Effect of Shengmai injection () on diaphragmatic contractility in doxorubicin-treated rats / 中国结合医学杂志

<p><b>OBJECTIVE</b>To explore the diaphragmatic toxicity in doxorubicin (DOX)-treated rats and the related mechanisms, as well as the effects of Shengmai Injection (SMI, ) on the diaphragmatic dysfunction.</p><p><b>METHODS</b>Thirty Sprague-Dawley male rats were randomly divided into three groups: control, DOX-treated and DOX+SMI treated groups. DOX was given to rats in DOX and DOX+SMI groups in 6 equal doses [2.5 mg/kg, intraperitoneal injection (i.p.)], on alternate days, over a period of 2 weeks for a cumulative dose of 15 mg/kg. SMI was given to DOX+SMI rats in 12 doses (3 mL/kg, i.p.) for a period of 2 weeks before the administration of DOX and 2 weeks during the administration of DOX. The rats in the control group received equal volume of normal saline. Subsequently, the twitch and tetanic characteristics and force-frequency relationships, and the malondialdehyde (MDA) levels and the superoxide dismutase (SOD) activities, as well as the mRNA content and proteins of inducible nitric oxide synthase (iNOS) were determined.</p><p><b>RESULTS</b>The DOX-treated rats had decreased the peak twitch tension (Pt), maximal tetanic tension (P0) and force-frequency relationship as compared with the control rats (P<0.01), while the diaphragm contractility in rats treated with SMI were significantly higher than that in DOX-treated rats (P<0.01). The DOX-treated rats had increased MAD levels and decreased SOD activities (P<0.05), and SMI decreased the MDA levels and increased the SOD activities in DOX-treated rats (P<0.05). Ultrastructure of diaphragm in the DOX-treated rats revealed typical alterations including fracture of diaphragm fibers, and edema and degeneration of mitochondria; these changes were relieved by SMI treatment. The mRNA content and protein of iNOS in DOX-treated rats were remarkably higher than those in control rats (P<0.01), while SMI decreased the mRNA expression level of iNOS in DOX-treated rats (P<0.05).</p><p><b>CONCLUSIONS</b>Lipid peroxidation is responsible for DOX-induced diaphragm toxicity. SMI protects diaphragm muscles and their function from DOX impairment, and these beneficial effects may be somehow correlated with the decrease in expression of iNOS and lipid peroxidation.</p>

Negative modulation of NO for diaphragmatic contractile reduction induced by sepsis and restraint position / 法医学杂志

In practice of forensic medicine, potential disease can be associated with fatal asphyxia in restraint position. Research has demonstrated that nitric oxide (NO) and nitric oxide synthase (NOS) are plentifully distributed in skeletal muscle, contributing to the regulation of contractile and relaxation. In the current study, respiratory functions, indices of diaphragmatic biomechanical functions ex vivo, as well as NO levels in serum, the expressions of diaphragmatic inducible NOS (iNOS) mRNA, and the effects of L-NNA on contractility of the diaphragm were observed in sepsis induced by cecal ligation and puncture (CLP) under the condition of restraint position. The results showed that in the CLP12-18h rats, respiratory dysfunctions; indices of diaphragmatic biomechanical functions (Pt, +dT/dt(max), -dT/dt(max), CT, Po, force over the full range of the force-frequency relationship and fatigue resistance) declined progressively; the NO level in serum, and iNOS mRNA expression in the diaphragm increased progressively; force increased significantly at all stimulation frequencies after L-NNA pre-incubation. Restraint position 1 h in CLP12 h rats resulted in severe respiratory dysfunctions after relative stable respiratory functions, almost all the indices of diaphragmatic biomechanical functions declined further, whereas little change took place in NO level in serum and diaphragmatic iNOS mRNA expression; and the effects of L-NNA were lack of statistical significance compared with those of CLP12 h, but differed from CLP18 h group. These results suggest that restraint position and sepsis act together in a synergistic manner to aggravate the great reduction of diaphragmatic contractility via, at least in part, the negative modulation of NO, which may contribute to the pathogenesis of positional asphyxia.

The changes of inducible nitric oxide synthase activity and apoptosis-related gene expression in endotoxemia-induced rat diaphragm / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To study the changes of inducible nitric oxide synthase (iNOS) activity and apoptosis-related genes Bcl-2, Bax and caspase-3 mRNA expressions in endotoxemia-induced rat diaphragm injury and analyze the related apoptosis mechanism.</p><p><b>METHODS</b>Thirty-two male SD rats were randomly divided into 4 groups (n = 8): control group (saline 0.5 ml ip), endotoxin 24 h, 48 h and 96 h group (endotoxin 12 mg/kg ip, animals were killed either 24, 48 or 96 h after injections). Body weight were measured, the ratio between diaphragm weight and body weight, activities of constitutive nitric oxide syntheses (cNOS), iNOS and succinate dehydrogenase (SDH) were also measured. The expressions of Bcl-2, Bax and caspase-3 mRNA were detected by RT-PCR analysis.</p><p><b>RESULTS</b>Endotoxin induced significant reductions in diaphragm mass in endotoxin 96 h group (P < 0.05). Endotoxin increased diaphragm cNOS or iNOS activities, and they were significantly higher in endotoxin 96 h group than those in endotoxin 24 h and 48 h groups, diaphragm SDH activity was reduced, and it was lower in endotoxin 96 h group than that in endotoxin 24 h and 48 h groups (P < 0.01). Endotoxin significantly increased Bax and caspase-3 mRNA expressions, and they were higher in endotoxin 48 h and 96 h groups than those in endotoxin 24 h group (P < 0.01). Endotoxin significantly reduced Bcl-2 mRNA expression and the ratio of Bcl-2/Bax, and they were lower in endotoxin 48 h and 96 h groups than those in endotoxin 24 h group (P < 0.01).</p><p><b>CONCLUSION</b>iNOS is activated in endotoxemia-induced rat diaphragm injury. It damages mitochondria, upregulates Bax expression and downregulates Bcl-2 expression, then induces caspase-3 related apoptotic pathway. These changes may cause diaphragm injury and atrophy.</p>

The role of nitric oxide in ethanol postconditioning induced cardioprotection / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate whether the release of nitric oxide (NO) was involved in the cardioprotection of ethanol postconditioning in isolated rat hearts.</p><p><b>METHODS</b>Hearts isolated from male SD rats were subjected to 30 min of regional ischemia (occlusion of left anterior descending artery) followed by 120 min of reperfusion. Ethanol postconditioning was fulfilled through perfusion of 50 mmol/L ethanol for 15 min (at the end of cardiac ischemia for 5 min and at the beginning of reperfusion for 10 min). The rats were divided into five groups: normal, ischemia and reperfusion, ethanol postconditioning, ethanol postconditioning + L-nitro-arginine-methylester (L-NAME) and ethanol postconditioning + atractyloside. The ventricular hemodynamic parameters and lactate dehydrogenase (LDH) release during reperfusion were measured. The infarct size was measured by TTC staining method and NO content was measured by nitric acid reductase method. The expressions of Bcl-2 and Bax mRNA were detected by RT-PCR analysis.</p><p><b>RESULTS</b>In contrast to ischemia and reperfusion, ethanol postconditioning improved left ventricular developed pressure, rate pressure product during reperfusion, reduced LDH release and infarct size. NO content was decreased. The ratio of Bcl-2/Bax was increased. Administration of nitric oxide synthase inhibitor L-NAME or mitochondrial permeability transition pore opener atractyloside both attenuated the role of ethanol postconditioning, which inhibited the recovery of hemodynamic parameters, the decreases of LDH and infarct size. NO content was decreased further. The ratio of Bcl-2/Bax was decreased.</p><p><b>CONCLUSION</b>The cardioprotection of ethanol postconditioning may be associated with reducing nitric oxide release, inhibiting the opening of mitochondrial permeability transition pore and decreasing the happening of apoptosis.</p>

Effects of restraint position on changes of diaphragmatic mechanical characteristic in rats / 法医学杂志

OBJECTIVE@#To observe effects of restraint position on the changes of diaphragmatic mechanical characteristic in rats, and try to explore the role of nitric oxide (NO).@*METHODS@#Rat model of restraint position was established. Rats were divided into control group, restraint position 12h and 24h groups. The markers of respiratory functions in vivo and the biomechanical markers of diaphragmatic characteristic ex vivo were evaluated. Serum NO levels were measured with spectrophotometry. The expressions of nNOS and iNOS mRNA in diaphragm were detected using RT-PCR.@*RESULTS@#Compared with control group, respiratory rate, tidal volume and minute ventilation were significantly decreased in the restraint position 12h and 24h groups. Pt of diaphragm significantly decreased and force-generating capacity reduced at low frequency stimulation in 12h group. Force-generating capacity over the full range reduced at low and high frequency stimulation in 24h group. Pt of diaphragm in control and restraint position groups increased after L-NNA pre-incubation. Force-frequency relationship after L-NNA pre-incubation reduced in 24h group. NO level in serum increased significantly in the restraint position groups. Diaphragmatic nNOS mRNA expression was upregulated significantly in the restraint position groups.@*CONCLUSION@#Restraint position induces the decreasement of diaphragmatic contractility and the decreasement is mediated by NO from diaphragm or circulation blood.

Activation of mitochondrial aldehyde dehydrogenase 2 and inhibition of mitochondrial permeability transition pore involved in cardioprotection of ethanol postconditioning / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate whether activation of mitochondrial aldehyde dehydrogenase 2 (ALDH2) and inhibition of mitochondrial permeability transition pore (mitoPTP) were involved in the cardioprotection of ethanol postconditioning in isolated rat heart.</p><p><b>METHODS</b>Hearts isolated from male Sprague-Dawley rats were perfused on a langendorff apparatus and subjected to 30 min of regional ischemia (occlusion of left anterior descending artery) followed by 120 min of reperfusion. The ventricular hemodynamic parameters and lactate dehydrogenase (LDH) release during reperfusion were measured. Infarct size was measured by TTC staining method and the expression of ALDH2 at mRNA level of left anterior myocardium was detected by RT-PCR.</p><p><b>RESULT</b>In contrast to ischemia and reperfusion, ethanol postconditioning improved the recovery of left ventricular developed pressure, maximal rise/fall rate of left ventricular pressure during reperfusion, reduced LDH release and infarct size. The expression of ALDH2 mRNA level was increased. Administration of mitoPTP activator atractyloside attenuated the effect of ethanol postconditioning, LDH release and infarct size were increased, and the recovery of hemodynamic parameters was inhibited. The expression of ALDH2 mRNA was decreased.</p><p><b>CONCLUSION</b>Ethanol postconditioning has cardioprotection effect, which may be associated with upregulating mitochondrial ALDH2 mRNA expression and inhibiting the opening of mitochondrial permeability transition pore.</p>