Effects of fulminant hepatic encephalopathy on the adult rat brain antioxidant status and the activities of acetylcholinesterase, (Na+,K+)- and Mg2+-ATPase: comparison of the enzymes’ response to in vitro treatment with ammonia

Hepatic encephalopathy can be a life-threatening complication of fulminant hepatic failure. By understanding the pathophysiology involved in the induction of this neuropsychiatric disorder, future therapeutic and/or preventive attempts could be considered. In this study, an attempt has been made in order to shed more light on the mechanisms involved in the effects of thioacetamide (TAA)-induced fulminant hepatic encephalopathy on: (a) the adult rat brain total antioxidant status (TAS) and (b) the activities of acetylcholinesterase (AChE), (Na(+),K(+))-ATPase and Mg(2+)-ATPase. Moreover, in vitro experiments were conducted in order to evaluate the possible role of ammonia (incubated as NH(4)Cl, in a toxic concentration of 3mM) in the observed effects of TAA-induced fulminant hepatic encephalopathy on the examined adult rat brain enzyme activities. Fulminant hepatic encephalopathy caused a significant decrease in TAS (-22%, p < 0.001) and the activity of Na(+),K(+)-ATPase (-26%, p < 0.001), but had non-significant effects on the whole brain AChE and Mg(2+)-ATPase activities. The in vitro experiments (conducted through a 3h incubation with ammonia), showed no significant alterations in any of the examined parameters. Our in vitro and in vivo findings suggest that alterations in AChE and Mg(2+)-ATPase activities are not involved in the pathophysiology of the adult-onset fulminant hepatic encephalopathy, while the observed Na(+),K(+)-ATPase inhibition could be a result of the oxidative stress, neurotransmission deregulation, and/or of the presence of other toxic substances (that appear to act as direct or indirect inhibitors of the enzyme) and not due to the excess accumulation of ammonia in the brain.     

Exogenous normal lymph reduces liver injury induced by lipopolysaccharides in rats

The liver is one of the target organs damaged by septic shock, wherein the spread of endotoxins begins. This study aimed to investigate the effects of exogenous normal lymph (ENL) on lipopolysaccharide (LPS)-induced liver injury in rats. Male Wistar rats were randomly divided into sham, LPS, and LPS+ENL groups. LPS (15 mg/kg) was administered intravenously via the left jugular vein to the LPS and LPS+ENL groups. At 15 min after the LPS injection, saline or ENL without cell components (5 mL/kg) was administered to the LPS and LPS+ENL groups, respectively, at a rate of 0.5 mL/min. Hepatocellular injury indices and hepatic histomorphology, as well as levels of P-selectin, intercellular adhesion molecule 1 (ICAM-1), myeloperoxidase (MPO), and Na⁺-K⁺-ATPase, were assessed in hepatic tissues. Liver tissue damage occurred after LPS injection. All levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in plasma as well as the wet/dry weight ratio of hepatic tissue in plasma increased. Similarly, P-selectin, ICAM-1, and MPO levels in hepatic tissues were elevated, whereas Na⁺-K⁺-ATPase activity in hepatocytes decreased. ENL treatment lessened hepatic tissue damage and decreased levels of AST, ALT, ICAM-1, and MPO. Meanwhile, the treatment increased the activity of Na⁺-K⁺-ATPase. These results indicated that ENL could alleviate LPS-induced liver injury, thereby suggesting an alternative therapeutic strategy for the treatment of liver injury accompanied by severe infection or sepsis.     

窒息新生儿脐血D-二聚体水平和红细胞膜Na~+-K~+-ATP酶活性变化

目的:分析窒息新生儿脐血pH、D-二聚体水平及红细胞膜Na+-K+-ATP酶活性变化。方法 :选择临产过程出现急性胎儿窘迫孕妇40例,其剖宫娩出新生儿以1min Apgar评分确定为正常者20例(窘迫组),出现窒息者20例(窒息组);另选无急性胎儿窘迫、同样剖宫娩出的正常新生儿20例作为对照组。取各组脐动脉血,血气分析仪检测pH值,免疫比浊法检测D-二聚体水平,定磷法检测红细胞膜Na+-K+-ATP酶活性。比较各组上述指标的差异。结果:方差分析显示,各组脐动脉血pH值、D-二聚体水平和红细胞膜Na+-K+-ATP活性差异均有统计学意义(P0.05)。窒息组脐动脉血pH值明显低于对照组和窘迫组(P均0.05),D-二聚体水平显著高于对照组和窘迫组(P均0.05),红细胞膜Na+-K+-ATP酶活性显著低于对照组与窘迫组(P均0.05);窘迫组pH值和红细胞膜Na+-K+-ATP酶活性显著低于对照组(P均0.05)。结论 :窒息新生儿纤溶和红细胞膜泵功能检测结果,可为新生儿窒息治疗措施的选择提供实验依据。     

Nesfatin-1对离体胃黏膜细胞胃酸分泌的影响

目的:研究nesfatin-1对离体培养的大鼠胃黏膜酸分泌的影响,探讨nesfatin-1对H+/K+-ATP酶mRNA及蛋白表达的影响.方法:酶解法分离大鼠胃黏膜细胞,细胞免疫荧光检测法鉴定细胞.用不同浓度的nesfatin-1(10-4-10-1μmol/L)对胃黏膜细胞进行处理0、1、2、3、4h,设立空白对照组,以14C-氨基比林摄取为酸分泌指标,检测nesfatin-1对大鼠离体的胃黏膜细胞酸分泌的影响.用RT-PCR法及Western印迹法检测nesfatin-1对胃黏膜细胞H+/K+-ATP酶alpha(α)亚基和beta(β)亚基mRNA及蛋白表达的影响.结果:Nesfatin-1在10-1μmol/L浓度下,在1、2h能够抑制离体培养的大鼠胃黏膜细胞的酸分泌.Nesfatin-1(10-1μmol/L)在1、2、3h均能够抑制H+/K+-ATP酶α亚基mRNA表达水平;在1、2h能够抑制H+/K+-ATP酶β亚基mRNA表达水平,分别与对照组相比,差异有统计学意义(均P<0.01).Nesfatin-1(10-4-10-1μmol/L)作用胃黏膜细胞2h时,呈剂量依赖性抑制α亚基和β亚基mRNA表达水平,分别与对照组相比,差异有统计学意义(均P<0.01).Nesfatin-1(10-1μmol/L)在1、2、3h能够抑制α亚基蛋白表达水平;在2、3h能够抑制β亚基蛋白表达水平,分别与对照组相比,差异有统计学意义(均P<0.01).Nesfatin-1(10-3-10-1μmol/L)作用胃黏膜细胞2h时,呈剂量依赖性抑制α亚基和β亚基蛋白表达水平,与对照组相比,差异有统计学意义(均P<0.01).结论:Nesfatin-1能抑制离体培养的大鼠胃黏膜细胞的酸分泌,有可能是通过下调H+/K+-ATP酶α亚基和β亚基的mRNA及蛋白表达的水平影响酸分泌.     

高碳酸血症对大鼠急性肺损伤Na+-K+-ATP酶活性的影响

目的: 研究高碳酸血症(HPC)对急性肺损伤(ALI)时肺泡Na -K -ATP酶活性的影响.方法: 将24只SD大鼠随机分为3组,每组8只:正常对照组(Ⅰ组);ALI组(Ⅱ组);ALI HPC组(Ⅲ组).用0.2 mol/L盐酸(2 ml/kg)气管内滴入建立大鼠急性肺损伤模型,吸入8% CO2气体建立高碳酸血症模型.以肺组织病理变化、支气管肺泡灌洗液(BALF)细胞计数和蛋白浓度、肺湿干重比(W/D)、血和BALF中TNF-α浓度及IL-8浓度为评估肺损伤的指标;以Na -K -ATP酶活性变化为评估HPC疗效的指标.结果: Ⅲ组BALF细胞计数(1.02±0.48),W/D(7.24±0.58),BALF蛋白浓度(0.25±0.16)和IL-8浓度(29.95±7.11)比Ⅱ组相应指标(1.79±0.73;8.60±1.24;0.53±0.35;59.52±36.00)明显降低(P＜0.01);Ⅲ组血TNF-α浓度(83.86±46.93)、IL-8浓度(80.00±24.72)比Ⅱ组相应指标(161.57±54.12;110.00±15.92) 明显降低(P＜0.01);Ⅲ组Na -K -ATP酶活性(13.23±1.20) 比Ⅱ组(10.77±2.21)明显增高(P＜0.01).结论: HPC对ALI时肺泡Na -K -ATP酶的活性有保护作用, 这可能是HPC对盐酸诱导的大鼠ALI保护作用的重要机制.     

心肌Na^＋，K^＋-ATP酶在抑郁症时的活性及mRNA表达

目的 探讨Na+,K+-ATP酶在抑郁症发病中的作用及其和单胺类神经递质之间的关系.方法 对SD大鼠进行慢性随机刺激建立抑郁症模型,检测大鼠心肌Na+,K+-ATP酶的活性及mRNA表达,海马组织及血液中去甲肾上腺素(NA)和5-羟色胺代谢物5-羟吲哚乙酸(5-HIAA)水平.结果 抑郁症大鼠心肌Na+,K+-ATP酶的转录水平下调(P＜0.01);酶的活性明显降低(P＜0.01);海马及血浆中的NA及5-HIAA水平显著下降(P＜0.01).结论 推测抑郁症时神经体液因素的变化可能是引起心肌细胞Na+,K+-ATP酶分子变化的原因之一,该酶在抑郁症的发病机制中有一定的生理和病理意义.     

高能冲击波对肾脏钙离子腺苷三磷酸酶活性的影响及川芎嗪的保护作用

目的 观察高能冲击波对肾脏钙离子腺苷三磷酸酶(Ca2+-ATPase)活性的影响及川芎嗪的保护作用,探讨高能冲击波肾损伤机制.方法 30只健康家兔制成单肾动物模型,按完全随机设计法分为对照组10只、高能冲击波组10只和川芎嗪组10只,对照组、高能冲击波组分别静脉注射等量生理盐水,高能冲击波冲击肾脏前3天,川芎嗪组静脉注射川芎嗪;冲击肾脏24h后,光学法检测肾细胞膜和线粒体膜Ca2+-ATPase活性;采用原位缺口末端标记法和流式细胞术检测凋亡细胞;采用生化分析测定内生肌酐清除率.结果 与对照组比较,高能冲击波组肾细胞膜和线粒体膜Ca2+-ATPase活性均降低(P<0.05,P<0.01)、细胞凋亡率增加(P<0.01)、内生肌酐清除率降低(P<0.01);川芎嗪组肾细胞膜Ca2+-ATPase活性和内生肌酐清除率变化不明显(P＞0.05),线粒体膜Ca2+-ATPase活性降低(P<0.05)、细胞凋亡率增加(P<0.05),但幅度明显小于高能冲击波组.结论 高能冲击波冲击肾脏后肾脏Ca2+-ATPase活性降低是发生肾细胞凋亡导致肾功能损伤的重要机制,川芎嗪有改善肾功能的作用,与其阻制肾脏Ca2+-ATPase活性降低、抗细胞凋亡有关.     

功能矫形前伸青春期大鼠下颌对颞肌后份Na＋/K＋-ATPase功能活性的影响

目的：研究功能矫形前伸青春期大鼠下颌对颞肌后份Na＋/K＋-ATPase功能活性的影响。方法：选用5周龄雄性SD大鼠40只,随机分为7个实验组及1个对照组,实验组大鼠佩戴可摘式上颌斜面导板功能矫治器。在不同的时间段,分别测定大鼠颞肌后份Na＋/K＋-ATPase功能活性。结果：在佩戴矫治器第3d、第7d颞肌后份Na＋泵功能活性显著升高,之后呈下降趋势,第28d、42d,颞肌后份Na＋/K＋-ATPase功能活性显著降低。结论：矫治器戴用的不同时段使Na＋泵活性先升高后降低,可能是由于建立了新的牙合关系,使下颌后收肌活动减弱。     

Effect of extracellular volume expansion on renal cortical and medullary Na+−K+-ATPase

Summary The role of renal Na⁺–K⁺-ATPase in the acute changes in sodium reabsorption caused by isotonic volume expansion was evaluatedin vivo andin vitro in the rat and the dog. Duringin vivo volume expansion with isotonic saline in the rat, renal medullary Na⁺–K⁺-ATPase specific activity increased, while the simultaneously determined cortical Na⁺–K⁺-ATPase specific activity and kinetics remained unchanged. Furthermore, experimentsin vitro failed to demonstrate a circulating inhibitor of renal Na⁺–K⁺-ATPase both in plasma dialysates from volume-expanded rats and in plasma dialysates concentrated 20-fold by ultrafiltration from volume-expanded dogs. These results suggest that the decreased proximal tubular reabsorption of sodium during volume expansion is not mediated by inhibition of renal cortical Na⁺–K⁺-ATPase. The acute increment in medullary Na⁺–K⁺-ATPase observed could represent an adaptive response to increased sodium reabsorption by the loops of Henle, and raises the possibility that this enzyme may participate in relatively rapid adjustments in the transport of sodium by the renal tubule.     

Osmoregulatory action of PRL,GH, and cortisol in the gilthead seabream (Sparus aurata L)

The osmoregulatory actions of ovine prolactin (oPRL), ovine growth hormone (oGH), and cortisol were tested in the euryhaline gilthead seabream Sparus aurata. Acclimated to sea water (SW, 40 ppt salinity, 1000 mOsm/kg H(2)O) or brackish water (BW, 5 ppt, salinity, 130 mOsm/kg H(2)O), injected every other day for one week (number of injections, 4) with saline (0.9% NaCl), oPRL (4 microg/g body weight), oGH (4 microg/g body weight) or cortisol (5 microg/g body weight), and transferred from SW to BW or from BW to SW 24h after the last injection. Fish were sampled before and 24h after transfer. Gill Na(+), K(+)-ATPase activity, plasma osmolality, plasma ions (sodium and chloride), plasma glucose, and muscle water moisture were examined. SW-adapted fish showed higher gill Na(+), K(+)-ATPase activity, plasma osmolality, and plasma ions levels than BW-adapted fish. Transfer from SW to BW decreased plasma osmolality and ions levels after 24h, while transfer from BW to SW increased these parameters, whereas gill Na(+),K(+)-ATPase activity was unaffected. oPRL treatment significantly decreased gill Na(+),K(+)-ATPase activity and increased plasma osmolality and ions in SW- and BW-adapted fish. This treatment minimizes loss of osmolality and ions in plasma after transfer to BW and increased these values after transfer to SW. No significant changes were observed in gill Na(+),K(+)-ATPase activity, plasma osmolality, and plasma ions in oGH-treated group with respect to saline group before or after transfer from SW to BW or from BW to SW. Treatment with cortisol induced, in SW-adapted fish, a significant increase of gill Na(+),K(+)-ATPase activity and decrease of plasma osmolality and plasma ions. In BW-adapted fish this treatment induced a significant increases in gill Na(+),K(+)-ATPase activity, plasma osmolality, and plasma ions. After transfer to SW cortisol-treated fish had higher plasma osmolality than the saline group. Our results support the osmoregulatory role of PRL in the adaptation to hypoosmotic environment in the gilthead seabream S. aurata. Further studies will be necessary to elucidate the osmoregulatory role of GH in this species. Cortisol results suggest a "dual osmoregulatory role" of this hormone in S. aurata.