Effects and molecular mechanism of exogenous L-carnitine on excessive endoplasmic reticulum stress-mediated hepatic pyroptosis in severely scald rats / 中华烧伤杂志

Objective: To investigate the effects and molecular mechanism of exogenous L-carnitine on hepatic pyroptosis mediated by excessive endoplasmic reticulum stress in severely scald rats. Methods: The experimental research method was adopted. According to the random number table (the same group method below), fifteen female Sprague Dawley rats aged 6-8 weeks were divided into sham-injury group, scald alone group, and scald+carnitine group (with 5 rats in each group), and full-thickness scald of 30% total body surface area were made on the back of rats in scald alone group and scald+carnitine group, and rats in scald+carnitine group were additionally given intraperitoneal injection of L-carnitine. At post injury hour (PIH) 72, The levels of aspartate aminotransferase (AST) and alanine dehydrogenase (ALT) of biochemical indicators of liver injury were detected by automatic biochemical analyzer with the sample number of 5. At PIH 72, liver tissue damage was detected by hematoxylin-eosin staining. At PIH 72, The mRNA levels of nucleotide-binding oligomerization domain-containing protein-like receptor family pyrin domain containing 3 (NLRP3), cysteine aspartic acid specific protease 1 (caspase-1), gasderminD (GSDMD), and interleukin 1β(IL-1β) in liver tissue as pyroptosis-related markers and glucose regulatory protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP) in liver tissue as endoplasmic reticulum stress-related markers were detected by real-time fluorescence quantitative reverse transcription polymerase chain reaction (RT-qPCR). Protein expression levels of GRP78, CHOP, NLRP3, caspase-1, caspase-1/p20, GSDMD-N, and cleaved IL-1β in liver tissue were detected by Western blotting, and the sample numbers were all 5. HepG2 cells as human liver cancer cells were divided into dimethyl sulfoxide (DMSO) group, 0.1 μmol/L tunicamycin (TM) group, 0.2 μmol/L TM group, 0.4 μmol/L TM group, and 0.8 μmol/L TM group and were treated accordingly. After 24 h of culture, cell viability was detected by cell counting kit 8, and the intervention concentration of TM was screened, and the sample number was 5. HepG2 cells were divided into DMSO group, TM alone group, and TM+carnitine group, and treated accordingly. After 24 h of culture, the protein expression levels of GRP78, CHOP, NLRP3, caspase-1, caspase-1/p20, GSDMD-N, and cleaved IL-1β in cells were detected by Western blotting, and the sample numbers were all 3. Data were statistically analyzed with one-way analysis of variance and least significant difference-t test. Results: At PIH 72, the AST and ALT levels of serum in scald alone group were (640±22) and (157±8) U/L, which were significantly higher than (106±13) and (42±6) U/L in sham-injury group, respectively, with t values of -46.78 and -25.98, respectively, P<0.01. The AST and ALT levels of serum in scald+carnitine group were (519±50) and (121±10) U/L, which were significantly lower than those in scald alone group, respectively, with t values of 4.93 and 6.06, respectively, P<0.01. At PIH 72, the morphology of liver tissue of rats in sham-injury group were basically normal with no obvious inflammatory cell infiltration; compared with those in sham-injury group, the liver tissue of rats in scald alone group showed a large number of inflammatory cell infiltration and disturbed cell arrangement; compared with that in scald alone group, the liver tissue of rats in scald+carnitine group showed a small amount of inflammatory cell infiltration. At PIH 72, the mRNA expression on levels of NLRP3, caspase-1, GSDMD, and IL-1β in liver tissue of rats in scald alone group were significantly higher than those in sham-injury group (with t values of 34.42, 41.93, 30.17, and 15.68, respectively, P<0.01); the mRNA levels of NLRP3, caspase-1, GSDMD, and IL-1β in liver tissue of rats in scald+carnitine group were significantly lower than those in scald alone group (with t values of 34.40, 37.20, 19.95, and 7.88, respectively, P<0.01). At PIH 72, the protein expression levels of NLRP3, caspase-1, caspase-1/p20, GSDMD-N, and cleaved IL-1β in liver tissue of rats in scald alone group were significantly higher than those in sham-injury group (with t values of 12.28, 26.92, 5.20, 10.02, and 24.78, respectively, P<0.01); compared with those in scald alone group, the protein expression levels of NLRP3, caspase-1, caspase-1/p20, GSDMD-N, and cleaved IL-1β in liver tissue of rats in scald+carnitine group were significantly decreased (with t values of 10.99, 27.96, 12.69, 8.96, and 12.27, respectively, P<0.01). At PIH 72, the mRNA levels of GRP78 and CHOP in liver tissue of rats in scald alone group were significantly higher than those in sham-injury group (with t values of 21.00 and 16.52, respectively, P<0.01), and the mRNA levels of GRP78 and CHOP in liver tissue of rats in scald+carnitine group were significantly lower than those in scald alone group (with t values of 8.92 and 8.21, respectively, P<0.01); the protein expression levels of GRP78 and CHOP in liver tissue of rats in scald alone group were significantly higher than those in sham-injury group (with t values of 22.50 and 14.29, respectively, P<0.01), and the protein expression levels of GRP78 and CHOP in liver tissue of rats in scald+carnitine group were significantly lower than those in scald alone group (with t values of 14.29 and 5.33 respectively, P<0.01). After 24 h of culture, the cell survival rates of 0.1 μmol/L TM group, 0.2 μmol/L TM group, 0.4 μmol/L TM group, and 0.8 μmol/L TM group were significantly decreased than that in DMSO group (with t values of 4.90, 9.35, 18.64, and 25.09, respectively, P<0.01). Then 0.8 μmol/L was selected as the intervention concentration of TM. After 24 h of culture, compared with that in DMSO group, the protein expression levels of GRP78 and CHOP in cells in TM alone group were significantly increased (with t values of 10.48 and 17.67, respectively, P<0.01), and the protein expression levels of GRP78 and CHOP in TM+carnitine group were significantly lower than those in TM alone group (with t values of 8.08 and 13.23, respectively, P<0.05 or P<0.01). After 24 h of culture, compared with those in DMSO group, the protein expression levels of NLRP3 and GSDMD-N in cells in TM alone group were significantly increased (with t values of 13.44 and 27.51, respectively, P<0.01), but the protein expression levels of caspase-1, caspase-1/p20, and cleaved IL-1β in cells were not significantly changed (P>0.05); compared with that in TM alone group, the protein expression levels of NLRP3 and GSDMD-N in cells in TM+carnitine group were significantly decreased (with t values of 20.49 and 21.95, respectively, P<0.01), but the protein expression levels of caspase-1, caspase-1/p20, and cleaved IL-1β in cells were not significantly changed (P>0.05). Conclusions: In severely scald rats, exogenous L-carnitine may play a protective role against liver injury by inhibiting the pathways related to excessive endoplasmic reticulum stress-mediated pyroptosis.

Influence of omega-3 polyunsaturated fatty acids on inflammation-related parameters in lung tissue of rats with severe scald / 中华烧伤杂志

<p><b>OBJECTIVE</b>To study the effect of omega-3 polyunsaturated fatty acids (omega-3 PUFA) on inflammation in lung tissue of rats with severe scald and its mechanism.</p><p><b>METHODS</b>Seventy-two adult SD rats were divided into sham scald group (SS, n = 8), treatment group 1 (T1, n = 32), treatment group 2 (T2, n = 32) according to the random number table. Rats in T1 group and T2 group were inflicted with 30% TBSA full-thickness scald, and then they were respectively injected with 100 g/L omega-3 PUFA (1 mL/kg) and 200 g/L long-chain fatty acid (2 mL/kg) via tail vein within 5 minutes after burn. The above two fatty acids with equivalent calories were continuously injected for 10 days (once a day). On post burn day (PBD) 1, 4, 7, and 10, serum level of TNF-alpha and level of macrophage inflammatory protein 1alpha (MIP-lalpha) in lung homogenate of T1 and T2 groups were detected, the levels of NF-kappaBp65 and macrophage migration inhibitory factor (MIF) in lung tissue of T1 and T2 groups were observed with immunohistochemical staining (recorded as score). Above-mentioned parameters were also determined in SS group. Data were processed with t test.</p><p><b>RESULTS</b>The levels of 4 parameters in T1 and T2 groups on PBD 1, 4, 7, 10 were higher than those in SS group (with t values from 3.411 to 8.782, P values all below 0.01), and those in T1 group on PBD 4, 7, 10 were lower than those in T2 group (with t values from 2. 321 to 2.785, P values all below 0.05). The serum level of TNF-alpha and levels of MIP-1alpha, NF-kappaBp65, and MIF in lung tissue in SS group was respectively (0.96 +/- 0.32) ng/mL, (76 +/- 16) pg/mL, 0.24 +/- 0.03, 1.31 +/- 0.03, and those in T1 and T2 groups all peaked on PBD 7 [(2.43 +/- 0.32) ng/mL, (210 +/- 56) pg/mL, 4.23 +/- 2.15, 4.69 +/- 1.83; (3.15 +/- 0.54) ng/mL, (274 +/- 64) pg/mL, 5.15 +/- 2.31, 5.37 +/- 2.16].</p><p><b>CONCLUSIONS</b>Omega-3 PUFA can effectively reduce serum level of TNF-alpha and levels of MIP-1alpha, NF-kappaBp65, and MIF in lung tissue of rats with severe scald, showing that it has a protective effect against injury of lung tissue.</p>

Analysis of drug resistance and risk factors of Enterobacteriaceae in burn units / 中华烧伤杂志

<p><b>OBJECTIVE</b>To study the risk factors of infection of extended-spectrum beta-lactamases (ESBL)-producing strains and drug resistance of Enterobacteriaceae that infected burn patients.</p><p><b>METHODS</b>A retrospective study was performed on clinical information of 92 patients with Enterobacteriaceae infection in our burn unit from January 2001 to December 2008. The distribution and drug resistance of Enterobacteriaceae, and the detection rate, drug resistance of ESBL-producing strains, and its risk factors of nosocomial infection were analyzed. Data were processed with Chi-square test.</p><p><b>RESULTS</b>One hundred and nine strains of Enterobacteriaceae were isolated, with 38 (34.9%) strains of Enterobacter cloacae, 25 (22.9%) strains of Escherichia coli, 22 (20.2%) strains of Klebsiella pneumoniae, 13 (11.9%) strains of Proteus mirabilis, and 11 (10.1%) other strains of Enterobacteriaceae. Enterobacteriaceae were moderately or highly resistant to antibiotics except imipenem, resistance rate of which was less than 8.0%. ESBL-producing strains accounted for 44.0% in Escherichia coli, and 77.3% in Klebsiella pneumoniae. Drug-resistance rate of ESBL-producing strains to antibiotics was obviously higher than that of non ESBL-producing strains. Length of hospital stay longer than 20 days, and use of the third-generation cephalosporin longer than 5 days, quinolone antibiotics longer than 7 days, and topical antibiotics longer than 5 days were the risk factors of nosocomial infection caused by ESBL-producing strains, comparing with non ESBL-producing strains, the difference was statistically significant (with chi2 value respectively 5.491, 4.441, 15.186, 4.938, P values all below 0.05).</p><p><b>CONCLUSIONS</b>Enterobacteriaceae strains in burn unit of our hospital are highly drug resistant, with high lactamase-producing rates, calling for intense monitor to control the risk factors that predispose the infection of ESBL-producing strains in order to lower the infection rate.</p>

The influence of changes in the levels of calcitonin gene-related peptide and neuropeptide Y on cardiac function of severe burn patients during shock stage / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the influence of the changes in the levels of calcitonin gene-related peptide (CGRP) and neuropeptide Y (NPY) on cardiac function of severe burn patients during shock stage.</p><p><b>METHODS</b>Sixty severe burn patients with total burn surface area larger than 30% were enrolled as experiment group (E group) , and they received fluid resuscitation and debridement during shock stage. Sixty healthy volunteers were enrolled as control group (C group). The changes in the plasma level of CGRP, NPY and cTnT in E and C groups were observed at 1, 3, 6, 12, 24, 48 post-burn hours (PBH). The correlation among the CGRP, NPY and cTnT in the C group were analyzed.</p><p><b>RESULTS</b>At 3 PBH, the plasma level of CGRP in E group (28 +/- 6) ng/L was lower than that in C group (55 +/- 7) ng/L , and it reached the lowest level at 12 PBH (15 +/- 4)ng/L . It was still lower than that in C group at 48 PBH (P < 0.05). The levels of NPY and cTnT in E group were significantly increased at 1PBH [(136 +/- 20) ng/L, (0.41 +/- 0.08) microg/L] compared with that in C group[ (86 +/- 13) ng/L, (0.16 +/- 0.06) microg/L], peaking at 12PBH [(189 +/- 31) ng/L, (1.78 +/- 0. 47) microg/L], and remaining higher than those in C group at 48PBH. There exhibited obvious negative correlation between the changes in the level of CGRP and cTnT ( r = -0.76, P < 0.01), while obvious positive correlation was found between the changes in level of NPY and cTnT ( r = 0.79, P < 0.01).</p><p><b>CONCLUSION</b>The decrease in CGRP level and the increase in NPY level might play important roles in myocardial injury during shock stage of severe burn patients.</p>