Immunohistochemical Localization of the Water Channels AQP4 and AQP5 in the Rat Pituitary Gland

The pituitary gland is composed of the adenohypophysis and neurohypophysis. The adenohypophysis contains endocrine cells, folliculo-stellate (FS) cells, and marginal layer cells, whereas the neurohypophysis mainly comprises axons and pituicytes. To understand the molecular nature of water transfer in the pituitary gland, we examined the immunohistochemical localization of the membrane water channels aquaporin-4 (AQP4) and AQP5 in rat tissue. Double immunofluorescence analysis of AQP4 and S100 protein, a known marker for FS cells, marginal layer cells, and pituicytes, clearly revealed that FS cells and marginal layer cells in the adenohypophysis and the pituicytes in pars nervosa are positive for AQP4. AQP5 was found to be localized at the apical membrane in some marginal layer cells surrounding the Rathke's residual pouch, in which AQP4 was observed to be localized on the basolateral membranes. These results suggest the following possibilities: 1) FS cells especially require water for their functions and 2) transepithelial water transfer could occur between the lumen of Rathke's residual pouch and the interstitial fluid in the adenohypophysis through the AQP4 and AQP5 channels in the marginal layer cells.     

糖性白内障渗透性膨胀期相关机制的研究进展

晶状体具有良好的透光性与适度的折光性,是一个近乎完美的视觉器官。它来源于表皮外胚叶,由外向内依次为晶状体囊、晶状体上皮、皮质及核,其中晶状体上皮细胞是整个晶状体的生命中枢,不仅分泌Ⅳ型胶原形成外层晶状体囊,并在赤道部衍化为纤维细胞,构成皮质与核;而且提供了晶状体代谢所需的全部能量。在长期高糖环境下,醛糖还原酶被激活,造成大量高渗性物质——山梨醇在细胞内堆积,引起皮质高度吸水膨胀;近年来还发现p糖-蛋白、细胞容积型氯离子通道和水通道蛋白也参与了糖性白内障渗透性膨胀期的发生发展。     

Water entry into astrocytes during brain edema formation

The process of brain edema formation has been studied extensively at the macroscopic level. In contrast, little is known about water fluxes and volume changes at the cellular level in the initial phase of brain edema. Insight in these "microscopic" events could pave the way for more efficient prevention and therapy. Here, we report measurements of brain cell volume responses recorded in vivo in a model of systemic hyponatremia. Transgenic mice expressing fluorescent proteins in astrocytes were subjected to hypo-osmotic stress and two photon laser scanning microscopy. Volume measurements of glial cells in the cerebellum and the visual cortex indicate that individual astrocytes undergo a position-dependent increase in cell volume by a factor of two or more during edema formation. Our data are the first to show that volume changes can be monitored at the cellular level in vivo and demonstrate that astrocytes are sites of water entry in the initial phase of brain edema formation. The uptake of water in astrocytes is likely to reflect the strong expression of aquaporin-4 in these cells.     

立体定向穿刺引流术治疗基底节区脑出血的价值探究

目的探究立体定向穿刺引流术治疗基底节区脑出血的临床应用价值。 方法回顾性分析长江大学附属荆州市第一人民医院颅脑外科自2019年6月至2020年6月治疗的66例基底节区脑出血患者的临床资料,根据手术方式的不同分为2组,其中行传统开颅手术治疗的33例患者为对照组,采用立体定向穿刺引流术治疗的33例患者为引流组,观察并比较2组患者围术期指标、疗效、血清水通道蛋白4（AQP4）、血小板反应蛋白（TSP）1和TSP2水平、脑水肿体积。 结果引流组手术时间及住院时间均短于对照组,术中失血量低于对照组,血肿清除率高于对照组,差异有统计学意义（P<0.05）;引流组术后疗效较对照组好,差异有统计学意义（P<0.05）;引流组患者血清AQP4、TSP1、TSP2水平较对照组低,脑水肿体积较对照组小,差异有统计学意义（P<0.05）。 结论立体定向穿刺引流术治疗可改善基底节区脑出血患者围术期指标、增强疗效、降低血清AQP4水平、减少脑水肿体积。     

Novel aspects of extracellular adenosine dynamics revealed by adenosine sensor cells

Adenosine modulates diverse physiological and pathological processes in the brain, including neuronal activities, blood flow, and inflammation. However, the mechanisms underlying the dynamics of extracellu-lar adenosine are not fully understood. We have recently developed a novel biosensor, called an adenosine sensor cell, and we have characterized the neuronal and astrocytic pathways for elevating extracellular adenosine. In this review, the physiological implications and therapeutic potential of the pathways revealed by the adenosine sensor cells are discussed. We propose that the multiple pathways regulating extracellular adenosine allow for the diverse functions of this neuromodulator, and their malfunctions cause various neurological and psychiatric disorders.     

水通道蛋白5在高氧肺损伤中的表达及调节机制

目的探讨水通道蛋白5(AQP5)在高氧肺损伤中的表达及其地塞米松对AQP5的调节作用。方法2周左右Wistar大鼠64只,按随机数字表法分为空气对照组、高氧暴露3、7、14d组和相应的地塞米松干预组。高氧暴露组置于常压氧仓中(O2体积分数≥95%);空气对照组置于同室常压空气中(O2体积分数为21%);各地塞米松干预组在暴露于空气或高氧的同时,经腹腔注射地塞米松5mg·kg-1·d-1,连续3d。采用逆转录聚合酶链反应(RT PCR)和免疫组化方法观察AQP5的mRNA表达和分布变化,并与地塞米松干预后进行比较分析。结果AQP5主要表达在肺泡型上皮细胞及气道分泌上皮顶质膜;与空气对照组相比,高氧暴露不同时间后,AQP5特异性表达部位保持不变,但随暴露时间延长,AQP5表达呈逐渐减弱趋势,高氧暴露3、7和14d,AQP5mRNA较空气对照组均降低(P均<0.05)。与同期高氧暴露组比较,地塞米松干预后不同时间点AQP5mRNA表达均无明显变化(P均>0.05)。结论高氧肺损伤时AQP5表达降低,可能是高氧肺损伤肺水肿形成的原因之一;而未见地塞米松对高氧肺损伤AQP5的表达有调节作用。     

Hypertonic saline reduces lipopolysaccharide-induced mouse brain edema through inhibiting aquaporin 4 expression

Introduction

Three percent sodium chloride (NaCl) treatment has been shown to reduce brain edema and inhibited brain aquaporin 4 (AQP4) expression in bacterial meningitis induced by Escherichia coli. Lipopolysaccharide (LPS) is the main pathogenic component of E. coli. We aimed to explore the effect of 3% NaCl in mouse brain edema induced by LPS, as well as to elucidate the potential mechanisms of action.

Methods

Three percent NaCl was used to treat cerebral edema induced by LPS in mice in vivo. Brain water content, IL-1β, TNFα, immunoglobulin G (IgG), AQP4 mRNA and protein were measured in brain tissues. IL-1β, 3% NaCl and calphostin C (a specific inhibitor of protein kinase C) were used to treat the primary astrocytes in vitro. AQP4 mRNA and protein were measured in astrocytes. Differences in various groups were determined by one-way analysis of variance.

Results

Three percent NaCl attenuated the increase of brain water content, IL-1β, TNFα, IgG, AQP4 mRNA and protein in brain tissues induced by LPS. Three percent NaCl inhibited the increase of AQP4 mRNA and protein in astrocytes induced by IL-1β in vitro. Calphostin C blocked the decrease of AQP4 mRNA and protein in astrocytes induced by 3% NaCl in vitro.

Conclusions

Osmotherapy with 3% NaCl ameliorated LPS-induced cerebral edema in vivo. In addition to its osmotic force, 3% NaCl exerted anti-edema effects possibly through down-regulating the expression of proinflammatory cytokines (IL-1β and TNFα) and inhibiting the expression of AQP4 induced by proinflammatory cytokines. Three percent NaCl attenuated the expression of AQP4 through activation of protein kinase C in astrocytes.     

水通道蛋白过表达对脊髓损伤大鼠便秘的影响

目的 探讨脊髓损伤大鼠结肠水通道蛋白(AQPs)的表达及其与粪便含水率的关系。方法 将48只雌性Sprague-Dawley大鼠分为对照组(n = 24)和脊髓损伤组(n = 24)。脊髓损伤组行T₈横断脊髓损伤,对照组仅行椎板切除术。于造模前,造模后第1、3、7、14、28天,采用Basso-Beattie-Bresnahan (BBB)评分评价后肢运动功能;于术前,术后第3、14、28天检测粪便含水率;于术后第3、14、28天取结肠标本,免疫组化检测AQP1、AQP3和AQP4的表达。结果 脊髓损伤组术后BBB评分(t > 69.230, P< 0.001)和粪便含水率(t > 5.814, P< 0.001)均显著低于对照组。术后第3、14、28天,脊髓损伤组结肠AQP1、AQP3和AQP4表达均明显高于对照组(|t|> 5.165,P < 0.01)。脊髓损伤后AQPs表达与粪便含水率呈显著负相关( r = -0791~-0.730, P< 0.001)。结论 脊髓损伤后大鼠结肠AQPs表达上调,可能与脊髓损伤后结肠过度吸收水分有关。