Theincreasedmicrovascularpermeabilityappearsmainlyinvenuleduringinflammation , shock ,andburns .Endothelialcellsplayanimportantroleinvenulepermeabilityenhancement.Therearetwo kindsofpathwayformacromoleculeextravasation .Oneisparacellularpathwayandanotheristranscellular pathway ,whicharerelatedtotheformationofendothelialgaportranscellularopeningsseperately .Thealter ationofintercellularrelatedprotein ,suchasoccludin ,claudin ,zonaoccludens (ZO) ,junctionaladhesion molecule (JAM) ,VE -cadherin ,catenin ,integrin ,etc ,andthealterationofendothelialcytoskeleton ,such asrearrangementofactinfilament,formationofstressfiberandfocaladhesion ,etc ,involveinthepathogenesis ofincreasedmicrovascularpermeability . [

Endogenous carbon monoxide (CO) is proposed to be an intracellular signaling molecule. As a new gaseous messenger, CO shares with nitric oxide (NO) the ability of modulating neuroendocrine function and inducing vasorelaxation, mainly by stimulating soluble guanylate cyclase and regulating the level of cGMP. This review emphasized the endogenous source of CO and the interaction of CO- and NO-generating systems. It also discussed the biological effects of CO and the underlying mechanisms.

The flow distribution of leukocytes in the microvasculature of rat skeletal muscle during hemorrhagic shock was measured by Microcirculation Image Multiple Parameters Computer Analysis System (MIMPCAS). It was found that the change of leukocyte flow distribution had taken place in V3 during hemorrhagic shock as follows: central axial-flowing leukocytes moved slowly, marginated to the vessel wall then started to roll along the wall, and stuck to the endothelium at last. During transfusion blood flow became faster, sticking leukocytes were rushed out to be rolling along the vessel wall and accelerated to enter the central stream. Total leukocyte -endothelium contact time (TLECT), which is a quantitative index for leukocyte endothelium interaction, is calculated, and it was found that TLECT was prolonged in shock state. The results show that it is not enough to increase blood pressure and shear stress to liberate sticking leukocytes, and it is necessary to search for a new approach to decrease the adhesive force between leukocyte and endothelium. Polygonum cuspidatum may not only increase wall shear rate but also decrease the adhesive force.

Vascular hyperpermeability is a cardinal feature of inflammation or burn in which an array of inflammatory mediators can cause such changes in the microvessels. The functional measures of microvascular exchange that represent the properties of microvascular walls are the permeability coefficients which have been reported from measurements on intact whole organisms (including human subjects), on perfused tissues and organs, on single perfused microvessels, and on monolayers of cultured microvascular endothelial cells. In this review, we summarize some experiments of vascular permeability in individually isolated perfused microvessels. [

NF-?B is thought of as a genetic switch to control expressions of many target genes and directly participates in pathogenesis of infection, inflammation, stress, immunoresponse, cellular apoptosis, toxic shock and tumor as well as cell-cycle regulation and cell differentiation. The overactivation of NF-?B is intimately involved in many human diseases. Various therapeutic strategies against NF-?B, to date, include anti-inflammatory drugs, antioxidants, immunosuppressive agents, inhibitors of protease and proteasome, prostaglandings, nitric oxide, IL-10, microbial products, synthetic inhibitors, antisense oligonucleotides and decoy deoxyoligonucleotides. Studies are underway to develop NF-?B member-specific and cell type-specific drugs that can inhibit the activation of NF-?B only in target cells and that may become a novel way to treat the human diseases.

AIM: To investigate whether small GTPase RhoA's downstream effector Rho kinase mediates burn serum-induced endothelial hyperpermeability. METHODS: Primary cultured rat dermal microvascular endothelial cells (DMECs) were exposed to serum isolated from burned or sham burn rats for 6 hours and 8 hours, respectively, and did or didn't pretreated or post-treated with Y-27632 (30 ?mol/L), a specific inhibitor of Rho kinase. ECs were then prepared for routine scanning electron microscopy observation, or stained with rhodamine-phalloidin for F-actin visualization. Permeability to FITC-albumin was evaluated using EC monolayers. RESULTS: Stimulation with 15% burn serum for 6 h changed the ultrastructure on cellular surface of DMECs with appearance of ripple marks instead of microvillus. The small protuberances at cellular lateral were shorten and the gaps were seen between adjacent cells. Post-treatment of Y-27632 reversed the changes of ultrastructure on the cellular surface. Burn serum induced a striking reorganization of actin cytoskeleton with a weakening of fluorescent intensity of the peripheral filament bands and formation of the long and thick stress fibers, lamellipodia and filopodia. The stress fibers were diminished by pretreatment or post-treatment of Y-27632. But lamellipodia and filopodia were not influenced by pretreatment or post-treatment of Y-27632. Pre-treatment of Y-27632 also attenuated significantly the increase in EC monolayer permeability stimulated by burn serum for 6 h. However, post-treatment of Y-27632 could not attenuated burn serum-induced endothelial hyperpermeability response although their Pa values were lower than simple burn serum group's. CONCLUSION: These findings indicate that Rho kinase is involved in the mediation of burn serum-induced endothelial actin cytoskeleton reorganization and early stage of barrier dysfunction. [

Objective To determine the effects of two fluid resuscitation strategies on the changes of hemodynamic variables,serum concentration of tumor necrosis factor-alpha(TNF-α)and interleukin-6 (IL-6)in a clinically relevant model of uncontrolled hemorrhagic shock in pregnant rabbits.Methods Hemorrhagic shock was induced by bleeding via carotied artery,followed by transection of a medium vessel in gestational sac.Experimental design consisted of three phases,shock phase(0-30 min),prehospital phase(30-90 min)and hospital phase(90-180 min).Twenty pregnant rabbits were randomly divided into two groups(n=10/group),aggressive fluid resuscitation group(PNL group)and limited volume resuscitation group(PLH group).In the shock phase,animals were hemorrhaged by blood withdrawal to mean arterial pressure(MAP)of 40-45 mm Hg(1 mm Hg=0.133 kPa)via carotid artery.In the prehospital phase,a medium vessel in the gestational sac was transected,then the animals in the PNL group and PLH group were resuscitated with 0.9% normal saline(NS)and shed blood to MAP of 80,60 mm Hg respectively.In the hospital phase,bleeding was controlled by surgical intervention and all the animals were reinfused with shed blood and NS to MAP 80 mm Hg.Hemodvnamic variables and respiration rate were monitored and blood samples were collected for TNF-α and IL-6 measurement.and finally subsequent volume resuscitation and survival rate were recorded.Results (1)At 120 min,the respiration rate and heart rate in the animals assigned to PLH group was(66±16)bpm,(235±41)bpm respectively,which were significantly lower than those in PNL group(P＜0.01),while MAP and central venous pressure in the PLH group was(80.4±7.2)mm Hg,(8.0±4.4)cm H2O,respectively,which were significantly higher than those in PNL group(P＜0.01);(2)The serum concentration of TNF-α,IL-6 of all the animals were markedly increased after hemorrhagic shock.and peak at 24 min.The serum concentration of TNF-α,IL-6 in animals assigned to PLH group were(105±67)ng/L,(118±51)ng/L respectively,which were significantly lower than those in PNL group(P＜0.01).The serum concentration of TNF-α,IL-6 in the animals assigned to PLH group were decreased to normal at 480 min;(3)The subsequent blood transfusion volume and NS resuscitation volume in PLH group in prehospital phase were(16.0±2.2)ml,(39.0±5.5)ml respectively,while those in hospital phase were(28.0±6.7)ml,(90.0±7.1)ml respectively,which were significantly lower than those in PNL group(P＜0.05);(4)The 24 and 72 hours survival rate in the animals assigned to PLH group were 100%,90% respectively;which were significantly higher than those in PNL group(P＜0.01).Conclusion Limited volume resuscitation improves thermodynamic changes of pregnant rabbit,attenuates the increase of serum concentration of TNF-α,IL-6,and results in higher survival rate.Limited volume resuscitation is an ideal means for hemorrhagic shock resuscitation in pregnant rabbit.

Microscopic studies of the skin and visceral microcirculation were made in rabbits with burn shock. Based upon the observations, the development of burn shock can be divided into 3 stages, namely: stage of excitation, stage of relative compensation and stage of decompensation. In the stage of relative decompensation, there is dilatation of the venules, margination of the WBC, agglomeration of RBC, stagnation of blood flow in the microcirculation. Margination of WBC increases the post-capillary resistance, and agglomeration of RBC hinders the blood flow in the microcirculation.Consequently, the stage of decompensation ensues. Histologically, extensive congestion of the heart, liver, spleen, lungs and kidneys was found. Hemorrhage in the lungs and thrombi in the pulmonary and renal venules were found as well.We suspected that the masses of the agglomerated cells or small thrombi obstructing pulmonary vessels might be one of the direct causes leading to the temporary stagnation or slowing down of the blood flow. As the shear velocity of the blood flow increases, dissociation of the agglomerated cell masses occurs, blood pressure will be lowered temporarily and blood flow will slow down. Obstruction of the pulmonary vessels by the cell masses, therefore, may play an important part in the development of burn shock.

AIM: To study the effect of microelement powder (MP) on membrane potential of vascular endothelial and smooth muscle cells of rats in order to elucidate the mechanism of microcirculation improvement by MP. METHODS: Cultured pulmonary vascular endothelial cells (EC) and aortic smooth muscle cells (SMC) of rats and detecting the changes of cellular membrane potentials by using potential-sensitive fluorescent probe and laser jet confocal microscope. RESULTS: MP hyperpolarized SMCs significantly. Glybenclamide (2 μmol/L), a blocker of KATP channel, which had no effect on membrane potential of SMCs, reversed the hyperpolarization of MP completely; MP hyperpolarized ECs slightly, but the effect was unaffected by glybenclamide. CONCLUSION: MP hyperpolarizes SMCs by activating KATP channels and leads to dilation of microvessels and improvement of microcirculation.

Objective To elucidate the role of P38 signaling pathway on heat-induced apoptosis in monocytic cell line Raw264.7.Methods Raw cells were transfected with constitutively active mutant MKK6b(E)and dominant negative mutant P38(AF),or the empty cloning vector pcDNA3 and apoptosis was detected by flow cytometric analysis.Results The ectopic expression of P38 mutant was confirmed by immunostaining with the antibody against the Flag-epitope tag.Expression of MKK6b(E)led to a marked increase in P38 kinase activity in transfected cells and induced a 4-fold increase in the number of apoptotic cells as compared to that in cultures of control transfected cells.Meanwhile the expression of MKK6b(E)increased the apoptotic rate of Raw cells induced by heat.In contrast,the dominant-negative mutant P38(AF)inhibited Raw cells apoptosis induced by heat.Conclusion The activation of the MKK6-P38 MAP kinase signaling pathway is required for heat-induced apoptosis in Raw264.7 cells.