Lipopolysaccharide pretreatment inhibits LPS-induced human umbilical cord mesenchymal stem cell apoptosis via upregulating the expression of cellular FLICE-inhibitory protein.

Mesenchymal stem cell (MSC)-based regenerative therapy is currently regarded as a novel approach with which to repair damaged tissues. However, the efficiency of MSC transplantation is limited due to the low survival rate of engrafted MSCs. Lipopolysaccharide (LPS) production is increased in numerous diseases and serves an essential function in the regulation of apoptosis in a variety of cell types. Previous studies have indicated that low-dose LPS pretreatment contributes to cytoprotection. In the current study, LPS was demonstrated to induce apoptosis in human umbilical cord mesenchymal stem cells (hUCMSCs) via the activation of caspase, in a dose-dependent manner. Low-dose LPS pretreatment may protect hUCMSCs against apoptosis induced by high-dose LPS, by upregulating the expression of cellular FADD-like IL-1ß-converting enzyme-inhibitory protein (c-FLIP). The results of the present study indicate that pretreatment with an appropriate concentration of LPS may alleviate high-dose LPS-induced apoptosis.

Comparison of the pharmacokinetics of linezolid in burn and non-burn rabbits.

Linezolid is effective on many resistant organisms for the treatment of severe infections in burns. However, its pharmacokinetics was difficult to predict after major burns. The study aimed to describe the pharmacokinetic properties of linezolid administered intravenously at a dose of 10 mg/kg in severely burned rabbits in comparison to that in non-burns. Linezolid concentrations were quantitatively analyzed by high-performance liquid chromatography. The direct consequence of the physiological changes after burn injury was lower plasma linezolid concentrations. In addition, burn injury induced significantly altered pharmacokinetic parameters with higher inter-individual variability. The distribution volume and clearance rate were increased (2.88 vs. 1.92 L/kg, P > 0.05; 0.28 vs. 0.20 L/h/kg, P < 0.05), and the AUC0-∞ was significantly lower (37.99 vs. 51.47 mg/L h, P < 0.05). However, there were almost no changes in half-life and mean residence time. These results suggested that therapeutic drug monitoring and dosage individualization of linezolid in patients with severe burns were necessary.

[Voltage dependent anion channel 2 involved mitochondrial apoptosis and its possible regulatory signal pathway in hearts of rats with severe scalds].

OBJECTIVE: To explore the role of voltage dependent anion channel 2 (VDAC2) involved mitochondrial apoptosis in heart injury of rats with severe scald injury and elucidate its possible regulatory signal pathway. METHODS: A total of 60 Wistar rats were divided into sham scald group (n = 30) and scald group (n = 30) according to a random digital table. Blood and heart tissue samples were harvested at Day 1, 7, 14 post scalding. Myocardial injury was assessed with cardiac troponin I (cTnI) by enzyme-linked immunosorbent assay (ELISA). Mitochondrial apoptosis activation was evaluated by the expressions of Bax/Bcl-2 ratio, cytoplasmic cytochrome C and VDAC2. And the levels of phosphatidylinositol 3-kinase, p-Glycogen Synthase Kinase-3ß and hexokinase 2 protein were determined by Western blot. RESULTS: The serum levels of cTnI were significantly higher in scald group than those in sham scald group at Day 1, 7, 14 ((1.41 ± 0.25) vs (0.53 ± 0.23) µg/L, (1.93 ± 0.53) vs (0.43 ± 0.23) µg/L, (1.62 ± 0.34) vs (0.41 ± 0.22) µg/L respectively, all P < 0.05). Compared with sham scald group, Bax/Bcl-2 ratio increased significantly in scald group at Day 1, 7 day post-scalding (3.360 ± 0.173 vs 0.623 ± 0.044, 2.736 ± 0.341 vs 0.698 ± 0.064, 1.290 ± 0.234 vs 0.718 ± 0.063 respectively, all P < 0.05), VDAC2 protein level in scald group decreased significantly at Day 1, 7, 14 (0.070 ± 0.009 vs 0.328 ± 0.026, 0.007 ± 0.002 vs 0.291 ± 0.025, 0.009 ± 0.004 vs 0.302 ± 0.037 respectively, all P < 0.05), the cytoplasmic levels of cytochrome increased significantly in scald group at Day 1, 7, 14 (0.418 ± 0.030 vs 0.022 ± 0.007, 1.685 ± 0.169 vs 0.030 ± 0.011, 0.300 ± 0.037 vs 0.098 ± 0.014 respectively, all P < 0.05), the expression of PI3K was significantly lower in scald group at Day 14 post-scalding (0.083 ± 0.015 vs 0.328 ± 0.011, P < 0.05), the expressions of p-GSK3ß all reduced significantly at Day 1, 7, 14 (0.098 ± 0.014 vs 0.446 ± 0.031, 0.064 ± 0.002 vs 0.476 ± 0.054, 0.074 ± 0.010 vs 0.442 ± 0.041, respectively, all P < 0.05) and the expressions of HK2 were lower at Day 7, 14 post-scalding (0.390 ± 0.027 vs 0.611 ± 0.070, 0.267 ± 0.018 vs 0.490 ± 0.042, respectively, all P < 0.05). CONCLUSIONS: VDAC2 involved mitochondrial apoptosis is activated in myocardium after severe scalds. And it may be regulated by the pathway of PI3K-GSK-HK2.

[Expressions of endoplasmic reticulum stress associated proteins in livers of severely burned rats].

OBJECTIVE: To explore the expression of endoplasmic reticulum stress (ERS) associated proteins in livers of severely burned rats and examine its potential significance. METHODS: Sixty-four Wistar rats were randomly divided into the control and burn groups (30% total body surface area full-thickness thermal injury) (n = 32 each). Livers were harvested at Day 1, 4, 7, 14 post-burn. Western blot was used to detect the expressions of endoplasmic reticulum stress associated proteins glucose regulated protein 78 (GRP78), C/EBP-homologous protein (CHOP), active caspase-12 and active caspase-3. Hepatic apoptosis was assessed by the assay of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL). RESULTS: Compared with the control group, the expression of GRP78 became elevated at Day 1, 4, 7, 14 post-burn (1.29 ± 0.11 vs 1.00 ± 0.00, 1.28 ± 0.12 vs 0.95 ± 0.16, 1.29 ± 0.14 vs 0.93 ± 0.06, 1.41 ± 0.17 vs 1.02 ± 0.13 respectively); the expression of CHOP was higher at Day 1, 4 (1.72 ± 0.07 vs 1.00 ± 0.00, 1.82 ± 0.18 vs 1.46 ± 0.08 respectively) while active caspase-12 and active caspase-3 increased at Day 1, 4, 7 post-burn (2.05 ± 0.65 vs 1.00 ± 0.00, 2.16 ± 0.69 vs 0.95 ± 0.21, 1.98 ± 0.56 vs 0.90 ± 0.22; 1.96 ± 0.15 vs 1.00 ± 0.00, 1.40 ± 0.14 vs 1.07 ± 0.12, 1.77 ± 0.17 vs 1.15 ± 0.21 respectively); the apoptotic index(%) of hepatocytes was higher at Day 1, 4, 7, 14 post-burn (27.20 ± 3.63 vs 5.00 ± 0.71, 16.40 ± 1.52 vs 5.40 ± 1.14, 27.60 ± 1.82 vs 7.40 ± 1.14, 10.20 ± 1.92 vs 5.20 ± 1.64 respectively). All results were statistically significant (all P < 0.05). CONCLUSION: ERS activates and expressions of associated proteins GRP78, CHOP, active caspase-12 and active caspase-3 increase in livers of severely burned rats.

[The protective effect of recombinant rat ghrelin on gastric mucosa in rats with hemorrhagic shock].

OBJECTIVE: To investigate the effect of recombinant rat ghrelin on gastric mucosa in rats with hemorrhagic shock. METHODS: Eighteen healthy male Sprague-Dawley (SD) rats were randomly assigned into three groups: control group, hemorrhagic shock group, and ghrelin treatment group, with 6 rats for each group. The hemorrhagic shock model was reproduced in hemorrhagic shock group and ghrelin treatment group, and recombinant rat ghrelin (20 microg/kg) was intravenously administered to rats in ghrelin treatment group when resuscitation begun. Two hours after resuscitation, the gastric mucosal blood flow (GMBF) was determined with laser Doppler flowmetry (LDF). The light microscope and transmission electron microscope (TEM) were used to assess gastric mucosal injury. RESULTS: The GMBF of the rats in hemorrhagic shock group was significantly lower than that in control group [(260.4+/-49.6) bpu vs. (418.6+/-57.3) bpu, P<0.01], and the gastric mucosa was injured, presenting cell necrosis, cytolysis and focal ulceration. The GMBF of the rats in ghrelin treatment group was remarkably richer than that in hemorrhagic shock group [(352.9+/-72.9) bpu vs. (260.4+/-49.6) bpu, P<0.05], but had no significant difference compared with that in control group (P>0.05), and the gastric mucosa injuries were greatly improved in the rats of ghrelin treatment group. CONCLUSION: Recombinant rat ghrelin, through enhancing the GMBF, can ameliorate the gastric mucosal ischemic/reperfusion injury in rats with hemorrhagic shock.