[Role of extracellular-signal regulated kinase cascade on cerebral ischemia and ischemic preconditioning in hippocampal neuron in gerbils].

AIM: To investigate the role of extracellular-signal regulated kinase (ERK) cascade on cerebral ischemia and ischemic preconditioning in hippocampal neuron. METHODS: Male gerbils were randomly divided into sham group (SH), ischemia/reperfusion group (I/ R), ischemia preconditioning group (IP), specific antagonist of ERK-PD98059 (PD), solvent control groups (VE group), PD98059 combined with IP group (PIP). Forebrain ischemia was induced by occlusion of bilateral common carotid arteries and confirmed by isoelectricity of EEG. Observations were carried out in each group 15 min, 2 h, 4 h, 6 h, 1 d, 3 d, 5 d and 7 d after ischemia. Open field test was used to examine the spontaneous motor activity, the survival and apoptotic neurons, Fos and NF-kappaB masculine neurons in hippocampal CA1 region were counted, the expression of HSP70 in hippocampal CA1 region and p-ERK in hippocampal CA3/DG regions were detected by SABC immunocytochemical technique. RESULTS: The spontaneous motor activity, the number of apoptotic neurons and NF-kappaB masculine neurons at 1 d, 3 d, 5 d, 7 d in CA1 region were much less in IP group than in I/R group (P < 0.01). The number of Fos masculine neurons at 15 min, 2 h, 4 h, 6 h, 1 d in CA1 region were significant more in IP group than in I/R group (P < 0.01). The expressions of p-ERK and HSP70 were significantly higher in IP group than in I/R group. The number of Fos masculine neurons at each point were more and apoptotic neurons at 1 d, 3 d were less in PD group than in I/R group. Results of observation in PIP group were within IP group and I/R group. CONCLUSION: Activation of ERK in CA3/DG regions were related to ischemic tolerance. Induction of the expression of Fos and HSP70, decreasing of the product of NF-kB which might be one of the molecule mechanisms playing an important role in neural protection of ischemic preconditioning.

[Effects of propofol on the changes in cytoskeleton and cellular permeability of human umbilical vascular endothelial cells monolayer induced by lipopolysaccharide].

OBJECTIVE: To investigate the effects of propofol on the changes in actin cytoskeleton and permeability of cultured human umbilical vascular endothelial cells (HUVECs) monolayer induced by lipopolysaccharide (LPS). METHODS: HUVECs were randomly assigned to one of the following seven groups: no additives (negative control), LPS alone (1 mg/L and 10 mg/L), propofol alone (4 mg/L), introlipid alone, LPS (10 mg/L ) combination with propofol (4 mg/L) and LPS (10 mg/L ) together with introlipid (4 mg/L). Changes in filtration coefficients (Kf) and osmotic reflection coefficients (sigma) were measured, and changes in filamentous actin (F-actin) measured by F-actin fluorometry, and expression of nitrotyrosine analyzed by immunocytochemistry were observed in cultured HUVECs. RESULTS: Compared with the control group, the LPS alone group Kf values were significantly increased and the sigma values decreased,the F-actin content was decreased and the expression of nitrotyrosine was increased (all P<0.01), especially in the high dose LPS alone group. The co-treatment of propofol and LPS significantly reduced levels of LPS-enhanced nitrotyrosine protein, and significantly attenuated the changes in Kf and sigma values (all P<0.01), while introlipid group had no such beneficial effects. CONCLUSION: Propofol rather than introlipid, significantly inhibit LPS-induced increase in permeability of HUVECs and alterations in F-actin organization. The scavenging actions of propofol on peroxynitrite may be helpful to attenuate endothelial barrier dysfunction as shown in our current study.

Rosiglitazone, a peroxisome proliferator-activated receptor-gamma agonist, reduces acute lung injury in endotoxemic rats.

OBJECTIVE: Rosiglitazone, a potent agonist of peroxisome proliferator-activated receptor (PPAR)-gamma, exerts anti-inflammatory effects in vitro and in vivo. This study was designated to determine the effects of rosiglitazone on endotoxin-induced acute lung injury in rats. DESIGN: Prospective, experimental study. SETTING: University research laboratory. SUBJECTS: Thirty-six male Wistar rats. INTERVENTIONS: All the animals were randomly assigned to one of six groups (n = 6 per group) and were given either lipopolysaccharide (6 mg/kg intravenously) or saline, pretreated with rosiglitazone (0.3 mg/kg intravenously) or vehicle (10% dimethyl sulphoxide) 30 mins before lipopolysaccharide. The selective PPAR-gamma antagonist GW9662 (0.3 mg/kg intravenously) or its vehicle (10% dimethyl sulphoxide) was given 20 mins before rosiglitazone. MEASUREMENTS AND MAIN RESULTS: Endotoxemia for 4 hrs induced evident lung histologic injury and edema, both of which were significantly attenuated by rosiglitazone pretreatment. The protective effects of rosiglitazone were correlated with the reduction by 71% of the increase of myeloperoxidase activity and the reduction by 84% of the increase of malondialdehyde in the lung tissue. The pulmonary hyperproduction of nitric oxide was reduced by 82% of the increase related to lipopolysaccharide challenge. Pretreatment with rosiglitazone also markedly suppressed lipopolysaccharide-induced expression of inducible nitric oxide synthase messenger RNA and protein in the lung, as demonstrated by reverse transcription-polymerase chain reaction or Western blot analysis. Immunohistochemical analysis revealed that rosiglitazone inhibited the formation of nitrotyrosine, a marker for peroxynitrite reactivity, in the lung tissue. In addition, the specific PPAR-gamma antagonist GW9662 antagonized the effects of rosiglitazone. CONCLUSIONS: This study provides evidence, for the first time, that the PPAR-gamma agonist rosiglitazone significantly reduces endotoxin-induced acute lung injury in rats.

Protective effect of genistein on lipopolysaccharide-induced acute lung injury in rats.

To investigate the protective effect of genistein on endotoxin-induced acute lung injury in rats, and explore the underlying mechanisms, 32 male Sprague-Dawley rats were randomly divided into 4 experimental groups: saline control, genistein alone, lipopolysaccaride alone, and genistein pretreatment. Each treatment group consisted of eight animals. Animals were observed for 6 h after LPS challenge, and the wet/dry (W/D) weight ratio of the lung and bronchoalveolar lavage fluid (BALF) protein content were used as a measure of lung injury. Neutrophil recruitment and activation were evaluated by BALF cellularity and myeloperoxidase (MPO) activity. RT-PCR analysis was performed in lung tissue to assess gene expression of ICAM-1. The histopathological changes were also observed using the HE staining of lung tissue. Our results showed that lung injury parameters, including the wet/dry weight ratio and protein content in BALF, were significantly higher in the LPS alone group than in the saline control group (P < 0.01). In the LPS alone group, a larger number of neutrophils and greater MPO activity in cell-free BAL and lung homogenates were observed when compared with the saline control group (P < 0.01). There was a significant increase in lung ICAM-1 mRNA in response to LPS challenge (P < 0.01, group 1 versus group S). Genistein pretreatment significantly attenuated LPS-induced changes in these indices. LPS caused extensive lung damage, which was also lessened after genistein pretreatment. All above-mentioned parameters in the genistein alone group were not significantly different from those of the saline control group. It is concluded that genistein pretreatment attenuated LPS-induced lung injury in rats. This beneficial effect of genistein may involves, in part, an inhibition of neutrophilic recruitment and activity, possibly through an inhibition of lung ICAM-1 expression.

Capillary leak syndrome in children with C4A-deficiency undergoing cardiac surgery with cardiopulmonary bypass: a double-blind, randomised controlled study.

BACKGROUND: Capillary leak syndrome is a life-threatening complication after cardiopulmonary bypass (CPB), with an incidence of about 4-37% in children worldwide. On the basis of previous results, we undertook a randomised controlled study to investigate the priming with plasma rich in the C4A isotype of complement component 4 on the incidence of capillary leak syndrome in children with C4A deficiency. METHODS: In a hospital in Wuhan, China, we randomly assigned 116 neonates, infants, and children lacking complement component C4A to receive C4A-free or C4A-rich plasma priming (n=58 each, 20 mL/kg). The primary outcome was capillary leak syndrome, identified as an increased transvascular escape rate of Evans blue dye from plasma. Concentrations of activated complement components C4 and C3, inflammatory mediators interleukin 6, interleukin 8, tumour necrosis factor (TNF) alpha, plasma protein, and PaO2/F(I)O2 ratios (ratio of the partial arterial pressure of oxygen to the fractional concentration of oxygen in inspired air) were measured before and 4 h after CPB. Analysis was by intention to treat. FINDINGS: Three (5%) patients given C4A-rich plasma priming had capillary leak syndrome compared with 56 (97%) given C4A-free plasma (p<0.0001). At 4 h after CPB, activated C4, interleukin 6, interleukin 8, and TNFalpha concentrations were higher, whereas PaO2/F(I)O2 ratios and plasma protein concentrations were significantly lower in the C4A-free group than changes in the C4A-rich group. Activated C3 rose equally in both groups. Activated C4 significantly correlated with interleukin 6, interleukin 8, and TNFalpha concentrations; PaO2/F(I)O2 ratios; and the escape rate of Evans blue dye at 4 h after CPB. Two patients in the C4A-free group died of respiratory and renal failure on day 3 after CPB. INTERPRETATION: In paediatric patients with C4A deficiency, C4A-rich plasma priming reduces the incidence of CPB-related capillary leak syndrome by blocking the activated C4 increase and attenuating the systemic inflammatory response after CPB.

Propofol effects on excitatory synaptic efficacy in the CA1 region of the developing hippocampus.

The anesthetic, propofol, effectively suppresses excitatory synaptic transmission and facilitates long-term depression (LTD) in the CA1 region of the hippocampus. Here, we have examined whether these effects are different in the developing hippocampus. We found that propofol in suppressing whole-cell excitatory postsynaptic currents (EPSC) was more effective in 21 day old rats than either in 7 day old rats or under the condition of high intracellular chloride concentration in 21 day old rats. Furthermore, the propofol concentration to facilitate the NMDA receptor-dependent LTD was lower at postnatal day 21 than at postnatal day 7. Interestingly, the decay time of EPSC was decreased during the development from postnatal day 7 to 21, but it was increased by the recording condition of high intracellular chloride concentration or by propofol administration. All these effects of propofol were dependent on the chloride channel opening. These observations suggest that propofol may induce differential anesthetic effects in the developing hippocampus, at least partially, depending on the intracellular chloride concentration.

The role of neutrophil collagenase in endotoxic acute lung injury.

The aim of this study was to determine the role of neutrophil collagenase in the pathogenesis of acute lung injury induced by endotoxin. 28 Sprague-Dawley were randomized into control group and LPS-enduced groups. Samples of left lung were obtained in 2 h (group L1), 6 h (group L2), 12 h (group L3) after intravenous LPS. Immunohistochemsitry was employed for detection of expression of neutrophil collagenase. Pathological scores, lung wet/dry weight ratio and the number of neutrophils were measured. The results showed that the concentration of neutrophil collagenase in LPS-enduced groups (group L1, L2, L3) were significantly higher than that of control group (P<0.01). Pathological scores, lung wet/dry weight ratio and the number of neutrophils in LPS-enduced groups (group L1, L2, L3) were also significantly higher than that of control group (P<0.01). Moreover, among group L1, L2 and L3, there were significant correlations in concentration of neutrophil collagenase and pathological scores, lung wet/dry weight ratio, the number of neutrophils (P<0.05). The present study showed that neutrophil collagenase play an important role in the pathogenesis and progress of endotoxic acute lung injury.

Therapeutic effect of propofol in the treatment of endotoxin-induced shock in rats.

To assess the potential therapeutic effect of propofol in the treatment of endotoxemia, 76 rats were randomly assigned to 5 groups: control group(A), endotoxemic group(B), pre-treatment group(C), simultaneous treatment group(D) and post-treatment group(E). Five h after endotoxin injection, PO2, pH, MAP, plasma concentrations of Nitrite/nitrate (NO2-/NO3-) and mortality rates were assessed in each group. After the rats were sacrificed, lung tissue was sampled to measure myeloperoxidase (MPO) activity and tumor necrosis factor (TNF)-alpha contents. It was found that endotoxin injection produced progressive hypotension, metabolic acidosis, and a large increase in the plasma NO2-/NO3- concentrations and increased mortality rates in 5 h. Endotoxin injection significantly increased MPO activity and TNF-alpha contents in lung tissue (P < 0.01 or P < 0.05). These changes response to endotoxin were significantly attenuated in the groups B, C and D. But these beneficial effects were blunted in the group E. The results suggest that propofol administration may offer advantages in endotoxemia.

The protective effects of early treatment with propofol on endotoxin-induced acute lung injury in rats.

UNLABELLED: To investigate the effects of treatment with propofol administration at different time point in acute lung injury of endotoxin-induced shock rats. METHODS: 76 male wistar rats were randomly assigned to five groups: A) control group; B) endotoxemic group, receiving intravenous lipopolysaccharide (LPS) 8 mg.kg-1; C) pretreatment group, treated identically to endotoxemic group with the additional administration of propofol (5 mg.kg-1 bolus, followed by infusion at 10 mg.kg-1.h-1) of 1 hr prior to the injection of LPS; D) simultaneously treatment group, treated identically to endotoxemic group with the additional administration of propofol simultaneously with the injection of LPS; E) post-treatment group, which was treated identically to endotoxemic group except for administration of propofol 1 hr after the injection of LPS. PaO2, pH, MAP and survival rate were recorded and plasma NO, TNF-alpha were measured during 5-hr after the injection of LPS. After the rats were killed, lung tissue was sampled to measured expression of inducible nitric oxide synthase (iNOS), nitrotyrosine (NT), myeloperoxidase (MPO) activity, malondialdehyde (MDA), wet-to-dry lung weight ratio (W/D), and pulmonary permeability index (PPI). RESULTS: Compared with the endotoxemic group, both the pretreatment and simultaneously treatment groups, significantly improved PaO2, pH, MAP and 5th hour survival rate of rats, and attenuated endotoxin-induced increased iNOSmRNA, NT expression, MPO activity and MDA level in lung tissue, and decreased pulmonary microvascular permeability, TNF-alpha, NO in plasma. But these beneficial efficacies were blunted in the post-treatment group. CONCLUSIONS: These findings showed that propofol administration may provide protective effects on acute lung injury in endotoxin-induced shock.