The study of cytokine content and ganglioside metabolism in experimental brain edema

A blood cytokine profile and also the brain content of lipid peroxidation (LPO) products and gangliosides were investigated in rats with experimental brain edema. The development of brain edema was accompanied by the increase in pro-inflammatory and a decrease in anti-inflammatory cytokine content. In parallel, accumulation of LPO products (conjugated dienes, hydroperoxides, and malondialdehyde) was observed. The study of ganglioside content under conditions of experimental brain edema revealed a decrease of their hydrolytic degradation product, sphingosine.     

Effects of tumor necrosis factor alpha on taurine uptake in cultured rat astrocytes

Taurine is known to play a major role in volume regulation in astrocytic swelling associated with stroke and brain trauma. Apart from brain edema, the severity of brain injury is related to the levels of inflammatory cytokines such as tumor necrosis factor alpha (TNFalpha). TNFalpha had been shown to be closely associated with brain edema formation since the neutralization of TNFalpha reduced brain edema. Considering taurine has osmoregulatory functions in astrocytes, experiments were performed to study the effects of TNFalpha on taurine uptake in cultured astrocytes. Astrocytes exposed to 20 ng/ml of TNFalpha for 48 h showed a 91% increase in taurine uptake and significant increase was observed after 24 h exposure. This cytokine caused neither significant changes in cell volume nor taurine release. The increased in taurine uptake induced by TNFalpha was unlikely resulted from the modification of Na(+) movement because TNFalpha decreased tyrosine uptake, Na(+)-dependent transport system. In contrast to TNFalpha, interferon-gamma (IFNgamma) did not significantly affect taurine uptake. Taken together, our results did not support a suggestion that TNFalpha affects cell volume regulation via modulating taurine uptake in astrocytes. Increasing lines of evidence have demonstrated that taurine has anti-inflammatory and anti-oxidative effects, these findings therefore suggested that the increase in taurine uptake might be an adaptive response or a tool for astrocytes against oxidative stress.     

Effects of Atorvastatin on Pathological Changes in Brain Tissue and Plasma MMP-9 in Rats with Intracerebral Hemorrhage

To explore the effects of atorvastatin on hydrocephalus, neurocyte apoptosis, and the level of plasma matrix metalloproteinase-9 (MMP-9) after intracerebral hemorrhage (ICH) in rats. A rat model of ICH was established by intracerebral injection of collagenase. The brain water content was determined by the wet/dry weight ratio, ultrastructural changes in brain tissue were observed by electron microscopy, and the level of plasma MMP-9 was quantified by ELISA. Atorvastatin showed significant effects in reducing the brain water content, blocking neuron apoptosis, and decreasing plasma MMP-9 in rats with ICH. There was a positive linear correlation between plasma MMP-9 and the brain water content. Atorvastatin can significantly relieve brain edema, decrease the brain injury caused by MMP-9 and protect neurons in rats with ICH.     

Experimental endotoxemia induces leukocyte adherence and plasma extravasation within the rat pial microcirculation

Disturbance of capillary perfusions due to leukocyte adhesion, disseminated intravascular coagulation, tissue edema is critical components in the pathophysiology of sepsis. Alterations in brain microcirculation during sepsis are not clearly understood. The aim of this study is to gain an improved understanding of alterations through direct visualization of brain microcirculations in an experimental endotoxemia using intravital microscopy (IVM). Endotoxemia was induced in Lewis rats with Lipopolysaccharide (LPS, 15 mg/kg i.v.). The dura mater was removed via a cranial window to expose the pial vessels on the brain surface. Using fluorescence dyes, plasma extravasation of pial venous vessels and leukocyte-endothelial interaction were visualized by intravital microscopy 4 h after LPS administration. Plasma cytokine levels of IL1-beta, IL-6, IFN-gamma, TNF-alpha and KC/GRO were evaluated after IVM. A significant plasma extravasation of the pial venous vessels was found in endotoxemia rats compared to control animals. In addition, a significantly increased number of leukocytes adherent to the pial venous endothelium was observed in septic animals. Endotoxemia also induced a significant elevation of plasma cytokine levels of IL1-beta, IL-6, IFN-gamma, TNF-alpha and KC/GRO. Endotoxemia increased permeability in the brain pial vessels accompanied by an increase of leukocyte-endothelium interactions and an increase of inflammatory cytokines in the plasma.     

Suppression of neuropeptides' mRNA expression by herbal medicines in a rat model of peripheral inflammation

The traditional Chinese medicines have been used clinically for a long time in some Asian countries, however, very few studies have been done to demonstrate the working mechanisms of these medicines using recently developed biochemical methodologies. In this study, we examined the anti-inflammatory effect of Huang-Lian-Jie-Du-Tang (HLJDT), a combination of herbs used in traditional Chinese medicine, on paw edema, thermal hyperalgesia and the mRNA increase of neuropeptides in spinal dorsal horn and hypothalamic neurons using a rat model of peripheral inflammation and hyperalgesia. The rats that received HLJDT from 3 days before the injection of complete Freund's adjuvant (CFA) into the plantar had significantly less edema and reduced thermal hyperalgesia compared to control rats that received CFA injection. The up-regulation of preprodynorphin mRNA in L4-5 dorsal horn neurons 8 hours after CFA injection that was observed in control rats, was also decreased in the HLJDT-treated rats. Moreover, there was a significant decrease in mRNA level of corticotropin-releasing factor in the paraventricular hypothalamic nucleus in the HLJDT-treated rats. These data demonstrate that HLJDT is anti-inflammatory, and produces changes in mRNA expression in dorsal horn and hypothalamic neurons. This is the first demonstrated that a traditional Chinese medicine can affect the excitability of neurons through an anti-inflammatory action.     

Rapid eye movement (rem) sleep deprivation: effect on acid mucopolysaccharides in rat brain.

The effect of rapid eye movement (REM) sleep deprivation on the total content and proportion of different mucopolysaccharides (AMPS) containing uronic acid in rat brain was studied. REM sleep deprivation was induced by the water tank methods. Five experimental groups of animals were used: control, stressed, REM sleep deprived, post-stress sleeping and post-deprivation sleeping rats. No changes of AMPS were observed in any of the experimental groups when the whole brain was analysed. A significant increase of AMPS was found in the cerebral hemispheres of stressed and REM deprived rats. A significant decrease of AMPS was observed in the cerebellum and brain stem. A further increase of AMPS was found in the cerebral hemispheres after the rebound of REM sleep following its deprivation, and after the recovery sleep following the stress. A significant increase of AMPS was found in the brain stem of rats allowed to recuperate after REM deprivation or stress as compared with the stressed and REM deprived animals. Recovery sleep induced a significant increase of AMPS in the cerebellum in previously stressed rats, while previously REM deprived rats exhibited a further decrease of AMPS from control values. The possible functional meaning of these results is discussed in relation to the role of REM sleep in protein synthesis and learning and memory processes. Intriguing, well-controlled positive findings and the fact that no experimental design is known where stress is minimal while REM deprivation is 100 per cent, justify and encourage continued efforts in studying the biochemical state of the brain during sleep and/or its alterations.     

Lipid composition of rat brain myelin in triethyl tin-induced edema

Chronic triethyl tin intoxication was induced in young adult rats by oral feeding of triethyl tin sulfate. Progressively severe brain edema developed during the 3-month experimental period. The yield of myelin from the brains of the experimental animals decreased to almost half normal per brain, but the isolated myelin appeared morphologically normal. The analysis of whole brain showed corresponding decreases in proteolipid protein and total lipid, particularly galactolipids. The proportions of the major constituents of isolated myelin (chloroform-methanol-insoluble residue, proteolipid protein, and total lipid) were unchanged despite the low yield. However, the proportion of cholesterol increased from 16 to 21% dry weight, and that of total galactolipid decreased from 21 to 15%, as the yield of myelin decreased. This decrease of total galactolipid was mainly due to the decrease in cerebroside. Total phospholipid remained constant initially but showed a slight decrease toward the end of the experiment, due mostly to decreased ethanolamine phospholipid. There was no preferential loss or preservation of phosphatidalethanolamine. The fatty acid composition of sulfatide showed statistically significant shifts to less long-chain fatty acids and less monoenoic acids, but cerebroside and sphingomyelin did not show significant changes in the fatty acid composition. There was no increase in esterified cholesterol. These findings generally support our hypothesis of nonspecific chemical abnormalities of the myelin sheath undergoing secondary degeneration. In an acute experiment, a single intraperitoneal injection of triethyl tin sulfate produced acute and transient brain edema. There were slight decreases in the yield of myelin, but no detectable changes in the chemical composition.     

Role of interleukin-4 in regulation of age-related inflammatory changes in the hippocampus

It is well documented that long term potentiation (LTP) is impaired in the hippocampus of the aged animal. Among the changes that contribute to this impairment is an increase in hippocampal concentration of the pro-inflammatory cytokine interleukin-1beta (IL-1beta), and increased IL-1beta-induced signaling. In this study we investigated the possibility that these changes were a consequence of decreased concentration of the anti-inflammatory cytokine, IL-4, and decreased IL-4-stimulated signaling. We report that functional IL-4 receptors are expressed on granule cells of the dentate gyrus and that receptor activation results in phosphorylation of JAK1 and STAT6. Hippocampal IL-4 concentration was decreased with age, and this was accompanied by a decrease in phosphorylation of JAK1 and STAT6. The evidence indicates that IL-4 modulates expression of IL-1beta mRNA and protein and that it attenuates IL-1beta-induced impairment of LTP and phosphorylation of JNK and c-Jun. We argued that, if a decrease in hippocampal IL-4 concentration significantly contributed to the age-related impairment in LTP, then restoration of IL-4 should restore LTP. To test this, we treated rats with VP015 (phospholipid microparticles-incorporating phosphatidylserine), which increases IL-4 concentration in hippocampus. The data indicate that the VP015-induced increase in IL-4 concentration in hippocampus of aged rats and lipopolysaccharide (LPS)-treated rats was accompanied by a reversal of the age-related and LPS-induced impairment in LTP in perforant path granule cell synapses. We propose that interplay between pro-inflammatory and anti-inflammatory responses impact significantly on synaptic function in the hippocampus of the aged rat.     

Effect of lithium oxybutyrate on lipid metabolic changes in pituitrin-induced pulmonary edema

The experiments on white rats have confirmed that the development of lung edema following pituitrin infusion is characterized by considerable changes in phospholipid and cholesterol lung metabolism and cholesterol blood metabolism. Lithium hydroxybutyrate preinjection at a dose of 400 mg/kg prevented a decrease in cholesterol lung content and an increase in cholesterol blood plasma level which was accompanied by less prominent lung edema.     

Brain Ion and Amino Acid Contents During Edema Development in Hepatic Encephalopathy

Abstract: Brain edema in hepatic encephalopathy has been associated with circulating ammonia that is metabolized to glutamine. We measured alterations in blood chemistry and brain regional specific gravity and ion and amino acid contents in models of simple hyperammonemia and liver failure induced by daily administrations of ammonium acetate (AAc) or thioacetamide (TAA), respectively. Serum and brain ammonia increased to similar levels (200 and 170% of control, respectively) in both experimental groups. Serum transaminase activities increased 10-fold in animals injected with TAA but were unchanged in animals given AAc injections. In both experimental groups glutamine was elevated in cerebral white matter, cerebral gray matter, and basal ganglia, whereas brain tissue specific gravity decreased in all brain regions, indicating edema formation. In the AAc group, we observed a decrease in glutamate and taurine contents concomitant with the development of brain edema. In these animals, cerebral gray matter specific gravity and taurine contents returned to control levels 24 h after the third AAc injection. TAA-injected animals demonstrated similar decreases in brain tissue specific gravity, whereas glutamine, glutamate, and taurine contents were all elevated. During hepatic encephalopathy, ammonia-induced changes in brain amino acid content may contribute to brain edema development.     

24R,25-dihydroxyvitamin D3 prevents aluminum-induced alteration of brain gangliosides in uremic rats by keeping the metal within perivascular astrocytes of the blood-brain barrier.

The administration of aluminum (Al) to uremic rats leads to Al accumulation in different brain regions with subsequent alteration of brain gangliosides. Addition of 24R,25-dihydroxyvitamin D3[24R,25-(OH)2D3] did not influence the brain Al content determined by plasma argon emission spectrometry, but prevented the decrease in brain gangliosides. By using electron microscopy and laser microprobe mass analysis, it was demonstrated that in rats given 24R,25-(OH)2D3 together with Al, the metal was mainly kept within perivascular astrocytes of the blood-brain barrier. On the contrary, in rats given Al only, the metal was evenly distributed throughout the brain areas causing extensive demyelination, chromatolysis of nerve cells in some brain regions (hippocampus) and brain edema. Our results could find application in the prevention of Al-induced encephalopathy in patients on hemodialysis.     

Neuroprotective effect of N-acylethanolamines in chronic morphine dependence. III. Influence on the content of neurotransmitters in the rat brain

The effect of the mixture of saturated and unsaturated N-acylethanolamines (NAEs) on the functional activity of catecholamine- and serotoninergic systems of the rat brain with experimental morphine dependence was investigated. A significant decrease of dopamine levels was found in the hypothalamus, midbrain and cortex of rats with morphine dependence. The administration of NAEs to rats with morphine dependence in time course dose of 35 mg/kg markedly increased the levels of dopamine in the hypothalamus, middle brain and cortex. Simultaneously the significant decrease of serotonine content was observed in the midbrain and cortex. The results obtained suggest that one of the important aspects of neuroprotective action of NAEs under morphine dependence is the restoration of dopamine content in the brain.     

Platelet activating factor (PAF) inhibitor (TCV-309) reduces caerulein- and PAF-induced pancreatitis. A morphologic and functional study in the rat.

Caerulein-induced acute pancreatitis was studied in rats. Consistent with this type of acute pancreatitis morphological (edema, leukocytic infiltration and acinar cell vaculization) and biochemical (increase in pancreatic protein content. PAF release and serum amylase) changes developed 5 hours after caerulein administration. In addition increase in pancreatic weight and decrease in pancreatic blood flow were noticed. PAF administration caused pancreatic damage similar in some parameters to caerulein-induced pancreatitis, along with reduction of pancreatic blood flow, increase in pancreatic protein content, and serum amylase. TCV-309, a selective PAF antagonist, administered prior to caerulein and/or PAF, reduced caerulein-induced pancreatitis and prevented PAF-induced pancreatitis. Results of our present studies indicate the crucial role of PAF in pathogenesis of experimental acute pancreatitis.     

噬菌体展示技术筛选大鼠佐剂性关节炎中PGE2受体的拮抗剂

目的：通过筛选PGE2受体拮抗剂,来探讨其在类风湿性关节炎（rheumatoid arthritis, RA）中的作用,为RA的治疗开辟新的途径。方法：应用噬菌体展示技术,以PGE2为靶点,对噬菌体环七肽库进行"吸附-洗脱-扩增"筛选过程,5轮筛选后,随机挑取噬菌体克隆进行亲和力鉴定,并选取亲和力高的克隆进行测序并对序列进行分析。合成环七肽后,建立佐剂性关节炎（AA）动物模型,通过分析足爪肿胀度,以及采用ELISA方法检测关节浸液中细胞因子的含量,对小肽的抗炎作用进行探讨。结果：噬菌体经过富集后,随机挑选的23个克隆中有21个阳性克隆,而在测序的8个克隆中4个具有相同的序列,其余也具有保守氨基酸。合成的环七肽能降低AA关节的肿胀度并减少关节浸液中前炎症细胞因子的含量。结论:噬菌体筛选PGE2受体拮抗剂的方法可行,并且得到的环七肽具有一定的抗炎作用。     

Mechanism of the decrease in intracranial pressure as affected by furosemide

The correlation was established between the increase in diuresis and natriuresis and fall of CSF pressure after intravenous injection of 10 mg/kg furosemide into dogs. Osmolarity and ion concentration in the serum and CSF did not change in these experiments. In nephrectomized dogs, furosemide did not changes CSF pressure. Furosemide dehydrated brain with traumatic edema, reduced brain Fe content probably due to diminishing brain blood content. The mechanism of intracranial pressure fall after furosemide injection can be explained by acute excretion of a large volume of fluid by the kidneys, leading to a decrease in the blood content of the skull cavity.     

脑水肿时紧密连接蛋白occludin及AQP4的表达变化

目的:采用枕大池内注入脂多糖(lipopolysaccharides,LPS)的方法建立大鼠脑水肿模型,观察脑组织病理形态学变化,脑组织含水量(brain water content,BWC),血脑屏障(blood brain barrier,BBB)的紧密连接蛋白Occludin和水通道蛋白-4(aquaporin 4,AQP4)表达水平的动态变化,研究AQP4及Occludin与脑水肿形成的关系,及其可能的作用机制,为临床脑水肿的治疗提供理论依据。方法:选用Wistar健康成年大鼠,随机分为正常对照组,生理盐水组和脂多糖组,后两组的观察时间点选定于造模后3 h、6h、12 h、24 h、72 h。采用经皮穿刺枕大池内注入脂多糖的方法制备脑水肿动物模型,正常对照组、生理盐水组及脂多糖组分别于各时间点进行开颅取脑,测定脑组织含水量,通过HE染色法观察脑组织的病理形态学变化,应用Western blot方法检测occludin的表达变化。应用RT-PCR技术测定脑组织内AQP4mRNA的表达变化。结果:生理盐水组各时间点中有少量AQP4mRNA及occludin蛋白的表达,与正常对照组之间无显著性差异;脂多糖组在造模后3 hAQP4的mRNA表达开始增加,6-12 h达高峰,此后明显下降,随后表达开始减弱,24-72 h表达显著低于生理盐水组;occludin蛋白表达下降出现于造模后3 h,12-24 h下降更明显,72 h表达开始升高。结论:枕大池内注入脂多糖(LPS)所建立脑水肿模型中,脑组织含水量及血脑屏障通透性增加,病理学特点是血管源性脑水肿出现早且持久,后期伴有细胞毒性脑水肿的改变。AQP4早期表达增强是胶质细胞的适应性反应,与血脑屏障的破坏有关,促进了血管源性脑水肿的发生。后期AQP4表达减弱是机体内在防御机制的表现,同时又促进细胞毒性脑水肿的形成。occludin在脑组织中表达量随脑水肿的加重而降低,即与脑水肿的程度呈负相关,目前认为这与脑水肿时内皮细胞通透性增加,血脑屏障的通透性改变,导致occludin的表达下调有关,促进了血管源性脑水肿的发生。针对以上特点,我们可以进一步研究调控AQP4及occludin表达的药物,从而减轻脑损伤后脑水肿的程度,为脑水肿的治疗提供新的临床策略。     

A pivotal role for interleukin-4 in atorvastatin-associated neuroprotection in rat brain

Inflammatory changes, characterized by an increase in pro-inflammatory cytokine production and up-regulation of the corresponding signaling pathways, have been described in the brains of aged rats and rats treated with the potent immune modulatory molecule lipopolysaccharide (LPS). These changes have been coupled with a deficit in long-term potentiation (LTP) in hippocampus. The evidence suggests that anti-inflammatory agents, which attenuate the LPS-induced and age-associated increase in hippocampal interleukin-1beta (IL-1beta) concentration, lead to restoration of LTP. Here we report that atorvastatin, a member of the family of agents that act as inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase, exerts powerful anti-inflammatory effects in brain and that these effects are mediated by IL-4 and independent of its cholesterol-lowering actions. Treatment of rats with atorvastatin increased IL-4 concentration in hippocampal tissue prepared from LPS-treated and aged rats and abrogated the age-related and LPS-induced increases in pro-inflammatory cytokines, interferon-gamma (IFNgamma) and IL-1beta, and the accompanying deficit in LTP. The effect of atorvastatin on the LPS-induced increases in IFNgamma and IL-1beta was absent in tissue prepared from IL-4(-/-) mice. The increase in IL-1beta in LPS-treated and aged rats is associated with increased microglial activation, assessed by analysis of major histocompatibility complex II expression, and the evidence suggests that IFNgamma may trigger this activation. We propose that the primary effect of atorvastatin is to increase IL-4, which antagonizes the effects of IFNgamma, the associated increase in microglial activation, and the subsequent cascade of events.     

Brain cholecystokinin-8 immunoreactivity in rats with experimental liver cirrhosis

Cholecystokinin-8 like immunoreactivity (CCK-8 IR) was measured in different brain regions of rats with experimental liver cirrhosis. A statistically significant reduction of CCK-8 content was observed in the hypothalamus of cirrhotic rats. No significant modification of brain CCK fractionation pattern was observed in treated animals as compared to controls. The decrease of CCK-8 IR parallels the recently reported hypothalamic depletion of beta endorphin in cirrhotic rats confirming that central neuropeptides are affected by chronic liver failure.     

Effect of adrenocorticotropic hormone on nucleic acid and protein synthesis and content in the brain of rat embryos in the early stages of neurogenesis]

The injection of adrenocorticotropic hormone (ACTH) of prolonged effect at the doses of 4 and 10 M. U. to the intact rats from the 11th till the 15th day of pregnancy resulted in the twofold increase of protein content in the brain and its decrease in the liver of 15 days old embryos, as compared with the control ones. The content of DNA, RNA and proteins in the placenta of experimental animals increased as well. The rate of incorporation of 3H-thymidine in the liver DNA and 14C-leucine in the liver and brain acid-soluble protein decreased within small intervals of time following the treatment. The total radioactivity of proteins in the liver, brain and placenta calculated per DNA unit was similar to the control one whereas the specific radioactivity of total protein in the liver of experimental embryos was higher than in the control.     

Low selenium diet increases the dopamine turnover in prefrontal cortex of the rat

It has been proposed that interaction of catecholamines and indoleamines with free radicals may result in the formation of endogenous neurotoxins. In order to better understand the mechanisms involved in neurodegenerative disorders showing evidence of oxidative stress, we have studied the basal concentrations and the turnover rates of dopamine, noradrenaline, serotonin and their metabolites in the prefrontal cortex of rats that were fed on control or low selenium diets. Nutritional deficit of selenium decreases the brain antioxidant protection in experimental conditions by the decrease in glutathione peroxidase activity.

The dopamine and serotonin turnover increased and noradrenaline and 5-hydroxy-3-indoleacetic acid turnover decreased compared to experimental control animals. The increase of dopamine turnover in experimental rats was accompanied by an increase in tyrosine hydroxylase activity. These results suggest that the decrease of brain protection against oxidative damage could induce brain damage by disturbing the turnover rate of some monoamines.