Analysis of microRNA expression profile in serum of patients with electrical burn or thermal burn / 中华烧伤杂志

Objective@#To explore the differential expression of microRNAs in the serum among patients with electrical burn or thermal burn and healthy persons and to explore the significance.@*Methods@#In this study we included three patients with electrical burn and three patients with thermal burn, conforming to the inclusion criteria and hospitalized in our burn ward from June to August 2015, and three healthy adult volunteers. Their serum samples were separated from whole blood and divided into electrical burn group, thermal burn group, and normal control group. Total RNA was extracted from their serum samples using Trizol method. The differentially expressed microRNAs (with differential ratio larger than or equal to 2.000, less than or equal to 0.500) among the three groups were screened by microRNA chip technique. Then cluster and Venn diagram analysis of the differentially expressed microRNAs were performed. Enrichment analysis of Kyoto encyclopedia of genes and genomes (KEGG) signaling pathway was performed on the distinctly changed microRNAs (with differential ratio larger than or equal to 5.000, less than or equal to 0.500).@*Results@#There were 220 differentially expressed microRNAs among serum of the three groups. MicroRNA expression profiles in serum of electrical burn and thermal burn groups were different from that in serum of normal control group. Compared with those in serum of normal control group, the expressions of 59 microRNAs changed more than 2.000 times in serum of electrical burn group, with 50 up-regulated microRNAs and 9 down-regulated microRNAs; the expressions of 40 microRNAs changed more than 2.000 times in serum of thermal burn group, with 21 up-regulated microRNAs and 19 down-regulated microRNAs. Compared with those in serum of thermal burn group, the expressions of 167 microRNAs changed more than 2.000 times in serum of electrical burn group. There were 17 exclusively expressed microRNAs in serum of thermal burn group and 26 exclusively expressed microRNAs in serum of electrical burn group, compared with those in serum of normal control group. Enrichment analysis of KEGG signaling pathway showed that compared with those in serum of normal control group, microRNAs which changed distinctly in serum of electrical burn group took part in the insulin secretion signaling pathway, arrhythmogenic right ventricular cardiomyopathy signaling pathway, hypertrophic cardiomyopathy signaling pathway, glutamatergic synapse signaling pathway, calcium signaling pathway, cyclic adenosine monophosphate signaling pathway, glycerophospholipid metabolism, pyrimidine metabolism, serotonergic synapse signaling pathway, etc, while microRNAs which changed distinctly in serum of thermal burn group took part in the tumor transcription misregulation signaling pathway, proteoglycans in tumor signaling pathway, microRNAs in tumor signaling pathway, long-term potentiation signaling pathway, citrate cycle signaling pathway, tumor necrosis factor signaling pathway, focal adhesion signaling pathway, endocytosis signaling pathway, insulin secretion signaling pathway, p53 signaling pathway, and estrogen signaling pathway, etc.@*Conclusions@#MicroRNA expression profiles in serum of electrical and thermal burn are different from that in serum of healthy adult. The signaling pathways enriched with target genes which are regulated by the differentially expressed microRNAs are related to the pathological changes and clinical manifestations after electrical or thermal burn.

Expression of microRNA-126 in myocardial tissue of rats in the early stage of severe burn injury and its relation with myocardial damage / 中华烧伤杂志

<p><b>OBJECTIVE</b>To observe the changes in the expressions of microRNA-126 in myocardial tissue and cardiac troponin I (cTnI) in serum of rats in the early stage of severe burn injury with analysis of their relationship, and to validate the relationship between microRNA-126 and myocardial damage in cellular level.</p><p><b>METHODS</b>(1) Forty-eight SD rats were divided into sham injury group (n=8, without fluid therapy after sham injury) and burn injury group (n=40, inflicted with 30% TBSA full-thickness scald on the back, hereinafter referred to as burn, and received intraperitoneally injection of lactic acid Ringer's solution) according to the random number table. Blood was collected from abdominal aorta of rats in sham injury group at post injury hour (PIH) 1, and then these 8 rats were sacrificed for obtaining left ventricular tissue. Blood was respectively collected from abdominal aorta of 8 rats in burn injury group at PIH 3, 6, 12, 24, and 48, and then they were sacrificed and the left ventricular tissue was obtained at each time point. The expression of microRNA-126 in myocardial tissue was assessed by real-time fluorescent quantitative RT-PCR. Serum level of cTnI was assessed by ELISA. (2) Rat myocardial cell line H9C2 was divided into normal control group (NC, routinely cultured), stimulation group (S), negative transfection+stimulation group (NT+S), and transfection+stimulation group (T+S) according to the random number table. Cells in S group were treated with hypoxia for 24 h after being cultured with DMEM containing 10% burn serum obtained from rats in burn injury group at PIH 6 in experiment (1). Cells in NT+S group and T+S group were respectively transfected with the negative control of microRNA mimics and microRNA-126 mimics for 24 h, and then were given the same treatment as that of S group. The expression of microRNA-126 in myocardial cells was determined by real-time fluorescent quantitative RT-PCR (with the sample number of 3). Cell counting kit 8 was used to examine the vitality of myocardial cell (with the sample number of 4, denoted as absorbance value). Apoptotic rate of myocardial cells was determined by flow cytometer (with the sample number of 3). Data were processed with one-way analysis of variance and LSD-t test. The relationship between microRNA-126 expression in myocardial tissue and serum level of cTnI of rats was assessed by linear correlation analysis.</p><p><b>RESULTS</b>(1) Compared with that of sham injury group at PIH 1, the expression levels of microRNA-126 in myocardial tissue of rats in burn injury group at PIH 3, 6, 12, 24, and 48 were significantly decreased (with t values from 5.68 to 9.79, P values below 0.01), reaching its nadir at PIH 24 (0.40 ± 0.08). Compared with that of sham injury group at PIH 1, the serum levels of cTnI of rats in burn injury group at PIH 3, 6, 12, 24, and 48 were significantly increased (with t values from 6.68 to 12.79, P values below 0.01), peaking at PIH 12 [(1 035 ± 177) pg/mL]. A significant negative correlation between the expression level of microRNA-126 in myocardial tissue and serum level of cTnI was observed in rats of burn injury group at each time point (r=-0.797, P<0.001). (2) Compared with those of NC group, the microRNA-126 expression levels in myocardial cells of S group and T+S group were respectively decreased and increased (with t values respectively 4.57 and 5.73, P<0.05 or P<0.01), the cell vitality levels were obviously decreased (with t values respectively 14.88 and 6.48, P values below 0.01), and the apoptotic rates were significantly increased (with t values respectively 13.82 and 6.96, P values below 0.01). Compared with that in NT+S group, the microRNA-126 expression level in myocardial cells of T+S group was significantly increased (t=6.77, P<0.01), the cell vitality level was obviously increased (t=8.23, P<0.001), and the apoptotic rate was significantly decreased (t=6.14, P<0.001).</p><p><b>CONCLUSIONS</b>Expression level of microRNA-126 in myocardial tissue of rat was decreased in the early stage of severe burn injury. It may participate in regulating myocardial damage and play a protective role.</p>

Effect of monocyte-secreted VEGF induced by electrical burn serum on monocyte-endothelial cell adhesion / 中国病理生理杂志

AIM: To observe the level of vascular endothelial growth factor (VEGF) secreted by monocytes cultured with electrical burn serum, and to explore the effect of VEGF on monocyte-endothelial cell adhesion.METH-ODS:The electrical burn serum of the rat was prepared.The normal serum from the rats without treating electric current was also collected for control.The contents of VEGF and its soluble receptor sFlt-1 in electrical burn group were determined by double-antibody sandwich ELISA.THP-1 cells were randomly divided into normal serum group and electrical burn serum group.The contents of VEGF and sFlt-1 in the culture supernatants were measured by double-antibody sandwich ELISA. THP-1 cells were also randomly divided into another 4 groups:normal serum group, electrical burn serum group, normal serum +inhibitor group and electrical burn serum +inhibitor group.THP-1 cells, which were incubated with the serum for 3 h and 6 h, were labeled with calcein-AM and then were added into the well with monolayer of endothelial cell line EA.hy926 to detect monocyte-endothelial cell adhesion.RESULTS:The levels of serum VEGF of the rats with electrical burns were significantly increased, the levels of serum sFlt-1 were significantly decreased as compared with the controls. The levels of VEGF secreted by THP-1 cells cultured with electrical burn serum were significantly increased, the levels of sFlt-1 were decreased correspondingly.Electrical burn serum enhanced monocyte-endothelial cell adhesion, sFlt-1 inhibi-ted the adhesion between monocytes and endothelial cells.CONCLUSION:The monocytes exposed to the electrical burn serum secrete VEGF, which enhance the adhesion between monocytes and endothelial cells.Blockage of VEGF activity may effectively inhibit monocyte-endothelial cell adhesion.

Effects of low molecular weight heparin on the inflammatory response and vascular injury in rat after electric burn / 中华烧伤杂志

<p><b>OBJECTIVE</b>To observe the effects of low molecular weight heparin (LMWH) on the inflammatory response and vascular injury in rat after electric burn.</p><p><b>METHODS</b>A homemade regulator and transformer apparatus was used to reproduce the model of electric burn (0.5 cm×0.5 cm in size) with depth from full-thickness to full-thickness skin plus muscle and bone on the middle of the inside of right hind limb in 60 Wistar rats. The open wounds were covered with 20 g/L sulfadiazine silver paste immediately after injury. The wound condition was observed every day. The injured rats were divided into group LMWH and control group (C) according to the random number table, with 30 rats in each group. Rats in group LMWH were given subcutaneous injection of LMWH (1 U/g) in abdominal wall, 2 times a day. No other treatment was given in rats in group C. On post burn day (PBD) 3, 5, and 10, 10 rats respectively of two groups were sacrificed. The damaged tissue of wound and that around the wound (1.0 cm×0.5 cm in size) were excised, and heart blood was obtained. The pathological changes and thrombosis in damaged tissue were observed with HE, Masson, and aldehyde fuchsin staining, and the thrombosis rate was calculated. Serum contents of TNF-α and endothelin-1 were determined with ELISA. The mRNA expression of TNF-α in damaged tissue was detected with RT-PCR. Data were processed with Levene homogeneity test, analysis of variance of factorial design, LSD- t test, SNK- q test, and Friedman M nonparametric test.</p><p><b>RESULTS</b>(1) The injured limb of rats was obviously swollen after electric burn, which reached deeply to the muscle and bone. Compared with those of group C, the swelling of rats subsided slightly faster and the inflammatory response was lighter in group LMWH at each time point. (2) The necrosis of damaged tissue and profuse infiltration of inflammatory cells were observed. Dilatation of blood vessels, congestion and thrombosis, and swelling, necrosis, and desquamation of vascular endothelial cells were observed in the damaged tissue. Damaged blood vessel wall, ruptured elastic fiber, loss of internal elastic membrane, and other pathological changes were observed in the damaged tissue of rats in the two groups. Above lesions were improved gradually along with the passage of time, and the improvement was more obvious in rats of group LMWH compared with that of group C on PBD 5 and 10. (3) The thrombosis rates of rats in group LMWH were obviously lower than those of rats in group C (F = 4.921, P < 0.05). The thrombosis rates of rats in group LMWH on PBD 3 and 10 were respectively (0.07 ± 0.11)% and (0.03 ± 0.05)%, which were significantly lower than those of rats in group C [(0.16 ± 0.15)% and (0.13 ± 0.18)%, with t values respectively 2.17 and 2.07, P values below 0.05]. In group LMWH, the thrombosis rate of rats on PBD 10 was obviously lower than that on PBD 3 (t = 3.61, P < 0.05). (4) The serum contents of TNF-α and endothelin-1 of rats in group LMWH were significantly lower than those of rats in group C (F = 47.161, χ(2) = 81.46, P values below 0.01). In group LMWH, TNF-α contents were respectively (71 ± 24), (74 ± 14), (72 ± 20) pg/mL, and endothelin-1 contents were respectively (20.9 ± 3.2), (19.8 ± 5.2), (18.6 ± 1.1) ng/mL on PBD 3, 5, and 10, and they were significantly lower than those of rats in group C [(195 ± 148), (96 ± 20), (159 ± 46) pg/mL and (38.8 ± 15.4), (27.9 ± 3.6), (25.6 ± 7.6) ng/mL, with t values from 3.81 to 8.05, q values from 4.41 to 7.85, P < 0.05 or P < 0.01]. (5) The mRNA expression levels of TNF-α in damaged tissue of rats in group LMWH were significantly lower than those of rats in group C (F = 199.113, P < 0.01). The mRNA expression levels of TNF-α of rats in group LMWH were respectively 0.93 ± 0.10, 1.15 ± 0.12, 1.21 ± 0.11 on PBD 3, 5, and 10, and they were significantly lower than those of group C (1.68 ± 0.15, 1.43 ± 0.12, 1.50 ± 0.13, with t values from 3.75 to 6.12, P < 0.05 or P < 0.01). In group LMWH, the mRNA expression level of TNF-α of rats on PBD 10 was obviously higher than that on PBD 3 (t = 3.61, P < 0.05).</p><p><b>CONCLUSIONS</b>LMWH intervention can ameliorate vascular injury and inflammatory response of electrically burned wounds in rats, and it decreases thrombosis rate in the vessels of injured limb.</p>

Effects of microRNA-21 on the myocardial cell apoptosis induced by ischemia and hypoxia in rat / 中华烧伤杂志

<p><b>OBJECTIVE</b>To explore the effects of microRNA-21 on apoptosis of myocardial cell of rats as induced by ischemia and hypoxia, and to analyze the underlying mechanisms.</p><p><b>METHODS</b>(1) Rat myocardial cell line H9C2 was cultured in a serum-free and low glucose DMEM medium using a hypoxic incubator which was filled with 1% oxygen, 5% carbon dioxide, and 94% nitrogen to simulate ischemic environment. The expression of microRNA-21 in normal myocardial cells and cells treated with low oxygen exposure for 6 and 24 h were assessed by real-time fluorescent quantitative RT-PCR. (2) Another portion of myocardial cells were divided into 4 groups according to the random number table: normal control group (NC, ordinary culture without any treatment), ischemia/hypoxia group (IH, treated with ischemia and hypoxia for 24 h), negative transfection control+ischemia/hypoxia group (NC+IH, treated with ischemia and hypoxia for 24 h after the transfection of microRNA mimics control for 24 h), microRNA-21+ischemia/hypoxia group (M+IH, treated with ischemia and hypoxia for 24 h after the transfection of microRNA-21 mimics for 24 h). The cells in the latter three groups were examined immediately after treatment, and cells in group NC were collected and examined at the same time point. Apoptosis rate of myocardial cells was determined by flow cytometer. The mRNA and protein expression levels of programmed cell death 4 (PDCD4) in myocardial cells were determined by real-time fluorescent quantitative RT-PCR and Western blotting respectively. The sample numbers in this experiment were 6 or 3. Data were processed with one-way analysis of variance and LSD- t test.</p><p><b>RESULTS</b>(1) The expression level of microRNA-21 in normal myocardial cells and cells treated with ischemia and hypoxia for 6 and 24 h were respectively 1.09 ± 0.17, 0.75 ± 0.08, and 0.67 ± 0.08 (F = 11.280, P = 0.009). Compared with expression level of microRNA-21 in normal myocardial cells, those of cells treated for 24 h (t = 4.461, P = 0.004) and 6 h (t = 3.642, P = 0.011) were both lower, and the former was more obvious. Therefore all the ischemia and hypoxia treatment time of cells in the following experiment was 24 h. (2) The apoptosis rate of myocardial cells in group NC was (3.5 ± 0.7)%. After being treated with ischemia and hypoxia for 24 h, the apoptosis rates of myocardial cells in groups IH, NC+IH, and M+IH were respectively (17.3 ± 3.2)%, (16.4 ± 3.0)%, and (7.6 ± 2.0)% (F = 15.176, P = 0.001). Compared with that of group NC, the apoptosis rate of myocardial cells of group IH was significantly increased (t = 5.641, P < 0.001), while it was significantly decreased in group M+IH as compared with group NC+IH (t = 3.588, P = 0.007). The mRNA expression level of PDCD4 in group NC was 1.06 ± 0.21. After being treated with ischemia and hypoxia for 24 h, the mRNA expression levels of PDCD4 in groups IH, NC+IH, and M+IH were respectively 3.01 ± 0.34, 3.05 ± 0.25, and 1.48 ± 0.24 (F = 44.952, P < 0.001). Compared with that of group NC, the mRNA expression level of PDCD4 in group IH was higher (t = 8.945, P < 0.001), while it was significantly lower in group M+IH as compared with group NC+IH (t = 7.253, P < 0.001). The protein expression level of PDCD4 in group NC was 0.44 ± 0.08. After being treated with ischemia and hypoxia for 24 h, the protein expression levels of PDCD4 in groups IH, NC+IH, and M+IH were respectively 0.96 ± 0.13, 1.05 ± 0.12, and 0.58 ± 0.12 (F = 18.804, P = 0.008). Compared with that of group NC, the protein expression level of PDCD4 in group IH was higher (t = 5.429, P = 0.006), while it was significantly reduced in group M+IH as compared with group NC+IH (t = 4.903, P = 0.008).</p><p><b>CONCLUSIONS</b>Ischemia and hypoxia reduce the expression of microRNA-21 in myocardial cells, while increasing the expression of microRNA-21 can alleviate the ischemia/hypoxia-induced apoptosis by lowering the expression of PDCD4.</p>

Mechanism of drug resistance of carbapenems-resistant Acinetobacter baumannii and the application of a combination of drugs in vitro / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the mechanism of drug resistance of carbapenems-resistant Acinetobacter baumannii (CRAB) in burn patients and the antimicrobial activity of a combination of drugs against this bacteria in vitro.</p><p><b>METHODS</b>A total of 135 strains of Acinetobacter baumannii (AB) from wound excretion, sputum, and venous catheter wall of patients hospitalized in our department from January 2011 to July 2013 were collected individually. Drug resistance of 135 strains of AB to 12 antibiotics commonly-used in clinic was detected using K-B paper diffusion method. Among the CRAB strains, double-disk synergy test was used to screen metallo-β-lactamase (MBL)-producing strains, and the drug resistance rates between MBL-producing strains and non-MBL-producing strains were compared. Minimal inhibitory concentration (MIC), 50% MIC (MIC50), and 90% MIC (MIC90) of cefoperazone/sulbactam, imipenem, cefepime, ampicillin/sulbactam, and amikacin used alone against MBL-producing CRAB were determined by broth microdilution method. MIC, MIC50, and MIC90 of amikacin respectively combined with imipenem, cefoperazone/sulbactam, cefepime, or ampicillin/sulbactam against MBL-producing CRAB were determined by checkerboard method with diluted agar. Fractional inhibitory concentration (FIC) index was calculated to determine the antibacterial effect of each combination of two antibiotics. Synergy with FIC lower than or equal to 0.5, or additivity with FIC higher than 0.5 and lower than or equal to 1.0 was regarded as effective, and indifference with FIC higher than 1.0 and lower than or equal to 2.0 or antagonism with FIC higher than 2.0 was regarded as ineffective. The effective rate was calculated. Data were processed with Chi-square test.</p><p><b>RESULTS</b>The resistant rates of the 135 strains of AB to imipenem, meropenem, and ceftazidime were high, and those of piperacillin/tazobactam and ampicillin/sulbactam were low. A total of 120 strains of CRAB was screened, accounting for 88.89%, among which the MBL-producing strains accounted for 78.33% (94/120). The resistant rates of MBL-producing strains to piperacillin/tazobactam, imipenem, meropenem, piperacillin, and cefepime were respectively 59.5%, 87.2%, 93.5%, 87.0%, 86.0%, and they were significantly higher than those of non-MBL-producing strains (respectively 43.0%, 81.3%, 87.5%, 78.4%, 64.0%, with χ(2) values from 4.571 to 8.260, P < 0.05 or P < 0.01). Among the inhibition concentrations of each of the 5 antibiotics used alone against MBL-producing strains, MIC, MIC50, and MIC90 of ampicillin/sulbactam were the lowest, respectively 4.00, 16, 64 µg/mL, while those of cefepime were high, respectively 32.00, 128, 512 µg/mL. MIC, MIC50, and MIC90 of amikacin combined with each of the other 4 antibiotics were decreased from 50.00% to 98.44% as compared with that of single administration of each antibiotic. Among the 94 strains of MBL-producing CRAB, the synergic, additive, indifferent, and antagonistic effects were respectively observed in 40, 33, 6, and 15 strains applied with combination of amikacin and ampicillin/sulbactam; 42, 30, 5, 17 strains applied with combination of amikacin and cefoperazone/sulbactam; 38, 15, 19, 22 strains applied with combination of amikacin and cefepime; 34, 2, 37, 21 strains applied with combination of amikacin and imipenem, among which the antibacterial effective rates decreased successively, respectively 77.7%, 76.6%, 56.4%, and 38.3%. The former two rates were respectively significantly higher than the latter two rates (with χ(2) values from 8.618 to 29.889, P values below 0.01).</p><p><b>CONCLUSIONS</b>Production of MBL is the main mechanism of resistance of the CRAB isolated from burn patients hospitalized in our department against carbapenems in about 3 years. The antibacterial effects of amikacin combined with each of the former-mentioned 4 agents are better than those of each of the five antibiotics used singly, and the effects are particularly obvious when combining amikacin with compound agent containing enzyme inhibitors.</p>

Role of phosphoinositide 3 kinase/protein kinase B signal pathway in monocyte-endothelial adhesion induced by serum of rats with electrical burn / 中华烧伤杂志

<p><b>OBJECTIVE</b>To observe the change in phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) signal pathway in monocytes as induced by serum of rats with electrical burn, and to explore the effects of PI3K/Akt pathway on monocyte-endothelial cell adhesion.</p><p><b>METHODS</b>Sixty-four SD rats of clean grade were inflicted with electrical burn for the collection of serum of rats with electrical burn; another group of twenty-four SD rats were used to obtain normal serum without treatment. (1) Human monocyte line THP-1 was routinely cultured. The THP-1 cells in logarithmic phase were divided into normal serum group (resuspended in RPMI 1640 medium with 20% normal rat serum) and burn serum group (resuspended with RPMI 1640 medium with 20% serum of rats with electrical burn) according to the random number table, with 6 wells in each group. Morphology of THP-1 cells in normal serum group was observed at post culture hour (PCH) 24, and that in burn serum group at PCH 3, 6, 24. The contents of TNF-α in culture supernatant were determined by double-antibody sandwich ELISA at the corresponding time point in each group. The state of Akt activation was determined by Western blotting at PCH 3, 6, 24. (2) Another portion of THP-1 cells were divided into 4 groups according to the random number table, with 6 wells in each group. Cells in normal serum group and burn serum group were given with the same culture condition as above; cells in normal serum+inhibitor group and burn serum+inhibitor group were cultured with the same culture conditions as in the former two groups correspondingly with addition of 100 nmol/L wortmannin in the nutrient solution. At PCH 3 and 6, THP-1 cells were added into the well with a monolayer of endothelial cell line EA.hy926 to observe the monocyte-endothelial cell adhesion. Data were processed with one-way analysis of variance and LSD- t test.</p><p><b>RESULTS</b>(1) In normal serum group, THP-1 cells showed growth in suspension, with uniform shape at PCH 24. In burn serum group, the cell shape became irregular though the membrane was complete at PCH 3; cellular size became irregular and cell membrane and cytoplasm were swollen at PCH 6; cell membrane was disrupted with death of cells at PCH 24. The contents of TNF-α in culture supernatant in normal serum group at PCH 24 and in burn serum group at PCH 3, 6, 24 were respectively (38.5 ± 1.4), (75.1 ± 1.5), (91.5 ± 1.8), (117.0 ± 1.4) pg/mL (F = 1 415.306, P < 0.01). The contents of TNF-α in culture supernatant in burn serum group at PCH 3, 6, 24 were all significantly higher than the content of TNF-α in normal serum group at PCH 24 (with t values respectively 29.614, 42.852, 63.485, P values below 0.01). The ratio values of phosphorylated Akt to Akt in burn serum group at PCH 3, 6, 24 were respectively 2.66, 3.69, 1.17 times of those in normal serum group at the corresponding time point. (2) In normal serum group, normal serum+inhibitor group, burn serum group, and burn serum+inhibitor group at PCH 3 and 6, the numbers of THP-1 cells adherent to endothelial cells were respectively (231 ± 45), (280 ± 47), (703 ± 169), (335 ± 85) per 100-time field; (219 ± 49), (235 ± 21), (562 ± 123), (226 ± 29) per 100-time field (with F values respectively 25.630 and 18.975, P values below 0.01). The number of THP-1 cells adhered to EA.hy926 cells was significantly more in burn serum group than in normal serum group at PCH 3 and 6 (with t values respectively 6.189 and 6.601, P values below 0.01). The number of THP-1 cells adherent to EA.hy926 cells was significantly fewer in burn serum+inhibitor group than in burn serum group at PCH 3 and 6 (with t values respectively 6.821 and 6.465, P values below 0.01).</p><p><b>CONCLUSIONS</b>The serum of rats suffering from electrical burn can induce the monocytes to secrete TNF-α, thus enhancing monocyte-endothelial cell adhesion, but it can be inhibited by blocking PI3K/Akt signal pathway.</p>

Expression of microRNA-21 in myocardial tissue of rats in the early stage of severe scald injury and its mechanism / 中华烧伤杂志

<p><b>OBJECTIVE</b>To explore the molecular mechanism of microRNA-21 in myocardial damage of rats in the early stage of severe scald injury by observing the expression of microRNA-21 and programmed cell death 4 (PDCD4) in myocardial tissue of rat and to validate the relationship between them in cell model.</p><p><b>METHODS</b>(1) Forty SD rats were divided into sham injury group (n =8, sham injured) and scald injury group (n =32, inflicted with 30% TBSA full-thickness scald on the back) according to the random number table. The left ventricular tissue was collected from rats in sham injury group at post injury hour 1 without any fluid infusion. Rats in scald injury group were given an intraperitoneal injection of lactic acid Ringer's solution and 8 rats were respectively sacrificed at post injury hour 3, 6, 12, 24 to harvest left ventricular tissue. The expression of microRNA-21 in myocardial tissue was assessed by real-time fluorescent quantitative RT-PCR. The protein expression of PDCD4 in myocardial tissue was assessed by Western blotting. (2) Rat myocardial cell line H9C2 was divided into microRNA-21 inhibitor group (cells were transfected with microRNA-21 inhibitor) and negative transfection control group (cells were transfected with negative control of microRNA inhibitor) according to the random number table. At post transfection hour 48, real-time fluorescent quantitative RT-PCR and Western blotting were performed respectively to determine the mRNA and protein expression levels of PDCD4 in cells. Data were processed with one-way analysis of variance, LSD-t and two independent samples t test. The relationship between microRNA-21 expression and PDCD4 protein level in myocardial tissue of rats was assessed by linear correlation analysis.</p><p><b>RESULTS</b>(1) The expression levels of microRNA-21 in myocardial tissue of rats in sham injury group at post injury hour 1 and in scald injury group at post injury hour 3, 6, 12, 24 were respectively 0. 96 ± 0. 13, 0. 44 ± 0. 08, 0. 42 ± 0. 10, 0.33 +0.07, and 0.61 0.10 (F = 27.331, P <0.001). Compared with that in myocardial tissue of rats in sham injury group at post injury hour 1, expression level of microRNA-21 was significantly decreased in scald injury group at post injury hour 3, 6, 12, 24 (with t values from 4. 558 to 9.410, P values below 0.01). The protein expression levels of PDCD4 in myocardial tissue of rats in sham injury group at post injury hour 1 and in scald injury group at post injury hour 3, 6, 12, 24 were respectively 0.44 ± 0.05, 0.60 ± 0.09, 0.92 ± 0. 15, 0. 86 ± 0.11, and 0.57 ± 0. 10 (F =8.622, P =0.003). Compared with that in sham injury group at post injury hour 1, protein expression level of PDCD4 was significantly increased in scald injury group at post injury hour 6 and 12 (with t values respectively 4. 968 and 4. 122, P values below 0.01). A significant negative correlation between the expression of microRNA-21 and PDCD4 protein in myocardial tissue of rats of scald injury group was observed at each time point (r = -0. 572, P = 0. 026). (2) The mRNA and protein expression levels of PDCD4 of myocardial cells in microRNA-21 inhibitor group were respectively 1.73 ± 0. 29 and 0. 38 ± 0. 08, which were significantly higher than those in negative transfection control group (0.95 ± 0.14 and 0.23 ± 0.03, with t values respectively 4. 857 and 3.356, P <0.05 or P <0.01).</p><p><b>CONCLUSIONS</b>Expression of microRNA-21 was decreased, while expression of PDCD4 was increased, in myocardial tissue of rats in the early stage of severe scald injury. MicroRNA-21 might participate in myocardial damage in the early stage of scald injury by negatively regulating expression of PDCD4.</p>

Analysis of diagnosis and management of 21 patients with Marjolin's ulcers / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the clinical manifestation, diagnosis, and treatment of patients with Marjolin's ulcers.</p><p><b>METHODS</b>The clinical materials of 21 patients with Marjolin's ulcers hospitalized from January 2007 to January 2013 were retrospectively analyzed, including age, gender, injury causes, duration time of primary disease in developing Marjolin's ulcer, duration of ulcer, lesion site, ulcer area, symptoms and signs of ulcer region, bacterial culture results before operation, histopathological type, grade of carcinoma cell differentiation, depth of invasion, treatment, and outcome.</p><p><b>RESULTS</b>(1) The age of 21 patients at the time of diagnosis of Marjolin's ulcers was 19-74 (47 ± 13) years, and the ratio of male to female was nearly 0.9:1.0. (2) The main primary lesions were flame burns and high temperature liquid scald, respectively occurred in 12 cases (57.1%) and 7 cases (33.3%). The time for development of Marjolin's ulcers from primary injury was 10-56 (40 ± 14) years. (3) Ulceration on top of scar lasted for longer than one year in 12 patients (57.1%). (4) Lesion site was mainly located in the limbs in 13 patients (61.9%), and on head and face in 6 patients (28.6%), respectively. (5) Ulcer area ranged 0.25-74.25 (39 ± 25) cm(2). Foul excretion, bleeding, intensified pain, and gradual enlargement of ulceration were observed in the lesion of most patients. (6) Bacterial culture of wound excretion before operation showed positive results in 16 patients (76.2%).</p><p><b>RESULTS</b>of bacterial culture of blood were negative in all patients. (7) Pathological examination revealed squamous cell carcinoma in 20 cases and basal cell carcinoma in 1 case, and mostly of high or medium differentiation. Cancer cells in nearly 40% patients had invaded the subcutaneous tissue or deeper area. (8) All patients were treated by surgery, among them autologous skin grafting was done after excision of lesion in 11 patients, and in 5 patients the defects were closed with skin flaps after excision of lesion, and in 5 patients limbs harboring the lesion were amputated. Twelve patients (57.1%) received postoperative rehabilitation treatment. Two patients with pulmonary metastasis received chemotherapy. (9) Most of the flaps and skin grafts survived well after surgery, and a few cases with failure of skin grafting or transplantation of flaps underwent skin grafts again. Patients were followed up for 6 months to 5 years, in 4 patients recurrence occurred after surgery, and 2 of them died. The other patients survived without recurrence.</p><p><b>CONCLUSIONS</b>Squamous cell carcinoma was the most common pathological type of Marjolin's ulcer admitted to our unit. A recurrent ulcer with long course should be considered as Marjolin's ulcer, and it should be scrutinized pathologically. Currently, surgery remains the optimal treatment for Marjolin's ulcer. Regular follow-up should be carried out after resection of the lesion to detect carcinoma recurrence and metastasis.</p>