Influence of microtubule depolymerization of myocardial cells on mitochondria distribution and energy metabolism in adult rats / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the influence of microtubule depolymerization of myocardial cells on distribution and activity of mitochondria, and energy metabolism of cells in adult rats.</p><p><b>METHODS</b>Myocardial cells of SD adult rats and SD suckling rats were isolated and cultured. They were divided into adult and suckling rats control groups (AC and SC, normally cultured without any stimulating factor), adult and suckling rats microtubule depolymerization agent groups (AMDA and SMDA, cultured with 8 micromol/L colchicine containing nutrient solution for 30 minutes) according to the random number table. (1) The expression of polymerized beta tubulin in myocardial cells of adult and suckling rats was detected with Western blot. (2) Myocardial cells of rats in AC and AMDA groups were collected. The expression of cytochrome c was detected with Western blot. Distribution of voltage-dependent anion channels (VDAC) and polymerized beta tubulin in myocardial cells were observed with immunofluorescent staining. Mitochondrial inner membrane potential was determined with immunocytochemical method. Activity of myocardial cells was detected with MTT method. Contents of ATP, adenosine diphosphate (ADP), and adenosine monophosphate (AMP) and energy charge of cells were determined with high performance liquid chromatography.</p><p><b>RESULTS</b>(1) The expression of polymerized beta tubulin:in AMDA group it was 0.52 + or - 0.07, which was obviously lower than that (1.25 + or - 0.12) in AC group (F = 31.002, P = 0.000); in SMDA group it was 0.76 + or - 0.12, which was significantly lower than that (1.11 + or - 0.24) in SC group (F = 31.002, P = 0.000), but was obviously higher than that in AMDA group (F = 31.002, P = 0.009). (2) The expression of cytochrome c in AC group was 0.26 + or - 0.03, which was obviously lower than that (1.55 + or - 0.13) in AMDA group (t = -24.056, P = 0.000). (3) Immunofluorescent staining result: in AC group, microtubules of myocardial cells were in linear tubiform, distributed in parallel with myocardial fiber; VDAC staining result showed that mitochondria were in granular form, distributed in the same direction as microtubules. In AMDA group, the normal distribution regularity of microtubules was destroyed, with weakened immune fluorescence intensity, microtubules structure indistinct, continuity lost, rough in appearance, and the distribution of mitochondria became disrupted. (4) Mitochondrial inner membrane potential in AC group fluorescent intensity was 1288 + or - 84, which was obviously higher than that (331 + or - 27) in AMDA group (t = 26.508, P = 0.000). (5) Cellular activity: in AC group absorbance value was 1.75 + or - 0.11, which was obviously lower than that (0.81 + or - 0.07) in AMDA group (t = 17.348, P = 0.000). (6) Energy metabolism: compared with those in AC group, content of ATP decreased, contents of ADP and AMP increased, and ATP/ADP value and energy charge decreased in AMDA group.</p><p><b>CONCLUSIONS</b>Microtubules and mitochondria distribute in the same direction in normal myocardial cells in adult rats. After microtubule depolymerization, mitochondria are arranged in disorder fashion; cytochrome c leaks from mitochondria; mitochondrial membrane potential, energy supply, and cellular activity decrease in the myocardial cells.</p>

Protective effect of enalaprilat injection against early postburn organ damage in rats / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the dose-effect relationship of enalaprilat (ENA) injection on the organ damage following early burn injury in rats.</p><p><b>METHODS</b>A total of 54 SD rats were subjected to 30% total body surface area III scald injury, and were randomly divided into simple scald group (B group, with conventional fluid transfusion after scald), ENA treated group (E1, E2, E3 group, with intraperitoneal enalaprilat injection of 1, 2, 4 mg/kg after scald respectively). Other 6 rats were taken as normal control. Aortic systolic pressure (AOSP), aortic diastolic blood pressure (AODP), mean arterial pressure (MAP), angiotensin 1, blood urea nitrogen (Bun), creatinine (Cr), creatinine kinase (CK), alanine aminotransferase (ALT), aspartate aminotransferase (AST) of the simple scald group, E1 group, E2 group and E3 group were investigated at 6 h and 12 h post burn.</p><p><b>RESULTS</b>Ang II, Bun, Cr, CK, ALT, AST levels in ENA treated group after 6 h and 12 hours were significantly lower than those of simple scald group (all P < 0.05). AOSP, AODP, MAP in ENA treated group after 6 and 12 hours were significantly higher than those of simple scald group (all P < 0.05).</p><p><b>CONCLUSION</b>Low-dose enalaprilat, injection (1 mg/kg) could alleviate organ damage in post-burned rats, but has little effect on AOSP and AODP.</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 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>

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>