型（40，XY），碱性磷酸酶染色阳性，SSEA-1，Oct-4表达阳性， ES细胞注入SCID鼠后可获得来自3个胚层的组织。 结论： 建立了两株具有长期自我更新能力和多向分化潜能的C57BL/6J×129/J杂交小鼠ES细胞系。     

Agonism of the endocannabinoid system modulates binge-like alcohol intake in male C57BL/6J mice: involvement of the posterior ventral tegmental area

Recent studies have indicated a role for the endocannabinoid system in the behavioral and physiological effects of alcohol (ethanol), particularly ethanol seeking behaviors. However, its role in modulating binge-like intake and/or the mechanism by which it may exert these effects remain poorly understood. The current study used a newly developed strain-specific animal model of binge drinking, dubbed ‘Drinking In the Dark’ (DID), to determine if facilitation of the endocannabinoid system with the synthetic cannabinoid agonist WIN 55-212,2 (WIN) modulates binge-like ethanol intake in male C57BL/6J (B6) mice. Based on the results of these systemic (i.p.) manipulations, and evidence in support of the involvement of subregions of the Ventral Tegmental Area (VTA) in governing self-administration of ethanol (Rodd-Henricks et al., (2000) Psychopharmacology (Berl) 149(3):217–224) as well as binge-like intake using the DID model (Moore & Boehm, (2009 Behav Neurosci 123(3):555–563), we extended these findings to evaluate the role of the endocannabinoid system within the anterior and posterior sub regions of the VTA using site-specific microinjections. Consistent with previous research, the lowest systemic dose of WIN (0.5 mg/kg) significantly increased ethanol intake in the first 30 minutes of access whereas the two highest doses (1 and 2 mg/kg) decreased ethanol intake within this time interval. Intra-posterior ventral tegmental area (pVTA) (but not aVTA (anterior ventral tegmental area) microinjections elicited time-dependent and dose-dependent increases (0.25 and 0.5 μg/side) and decreases (2.5 μg/side) in ethanol intake. Importantly, follow-up studies revealed that in some cases alterations in fluid consumption may have been influenced by competing locomotor activity (or inactivity). The present data are consistent with previous research in that agonism of the endocannabinoid system increases ethanol intake in rodents and implicate the pVTA in the modulation of drinking to intoxication. Moreover, the dose-dependent alterations in locomotor activity emphasize the importance of directly assessing multiple (possibly competing) behaviors when evaluating drug effects on voluntary consumption.     

Abnormality in the cerebellar folial pattern of C57BL/6J mice

The characteristic folial pattern of the mouse cerebellum is formed during postnatal development. We observed this process in C57BL/6J (B6) mice in detail, and found an abnormal folial pattern in a specific region (lobules VIII and IX of the vermis) in a substantial number of B6 mice. The frequency of this abnormality increased during postnatal development and reached 55% in the adult. Thus, the present study showed an abnormality in the cerebellar folial pattern of B6 mice, a mouse widely used in knockout studies, and called for caution in the phenotypic analysis of knockout mice of the B6 genetic background.     

Using drinking in the dark to model prenatal binge-like exposure to ethanol in C57BL/6J mice

Animal models of prenatal ethanol exposure are necessary to more fully understand the effects of ethanol on the developing embryo/fetus. However, most models employ procedures that may produce additional maternal stress beyond that produced by ethanol alone. We employed a daily limited-access ethanol intake model called Drinking in the Dark (DID) to assess the effects of voluntary maternal binge-like ethanol intake on the developing mouse. Evidence suggests that binge exposure may be particularly harmful to the embryo/fetus, perhaps due to the relatively higher blood ethanol concentrations achieved. Pregnant females had mean daily ethanol intakes ranging from 4.2 to 6.4 g/kg ethanol over gestation, producing blood ethanol concentrations ranging from 115 to 182 mg/dL. This level of ethanol intake produced behavioral alterations among adolescent offspring that disappeared by adulthood, including altered sensitivity to ethanol's hypnotic actions. The DID model may provide a useful tool for studying the effects of prenatal ethanol exposure in mice.     

High frequency mechanical ventilation affects respiratory system mechanics differently in C57BL/6J and BALB/c adult mice

We tested the hypothesis that high frequency ventilation affects respiratory system mechanical functions in C57BL/6J and BALB/c mice. We measured respiratory mechanics by the forced oscillation technique over 1 h in anesthetized, intubated, ventilated BALB/c and C57BL/6J male mice.     

Age and brightness discrimination learning by C57BL/6J mice

Groups of 20–34 C577BL/6J mice, aged 75, 225, 375, and 525 days, learned a brightness discrimination for water. The error scores of the 75- and 525-day groups were almost identical, and both made significantly more errors than the 225-day-old mice. Both immature and older mice appear to be deficient in learning ability compared to young adults.     

Expression of connexin 35/36 in retinal horizontal and bipolar cells of carp

Connexin 35/36 (Cx35/36) gap junction protein is expressed in various regions of the brain, including the retina. In this work, the expression of Cx35/36 in the outer retina of carp was studied by immunocytochemistry. By light microscopy, strong punctate Cx35/36-immunoreactivity was observed in the outer plexiform layer. Double labeling experiments on vertical retinal sections showed that Cx35/36 puncta were localized beneath cone pedicles, stained by recoverin, but not on them. In addition, few of the dendrites of rod-dominant ON type bipolar cells (rod-ON-BCs), stained by PKCα, were labelled with Cx35/36 in the retinal sections. In isolated cell preparations, Cx35/36 was clearly expressed on the dendrites of cone-dominant ON type bipolar cells (cone-ON-BCs), but the expression was much less on rod-ON-BCs. Moreover, Cx35/36 puncta were found in the dendrites of isolated horizontal cells (labelled by GAD 65/67) driven by cones, including H1 and H2 cells, but not in those of cells driven by rods (H4 cells). At the ultrastructural level, reaction product was found in H1 and H2 cell dendrites invaginating cone terminals, but not in H4 cell dendrites invaginating rod terminals. Moreover, dendrites of cone-ON-BCs, were also labebed. These results suggest that Cx35/36 could be specifically involved in modulation of the cone signal pathway in the outer retina of carp.