Pro-apoptotic role of NF-kappaB pathway inhibition in lipopolysaccharide-stimulated polymorphonuclear neutrophils / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the role of nuclear factor kappa B (NF-kappaB) pathway inhibition in lipopolysaccharide (LPS)-stimulated apoptosis of polymorphonuclear neutrophils (PMNs).</p><p><b>METHODS</b>Rats with acute lung injury induced by LPS intratracheal instillation and cultured human venous PMNs were studied. Pyrrolidine dithiocarbamate (PDTC) and gliotoxin were used as NF-kappaB inhibitors. Additionally, to explore the role of extracellularly regulated protein kinase as an upstream signal in NF-kappaB pathway on regulating LPS-stimulated PMN apoptosis, PD098059, the specific inhibitor of extracellularly regulated protein kinase, was also applied. The lung injury was determined by protein content and PMN numbers in bronchoalveolar lavage fluid. PMN apoptosis was measured by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) end labeling and DNA fragmentation. IkappaBalpha degradation was analyzed by Western blot. NF-kappaB DNA binding activity was detected by an electrophoretic mobility shift assay.</p><p><b>RESULTS</b>(1) The increase of protein content and PMN numbers in bronchoalveolar lavage fluid induced by LPS (100 micro g per rat) intratracheal instillation were alleviated by PDTC (50, 100, or 200 mg/kg, i.p.) in a dose-dependent manner. (2) PMNs apoptosis in vivo or in vitro was delayed by LPS, and accelerated by PDTC, gliotoxin or PD098059 pretreatment. (3) IkappaBalpha degradation and increased NF-kappaB DNA binding activity mediated by LPS were inhibited by PDTC, gliotoxin or PD098059 pretreatment.</p><p><b>CONCLUSION</b>Inhibition of either NF-kappaB itself or the upstream signals in NF-kappaB pathway such as extracellularly regulated protein kinases has therapeutic effect on LPS-induced acute lung injury, in which the dysregulation of PMN apoptosis plays an important role.</p>

Expression of heme oxygenase in injured lung following ischemia-reperfusion of limbs in rats / 中国病理生理杂志

AIM:To observe the changes in heme oxygenase-1(HO-1) expression in the lung after ischmia-reperfusion of hind limbs in rats.METHODS:Hind limbs ischemia was made by clamping infrarenal aorta with a microvascular clip and lung injury was made by following reperfusion. Lung tissue was obtained from the animals subjected to sham operation, 4 h ischemia without reperfusion and 4 h, 8 h, 16 h, 24 h, 48 h reperfusion following 4 h ischemia. The levels of HO-1 mRNA and protein were measured at different times by Northern blot and Western blot. Immunohistochemistry technique was used to determine the cell types responsible for limb ischemic reperfusion induced HO-1 expression. RESULTS:After ischemia-reperfusion of limbs, HO-1 mRNA increased by 4 h, reached a peak at 16 h, and returned toward baseline at 24-48 h. This time course correlated with increased HO-1 protein. Immunohistochemical studies showed HO-1expressed in a variety of cell types, including the airway epithelium, alveolar macrophages and vascular smooth muscular cells. There were no positive signals in sham group and ischemia group both in mRNA levels and protein levels. CONCLUSION:The expression of HO-1 in the lung is not induced by limb ischemia or sham operation, but induced by limb reperfusion after ischemia in rats.

Expression of heme oxygenase in injured lung following ischemia-reperfusion of limbs in rats / 中国病理生理杂志

AIM: To observe the changes in heme oxygenase-1(HO-1) expression in the lung after ischmia-reperfusion of hind limbs in rats.METHODS: Hind limbs ischemia was made by clamping infrarenal aorta with a microvascular clip and lung injury was made by following reperfusion. Lung tissue was obtained from the animals subjected to sham operation, 4 h ischemia without reperfusion and 4 h, 8 h, 16 h, 24 h, 48 h reperfusion following 4 h ischemia. The levels of HO-1 mRNA and protein were measured at different times by Northern blot and Western blot. Immunohistochemistry technique was used to determine the cell types responsible for limb ischemic reperfusion induced HO-1 expression. RESULTS: After ischemia-reperfusion of limbs, HO-1 mRNA increased by 4 h, reached a peak at 16 h, and returned toward baseline at 24-48 h. This time course correlated with increased HO-1 protein. Immunohistochemical studies showed HO-1expressed in a variety of cell types, including the airway epithelium, alveolar macrophages and vascular smooth muscular cells. There were no positive signals in sham group and ischemia group both in mRNA levels and protein levels. CONCLUSION: The expression of HO-1 in the lung is not induced by limb ischemia or sham operation, but induced by limb reperfusion after ischemia in rats.

Reversion of the decline of cardiac function in endotoxin shock rats by cholecystokinin octapeptide / 中国病理生理杂志

AIM: To verify the effect of cholecystokinin octapeptide(CCK-8) on cardiac function in endotoxin shock (ES) rats.METHODS: The rats were divided into four groups:control,lipopolysaccharide(LPS),CCK-8 and CCK-8+LPS.The left ventricle pressure(LVP),the maximal/minimum rate of LVP(?LVd p /d t max ),heart rate (HR) and mean arterial pressure (MAP) were measured.The activity of superoxide dismutase (SOD),the contents of malondialdehyde (MDA) and nitric oxide (NO) in both serum and myocardium were also measured,respectively.RESULTS: CCK-8 (40 ?g?kg -1 , iv) elicited bradycardia in short time and gently increase MAP,LVP and ?LV d p /d t max . Lipopolysaccharide(LPS, 8 mg?kg -1 , iv) caused a variation in heart rate (HR)(a bradycardia following a tachycardia) and rapid decreases in MAP,LVP and ?LVd p /d t max . The rapid variation of HR and the decline of MAP,LVP and ?LVd p /d t max were reversed by pretreatment with CCK-8 in ES rats, but didn't restore to normal.The activity of SOD was increased and the contents of MDA and NO were decreased by pretreatment with CCK-8 in ES rats.CONCLUSION: The decline of cardiac function in ES rats could be reversed by pre-administration of CCK-8 and the decrease in NO production may be one of the mechanisms.

Mechanism of exogenous nitric oxide in attenuating endotoxin-induced increase of rat pulmonary microvascular permeability / 中国病理生理杂志

AIM and METHODS: The animal model of acute lung injury (ALI) caused by intratracheal instillation of lipopolysaccharides(LPS) in vivo and human peripheral blood polymorphonuclear neutrophil (PMN) in vitro were used to study the effects of sodium nitroprusside (SNP), nitric oxide (NO) donor, on LPS-induced PMN accumulation, microvascular permeability and PMN apoptosis. RESULTS: ① In vivo , PMN accumulation in lung, the protein content in bronchoalveolar lavage fluid (BALF) and the Evans blue dye and monastral blue dye extravasation in lung tissue of LPS group were markedly higher than those of both sham operation group and LPS+SNP group. ② In vitro, the apoptotic percentage of SNP group was much higher than that of control group, while compared with LPS group, SNP+LPS group has significantly higher apoptotic percentage. CONCLUSIONS: SNP intratracheal instillation attenuated LPS-induced microvascular permeability and alleviated ALI. PMN apoptosis induced by SNP may be one of the potential mechanisms underlying the decrease of PMN accumulation in lung tissue.

Effects of endogenous carbon monoxide/nitric oxide on cholecystokinin octapeptide reversed vascular hyporeactivity in endotoxemic rats / 中国病理生理杂志

AIM: To explore the effects of cellular signal transduction pathways of heme oxygenase-1(HO-1)-carbon monoxide (CO)-cyclic GMP (cGMP) and nitric oxide synthase (NOS)-nitric oxide (NO)-cGMP on cholecystokinin octapeptide (CCK-8) reversed vascular hyporeactivity in endotoxemic rats. METHODS: According to the treatments given in vivo , rats were devided into four groups: control; lipopolysaccharide (LPS); CCK and CCK+LPS. Using isolated vascular ring tension detecting technique, thoracic aortic rings (TARs) were prepared and accumulation of contractive responses to phenylephrine (PE) were measured under which the TARs were incubated with Hemin (He, donor of CO), Zinc-protoporphyrin-IX (ZnPP-IX, selective inhibitor of HO-1), L-arginine (L-Arg, substrate of NOS), aminoguanidine (AG, selective inhibitor of iNOS), N ?-nitro-L-arginine (L-NNA, inhibitor of NOS) or methylene blue (MB, inhibitor of guanylyl cyclase), respectively. RESULTS: CCK-8 alone did not affect vascular tension. Injection of LPS induced the hyporeactivity of the TARs and was reversed by pretreatment of CCK-8. In LPS and CCK+LPS groups, the hyporeactivity was partly reversed by incubation of TARs with ZnPP-IX or AG, and restored to normal by incubation of TARs with L-NNA or MB. Incubation of TARs with He or L-Arg showed to make the vascular hyporeactivity worse in different degree. CONCLUSIONS: CCK-8 alone did not affect the activity of HO-1 and iNOS but influenced the activity of these enzymes induced by LPS, which lead to reduced CO/NO production, decreased the content of cGMP and plays its important role in reversing vascular hyporeactivity in endotoxemic rats.

Effect of interleukin - 10 on attenuating endotoxin - induced acute lung injury / 中国病理生理杂志

AIM: To study the role of polymorphonuclear neutrophile(PMN) in lipopolysaccharide (LPS)- induced acute lung injury (ALI) and the protective effect of interleukin - 10(IL - 10) on ALI. METHODS: LPS alone (100 ?g) or LPS+ IL-10 (l ug) was instilled intratracheally into rats. PMN numbers, protein content and malondialdehyde (MDA) content in bronchoalveolar lavage fluid (BALF) were measured. Histological change of lung was also observed. RESULTS: LPS increased significantly PMN numbers, protein content and MDA content in BALF. Histological finding shows PMN accumulation in lung. IL - 10+LPS reduced remarkably PMN numbers ,pro- tein content and MDA content in BALF than those caused by LPS. PMN decreasing was also identified by light microscopy. CONCLUSION: LPS instilled intratracheally causes PMN accumulation in lung and ALI, while IL - 10 could alleviate ALI through reducing PMN accumulation.