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Background: Severe burn causes acute lung injury in many victims, but the related mechanisms have been barely investigated. microRNAs (miRNAs) important regulators in numerous physiological and pathophysiological process. However, the roles of miRNAs in burn lung injury are untested., Methods: Six healthy male Sprague-Dawley rats were randomly assigned into burn and sham groups. Lung injury was evaluated by hematoxylin and eosin (HE) staining at 24 h after injury. Differentially expressed miRNAs were determined by array hybridization and verified by real-time quantitative polymerase chain reaction (RT-qPCR). Bioinformatics analysis was undertaken to predict the target genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases were employed to identify potentially related biological processes and pathways, respectively. Neutrophil infiltration and apoptosis of the lung were confirmed by immunohistochemical staining of myeloperoxidase (MPO) and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)., Results: HE sections showed obvious lung injury, and 21 upregulated and three downregulated miRNAs were detected. Target genes of these miRNAs were most highly enriched in inflammation and apoptosis related GO biological processes and pathways. Inflammation and apoptosis were confirmed by MPO and TUNEL staining., Conclusion: The differentially expressed miRNAs most likely participate in burn-induced lung injury by being involved in inflammation and apoptosis.

Objective: To investigate the effects of PRX-2 gene on phenotype changes in epidermal stem cells differentiating into sweat gland cells., Methods: Epidermal stem cells and sweat gland cells separated and cultured from healthy foreskin and adult full-thick skin respectively, were identified by immunofluorescence staining. Lentiviral vector-mediated overexpression and knockdown of PRX-2 gene in epidermal stem cells were performed respectively,with empty vector-mediated epidermal stem cells as a control group. Overexpression blank control and know down group's PRX-2 expressions in gene and protein levels were detected using RT-PCR and Western blot technology. The ESCs of each group were co-cultured with sweat gland cells through transwell plate, and the expressions of CEA and β1 integrin in epidermal stem cells were determined by flow cytometry before and after co-culturing., Results: Epidermal stem cells and sweat gland cells were in line with their respective specific antigens .Before co-cultured, epidermal stem cells highly expressed β1 integrin (98.69 ± 0.67)％,hardly expressed CEA (6.20 ± 3.15)％.After co-cultured,β1 integrin expression levels were showed as knockdown group (19.30 ± 0.53) ％ ＜blank control group (65.77 ± 2.32)％ ＜ overexpress group (92.63 ± 10.97)％,and CEA expression levels as knockdown (95.43 ±2.36)％ ＞ blank control group (51.20 ±0.79)％ ＞ overexpress group (45.91 ±0.93)％.There had significant differences between those of each two groups., Conclusions: PRX-2 gene can inhibit the phenotypic change of Epidermal Stem Cells differentiating into Sweat Gland Cells and improve the ability to maintain their own specific antigens.

Skeletal muscle atrophy, a conventional clinical feature in patients with cancer, chronic obstructive pulmonary disease, sepsis and severe burns, is defined as a reduction in muscle mass. During atrophy, the protein degradation is abnormally activated and the aberrance between protein synthesis and protein degradation results in muscle atrophy. Previous studies have demonstrated that miRNAs, small non-coding RNA molecules, serve an important role in the regulation of muscle atrophy. Further studies have indicated the implications of the ubiquitin-proteasome and PI3K/Akt/FoxO signaling pathways and myogenic regulatory factors in miRNA-mediated muscle atrophy. Therefore, in this review, the effects and molecular mechanisms of miRNAs on muscle atrophy are summarized, leading to the suggestion that miRNAs may serve as potential therapeutic targets in muscle atrophy.

Objective: To explore the phenotypic changes of epidermal stem cells (ESCs) differentiating into sweat glands cells (SGCs) in vitro and its mechanisms., Methods: ESCs and SGCs were isolated and cultured in vitro, which were identified using immunofluorescence staining. ESCs at passage 2 were divided into 4 groups: ESCs and SGCs co-cultured by Transwell plates in group A, ESCs cultured by simply adding sweat supernatant in group B, ESCs and SGCs co-cultured on Transwell plate adding epidermal growth factor (EGF) (60 ng/mL) in group C, and ESCs and SGCs co-cultured on transwell plate adding PD98059 (10 mmol/L) in group D. The inverted microscope was used for observing the morphology of ESCs, flow cytometry for detecting ESCs positive phenotype, and Western blot for exploring mitogen-activated protein kinase/extracellular signal regulated kinase (MAPK/ERK) pathway., Results: The morphology observation and immunofluorescence staining suggested that cultured cells were ESCs and SGCs. The inverted phase contrast microscope observation showed that cells had similar morphological changes, with flat polygonal shape at 9 days in groups A, C, and D; cells had slow morphological change in group B, and had similar change to that of other groups at 12 days. Significant decreasing of beta1-integrin expression and increasing of carcino-embryonic antigen (CEA) expression of ESCs were observed in group A when compared with group B, which was inhibited by EGF (group C) and enhanced by PD98059 (group D), and there were significant differences among groups A, C, and D (P<0.05). High level of ERK expression was displayed in 4 groups, but it was significantly lower in group B than the other 3 groups (P<0.05). The expression of phosphorylation ERK was the highest in group A and was the lowest in group C, showing significant difference among 4 groups (P<0.05)., Conclusion: ESCs can be induced to differentiate into SGCs with the phenotypic changes under the condition of co-cultured by Transwell plates. The MAPK/ERK pathway plays a key role in the diffrentation of ESCs into GCCs

Background: In this study, we will establish a stable and optimized rat model that can meet strictly diagnosed criteria and serve as a tool to investigate the potential of novel therapeutics in this preclinical model through comparative analysis of systemic alterations, levels of pro-inflammatory cytokines in serum and infiltrated numbers of inflammatory cells in distant organ between 30% and 50% TBSA with a full-thickness burn., Materials and Methods: The adult male Wistar rats were randomly divided into the following groups: control group, 30% TBSA with a full-thickness burn group, and 50% TBSA with a full-thickness burn group. The blood and serum samples in the 3 groups were collected and detected by blood routine examination and biochemical detection at 6 h, 12 h, 24 h and 48 h post burn. The levels of TNF-α, IL-1β and IL-6 in serum were detected by ELISA. The sections of lung, renal, liver and heart were analyzed by H&E and immunohistochemical staining detection., Results: Our results showed that temperature in 50% TBSA with a full-thickness burn group was always hypothermia, and lower than 36°C at defined timepoints post burn, that was in 30% TBSA with a full-thickness burn group was lower than 36°C only at 48 h post burn. The levels of TNF-α, IL-1β and IL-6 were significantly increased in 30% and 50% groups at 6 h, 12 h, 24 h and 48 h post burn. The apoptosis in distant organs and the biochemical parameters such as ALT, AST, troponin, CK, CK-MB, LDH, urea and creatinine in 30% and 50% groups were also increased at different degrees at defined timepoints after burn, but changes in 50% group were more obvious than that in 30% group., Conclusion: We choose 50% TBSA with a full-thickness burn to establish a stable and optimized rat model that can meet strictly diagnosed criteria and serve as a tool to investigate the potential of novel therapeutics in this preclinical model.

Objective: To explore the efficacies of resuscitation fluid volume after combined burn-blast injury versus a simple burn., Methods: A total of 24 beagle dogs were randomly assigned into 3 groups of normal volume (N), decreased volume (D) and increased volume (I). Fluid volume for group N was calculated with the Parkland formula while groups D and I decreased or increased by 20% respectively. Urinary output (UOP), hemoglobin concentration (HB), cardiac output (CO), intrathoracic blood volume (ITBV), extravascular lung water index (ELWI), oxygen delivery (DO(2)) and oxygen consumption (VO(2)) were determined before and 4, 8, 24, 48 h after injury to evaluate the sufficiency of resuscitation in each group and examine the superiority., Results: UOP were [(0.41 ± 0.13), (0.77 ± 0.17), (0.30 ± 0.13)] ml · kg(-1) · h(-1) at 4 h post-injury in groups N, I and D respectively. Group I was significantly higher than groups N and D (P < 0.001).It were [(0.59 ± 0.05), (0.88 ± 0.05), (0.53 ± 0.06)] ml · kg(-1) · h(-1) at 24 h post-injury in groups N, I and D respectively. Group I was significantly higher than groups N and D (P < 0.001). CO in group I was remarkably higher than those in groups N and D at 4 h and 8 h post-injury [(1.57 ± 0.19) vs (1.25 ± 0.17), (1.05 ± 0.17) L/min; (1.87 ± 0.20) vs (1.57 ± 0.24), (1.20 ± 0.19) L/min respectively] (P < 0.05); ITBV also significantly increased in group I than two other groups at 4 h and 8 h post-injury [(169 ± 16) vs (140 ± 12), (121 ± 12) ml; (161 ± 14) vs (135 ± 22), (112 ± 12) ml] (P < 0.05). VO2 in group I was significantly higher than that in group N at 24 h post-injury [(129 ± 10) vs (106 ± 12) ml · min(-1) · m(-2)] (P < 0.05). No differences were detected among 3 group in ELWI (P > 0.05)., Conclusion: Larger fluid volume may compensate circulatory volume loss sooner, alleviate declining cardiac output better, maintain adequate organ perfusion, promote tissue oxygenation and improve anti-hypervolemia and anti-hypoxia.

Objective: To comprehensively analyze the recent advancements in the field of mesenchymal stem cells (MSCs) derived exosomes (MSCs-exosomes) in tissue repair., Methods: The literature about MSCs-exosomes in tissue repair was reviewed and analyzed., Results: Exosomes are biologically active microvesicles released from MSCs which are loaded with functional proteins, RNA, and microRNA. Exosomes can inhibit apoptosis, stimulate proliferation, alter cell phenotype in tissue repair of several diseases through cell-to-cell communication., Conclusion: MSCs-exosomes is a novel source for the treatment of tissue repair. Further research of MSCs-exosomes biofunction, paracellular transport, and treatment mechanism will help the transform to clinical application.

Objective: To observe the therapeutic effects of exogenous pulmonary surfactant (PS) on acute lung injury induced by severe burn-blast combined injury in a rat model., Methods: A total of 180 adult male SD rats were randomly divided into 3 groups of sham, treatment and control (n=60 each). Severe burn-blast combined injury was induced by inflicting rats with a moderate blast injury and a full-thickness burn injury of 25% total body surface area. The treatment and control groups received exogenous PS (2 ml/kg) and saline (2 ml/kg) by trachea respectively. At the time points of 0, 6, 24, 48 and 72 h, 12 rats per timepoint in each group underwent PaO2, PaCO2 and pulmonary function tests respectively. And they were then sacrificed for other analyses. Lung tissues were harvested for histological studies. Their arterial blood samples were collected for blood gas analysis. All data were expressed as mean ± standard deviation and analyzed with SPSS 20.0 (SPSS Inc., Chicago, IL, USA). The differences were considered to be statistically significant at P < 0.05., Results: After removing death drain during the experiment, 8 rats were put equally into five phase points of the last three groups, the results were analyzed statistically. PaO2: At each timepoint of 6, 24, 48, 72 h, the control group PaO2 were obviously lower than the sham group ((69.55 ± 5.11), (62.05 ± 6.54), (53.24 ± 7.65), (50.00 ± 7.45) vs (93.75 ± 3.41), (94.25 ± 2.19), (93.63 ± 2.33), (93.25 ± 1.83) mmHg (1 mmHg = 0.133 kPa), all P < 0.01); at 6 h treatment group was close to sham group ((92.63 ± 3.74) vs (93.75 ± 3.41) mmHg, P=0.594); at 6 h control group PaO2 decreased to 70 mmHg and then gradually declined. And at each timepoint the treatment group PaO2 was significantly higher than the control group ((92.63 ± 3.74), (87.50 ± 3.34), (78.75 ± 3.11), (71.38 ± 3.74) vs (69.55 ± 5.11), (62.05 ± 6.54), (53.24 ± 7.65), (50.00 ± 7.45) mmHg, all P < 0.01); PaCO2: treatment group PaCO2 was lower than that of control group at 6, 24, 48 h ((45.50 ± 6.79), (49.38 ± 7.52), (54.13 ± 4.82) vs (53.25 ± 2.76), (59.50 ± 6.61), (63.60 ± 7.33) mmHg, all P < 0.01), both treatment and control groups were significantly higher than those in the sham group ((59.63 ± 6.87), (68.88 ± 6.85) vs (36.38 ± 1.85) mmHg, all P < 0.01). No difference existed between the control and treatment groups (P = 0.051). Deep inspiratory capacity, central airway resistance, lung compliance and tissue elasticity, treatment group was significantly better than control group at 24 h (P < 0.05). And it was close to sham group (P > 0.05). The treatment group alveolar structural damage and pulmonary hemorrhage and edema were better than those in the control group., Conclusion: Exogenous pulmonary surfactant (PS) can improve oxygenation and alleviate pulmonary edema and pulmonary capillary membrane permeability of rats with severe burn blast combined injury.

Background: Several lines of evidence have reported that serum angiotensin-converting enzyme (CD143) levels are genetically regulated by insertion/deletion (ins/del) polymorphism in intron 16 of the CD143 gene. In addition, published data on the association of ins/del polymorphism and sepsis risk yielded contradictory conclusions. Therefore, we determined to perform a meta-analysis to validate the association of much debate. Methods and major findings: Relevant literature was identified through weekly searches in databases and references of systematic reviews and the single studies incorporated in this meta-analysis. We combined ORs and its 95% CIs for several genetic models to evaluate the risk of sepsis associated with ins/del polymorphism. A total of seven studies were considered eligible for this analysis. We found significantly increased risk of sepsis in relation to the homozygote ins/ins (OR: 1.32, 95% CI: 1.04-1.68, P: 0.4201, for ins/ins vs. del/del), heterozygote del/ins (OR: 1.33, 95% CI: 1.11-1.61, P: 0.7937, for del/ins vs. del/del) and the two genotypes combined (OR: 1.33, 95% CI: 1.11-1.59, P: 0.7018, for ins/ins + del/ins vs. del/del). Subgroup analysis by age group showed a significant association in pediatric sepsis, but not in adult sepsis., Conclusions: The statistical data suggest that the CD143 gene ins/del polymorphism may influence the risk of sepsis, especially pediatric sepsis.

Objective: To investigate the effect of burn on brown adipose tissue (BAT) in BALB/c mice., Methods: Forty 3-4 months old male BALB/c mice with initial body weight of (20 ± 3) g were randomly divided into control group and burn group (n = 20). BALB/c mice in burn group were subjected to a 30% total body surface area (TBSA) full-thickness thermal injury. BALB/c mice in control group were not treated. The body weight and temperature were observed before and after burn. At 7 days after burn, morphological changes of white adipose tissue (WAT) and BAT were observed, the gene and protein expressions of uncoupling protein 1 (UCP-1) were detected., Results: There was no significant difference in the body weight and body temperature before burn (P > 0.05). At 1, 2, 3, and 4 weeks after burn, the body weight was significantly lower in burn group than in control group (P < 0.05). At 1, 2, 3, and 7 days after burn, the body temperature was significantly higher in burn group than in control group (P < 0.05). At 7 days after burn, the weight of WAT was significantly reduced, and the weight of BAT was significantly increased in burn group (P < 0.05); WAT and BAT cells became smaller, cell number increased, the cytoplasm and mitochondria appeared as compact. The UCP-1 gene and protein expressions of burn group were significantly higher than those of control group (P < 0.05)., Conclusion: BAT plays an important role in burn-induced hypermetabolism.

Objective: To investigate the effect of burn on the fat metabolism by observing the effect of burn serum on the proliferation and adipose differentiation of 3T3-L1 preadipocytes., Methods: Forty-eight male Sprague Dawley rats were randomly divided into sham burn group and burn at 1, 4, 7, 14, and 21 days groups, 8 rats in each group. The rats in burn groups were made the full-thickness thermal burns comprising 30% total body surface area. At 1, 4, 7, 14, and 21 days after burn, the serum of burn rats was collected. The rats in sham burn group were not treated as normal control. The proliferation activity of 3T3-L1 cells was detected using MTT method after treated by normal and burn serum. The burn serum having the highest proliferation inhibitory effect was chosen for subsequent study. The growth of 3T3-L1 cells in normal serum group (group A), burn serum group (group B), normal serum and adipogenic induction group (group C), burn serum and adipogenic induction group (group D) was observed using inverted microscope. After 7 days of treatment, the adipocytes was stained by oil red O and the absorbance (A) value was measured. The mRNA and protein levels of preoxisome proliferator-activated receptor γ (PPAR-γ) and lipoprotein lipase (LPL) were detected by real-time quantitative PCR and Western blot., Results: The proliferation ability of 3T3-L1 cells was significantly reduced in the group treated by 4- or 7-day burn serum (P < 0.05), especially 7-day burn serum treatment group (P < 0.05). Under inverted microscope, the cell morphology in group A and group B had no obvious change, but a large number of fat cells were observed in group C and a few were observed in group D. The positive or weak positive oil red O staining was observed in group C or group D, respectively. The cell counting and A value were significantly higher in group A than in group B, and in group C than in group D (P < 0.05). The mRNA level of PPAR-γ in group B was significantly reduced when compared with that in group A (P < 0.05). No significant difference was found in LPL mRNA levels and protein levels of PPAR-γ and LPL between group A and group B (P > 0.05). The mRNA and protein levels of PPAR-γ and LPL were significantly attenuated in group D when compared with those in group C (P < 0.05)., Conclusion: The adipose differentiation of 3T3-L1 preadipocytes can be significantly reduced after treated by 7-day burn serum of rat.

Objective: To observe the effects of continuous sedation with propofol on peripheral blood mononuclear cell (PBMC) and intercellular adhesion molecule 1 (ICAM-1) in beagles with combined burn-blast injuries., Methods: A total of 32 male beagles were randomly divided into 4 groups of normal control (NC), combined injury control (CC), propofol 1 (P1) and propofol 2 (P2) (n = 8 each). Except for NC group, the other 3 groups were subject to severe combined burn-blast injury. And sodium lactate Ringer's solution was infused after trauma according to the Parkland formula, including NC group. At the same time, P1 and P2 groups received continuous intravenous infusions of 2 mg×kg(-1)×h(-1), 5 mg×kg(-1)×h(-1) doses of propofol respectively for 72 hours. The serum concentrations of ICAM-1 and lymphocyte function associated antigen-1 (LFA-1) were measured by enzyme-linked immunosorbent assay (ELISA) at 6, 24, 48, 72 h post-injury. Flow cytometry was used to detect the major histocompatibility complex (MHC) antigen expression on CD14(+) monocytes, CD4(+)/CD8(+) T lymphocyte rate and PBMC apoptosis rate., Results: The level of ICAM-1 in CC group ((10.5 ± 1.1), (10.8 ± 1.3), (12.3 ± 1.4) ng/ml) was significantly higher than that in NC group ((7.4 ± 1.4), (7.4 ± 1.1), (7.4 ± 1.6) ng/ml) at 12, 24, 48 h post-injury (all P < 0.05). The level of ICAM-1 in P1 group was significantly lower than that in CC group ((10.7 ± 1.3) vs (12.3 ± 1.4) ng/ml) while the level of ICAM-1 in P2 group was significantly lower than that in P1 group at 72 h post-injury ((8.8 ± 1.4) vs (10.7 ± 1.3) ng/ml) (both P < 0.05). The level of LFA-1 in CC group ((7.3 ± 1.3), (8.4 ± 1.3), (9.6 ± 1.7) ng/ml) was significantly higher than that in NC group ((5.1 ± 1.2), (5.4 ± 1.3), (5.8 ± 1.2) ng/ml) at 24, 48, 72 h post-injury (all P < 0.05). MHC antigen expression on the CD14(+) monocytes of P2 group was obviously higher than that of CC and P1 groups ((46 ± 13)% vs (26 ± 15)% and (32 ± 12)%, both P < 0.05). The CD4/CD8 rate in P1 and P2 was significantly higher than that in CC group (1.71 ± 0.26, 1.82 ± 0.31 and 1.81 ± 0.24, 1.96 ± 0.24 vs 1.41 ± 0.34, 1.34 ± 0.26) at 48, 72 h post-injury (all P < 0.05). At 72 h post injury, the PBMC apoptosis rate in CC and P1 group was obviously higher than that of the NC group ((2.57 ± 0.21)% and (1.64 ± 0.10)% vs (0.81 ± 0.11)%) (both P < 0.01); the apoptosis rate in P2 group was significantly lower than that in P1 group ((1.09 ± 0.15)% vs (1.64 ± 0.10)%) (P < 0.01)., Conclusion: Propofol may improve the immune function after combined burn-blast injuries through suppressing an excessive release of ICAM-1 and PBMC apoptosis in a concentration-dependent manner.

Objective: To explore the effects of lipopolysaccharide (LPS) pretreatment on endotoxin tolerance of human umbilical cord mesenchymal stem cells (hUCMSCs) and its possible mechanism., Methods: hUCMSCs (1×10(4) cells/well) were exposed to 0, 0.1, 1.0, 10.0, 20.0, 30.0, 40.0, 50.0 µg/ml LPS for 24 h respectively. And the cell viability of hUCMSCs was detected by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT). 1 µg/ml and 50.0 µg/ml LPS were used as pretreatment and apoptosis induction concentrations respectively. Pyrrolidine dithiocarbamate (PDTC) (20 µmol/L, pretreatment for 20 min) was used as a specific inhibitor of nuclear transcription factor NF-κB. hUCMSCs were randomly divided by Stata software into 7 groups: control (A), LPS induction (B), pretreatment + LPS induction (C), PDTC (D), PDTC+ pretreatment + LPS induction (E), pretreatment (F) and PDTC + pretreatment (G). The apoptosis of hUCMSCs was measured by Hoechst 33258 staining and flow cytometry (FCM). The expressions of NF-κB p65 and cellular FLICE-inhibitory protein (c-FLIP) were measured by Western blot., Results: The cell viability of 0, 0.1, 1.0, 10.0, 20.0, 30.0, 40.0, 50.0 µg/ml LPS groups were 100%, (117.0 ± 8.8)%, (134.7 ± 6.9)%, (105.3 ± 8.3)%, (99.2 ± 8.3)%, (84.2 ± 9.3)%, (66.4 ± 6.6)% and (59.2 ± 8.0)% respectively. In comparison with 0 µg/ml LPS group, the cell viability of 1.0 µg/ml LPS group increased significantly (P = 0.004) while decreased in 40 and 50 µg/ml LPS groups (P = 0.005, 0.002). Hoechst 33258 staining indicated that chromatin of hUCMSCs was distributed evenly in group A; the apoptotic cell in group B dramatically increased; and the apoptotic cell in group C significantly decreased in comparison with that in group B. Apoptotic rates of groups A, B, C, D and E were (2.8 ± 0.8)%, (29.7 ± 3.4)%, (17.8 ± 3.0)%, (2.9 ± 0.4)% and (23.2 ± 2.6)% respectively. Compared with group A, apoptosis rate significantly increased in group B (P < 0.001). The apoptotic rate in group C significantly decreased than that in group B (P < 0.001) while group E was higher than group C (P = 0.015). The levels of NF-κB p65 and c-FLIP in group F (0.851 ± 0.031, 0.534 ± 0.053) was higher than that in group A (0.220 ± 0.021, 0.049 ± 0.009) (both P < 0.001), G (0.418 ± 0.007, 0.299 ± 0.061) (P < 0.001, P = 0.007)., Conclusions: LPS pretreatment can resist LPS-induced hUCMSCs apoptosis and enhance the ability of endotoxin tolerance. And the mechanism may be related with activating the NF-κB signaling pathway and up-regulating the expression of c-FLIP.

Objective: To observe and study the effects of sivelestat on acute lung injury in dogs with severe burn-blast combined injury., Methods: Thirty-two male beagle dogs of clean grade were divided into 4 groups: uninjured group (U), combined injury control group (CIC), combined injury+low dose of sivelestat group (CI+LS), combined injury+high dose of sivelestat group (CI+HS), with 8 dogs in each group. Except for the dogs in group U which were not injured, the dogs in the other 3 groups were inflicted with severe burn-blast combined injury. According to the Parkland formula, the dogs in groups U and CIC were infused with physiological saline, and the dogs in groups CI+LS and CI+HS received sivelestat with the dosage of 0.5 and 2.0 mg·kg(-1)·h(-1) respectively in addition. The 24 h continuous intravenous infusion was carried out for 2 days. At post injury hour (PIH) 6, CT scanning was conducted to observe the lung damage. At PIH 2, 6, 12, 24, and 48, mean arterial pressure (MAP), respiratory rate (RR), extra vascular lung water (EVLW), pulmonary vascular permeability index (PVPI), PaO2, and PaCO2 were measured; the contents of neutrophil elastase (NE), IL-8, and TNF-α were determined by ELISA. At PIH 48, all the dogs were sacrificed, and the lung tissues were harvested to measure the wet to dry lung weight ratio. The same examination was carried out in the dogs of the group U at the same time points. Data were processed with analysis of variance of repeated measurement and LSD test., Results: (1) CT images showed some exudative lesions in the dogs of groups CIC and CI+LS but not in the dogs of groups U and CI+HS. (2) No statistically significant differences were observed in MAP at each time point between every two groups (with P values above 0.05). The RR values in group U were significantly different from those of the other 3 groups at all time points (with P values below 0.05). The values of EVLW and PVPI in 3 combined injury groups were significantly different from those in group U at PIH 6, 12, 24, and 48 (with P values below 0.05). The values of RR and EVLW in group CI+LS were significantly different from those in group CI+HS at PIH 12, 24, and 48 (with P values below 0.05). The values of PVPI in group CI+LS were significantly different from those in group CI+HS at PIH 24 and 48 (with P values below 0.05). (3) The levels of PaO2 and PaCO2 showed significant differences between group U and the other 3 groups at each time point (with P values below 0.05). The levels of PaO2 in group CI+LS were significantly different from those in CI+HS group at PIH 12, 24, and 48 (with P values below 0.05). The level of PaCO2 showed significant differences between group CI+LS and group CI+HS at PIH 24 and 48 (with P values below 0.05). (4) The contents of NE (except for PIH 2), TNF-α, and IL-8 showed significant differences between group U and the other 3 groups at each time point (P < 0.05 or P < 0.01). At PIH 2, 6, 12, 24, and 48, the contents of NE in groups U, CIC, CI+LS, and CI+HS were respectively (69 ± 21), (83 ± 24), (80 ± 20), (75 ± 17), (72 ± 27) pg/mL; (66 ± 24), (196 ± 20), (231 ± 26), (252 ± 25), (266 ± 22) pg/mL ; (71 ± 22), (180 ± 27), (214 ± 21), (194 ± 24), (218 ± 20) pg/mL; (68 ± 22), (136 ± 24), (153 ± 22), (146 ± 26), (150 ± 28) pg/mL. NE values in group CI+HS were statistically different from those in groups CIC and CI+LS at PIH 6, 12, 24, and 48 (with P values below 0.05). The contents of TNF-α in group CI+LS were statistically different from those in groups CIC and CI+HS at PIH 24 and 48 (with P values below 0.05). The contents of IL-8 in group CI+LS were statistically different from those in group CI+HS at PIH 24 and 48 (with P values below 0.05). (5) At PIH 48, the wet to dry lung weight ratio of group CIC was statistically different from that in group CI+LS or group CI+HS (with P values below 0.05); there was also difference between group CI+LS and group CI+HS (P < 0.05)., Conclusions: Sivelestat, especially in a high dose, exerts a protective effect in acute lung injury after burn-blast combined injury through improving the index of blood gas analysis, ameliorating pulmonary edema, and lowering the production of pro-inflammatory mediators.

Objective: To investigate the effects of different concentrations of lipopolysaccharide (LPS) on proliferation and apoptosis of human umbilical cord mesenchymal stem cells (hUCMSCs) in vitro, and to explore their possible mechanism., Methods: hUCMSCs from umbilical cord tissue of full-term healthy fetus delivered by caesarean section were isolated and cultured in vitro using tissue attachment method. The 3rd passage hUCMSCs were used in the study. Cells were divided into groups A, B, C, D, and E, which were treated with DMEM/F12 medium containing 0, 0.1, 1.0, 10.0, and 100.0 µg/mL of LPS respectively. In groups B, C, D, and E, methyl-thiazole-tetrazolium assay was used to detect proliferative activity of hUCMSCs at post treatment hour (PTH) 12, 24, and 48 (denoted as absorption value), with 5 samples in each group at each time point; apoptosis of hUCMSCs at PBH 24 was identified with acridine orange-ethidium bromide (AO-EB) staining, with 4 samples in each group; apoptotic rate of hUCMSCs was determined by flow cytometer, with 5 samples in each group. Above-mentioned indexes were determined in group A at the same time points. Data were processed with analysis of variance and LSD- t test., Results: (1) There was no statistically significant difference in proliferative activity of hUCMSCs at PTH 12 among groups A, B, C, D, and E (with t values from -1.67 to 1.33, P values above 0.05). Compared with that of group A, proliferative activity of hUCMSCs was increased in groups B, C, and D at PTH 24 and 48 (with t values from -13.42 to 17.34, P < 0.05 or P < 0.01), especially so in group C. Proliferative activity of hUCMSCs was lower in group E at PTH 24 and 48 than in group A (with t values respectively 8.64 and 17.34, P values below 0.01). (2) Obvious apoptosis of hUCMSCs was observed in group E but not in the other 4 groups with AO-EB staining. (3) Apoptosis rates of hUCMSCs in groups A, B, C, D, and E were respectively (3.1 ± 0.6)%, (2.6 ± 0.7)%, (2.9 ± 0.8)%, (3.1 ± 0.4)%, (25.1 ± 2.7)% (F = 272.19, P < 0.01). Apoptotic rate of hUCMSCs in group B, C, or D was respectively close to that in group A (with t values respectively 1.22, 0.57, -0.14, P values above 0.05), but it was higher in group E than in group A (t = -17.63, P < 0.01)., Conclusions: hUCMSCs proliferation may be promoted by low concentration of LPS. hUCMSCs proliferation is inhibited or induced to apoptosis along with the increase in concentration of LPS, and it may be related to activation of different major molecular signaling pathways by different concentrations of LPS.

Wound healing is a dynamic and complicated process, which generally takes three overlapping phases: inflammation, proliferation, and remodeling. If wounds complicated by severe trauma, diabetes, vascular dysfunction disease, or a massive burn injury failed to pass through the three normal phases of healing, they might end up as chronic and refractory wounds. Mesenchymal stem cells (MSCs) play different important roles in the regulation of all the phases of wound healing. MSCs can be recruited into wound and differentiated into wound repair cells, as well as promote wound healing by exerting functions like anti-inflammation, anti-apoptosis, and neovascularization. This review focuses on the role and mechanism of MSCs in each phase of the wound healing process.

Objective: To investigate the effect of the serum from severe burn patients on the biology characteristics of human umbilical cord mesenchymal stem cells (hUCMSCs) in vitro, so as to explore the feasibility of hUCMSCs transplantation for treating severe burn., Methods: The 3rd passage of hUCMSCs were randomly divided into 3 groups: 10% fetal bovine serum group (group A), 10% normal serum group (group B), and 10% burn serum group (group C). At 24 hours, 72 hours, and 6 days after culture, the cell morphology and density were observed by inverted microscope; the cell proliferation was assessed by MTT; after 6 days of culture, the cell cycle by propidium iodide staining and flow cytometry, the apoptosis by acridine orange/ ethidium bromide staining, and the cell senescence by beta-galactosidase staining; the levels of tumor necrosis factor alpha (TNF-alpha), interleukin 1 (IL-1), platelet-derived growth factor (PDGF), and insulin-like growth factor 1 (IGF-1) in serum were detected by a double-antibody sandwich ELISA kit., Results: hUCMSCs were long spindle/polygon in 3 groups. The cell fusion of group C was obviously faster than that in group A and group B. The cell proliferation curves showed that the velocity and number of cell proliferation in group C were significantly higher than those in group A and group B at 2-6 days after culture (P < 0.05). The rates of proliferation period (S) of hUCMSCs were 9.21% +/- 1.02%, 11.79% +/- 1.87%, and 20.54% +/- 2.03%, respectively in groups A, B, and C at 6 days, and group C was significantly higher than that of group A and group B (P < 0.05). The hUCMSCs showed normal morphology and structure in 3 groups, and no apoptosis cells was observed. The positive cells percentage of group C (2.6% +/- 0.1%) was significantly lower than that of group A (4.8% +/- 0.2%) and group B (3.8% +/- 0.4%) (P < 0.05). The levels of TNF-alpha, IL-1, PDGF, and IGF-1 in group C were significantly higher than those in group B (P < 0.05)., Conclusion: The higher levels of cytokines in serum from the severe burn patients can significantly stimulate hUCMSCs proliferation, prevent cells apoptosis, and reduce cells senescence. Therefore, it is feasible to use hUCMSCs transplantation for treating severe burn patients.

Objective: To review the research progress of mesenchymal stem cells (MSCs) in burn wound repair., Methods: The recent literature about MSCs involved in burn wound repair and mechanism was extensively reviewed and analyzed., Results: MSCs have the capacity of self-renew, rapid proliferation, differentiation and paracrine, and promote burn wound repair through differentiating into a series of skin wound cells and regulating wound microenvironment., Conclusion: MSCs have great potentials in the burn field. However, the cell survival and outcome are also facing challenges from poor microenvironment of the burn wound.

Objective: To establish a simple and efficient method to isolate and culture the umbilical vein vascular endothelial cells in canine., Methods: Twelve umbilical cords [(13.0 +/- 1.5) cm in length] were taken from 12 newborn pups of Beagles. And then the vascular endothelial cells were isolated from these umbilical cords digested by 1% collagenase type I for 5, 7, and 10 minutes respectively (4 umbilical cords in each group). After cultured, the vascular endothelial cells were identified by morphology, immunofluorescence, and flow cytometry. And the growth curvature of umbilical vein vascular endothelial cells was detected by MTT assay., Results: Few vascular endothelial cells were collected at 5 and 10 minutes after digestion; many vascular endothelial cells were seen at 7 minutes, and became cobblestone with culture time, with a large nucleus; after passage, cell morphology had no obvious change. Fluorescence microscope results showed that positive von Willebrand factor (vWF) and CD31 cells were observed in most of cells. The flow cytometry test displayed that the positive cell rates of vWF and CD31 were 99.0% +/- 0.7% and 98.0% +/- 1.2%, respectively. The above results indicated that cultured cells were vascular endothelial cells. MTT assay showed that vascular endothelial cells proliferation increased significantly with culture time., Conclusion: Enzyme digestion is a convenient method to isolate vascular endothelial cells from canine umbilical vein, and a large number of cells and high purity of cells can be obtained by the method.

Objective: To summarize the research progress of biological characteristics and advantages of Wharton's jelly-mesenchymal stem cells (WJ-MSCs)., Methods: The related literature on the biological characteristics of WJ-MSCs, umbilical cord blood MSCs (UBMSCs) and bone marrow MSCs (BMSCs) was extensively reviewed and analyzed., Results: A large number of MSCs which are able to self-replicate, self-renew and have high proliferation and multipotent differentiation can be isolated from the Wharton's jelly of umbilical cord. WJ-MSCs have many advantages in isolation time, isolation efficiency, expansion time, passage capacity, expansion capacity when compared with UBMSCs and BMSCs., Conclusion: WJ-MSCs have numerous advantages of convenient and abundant sources, relatively pure, non-ethical issues, and so on, which can be used for cell transplant therapy, gene therapy, and the ideal seed cells of building tissue engineered organ, so they provide new ideas for tissue regeneration repair and reconstruction.

Objective: To prepare and study the biocompatibility of selectively decellular xenoskin which has the character of the lower antigen, continuous epidermis, and the dermal matrix without any cellular components., Methods: The porcine skin was treated with glutaraldehyde solution, trypsin, and detergent solution TritonX-100 to prepare the selectively decellular xenoskin. The cytotoxicity was tested according to GB/T16886.5-2003 biological evaluation of medical devices for in vitro cytotoxicity, and the levels of cytotoxicity were evaluated with the United States Pharmacopeia. Subdermal implantation was tested according to GB/T16886.6-1997 biological evaluation of medical devices for local effects after implantation. Seventy-two mature Wistar rats were randomly assigned to groups A, B, and C (n = 24). Three kinds of materials were implanted into subcutaneous of rats back. Selectively decellular xenoskin was transplanted into group A, fresh porcine skin was transplanted into group B, and allogeneic skin was transplanted into group C. The samples were collected to make the observation of gross and histology after 1, 2, 4, 8, 12, and 16 weeks., Results: The cytotoxicity was proved to be first grade by biocompatibility test. The gross and histological observation of subdermal implantation: after implantation, the most severe inflammatory reactions were seen in group B which dispersion was very slow. Inflammatory reactions in groups A and C alleviated gradually. In groups A and C, there was an increased collagen fiber density and angiogenesis at late stage; the transplanted skin was gradually degraded and absorbed. In group B, no obvious degradation and absorption were observed., Conclusion: Selectively decellular xenoskin, prepared with glutaraldehyde solution, trypsin, and detergent solution, possesses characteristics of integral skin structure and excellent biocompatibility, so it can be used as a new type substitute to repair the burn wound.