Nestin 和GFAP在缺氧大鼠视网膜神经胶质细胞中的表达及高氧治疗的作用

目的： 探讨巢蛋白（nestin）和胶质纤维酸性蛋白（GFAP）在缺氧大鼠视网膜神经胶质细胞中的表达情况及高氧治疗对其表达的影响。方法: 制作大鼠缺氧模型及缺氧后高氧治疗模型,行眼球矢状位切片及视网膜铺片,行GS/nestin、GS/GFAP、GFAP/nestin免疫荧光双标染色。结果: 正常大鼠视网膜中几乎看不到nestin阳性染色,GFAP阳性染色仅位于星形胶质细胞上。缺氧后,在Müller细胞和星形胶质细胞上出现了nestin的表达,GFAP的表达没有明显变化。高氧治疗后,nestin在Müller细胞上的表达明显减弱,但在星形胶质细胞上仍有较强的表达。GFAP仍然只在星形胶质细胞上表达。结论: Müller细胞和星形胶质细胞针对缺氧损伤和高氧处理发生不同的细胞骨架蛋白重塑,这与它们和视网膜神经节细胞以及视网膜血管在解剖和功能关系上的差异有关。     

黄芪甲苷对糖尿病大鼠视网膜Müller细胞的影响

目的探讨黄芪甲苷(AS)对糖尿病大鼠视网膜氧化应激的影响及其对Müller细胞的保护作用。方法利用链脲佐菌素诱导糖尿病大鼠模型。实验分为对照组、糖尿病组及AS治疗组,3个月后试剂盒检测视网膜丙二醛(MDA)和还原型谷胱甘肽(GSH)含量,免疫组化及Western blot检测视网膜神经胶质酸性蛋白(GFAP)变化,Western blot检测Müller细胞功能性蛋白酶——谷氨酰胺合成酶(GS)表达变化。结果与对照组相比,糖尿病组视网膜MDA含量增加,GSH含量减少,GFAP表达增加,GS表达减少(均0.01),AS治疗组视网膜MDA及GSH含量、GFAP及GS表达较糖尿病组均无明显变化(均0.05)。结论 AS抑制糖尿病大鼠视网膜氧化应激反应,恢复视网膜Müller细胞功能性蛋白酶GS的表达。     

钠尿肽受体A在小鼠视网膜发育过程中的表达

目的检测钠尿肽受体(NPR)在不同年龄小鼠视网膜内的表达,探讨其在视网膜发育过程中的作用。方法收集从受孕16日(E16)到出生90日(P90)小鼠眼球标本共127只,对NPR-A进行免疫荧光检测。结果NPR-A广泛存在于视网膜神经元中,例如,在外核层,NPR-A于P7开始高表达在视锥、视杆细胞内、外突起上,于P14减弱,P30之后持续稳定弱表达;在内核层,从P7开始NPR-A持续弱表达在双极细胞的突起中,而在水平细胞中未见NPR-A表达;在神经节细胞层,NPR-A于E16开始高表达在神经节细胞胞体中,P14明显减弱,而在神经纤维层,即神经节细胞的轴突中,NPR-A从胚胎期至成年持续高表达;在外网状层和内网状层,NPR-A于P14均高表达,但于P30之后逐渐减弱。此外,NPR-A还广泛的存在于Müller细胞的突起中。结论 NPR-A参与了视网膜的发育,可能是小鼠视网膜神经元发育过程中的关键分子,并对Müller细胞的功能活动起着重要的调节作用。     

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。     

Müller细胞在增殖性糖尿病视网膜病变中的最新研究进展

Müller细胞是脊椎动物视网膜中的主要胶质细胞, 其纵向跨越整个视网膜, 几乎与视网膜中的每一种细胞类型都有接触。因其独特的定位, 可以参与维持视网膜内稳态所需的各种功能。增殖性糖尿病视网膜病变(proliferative diabetic retinopathy, PDR)是糖尿病的眼部并发症, 在炎症的作用下内皮细胞、神经元和神经胶质细胞之间相互作用造成眼底微血管病变。在PDR中, Müller细胞经历反应性胶质增生, 一方面起到保护视网膜的作用, 另一方面, 由于炎性细胞因子/趋化因子的水平升高, 可导致瘢痕和视网膜新生血管形成, 损害玻璃体。由此可见, Müller细胞胶质化对于视网膜有着双重作用。另外, Müller细胞表达低密度脂蛋白受体相关蛋白-1(low density lipoprotein receptor associated protein 1, LRP1), LRP1对新生血管和炎症有着密切联系。对Müller细胞、PDR玻璃体和LRP1展开研究可能为"趋利避害"提供新思路。     

视网膜神经胶质细胞及其分泌的细胞因子与视网膜病变

视网膜内常见的神经胶质细胞包括星形胶质细胞、Müller细胞(放射状胶质细胞)和小胶质细胞。最近研究表明,这些神经胶质细胞能释放多种细胞因子,包括VEGF、bFGF、TGF、IGF、TNF及IL等,这些细胞因子不仅在调节视网膜神经细胞生长发育中起着重要作用,而且是参与视网膜病变的重要因素。     

GMFB在高糖处理的Müller细胞中的表达及其对Müller细胞的影响

目的:利用高糖处理Müller细胞,研究高糖条件下胶质细胞成熟因子B(glia maturation factor-β,GMFB)的表达情况和GMFB对Müller细胞的影响,揭示GMFB细胞在糖尿病视网膜病变中可能的作用机制,为糖尿病视网膜病变的治疗提供新的策略。方法:(1)用25mmol/L葡萄糖处理Müller细胞0,1,2,4和6 h,采用Western Blot检测GMFB的表达;(2)用自噬双标腺病毒(mRFP-GFP-LC3)感染Müller细胞后,1μg/ml重组蛋白GMFB处理Müller细胞0,2,4,8,12 h,采用Western Blot和免疫荧光检测自噬情况;(3)1μg/ml GMFB处理Müller细胞24 h为实验组,以未处理组作为对照组,进行RNAseq,检测其基因差异表达谱,选取其中表达差异大于1.5倍且P0.05的基因作为差异表达的基因,对其进行基因本体论(gene ontology,GO)分析及京都基因和基因组百科全书(Kyoto Encyclopedia of Genes and Genomes,KEGG)富集分析。结果:(1)经高糖处理的Müller细胞早期出现GMFB表达上调,以2 h处理组的GMFB上调最为显著,提示高糖刺激早期能引起Müller细胞的GMFB表达升高;(2)重组蛋白GMFB处理Müller细胞后,Western Blot在第4 h检测到自噬被诱导,但很短暂。我们在24 h用免疫荧光检测,没有发现红绿荧光强度变化,提示双标自噬系统检测未检测到自噬发生,可能与不同检测方法的敏感性不同有关。(3)对GMFB处理24 h的Müller细胞抽提总RNA,进行RNAseq检测,显示在被检测的14411个基因中,实验组和正常组间有显著差异表达的基因有152个。与对照组相比,实验组基因表达显著上调的有103个,下调的有44个。通过GO分析表明,GMFB与细胞代谢、细胞催化等生物过程相关。KEGG分析进一步发现GMFB与细胞黏附分子、轴突导向和胞质DNA感受通路等多条信号通路密切相关。同时,炎症基因IL-33表达降低,提示GMFB有神经保护的作用。结论:GMFB在高糖诱导的Müller细胞中表达明显上调,说明GMFB可能影响细胞间连接,参与炎症反应信号通路等。该工作为理解GMFB在糖尿病视网膜病变中的作用机制提供了有益的线索。GMFB在糖尿病视网膜病变的作用机制需要进一步验证。     

N-甲基-N-亚硝脲诱导的大鼠视网膜感光细胞损伤模型中Müller细胞增殖和细胞因子分泌的变化

目的:建立N-甲基-N-亚硝脲(N-methyl-N nitrosourea,MNU)损伤视网膜的模型,研究视网膜神经元凋亡对Müller细胞生物学特性的影响及神经营养因子的表达变化。方法:腹腔注射MNU建立视网膜损伤模型,免疫荧光染色方法研究感光细胞缺失对Müller细胞的生物学特性的影响,并检测主要神经营养因子表达的变化。结果:TUNEL法显示,腹腔注射MNU后2 d,视网膜外核层细胞凋亡现象明显。核增殖抗原(PCNA)及细胞周期素CyclinD_1的表达明显增高。与此同时,Müller细胞也开始表达神经干细胞抗原巢蛋白(nestin);RT-PCR显示胰岛素样生长因子(IGF),碱性成纤维细胞生长因子(bFGF)和肝细胞生长因子(HGF)mRNA的表达均升高。结论:在视网膜受到损伤时,Müller细胞增殖、去分化呈现出干细胞的特性。而视网膜中IGF、bFGF和HGF等细胞因子的表达明显增高,提示视网膜损伤后可能通过大量分泌细胞生长因子,促进Müller细胞的增殖。     

新生小鼠吸入高氧视网膜的血管发育与胶质纤维酸性蛋白表达的变化

目的:研究新生小鼠吸入高氧视网膜病(ROP)过程中胶质纤维酸性蛋白(GFAP)表达的变化规律,探讨Müller细胞与血管发育的关系。方法:实验用生后7 d(P7)C57BL/6J小鼠。ROP模型组在75%氧环境中饲养。在P9、P12、P14、P17和P21等不同时间取眼球,分别用ADP酶组织化学染色方法显示视网膜血管发育及免疫组织化学方法标记视网膜GFAP的表达。结果:小鼠视网膜血管生后开始发育,P21基本成熟;吸高氧后从P14开始出现新生血管,在P17~P21达到高峰。模型鼠视网膜Müller细胞从P14起内侧突起开始表达GFAP,到P21已遍布细胞全层。结论:高氧可导致视网膜发育晚期大量血管新生,且与GFAP表达的变化规律相一致,提示Müller细胞与视网膜血管发育关系密切。     

过表达Cdh1蛋白对高糖诱导的视网膜Müller细胞株GFAP表达的影响

目的 探讨过表达Cdh1蛋白对高糖诱导的视网膜Müller细胞株GFAP表达的影响.方法 培养的Müller细胞分为4组:对照组(Control)、高糖组(HG group,30 mmol/L葡萄糖)、Cdh1过表达组(Cdh1,30 mmol/L葡萄糖+过表达Cdh1蛋白的慢病毒载体)、病毒阴性对照组(NC-Cdh1,30 mmol/L葡萄糖+慢病毒载体稀释液),显微镜下观察Müller细胞一般生长状况,免疫荧光检测GFAP在Müller细胞的表达情况,Western blot检测Müller细胞GFAP及Cdh1蛋白的相对表达.结果 HG组和NC-Cdh1组GFAP表达水平明显高于Control组,Cdh1明显低于Control组(P＜0.05);Cdh1组GFAP表达水平明显低于HG组,Cdh1高于HG组(P＜0.05),而HG组和NC-Cdh1组之间无统计学意义(P＞0.05).结论 过表达Cdh1蛋白下调高糖诱导的视网膜Müller细胞GFAP表达,对高糖诱导的Müller细胞损伤起到保护作用.     

Pain and Effusion and Quadriceps Activation and Strength

Context:

Quadriceps dysfunction is a common consequence of knee joint injury and disease, yet its causes remain elusive.

Objective:

To determine the effects of pain on quadriceps strength and activation and to learn if simultaneous pain and knee joint effusion affect the magnitude of quadriceps dysfunction.

Design:

Crossover study.

Setting:

University research laboratory.

Patients or Other Participants:

Fourteen (8 men, 6 women; age = 23.6 ± 4.8 years, height = 170.3 ± 9.16 cm, mass = 72.9 ± 11.84 kg) healthy volunteers.

Intervention(s):

All participants were tested under 4 randomized conditions: normal knee, effused knee, painful knee, and effused and painful knee.

Main Outcome Measure(s):

Quadriceps strength (Nm/kg) and activation (central activation ratio) were assessed after each condition was induced.

Results:

Quadriceps strength and activation were highest under the normal knee condition and differed from the 3 experimental knee conditions (P < .05). No differences were noted among the 3 experimental knee conditions for either variable (P > .05).

Conclusions:

Both pain and effusion led to quadriceps dysfunction, but the interaction of the 2 stimuli did not increase the magnitude of the strength or activation deficits. Therefore, pain and effusion can be considered equally potent in eliciting quadriceps inhibition. Given that pain and effusion accompany numerous knee conditions, the prevalence of quadriceps dysfunction is likely high.Key Words: arthrogenic muscle inhibition, central activation failure, voluntary activation, muscles

Key Points

• Knee pain and effusion resulted in arthrogenic muscle inhibition and weakness of the quadriceps.
• The simultaneous presence of pain and effusion did not increase the magnitude of quadriceps dysfunction.
• To reduce arthrogenic muscle inhibition and improve muscle strength, clinicians should employ interventions that target removing both pain and effusion.

Quadriceps weakness is a common consequence of traumatic knee joint injury^1,2 and chronic degenerative knee joint conditions.^3,4 Arthrogenic muscle inhibition (AMI), a neurologic decline in muscle activation, results in quadriceps weakness and hinders rehabilitation by preventing gains in strength.⁵ The inability to reverse AMI and restore muscle function can lead to decreased physical abilities,⁶ biomechanical deficits,⁷ and possibly reinjury.⁵ Furthermore, researchers^8,9 have suggested that quadriceps weakness resulting from AMI may place patients at risk for developing osteoarthritis in the knee. In light of the substantial influence of quadriceps AMI on these clinically relevant outcomes, we need to improve our understanding of the factors that contribute to this neurologic decline in muscle activity so efforts to target and reverse it can be implemented and gains in strength can be achieved more easily.Joint injury and disease are accompanied by numerous sequelae (ie, pain, swelling, tissue damage, inflammation), so ascertaining which one ultimately leads to neurologic muscle dysfunction is difficult. Whereas a joint effusion can result in AMI,^10–12 the effects of pain are less understood despite many clinicians attributing AMI to pain. Using techniques that introduce knee pain without accompanying injury may provide insights into the role of pain in eliciting AMI.The degree of knee joint damage may play a role in the quantity of AMI that manifests. Hurley et al^13,14 demonstrated that quadriceps AMI, measured using an interpolated-twitch technique, was greater in patients with extensive traumatic knee injury (eg, fractured tibial plateau, ruptured medial collateral ligament, and medial meniscectomy) than patients with isolated joint trauma (ie, isolated anterior cruciate ligament [ACL] rupture). Similarly, patients with more knee joint symptoms (ie, greater number of symptoms and increased severity of symptoms) may present with greater magnitudes of quadriceps inhibition. Recently, investigators¹⁵ have suggested that patients with more pain display less quadriceps strength, supporting this tenet. Given that effusion and pain often present simultaneously with joint injuries and diseases, such as ACL injury and osteoarthritis, examining both the isolated and cumulative effects of these sequelae appears warranted to determine if they influence the magnitude of muscle inhibition.Experimental joint-effusion and pain models are safe and effective experimental methods that allow for the isolated examination of their effects on muscle function. The effusion model, whereby sterile saline is injected directly into the knee joint capsule,⁷ produces a clinically relevant magnitude of the joint effusion that may be present with traumatic injury. Effusion is thought to activate group II afferents responding to stretch or pressure,^16–18 which in turn may facilitate group Ib interneurons and result in quadriceps AMI.⁵ The pain model involves injecting hypertonic saline into the infrapatellar fat pad to produce anteromedial knee pain similar to that described in patients with patellofemoral pain syndrome.¹⁹ Pain is considered to initiate AMI through activation of group III and IV afferents that act as nocioceptors to signal damage or potential damage to joint structures.^16–18 The firing of these afferents then may lead to facilitation of group Ib interneurons, the flexion reflex, or the gamma loop, ultimately resulting in quadriceps inhibition.²⁰ Thus, these models allow us to create symptoms that are associated with knee injury and have the added benefit of providing a way to examine their effects in isolation.Therefore, the purpose of our study was to determine the effects of pain on quadriceps strength and activation and to learn if simultaneous pain and knee joint effusion would affect the magnitude of quadriceps dysfunction. We hypothesized that pain alone would result in quadriceps inhibition and that the magnitude of inhibition would be greater when effusion and pain were present simultaneously.     

即早基因c-fos与脑血管病及学习记忆

即早基因c-fos是广泛存在于原核细胞和真核细胞的高度保守基因.在正常情况下,c-fos基因参与细胞生长、分化、信息传递、学习和记忆等生理过程,而在病理情况下c-fos基因表达及调控变化与多种疾病的发生和发展有关.C-fos在中枢神经系统的某些部位可有基础水平的表达,但表达很低,当受到如脑缺血、脑出血、痫性发作、应激等刺激后,其在数十分钟内做出反应,在对外界刺激-转录耦联的信忠传递过程中起着核内第三信使的重要作用.     

Opportunities and challenges in the prevention and control of cancer and other chronic diseases: children's diet and nutrition and weight and physical activity

OBJECTIVE: The purpose of this article is to review the role of behavioral research in disease prevention and control, with a particular emphasis on lifestyle- and behavior-related cancer and chronic disease risk factors--specifically, relationships among diet and nutrition and weight and physical activity with adult cancer, and tracking developmental origins of these health-promoting and health-compromising behaviors from childhood into adulthood. METHOD: After reviewing the background of the field of cancer prevention and control and establishing plausibility for the role of child health behavior in adult cancer risk, studies selected from the pediatric published literature are reviewed. Articles were retrieved, selected, and summarized to illustrate that results from separate but related fields of study are combinable to yield insights into the prevention and control of cancer and other chronic diseases in adulthood through the conduct of nonintervention and intervention research with children in clinical, public health, and other contexts. RESULTS: As illustrated by the evidence presented in this review, there are numerous reasons (biological, psychological, and social), opportunities (school and community, health care, and family settings), and approaches (nonintervention and intervention) to understand and impact behavior change in children's diet and nutrition and weight and physical activity. CONCLUSIONS: Further development and evaluation of behavioral science intervention protocols conducted with children are necessary to understand the efficacy of these approaches and their public health impact on proximal and distal cancer, cancer-related, and chronic disease outcomes before diffusion. It is clear that more attention should be paid to early life and early developmental phases in cancer prevention.