Objective To investigate the effects of norepinephrine (NE) on vascular endothelial growth factor (VEGF) expression of brain tissues in severe burn rats. Methods The healthy male Wistar rats were made into 40%TBSAⅢ?burn models to observe the effect of NE on blood brain barrier. In the meantime, effect of NE was examined by means of immunocytochemistry and real time PCR. Results (1) Permeability of blood brain barrier was increased in burn and burn with NE stimulating rats, with significantly statistical difference compared with normal control group (P

Objective To investigate the effects of norepinephrine on brain edema of rats in 24 h after severe burn.Methods A total of 48 healthy Wistar rats were randomly divided into 8 groups: normal control group,1,2,5 mg/kg norepinephrine,burn group,burn with 1,2,5 mg/kg norepinephrine pretreatment groups(n=6 in each group).The rats in all burn groups were scalded into 40%TBSAⅢ degree burn.Pathological features were observed,and blood brain barrier,brain water(%) were examined in postburn 24 h.Results Pathological evidence of brain edema exhibited in the burn group and burn group with norepinephrine pretreatment,and increased permeability of blood brain barrier and brain water were observed.The burn with norepinephrine pretreatment groups were more significantly severe in comparison with simple burn groups and normal control group.Conclusion Norepinephrine may play an important role in brain edema in postburn 24 h,suggesting that stress of postburn may induce brain edema.

To explore the role of apoptosis, apoptosis regulating genes in the pathogenesis and development of smoke inhalation injury. With smoke inhalation injury rat model, the changes int the expression of Bcl 2, Bax, Fas, FasL genes mRNA and protein contents and their relationship with apoptosis of lung tissue cells at different time points after the injury were observed with TUNEL, immunohistochemistry and RT PCR techniques. The results showed that: ①apoptosis indet of lung colls after smoke inhalation injury increased, ②expressions of Bcl 2, Bax, Fas, FasL genes were obviously up regulated in injury group, peaking at the 12th hour, whereas the peak of protein expression was at the 24th hour. Furthermore, a significant correlation was found between the expression of Fas, Fasl, Bax gene and apoptosis indices in lung cells. The results suggested that apoptosis participated in the early pathological process of smoke inhalation injury, and apoptosis regulating genes foot part in the regulation of apoptosis in smoke inhalation injury.

Objective To screen and analyze genes up regulated in human umbilical vein endothelial cells (HUVEC) stimulated by lipopolysaccharide (LPS). Methods Suppression subtractive hybridization (SSH) was performed between the unstimulated HUVEC(driver) and HUVEC stimulated with LPS(tester) to generate subtractive cDNA library. The library was screened with colony dot hybridization to further verify the differentially expressed cDNA clones. Positive clones were sequenced and BLAST analyzed. The 3 novel cDNA sequences were verified by RT PCR. Results Twenty five up regulated genes related to inflammation, cellular cytoskeletal rearrangement, cellular proliferation and apoptosis, intercellular message transduction, and 3 new expression sequence tags (EST) were acquired. RT PCR indicated the expression of the new ESTs only in HUVEC stimulated by LPS. Conclusion SSH is a powerful technique of high sensitivity for the detection and clone of up regulated gene expressed in HUVEC stimulated by LPS, which may be helpful to clarify the mechanism of endothelial cells activation stimulated by LPS.

Objective To investigate the changes of myocardial mitochondrial permeability transition pore(PTP) and its mechanism in the early stage after severe burns. Methods An experimental model of 30% TBSA full thickness skin scalding was established in rats. All rats were injected with deoxyglucose(DOG) before sacrifice. Myocardial mitochondrial DOG and cytochrome c content, Ca 2+ concentration([Ca 2+ ] m) and MDA content were determined. Results ① There were no obvious changes of mitochondrial DOG and cytochrome c content at 1 h after burns, but mitochondrial DOG increased evidently at 3, 6, 12 and 24 h after burns. Meanwhile, cytochrome c content was significantly lower than that of the control, being 68.8%, 50.0%, 77.1% and 72.9% of that in the control, respectively. ② [Ca 2+ ] m and MDA content were significantly higher than those of the control at 3, 6, 12 and 24 h after burns. ③ Mitochondrial DOG content was positively correlated with [Ca 2+ ] m and MDA content, respectively, after burns. Conclusion There is no obvious change in myocardial mitochondrial permeability transition pore, but PTP opening increases markedly at 3, 6, 12 and 24 h after burns. Mitochondrial Ca 2+ overloading and increase in free radicals may be the cause leading to PTP opening.

Objective To investigate the roles of the activated p38 kinase in cell injury by observation of the effects of hypoxia and burn serum on cardiomyocyte p38 kinase and JNK activation. Methods Phosphorylation of p38 kinase and JNK in primary cultured neonatal rat cardiomyocytes before and after hypoxia and burn serum was determined by Western blotting. Effects of pretreatment with SB203580 at the dose of 10 ?mol/L on the changes of phosphorylation of p38 kinase in cardiomyocytes, lactate dehydrogenase (LDH) activity, cell vitality and apoptosis were investigated, respectively. Results Exposure of rat neonatal cardiomyocytes to hypoxia and burn serum resulted in a rapid and long lasting activation of p38 kinase but no significant activation of JNK. SB203580(10 ?mol/l), a selective inhibitor of p38 kinase, could inhibit p38 kinase activation dramatically, decrease the LDH activity in culture media and cell apoptosis significantly and improve cell vitality. Conclusion In the two stress activated signal pathways of MAPKs family, p38 kinase pathway, but not JNK, is the major pathway activated by hypoxia and burn serum and participates in the cardiomyocyte injury.

Objective To investigate the protective effects of diazoxide on cardiomyocytes after severe burn injury Methods A total of 24 healthy Wistar rats were randomized into normal control group(Control), burn group(Burn) and diazoxide treated group(Diazo)( n =8) Rats in Burn and Diazo groups were inflicted with 30%TBSA Ⅲ degree burn and resuscitated with Ringer's solution intraperitoneally 30 min after burn Diazoxide was injected into rats in Diazo group at the dose of 10 mg/kg through the external jugular vein After rats were sacrificed at 6 h after burn, myocardial mitochondrial K + influx, respiratory function, Ca 2+ concentration ([Ca 2+ ]m), MDA content, serum CK and LDH levels were determined Results Mitochondrial K + influx of Diazo group was evidently higher than that in Control and Burn group Mitochondrial respiratory control rate(RCR) and ST 3 in Diazo group were higher than that in Burn group However, [Ca 2+ ]m, MDA, CK and LDH levels in Diazo group were significantly lower than those in Burn group Conclusion Diazoxide can attenuate the damage to cardiomyocytes after severe burn injury, which might be related to the opening of mitochondrial K + channel, inhibition of mitochondria from Ca 2+ overloading and decrease of free radical production

AIM: To study the effects of nitric oxide (NO) on mitochondrial damage caused by exogenous calcium. METHODS: Normal myocardial mitochondria were divided into three groups; L- arginine control group (CG), Ca2 + - damaged group (DG) and L - NAME - preserved group (PG). Mitochondria of all groups were incubated at 30℃ with reaction medium containing 20μmol/L EDTA, 100μmol/L CaC12 and 1 μmol/L L- NAME with 100μmol/L CaCl2 respectively. Then the NO2-/NO3- contents, mitochondrial viability and membrane potential were investigated. RESULTS: The NO2-/NO3 contents of DG was obviously higher than that of CG and PG, meanwhile, there was no obvious difference between CG and PG. Mitochondrial viability and membrane potential of DG were significantly lower than that of CG and PG, and negatively related to NO2-/NO3- contents ( r = - 0.5297, P < 0.01; r = -0.6041, P < 0.01 ). But, the mitochondrial viability and membrane potential of PG were still lower than that of CG. CONCLUSION: Exogenous calcium could activate mitochondrial nitric oxide synthase resulting in NO production and the latter play an important role in decreasing mitochondrial viability and membrane potential.

Objective To investigate the therapeutic effects of delayed lung lavage with exogenous pulmonary surfactant(PS)diluent on endogenous surfactant system dysfunction and acute respiratory failure caused by severe smoke inhalation in rats.Method Ninety Wistar rats were randomly separated into five groups:Group I,normal control(n=14);Group Ⅲ,smoke inhalation(n=27);GroupⅢ,smoke+PS lavage+mechanical ventilation(MV),n=21;Group IV,smoke+saline lavage+MV,n=10;Group V,smoke+MV,n=18.The lungs were lavaged with 30 ml/kg normal ssdine containing 100 mg/kg PS or same volume of saline via tra cheal catheter at 2 h after smoke inhalation,then the animals were placed on a ventilator for 4 h,and observed until 24 h after injury.The arterial blood gas level,lung water volume,static lung compliance(Cst),total protein and albumin contents in bronchoalveolar lavage fluid(BALF),surface tension properties of BALF,and fatality rate at 24 h were measured.Results Smoke inhalation caused a similar acute hypoxia and severe carbon monoxide poisoning immediately in all injured groups.The animals in group Ⅱ showed acute respiratory failure,serious hish permeability pulrnonary edema,and surfactant system dysfunction.The surface tension properties of BALF and Cst were significantly improved by delayed lung lavage treated with exogenous PS diluent in group m(P<0.05).However,the lung water volume,total protein and albumin contents in BALF and the oxygenation had not significant difference between group Ⅲ and group Ⅱ(P>0.05).Conclusions Delayed lung lavage with exogenous PS diluent,at a certain extemt,restored endogenous suffactant function inhibited by smoke inhalation and improved lung function.Nevertheless,the trent could not alleviate rash permeability pulmonary edema and respiratory failure drarnatically.The expected decrease of mortality at early stage after smoke inhalation injury was not showed yet.

AIM: To study the effects of nitric oxide (NO) on mitochondrial damage caused by exogenous calcium. METHODS: Normal myocardial mitochondria were divided into three groups; L-arginine control group (CG), Ca 2+-damaged group (DG) and L-NAME-preserved group (PG). Mitochondria of all groups were incubated at 30℃ with reaction medium containing 20 ?mol/L EDTA, 100 ?mol/L CaCl 2 and 1 ?mol/L L-NAME with 100 ?mol/L CaCl 2 respectively. Then the NO- 2/NO- 3 contents, mitochondrial viability and membrane potential were investigated.RESULTS: The NO- 2/NO- 3 contents of DG was obviously higher than that of CG and PG, meanwhile, there was no obvious difference between CG and PG. Mitochondrial viability and membrane potential of DG were significantly lower than that of CG and PG, and negatively related to NO- 2/NO- 3 contents (r=-0.5297, P