Effects of Preoperative Isokinetic Eccentric Training and Whey Protein Isolate Supplement on Quadriceps Strength and Knee Function in Patients with Anterior Cruciate Ligament Rupture / 中国医学科学院学报

Objective To explore the effect of preoperative isokinetic eccentric training with or not whey protein isolate supplement before operation on lower limb muscle strength and knee function in patients with anterior cruciate ligament (ACL) rupture. Methods A total of 22 male volunteers aged 18-40 years with ACL rupture were recruited in outpatient service. With randomized block design,subjects were randomly assigned to isokinetic eccentric training (IE) group and isokinetic eccentric training with whey protein isolate supplement (IE+WPI) group. The IE group received isokinetic eccentric training of the injured limb on an isokinetic dynamometer under the guidance of physiatrist in laboratory before operation. There were 3-4 sets per day with 8-10 repetitions for each set,twice a week,with at least one day between sessions. The IE+WPI group were supplied with whey protein isolate 22 g per day on the basis of isokinetic eccentric training,taking breakfast or 30-60 minutes after the training. The intervention lasted for 6 weeks. Isokinetic muscle strength of limbs,the function and laxity of knee,the circumferences of thigh and knee,and the body composition were measured before and after the treatment. Results Compared with baseline,the peak torque (PT) of isokinetic-eccentric contraction (IE group:41.0%,P=0.018;IE+WPI group:46.7%,P=0.008) and the concentric contraction (IE group:29.6%,P=0.018;IE+WPI group:38.9%,P=0.038) of quadriceps in the two training groups significantly increased after isokinetic eccentric training. The Lysholm score increased significantly in IE+WPI group compared with baseline (P=0.018). Conclusions Isokinetic eccentric training before operation for ACL rupture patients can increase the strength of quadriceps and improve the function of knees. Protein isolate supplement can improve such effect.

Infection-stimulated anemia results primarily from interferon gamma-dependent, signal transducer and activator of transcription 1-independent red cell loss / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Although the onset of anemia during infectious disease is commonly correlated with production of inflammatory cytokines, the mechanisms by which cytokines induce anemia are poorly defined. This study focused on the mechanism research.</p><p><b>METHODS</b>Different types of mice were infected perorally with Toxoplasma gondii strain ME49. At the indicated times, samples from each mouse were harvested, processed, and analyzed individually. Blood samples were analyzed using a Coulter Counter and red blood cell (RBC) survival was measured by biotinylation. Levels of tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), and inducible protein 10 (IP-10) mRNA in liver tissue were measured by real-time polymerase chain reaction.</p><p><b>RESULTS</b>T. gondii-infected mice exhibited anemia due to a decrease in both erythropoiesis and survival time of RBC in the circulation (P < 0.02). In addition, infection-stimulated anemia was associated with fecal occult, supporting previous literature that hemorrhage is a consequence of T. gondii infection in mice. Infection-induced anemia was abolished in interferon gamma (IFNγ) and IFNγ receptor deficient mice (P < 0.05) but was still evident in mice lacking TNF-α, iNOS, phagocyte NADPH oxidase or IP-10 (P < 0.02). Neither signal transducer and activator of transcription 1 (STAT1) deficient mice nor 129S6 controls exhibited decreased erythropoiesis, but rather suffered from an anemia resulting solely from increased loss of circulating RBC.</p><p><b>CONCLUSIONS</b>Infection-stimulated decrease in erythropoiesis and losses of RBC have distinct mechanistic bases. These results show that during T. gondii infection, IFNγ is responsible for an anemia that results from both a decrease in erythropoiesis and a STAT1 independent loss of circulating RBC.</p>

Protein and mRNA expression of CTGF, CYR61, VEGF-C and VEGFR-2 in bone marrow of leukemia patients and its correlation with clinical features / 中国实验血液学杂志

This study was aimed to investigate the mRNA and protein expression of CTGF, CYR61, VEGF-C and VEGFR-2 in bone marrow of patients with leukemia, and to analyze the role and clinical significance of these 4 factors in genesis and development of leukemia, infiltration and metastasis of leukemic cells. A total of 100 cases of newly diagnosed leukemia, 26 cases of acute leukemia in complete remission and 30 controls were enrolled in this study. The mononuclear cells of bone marrow were collected, the mRNA and protein expression levels of CTGF, CYR61, VEGF-C, VEGFR-2 in leukemia patients and controls were detected by real time PCR and Western blot, respectively. The results showed that the mRNA and protein expression levels of above mentioned 4 factors were significantly higher than those in control (P < 0.05), only CTGF mRNA expression in AL patients after complete remission showed statistical difference as compared with control (P < 0.05), but the expression of CTGF mRNA showed statistical significance in different bone marrow hyperplasia of acute leukemia (P < 0.05). The expression level of CTGF protein showed difference in different chromosome karyotypes of leukemia (P < 0.05). The expression levels of CYR61 and VEGF-C proteins showed statistical difference in different bone marrow hyperplasia of acute leukemia (P < 0.05). The expression level of CTGF, CYR61, VEGF-C mRNA and protein in CML group were higher than that in control group. The expression levels of CTGF and CYR61 protein were higher than that in control. The mRNA and protein expression levels of above-mentioned 4 factors in sex and infiltration lf leukemic cells did not show statistical significance(P < 0.05). In correlative analysis, the mRNA expressions of above mentioned 4 factors were positively correlated with bone marrow blast count(P < 0.05), the protein expression of CTGF, CYR61 and VEGF-C were positively correlated with bone marrow blast count. It is concluded that the CTGF, CYR61, VEGF-C and VEGFR-2 mRNA and protein play a role in acute leukemia. In acute leukemia (AML/ALL), the expression of above mentioned factor was high, but except VEGFR-2. Most of them were positively correlated with bone marrow blast count. Joint block of these angiogenesis-related factors is likely to play an important role in targeting treatment of leukemia.

Expression of CYR61, CTGF, VEGF-C, VEGFR-2 mRNA in bone marrow of leukemia patients and its clinical significance / 中国实验血液学杂志

The study was aimed to detect the levels of CYR61, CTGF, VEGF-C, VEGFR-2 mRNA in bone marrow (BM) of leukemia patients and investigate the interaction of CYR61, CTGF, VEGF-C, VEGFR-2 proteins in occurrence, development, infiltration and metastasis of leukemia and its clinical significance, to find a new tumor marker for diagnosis and treatment of leukemia with some new directions. 74 patients with leukemia were enrolled in this study, 38 out of them were males and 36 were females, aged from 6 to 77 years old with the median age of 45 years old. In the control group, 7 males and 5 females, aged from 16 to 78 years old with the median age of 46. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to detect the levels of CYR61, CTGF, VEGF-C, VEGFR-2 mRNA. The results showed that the levels of CYR61, CTGF, VEGF-C, VEGFR-2 mRNA in BM of newly diagnosed patients with acute and chronic leukemia of each group were significantly higher as compared with the control group (p < 0.05). The levels of CYR61, CTGF mRNA in acute leukemia remission group were significantly higher than those in control group (p = 0.039, 0.025). The level of CTGF mRNA was highest in B-ALL group, and was higher than that in AML, CML, CLL, T-ALL groups (p = 0.002, 0.034, 0.002, 0.010). In AML group, mRNA expressions of CYR61 and CTGF, CYR61 and VEGF-C, CTGF and VEGFR-2 were positively correlated (r = 0.452, 0.466, 0.464; p = 0.045, 0.038, 0.039), and in CML group mRNA expression of CYR61 and VEGF-C was positively correlated (r = 0.882, p = 0.000). The expression levels of VEGF-C, VEGFR-2 mRNA in acute leukemia patients with extramedullary infiltration were higher than those in acute leukemia patients without extramedullary infiltration (p = 0.028, 0.047). VEGF-C mRNA expression and the original cell counts in AML group were positively correlated (r = 0.418, p = 0.034). It is concluded that CYR61, CTGF, VEGF-C and VEGFR-2 interact each other in the pathogenesis of leukemia, promote the development, metastasis and infiltration of leukemia; and these factors in different types of leukemia and extramedullary infiltration are different, which may become tumor markers of leukemia; and blocking VEGF-C and VEGFR-2 may block tumor growth and metastasis.

Expression of heparanase and its coagulation proteins on the surface of leukemic cells / 白血病·淋巴瘤

Objective To explore whether the expression level of heparanase (HPA) and its coagulation proteins on leukemic blast membrane could determine the hemostatic balance on the surface of leukemia cells.Methods Forty patients of leukemia were studied,and 20 patients with iron dificient anemia as the control group.Expression of tissue factor (TF),heparanase (HPA),tissue factor pathway inhibitor (TFPI),and urokinase plasminogen activator receptor (UPAR) on leukemic blast surfaces were analyzed by flowcytometry.Results The expression of TF,UPAR,and HPA in AML,ALL,CML,CLL and CRAL groups were significantly higher compared with the control group (t =.3.289,3.507,2.701,P ＜0.05; t =2.498,0.802,3.090,P ＜0.05; t =2.642,3.308,2.696,P ＜0.05; t =3.417,3.434,2.382,P ＜0.05; t =2.193,2.272,2.263,P ＜0.05).There were no significantly differences between the leukemic cell expression of TFPI and the control group (P ＞0.05).Expression of TF,UPAR,HPA in AML patients were significantly higher than ALL,CML and CLL groups (t =2.463,2.179,2.276,P ＜0.05; t =2.637,2.402,2.095,P ＜0.05; t =2.548,2.425,2.412,P ＜0.05).The levels of TF,UPAR and HPA in M3,M4 and M5 patients were higher than that of M1,M2 groups (P ＜0.05).There were no significantly differences among M3,M4 and M5 (P ＞0.05).Conclusions These results suggest that TF,UPAR and HPA are predominately expressed on leukemic blast surface,particularly in M3and M4,5 subtypes.The expression of coagulation proteins on blast membrane might determine the hemostatic balance on the surface of leukemia cells.

Expression of cyclooxygenase-2 in bone marrow cells of leukemia patients and its association with angiogenesis / 中国实验血液学杂志

The objective of this study was to investigate the effect of cyclooxygenase-2 (COX-2) in the angiogenesis of bone marrow in leukemia patients. 51 patients with newly diagnosed acute leukemia were taken as study objects, 18 healthy volunteers were enrolled in the control group. Bone marrow microvessel density (MVD) in bone marrow biopsy tissue section was determined with immunohistochemistry method, the vascular endothelial growth factor level in serum was detected with ELISA method and the expression of cyclooxygenase-2 in bone marrow cells was assayed by flow cytometry. The results showed that the MVD, VEGF level, positive rate of COX-2 expression in leukemia group all obviously increased as compared with the control group (p < 0.05). The correlative coefficients of MVD, VEGF level and COX-2 expression rate were 0.614, 0.423 and 0.577 respectively (p < 0.05). In conclusion, as well as solid tumors, leukemia may be also a angiogenesis-dependent malignant tumor. Coordination of COX-2 with VEGF may promote angiogenesis in bone marrow.

Effects of glycine on apoptosis in murine cardiomyocyte suffering from ischemia and hypoxia / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the effects of glycine on apoptosis in murine cardiomyocyte suffering from ischemia and hypoxia.</p><p><b>METHODS</b>The primary passage of cultured cardiomyocytes from neonatal rats were subjected to ischemia and hypoxia, and the cells were divided into IH (without other treatment), and G (with treatment of 5 mmol/L glycine) groups. Normal murine cardiomyocytes served as control (C group). Cardiomyocytes were cultured for 6 hours in vitro. Apoptosis, mitochondrial membrane potential and its distribution, the condition of mitochondria permeability transition pore (mPTP) were observed with expression of fluorescence intensity. The activity of caspase-3 was observed by Laser Scanning staining.</p><p><b>RESULTS</b>(1) Apoptosis: the fluorescence intensity in IH group was obviously higher than that in G and C groups (P < 0.01). (2) Mitochondrial membrane potential: the fluorescence intensity in IH group was 32 +/- 7, which was obviously lower than that in G and C groups (52 +/- 4, 73 +/- 4, respectively, P < 0.01). (3) The condition of mPTP: the intensity in IH group was 27 +/- 4, which was obviously lower than that in G and C groups (62 +/- 8, 90 +/- 7, respectively, P < 0.01). (4) The activity of caspase-3: the activity of caspase-3 in IH group was obviously higher than that in G and C groups (P < 0.01).</p><p><b>CONCLUSION</b>Glycine can inhibit apoptosis in cardiomyocytes subjected to ischemia and hypoxia,and the effect may be attributable to changes in mitochondrial membrane potential, lessening opening of mPTP, alleviation of calcium overload , and decrease in activity of caspase-3.</p>

Protective effects of enalaprilat on the myocardial kinetics in rats at early stage of severe scald / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the therapeutic effects of Enalaprilat on the myocardial kinetics in rats at early stage of severe scald.</p><p><b>METHODS</b>Eighty-four SD rats were inflicted with 30% TBSA full-thickness scald, and randomly divided into scald (S, with intraperitoneal injection of isotonic saline according to Parkland formula, n=30), L (n=30), M (n=12) and H (n=12) groups. The rats in L,M,H groups were intraperitoneally injected with 1,2,4 mg/kg Enalaprilat. Other 6 healthy rats were enrolled into study as control (C group). The myocardial kinetic parameters including left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP), +/- dp/dt max and the levels of A II in myocardium were observed at 1,3,6,12 and 24 post scald hour (PBH) in L and S groups,and at 6,12 PBH in M and H groups. The above indices in C group were also examined.</p><p><b>RESULTS</b>The levels of LVSP, LVEDP, +/- dp/dt max in C group were higher than those in other groups during 3-24 PBH (P < 0.05 or P < 0.01), while those in L,M,H groups were obviously higher than those in S group (P < 0.05 or P < 0.01). The level of +/- dp/dt max in H group at 6,12 PBH were obviously lower than those in L and M groups. The level of A II in S group at 1 PBH was (53.0 +/- 2.6) pg/200 mg, which was significantly higher than thatin C group [(14.8 +/- 0.7) pg/200 mg, P < 0.05 or P < 0.01]; it peaked at6 PBH and lowered afterwards, and they were significantly higher than that in C group at 24 PBH (P < 0.01). The levels of A II in L group during 3-24 PBH were obviously higher than those in C group (P < 0.01), which were also lower than those in S group. The level of A II in S group was significantly higher than in L,M,H groups at 6 PBH [(145.2 +/- 14.5) pg/200 mg. vs. (65.1 +/- 0.9) pg/200 mg, (53.6 +/- 1.1) pg/200 mg, (34.2 +/- 0.9) pg/200 mg, respectively, P < 0.01].</p><p><b>CONCLUSION</b>Myocardium can be obviously damaged at early stage after severe scald,cardiac function is impaired. Enalaprilat injection (especially at low dose) can significantly ameliorate the myocardial kinetics indices, and it seems to exert a protective effect on cardiac function.</p>

Protective effects of administration of enalapril maleate on rat myocardial damage in early stage of burns / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the preventive and therapeutic effects of enalapril maleate (Enalaprilat) (E) on myocardial damage in early stage after burns.</p><p><b>METHODS</b>A total of 60 SD rats were subjected to 30% TBSA III degree scald injury, and randomly divided into scald group (with conventional fluid transfusion after scald) and ENA group (with intraperitoneal injection of 1 mg/kg Enalaprilat after scald). Normal control consisted of 6 rats. Plasma levels of cTnI and CK-MB were determined in all the groups at 1, 3, 6, 12, 24 post-scald hours (PSH) by enzyme linked immunosorbent assay. The pathological changes in myocardium were observed at the same time-points.</p><p><b>RESULTS</b>(1) The serum level of cTnI and CK-MB in scald group were significantly higher than that of normal controls at each time-point (P < 0.01). The serum level of cTnI and CK-MB in ENA group were (1.32 +/- 0.12 microg/L to 2.47 +/- 0.22 microg/L) and (438 +/- 68 U/L to 5569 +/- 322 U/L), respectively, which were obviously lower than those in B group (6.42 +/- 0.96 microg/L to 15.10 +/- 3.69 microg/L) and (2556 +/- 74 U/L to 8047 +/- 574 U/L, P < 0.05 or P < 0.01) at different time-points. (2) Compared with normal controls, cloudy swelling, stromal blood vessel dilatation and congestion inflammatory cell infiltration were observed in scald group, but these pathological changes were less marked in ENA group.</p><p><b>CONCLUSION</b>Severe myocardial damage in rat occurred early after burns. Enalaprilat injection can markedly alleviate myocardial damage.</p>

The influence of insulin growth factor-I on the apoptosis of cardiomyocytes subjected to ischemia and hypoxia / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the influence of insulin growth factor-I (IGF-I) on apoptosis of cardiomyocytes subjected to ischemia and hypoxia and its possible mechanism.</p><p><b>METHODS</b>Cardiomyocytes were cultured in vitro, and randomized into hypoxia group, treatment group (T, the cells were treated with IGF-1 before subjected to hypoxia and ischemia) and control group (C, normal cardiomyocytes as controls). Changes in the OD value of cell apoptosis, mitochondrial membrane potential and relative amount of phospho-Akt protein were observed at different time-points by ELISA, laser scanning with TMRE staining and Western blot, respectively.</p><p><b>RESULTS</b>The OD value of cell apoptosis in control group was 0.18 +/- 0.03, while that in hypoxia group was gradually increased to 0.33 +/- 0.05, 0.61 +/- 0.06, 1.17 +/- 0.08, 2.25 +/- 0.11, respectively at 1, 3, 6, 12 post-hypoxia hours (PHH), showing an increasing tendency (P < 0.01). The OD values of cell apoptosis in T group were 0.26 +/- 0.04, 0.49 +/- 0.05, 0.84 +/- 0.06, 1.63 +/- 0.09, respectively, which were obviously lower than those in hypoxia group (P < 0.05 or P < 0.01). The mitochondrial membrane potential (Dymt) values in hypoxia group at 6 and 12 PHH were 18.7 +/- 5.1 and 6.3 +/- 1.9, respectively, which were obviously lower than that in control group (40.2 +/- 10.1, P < 0.01). The DYmt in T group at 6 and 12 PHH were 28.8 +/- 6.2, 12.5 +/- 3.1, respectively, which were obviously higher compared with those in hypoxia group (P < 0.05). The amount of phospho-Akt protein was increased by IGF-I administration.</p><p><b>CONCLUSION</b>IGF-I exhibits an anti-apoptotic effect on cardiomyocytes subjected to ischemia and hypoxia, and this may be related to the activation of PI3K/Akt signal pathway and stabilization of mitochondrial membrane potential.</p>

Role of p38 mitogen activated protein kinase in the regulation of membrane myocardiac phospholipids degradation in early stage of severe burn rat / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the role of p38 mitogen activated protein kinase ( p38 MAPK) in the regulation of cytosolic phospholipase A2 ( cPLA2 ) expression and degradation of membrane phospholipids in myocardium in early stage of burn rats.</p><p><b>METHODS</b>Wistar rats were randomized into normal group (n = 8), burn(n =40) , burn and SB203580(n = 16), burn and isotonic saline( n = 16) groups, with 8 rats at each time-points. There were 5 time-points in burn group, and 2 time-points in other groups. The rats in the latter 3 groups were inflicted with 40% TBSA full-thickness burns, and those in burn and SB203580, burn and isotonic saline groups were administered with SB203580 (p38 MAPK inhibitor) or isotonic saline, respectively. The levels of cPLA2 mRNA and membrane phospholipids in myocardium were detected with RT-PCR. In the same experiment, the effect of SB203580 on cPLA2 expression in rat myocardial cells was determined after hypoxia and burn serum treatment in vitro.</p><p><b>RESULTS</b>The level of myocardial cPLA2 mRNA in burn group at each time-point was obviously higher than those in normal group (0. 280 +/- 0. 020) , and it reached the peak value at 3 PBH. In contrast, the level of cardiac membrane phospholipids was lowered immediately after burns, and it reached the lowest level at 6 PBH [(0. 052 +/- 0. 017) mg phosphorus/mg protein]. Herein, a significant negative correlation was showed between the levels of cPLA2 mRNA and cardiac membrane phospholipids ( r = - 0. 53, P < 0. 05). Administration of SB203580, however, inhibited the increased activity of p38 MAP kinase, suppressed the upregulation of cPLA2(72% and 51% of those in burn and saline group, P <0. 01) , and markedly increased the levels of membrane phospholipids in myocardium at 6 and 12 PBH. In addition, treatment of cardiac myocytes with SB203580 also abolished the upregulation of cPLA2 mRNA elicited by hypoxia and burn serum challenge.</p><p><b>CONCLUSION</b>p38 MAP kinase play an important role in the burn-induced degradation of cardiac membrane phospholipids in rat through the upregulation of myocardial expression of cPLA2 mRNA in the myocardial cells.</p>

Protective effects of Astragaloside and Quercetin on rat myocardial cells after hypoxia / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate and compare the protective effects of Astragaloside IV (AST) and Quercetin (QUE) on rat myocardial cells after their exposure to hypoxia, and to determine their dose-effect relationship.</p><p><b>METHODS</b>Myocardial cells from fetal SD rat were cultured in vitro and divided into 7 groups: i.e. A (hypoxia), B (hypoxia and 100 mg/L of QUE), C (hypoxia and 50 mg/L of QUE), D (hypoxia and 25 mg/L of QUE), E (hypoxia and 50.0 mg/L of AST), F (hypoxia and 25.0 mg/L of AST), G (hypoxia and 12.5 mg/L AST) H(hypoxia and 10 mg/L of VitE) groups. Different doses of AST and QUE were added into the culture media cells in each group before the myocardial cells receiving hypoxia for 12 hrs. The number of viable cells (CCK-8) and the content of lactate dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA), active oxygen (ROS, with detection only in A, C, F and H groups) were determined after hypoxia.</p><p><b>RESULTS</b>The amount of LDH, MDA, ROS (C, F groups) in group B - G decreased significantly compared with those of group A, while the number of viable cells and the SOD content increased significantly. The protective effects were better in group B - G than that of the group H. With the same dosage, levels of LDH, CCK-8 in AST-treated groups were significantly lower than those in QUE-treated group (the number of viable cells in group C, F was 0.454 +/- 0.018, 0.471 +/- 0.017, and the content of lactate dehydrogenase was 2800 +/- 9,2312 +/- 52). There were no significant differences in MDA, SOD and ROS levels between AST and QUE treated groups (ROS in C and F groups were 16.0 +/- 5.3 vs 22.4 +/- 8.7, P > 0.05).</p><p><b>CONCLUSION</b>AST and QUE might be beneficial in the protection of myocardial cells against hypoxia because of attenuation of oxidative damage. The protective effects of both AST and QUE are better than that of VitE, and that of AST is better than QUE as shown by a decrease in the amount of LDH and increase in the number of viable cells with the same dosage, but no obvious difference is shown between them in attenuating oxidative damage.</p>

Study on the mechanism of alleviation of myocardial injury after early escharectomy en masse of several burns in rat / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the alleviation of myocardial injury of rats after early escharectomy en masse of severe burns, and to explore its molecular mechanism.</p><p><b>METHODS</b>Totally 66 SD rats were randomly divided into normal control (n=6), non-escharectomy (NE, n=30) and escharectomy (E, n=30, with total escharectomy 20 minutes after burns ) groups. The rats in the NE and E groups were inflicted with 30% TBSA full-thickness scald. The content of ATP in mitochondria, troponin I (Tn I) in serum and 4.8-kb deletion of myocardial mitochondrial DNA (mtDNA) of the rats in each group were determined at 1, 3, 6, 12 and 24 post-scald hours (PSH).</p><p><b>RESULTS</b>(1) The content of ATP in myocardial mitochondria was decreased in both E and NE groups, but it was obviously increased at 1 and 6 PSH (0.90 +/- 0.27 microg/mg 0.66 +/- 0.19 microg/mg) in E group when compared with those in NE group (0.74 +/- 0.18 microg/mg, 0.46 +/- 0.21 microg/mg, P < 0.05). (2) There was no obvious change in the serum content of Tn I in E group at 1 and 3 PSH, but the respective content in 1, 3 and 6 PSH was markedly lower than those in NE group (P < 0.05). (3) The 4.8 kb deletion of myocardial mtDNA was found at 1, 3, 24 PSH in NE group, while it was observed only at 1, 12 PSH in E group. The partial and whole deletion rate in E group was lower than that in NE group.</p><p><b>CONCLUSION</b>Early escharectomy en masse can significantly alleviate the myocardial injury after burns,which might be related to its effect in lowering the deletion rate of myocardial mtDNA at early postburn stage.</p>

Study on the influence of hypoxia induced microtubule damage on the opening of mitochondrial permeable transition pore of cardiac myocytes in rat / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the influence of hypoxia induced microtubule damage on the opening of mitochondrial permeable transition pore (MPTP)of cardiac myocytes and on the decrease of respiratory function in rat.</p><p><b>METHODS</b>Primary cultured myocardial cells from 30 neonatal rats were randomized as normoxic group (A), hypoxia group (B), normoxia with microtubule destabilizing agent group (C, with treatment of 8 micromol/L colchicines for 30 minutes before normoxia), and hypoxia with microtubule stabilizing agent group (D, with treatment of 10 micromol/L taxol for 30 minutes before hypoxia). beta-tubulin immunofluorescence ,the opening of mitochondria permeability transition pore, and the mitochondrial inner membrane potential were detected at 0.5, 1, 3, 6 and 12 post-treatment hours (PTH), and the mitochondrial respiratory function was determined by MTT method. The changes in these indices were also determined in A group at the corresponding time-points.</p><p><b>RESULTS</b>Obvious damage of polymerized microtubule, opening of MPTP, mitochondrial inner membrane potential loss and decrease of myocardial respiratory activity were observed in both group B and C at 0.5 PTH, and they became more and more serious afterwards. However, the changes in the above indices in D group were much better than those in B group (P < 0.05 or 0.01), and no difference was found between D (92.8 +/- 4.0)% and C [(100.0 +/- 0.0) %, P > 0.05] groups.</p><p><b>CONCLUSION</b>Hypoxia played a role in the myocardial microtubule damage as well as in the opening of MPTP. Moreover, hypoxia could also impair the mitochondrial respiratory function. Microtubule destabilizing agent could reproduce well the process of hypoxia induced microtubule damage, while the stabilizing agent exerted protective effect by improving the transition of mitochondrial permeability and the mitochondria respiratory function.</p>

An experimental study on large fragment deletion of rat myocardial mitochondrial DNA during early postburn stage / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the influence of peroxidative injury in rat myocardium on the mitochondrial DNA (mtDNA) during early postburn stage.</p><p><b>METHODS</b>Thirty-six Sprague-Dawley (SD) rats were employed in the study and were randomly divided into sham scald (SS) and scald groups. The rats in scald groups were inflicted with 30% TBSA III degree scalding and were further divided into 1, 3, 6, 12 and 24 post-scald hour (PSH) groups. The mtDNA deletion was determined by semi-quantitative PCR. The rat myocardial tissue samples were harvested and homogenized and the contents of superoxide dismutase (SOD) and malondialdehyde (MDA) were determined.</p><p><b>RESULTS</b>There was no mtDNA deletion in the rat myocardium in SS group. Partial or complete large fragment (4.8 kb) mtDNA deletion in the rat myocardium was identified at 1, 3 and 24 PSHs (P < 0.05 or 0.01). The SOD activity in the rat myocardium significantly decreased at 1 PSH, reaching the lowest level (76.90 +/- 8.30 U/mg) at 6 PSH, but the MDA content increased evidently at 1 PSH, peaking [(3.17 +/- 0.80) nmol/mg] at 6 PSH (P < 0.05).</p><p><b>CONCLUSION</b>Peroxidative injury to the rat myocardium during early postburn stage might be the principal cause of the 4834 bp deletion of mtDNA in rat myocardium.</p>

Inhibition of the expression of cardiomyocytic hypoxic induction factor-1alpha during hypoxic state by double chain siRNA / 中华烧伤杂志

<p><b>OBJECTIVE</b>To construct hypoxic induction factor-1alpha (HIF-1alpha) siRNA expression cassette containing U6 promoter, alpha HIF-1alpha sense or antisense target sequence, and to observe its influence on the expression of cardiomyocytic HIF-1alpha during hypoxic state.</p><p><b>METHODS</b>Neonatal murine cardiomyocytes cultured in the mixed gas were employed as the hypoxic model and were divided into normal control (cultured in normal oxygen), RNAi control (invalidated transfection interference sequence IV) and RNAi effective inhibition (effective transfection interference sequence, which was further divided into I, II and III groups according to the difference of downstream primer) groups. Three pairs (I, II and III) of PCR downstream primer containing HIF-1alpha encoded gene fragments (sense and antisense) and one pair of randomize sequence (IV) PCR downstream primer were designed and synthesized. U6 starter expression frame was constructed by PCR method. The cardiomyocytes were transfected simultaneously by sense and antisense sequence expression frame. Five plates of the cells were set at each time points in each group. The expression of HIF-1alpha mRNA was detected by RT-PCR at 6 hours of hypoxia. The change in the protein expression level at 1 hour of hypoxia was determined by Western blot, and the interference effects were monitored by immunohistochemistry.</p><p><b>RESULTS</b>The best inhibition fragment screened was group II sequence. After the transfection and hypoxic culture, it was found that the cardiomyocytic HIF1alpha mRNA and protein levels in RNAi effective inhibition group were evidently lower than those in normal control and RNAi control groups (P < 0.01). While the protein inhibition rate (60% - 80%) between the former group and normal and RNAi control groups was no difference (P > 0.05).</p><p><b>CONCLUSION</b>The expression of the HIF1alpha in hypoxic rat cardiomyocytes could be effectively inhibited by our constructed HIF1alpha siRNA expression cassette group II.</p>