Dual role of polyamines in heart ischemia/reperfusion injury through regulation of mitochondrial permeability transition pore / 生理学报

Polyamines (putrescine, spermidine, and spermine) are essential polycations that play important roles in various physiological and pathophysiological processes in mammalian cells. The study was to investigate their role in cardioprotection against ischemia/reperfusion (I/R) injury and the underlying mechanism. Isolated hearts from male Sprague-Dawley rats were Langendorff-perfused and cardiac I/R was achieved by 30 min of global ischemia followed by 120 min of reperfusion. Different concentrations of polyamines (0.1, 1, 10, and 15 μmol/L of putrescine, spermidine, and spermine), cyclosporin A (0.2 μmol/L), or atractyloside (20 μmol/L) were given 10 min before the onset of reperfusion. The hemodynamics were monitored; the lactate dehydrogenase (LDH) levels in the coronary effluent were measured spectrophotometrically; infarct size was determined by the 2,3,5-triphenyltetrazolium chloride staining method; and mitochondrial permeability transition pore (MPTP) opening was determined spectrophotometrically by the Ca-induced swelling of isolated cardiac mitochondria. The results showed that compared to I/R alone, 0.1 and 1 μmol/L polyamines treatment improved heart function, reduced LDH release, decreased infarct size, and these effects were inhibited by atractyloside (MPTP activator). In isolated mitochondria from normal rats, 0.1 and 1 μmol/L polyamines treatment inhibited MPTP opening. However, 10 and 15 μmol/L polyamines treatment had the opposite effects, and these effects were inhibited by cyclosporin A (MPTP inhibitor). Our findings showed that polyamines may have either protective or damaging effects on hearts suffering from I/R by inhibiting or activating MPTP opening.

Effect of glucocorticoid on neurokinin A in plasma and lungs of guinea pigs with asthma and molecular mechanism of the effect / 中华儿科杂志

<p><b>OBJECTIVE</b>Bronchial asthma is a chronic inflammatory disorder of the airways caused by many complicated elements. Recently, a close attention has been paid to the neurogenic inflammation in airways, which is mediated by sensory neuropeptides secreted by sensory nerve. Neurokinin A (NKA) is an important transmitter of non-cholinergic excitatory nerves in the lung which is an important sensory neuropeptide causing airway neurogenic inflammation. The purpose of this study was to investigate the effect of glucocorticoid (dexamethasone) on neurokinin A in plasma and lungs of guinea pigs with asthma and to explore its molecular mechanism.</p><p><b>METHODS</b>Thirty guinea pigs (1.5 months old and weighed 200 - 225 g) were sensitized by exposure to aerosolized ovalbumin and challenged with the same antigen to establish asthma model. These animals were divided randomly into dexamethasone-treatment group and non-dexamethasone-treatment group (15 guinea pigs in each group). Normal control group animals (n = 15) were treated with normal saline (NS) instead of aerosolized ovalbumin. The guinea pigs in the dexamethasone-treatment group were treated with dexamethasone (5.0 mg/kg, intraperitoneal injection) one day before asthma-inducement, on the day of inducement and 24 h after inducement. The non-dexamethasone-treatment group animals were treated with NS (5.0 mg/kg, intraperitoneal injection) on the same days as the dexamethasone-treatment group was treated. The normal control group animals were treated with NS (5.0 mg/kg, intraperitoneal injection). The contents of NKA in the plasma and lung tissues were detected by ELISA; the expression of NKA mRNA in lung tissues was examined by RT-PCR.</p><p><b>RESULTS</b>(1) The contents of NKA in the plasma (2.20 +/- 0.46 ng/ml), lung tissues (5.02 +/- 2.11 ng/g x protein) and the NKA mRNA expression in the lung tissues (1.10 +/- 0.06) of guinea pigs with induced asthma were significantly higher than those of the normal control group (plasma 0.84 +/- 0.33 ng/ml, lung tissues 2.56 +/- 0.80 ng/g x protein, mRNA 0.30 +/- 0.04; P < 0.001, respectively). (2) The contents of NKA in the plasma, lung tissues and the NKA mRNA expression in the lung tissues of guinea pigs with induced asthma were significantly lower in dexamethasone-treatment group (plasma 0.98 +/- 0.23 ng/ml, lung tissues 2.71 +/- 0.50 ng/g x protein, mRNA 0.35 +/- 0.07) than those in the non-dexamethasone-treatment group (plasma 2.20 +/- 0.46 ng/ml, lung tissues 5.02 +/- 2.11 ng/g x protein, mRNA 1.10 +/- 0.06; P < 0.001, respectively). No significant difference was found between the dexamethasone-treatment group and the normal control group (P > 0.05, respectively).</p><p><b>CONCLUSIONS</b>(1) NKA mRNA expression in the lungs of guinea pigs with asthma was up-regulated and NKA contents were higher in plasma and lungs; (2) Glucocorticoid could significantly decrease the contents of NKA in plasma, lung tissues of guinea pigs with induced asthma; the mechanism of the effect may be related to down-regulation of NKA mRNA expression in lung tissues caused by glucocorticoid.</p>

Change of neurokinin A plasma level in asthmatic children / 中华儿科杂志

<p><b>OBJECTIVE</b>Chronic inflammation of airway in bronchial asthma is caused by many complicated elements. Recently, a close attention has been paid to the neurogenic inflammation in airway which is mediated by sensory neuropeptides secreted by sensory nerve in the lung. Neurokinin A (NKA) is an important sensory neuropeptide leading to neurogenic inflammation in airway. Experimental studies showed that NKA has a close relation to asthma. The purpose of the present study was to investigate the changes of NKA in plasma of asthmatic children and possible relationship between sensory neuropeptides and asthma in children.</p><p><b>METHODS</b>Thirty-five children with bronchial asthma were studied; 16 of the cases were < 3 yrs and 19 were >or= 3 yrs. Eighteen of the cases had severe asthma and 16 had mild asthma. None of the subjects was treated with glucocorticoid within 3 days before the study started; 15 healthy children without history of asthma or family history of asthma were enrolled as control subjects. Plasma was collected from each case during acute attack of asthma and their clinical remission of the asthmatic children. After purifying with SEP-pak C(18), NKA content was detect by enzyme-linked immunosorbent assay (ELISA) as instructed by the manufacturer of the NKA Kit (NKA unit: ng/L).</p><p><b>RESULTS</b>(1) The content of plasma NKA of asthmatic children was significantly higher at the asthma attack (256 +/- 153) than that at their clinical remission stage (70 +/- 66; q = 9.497, P < 0.01) and than that of the normal control group (38 +/- 6; q = 8.599, P < 0.01); no significant difference in plasma NKA was found between the clinical remission stage and the normal control group (q = 1.245, P > 0.05). (2) There was a significant positive correlation between the asthmatic clinical state and the levels of plasma NKA; the contents of plasma NKA at the stage of acute attack in severe asthma (296 +/- 170) were significantly higher than those of the mild asthmatic children (190 +/- 99; q = 3.77, P < 0.05).</p><p><b>CONCLUSIONS</b>The contents of plasma NKA were significantly higher during the asthma attack stage of children, and the higher was the level of NKA, the more severe the attack.; with asthma remission, the contents of plasma NKA decreased to normal; the contents of plasma NKA has a close relation to the asthmatic children.</p>