Changes of pulmonary beta-adrenergic receptors and their relationship with membranous phospholipid metabolism in endotoxin-induced lung injury in rats

The changes of beta-adrenergic receptors (AARs) in lung tissue in endotoxin-induced acute lung injury was investigated with radioligand bindig assay in rats. The lipid fluidity and phospholipid content of the cellular membrane of lung tissue were measured with fluorescent polarization and high performance liquid chromatography respectively. The findings were as follows:1- Four hours after endotoxin injection, there was a 47% decrease of the maximal binding capacity of fyARsas compared with the control.2. Endotoxin was able to decrease the lipid fluidity and phospholipid content of the pulmonary cellular membrane markedly and at the same time. There was an elevated activity of phospholipase A2 in the pulmonary tissueThese findings suggest that the decrease of the binding capacity of &ARs results in a decrease of the PAR mediated functions, which plays a ro1e in the pathogensis of endotoxin-induced acute lung injury and the activation of phospholipase A2 which is an important factor to reduce the phospholipid content of cell membrane and subsequently to decrease its lipid fluidity, can result in a reduction of the lateral diffusion and rotatory movement of β-ARs and to decrease the chances of β-ARs to bind with the ligands.

Anthrahydroquinone-2,6-disulfonate alleviates paraquat-induced kidney injury via the apelin-APJ pathway in rats

Objective:To explore the protective effects of anthrahydroquinone-2,6-disulfonate(AH_(2)QDS)on the kidneys of paraquat(PQ)poisoned rats via the apelin-APJ pathway.Methods:Male Sprague Dawley rats were divided into four experimental groups:control,PQ,PQ+sivelestat,and PQ+AH_(2)QDS.The PQ+sivelestat group served as the positive control group.The model of poisoning was established via intragastric treatment with a 20%PQ pesticide solution at 200 mg/kg.Two hours after poisoning,the PQ+sivelestat group was treated with sivelestat,while the PQ+AH_(2)QDS group was given AH_(2)QDS.Six rats were selected from each group on the first,third,and seventh days after poisoning and dissected after anesthesia.The PQ content of the kidneys was measured using the sodium disulfite method.Hematoxylin-eosin staining of renal tissues was performed to detect pathological changes.Apelin expression in the renal tissues was detected using immunofluorescence.Western blotting was used to detect the expression levels of the following proteins in the kidney tissues:IL-6,TNF-α,apelin-APJ(the apelin-angiotensin receptor),NF-κB p65,caspase-1,caspase-8,glucose-regulated protein 78(GRP78),and the C/EBP homologous protein(CHOP).In in vitro study,a PQ toxicity model was established using human tubular epithelial cells treated with standard PQ.Twenty-four hours after poisoning,sivelestat and AH_(2)QDS were administered.The levels of oxidative stress in human renal tubular epithelial cells were assessed using a reactive oxygen species fluorescence probe.Results:The PQ content in the kidney tissues of the PQ group was higher than that of the PQ+AH_(2)QDS group.Hematoxylin-eosin staining showed extensive hemorrhage and congestion in the renal parenchyma of the PQ group.Vacuolar degeneration of the renal tubule epithelial cells,deposition of crescent-like red staining material in renal follicles,infiltration by a few inflammatory cells,and a small number of cast formation were also observed.However,these pathological changes were less severe in the PQ+sivelestat group and the PQ+AH_(2)QDS group(P<0.05).On the third day after poisoning,immunofluorescence assay showed that the level of apelin in the renal tissues was significantly higher in the PQ+AH_(2)QDS group than in the PQ group.Western blotting analysis results showed that IL-6,TNF-α,NF-κB p65,caspase-1,caspase-8,GRP78,and CHOP protein levels in the PQ group were higher than in the PQ+AH_(2)QDS group(P<0.05).The expression of apelin-APJ proteins in the PQ+AH_(2)QDS group was higher than in the PQ+sivelestat and PQ groups(P<0.05);this difference was significant on Day 3 and Day 7.The level of oxidative stress in the renal tubular epithelial cells of the PQ+AH_(2)QDS group and the PQ+sivelestat group was significantly lower than in the PQ group(P<0.05).Conclusions:This study confirms that AH_(2)QDS has a protective effect on PQ-poisoned kidneys and its positive effect is superior to that of sivelestat.The mechanism of the protective effects of AH_(2)QDS may be linked to reduction in cellular oxidative stress,PQ content of renal tissue,inflammatory injury,endoplasmic reticulum stress,and apoptosis.AH_(2)QDS may play a role in the treatment of PQ poisoning by upregulating the expression of the apelin-APJ.

The relationship between platelet endothelial cell adhesion molecule-1 and paraquat-induced lung injury in rabbits

BACKGROUND:Platelet endothelial cell adhesion molecule-1(PECAM-1),also known as CD31,is mainly distributed in vascular endothelial cells.Studies have shown that PECAM-1 is a very significant indicator of angiogenesis,and has been used as an indicator for vascular endothelial cells.The present study aimed to explore the relationship between the expression of PECAM-1 and the degree of acute lung injury(ALI) and fibrosis in paraquat(PQ) induced lung injury in rabbits.METHODS:Thirty-six adult New Zealand rabbits were randomly divided into three groups(12rabbits in each group) according to PQ dosage:8 mg/kg(group A),16 mg/kg(group B),and 32 mg/kg(group C).After PQ infusion,the rabbits were monitored for 7 days and then euthanized.The lungs were removed for histological evaluation.Masson staining was used to determine the degree of lung fibrosis(LF),and semi-quantitative immune-histochemistry analysis to determine the expression of PECAM-1.Pearson's product-moment correlation analysis was performed to evaluate the relationship between the expression of PECAM-1 and the extent of lung injuries expressed by ALI score and degree of LF.RESULTS:Rabbits in the three groups showed apparent poisoning.The rabbits survived longer in group A than in groups B and C(6.47±0.99 days vs.6.09±1.04 days vs.4.77±2.04 days)(P<0.05).ALI score was lower in group A than in groups B and C(8.33±1.03 vs.9.83±1.17 vs.11.50±1.38)(P<0.05),and there was statistically significant difference between group B and group C(P=0.03).LF was slighter in group A than in groups B and C(31.09%±2.05%vs.34.37%±1.62%vs.36.54%±0.44%)(P<0.05),and there was statistically significant difference between group B and group C(P=0.026).The PEACAM-1 expression was higher in group A than in groups B and C(20.31%±0.70%vs.19.34%±0.68%vs.18.37%±0.46%)(P<0.05),and there was statistically significant difference between group B and group C(P=0.017).Pearson's correlation analysis showed that the expression of PECAM-1 was negatively correlated to both ALI score(Coe=-0.732,P=0.001)and degree of LF(Coe=-0.779,P<0.001).CONCLUSIONS:The PECAM-1 expression significantly decreases in New Zealand rabbits after PQ poisoning,and the decrease is dose-dependent.The PECAM-1 expression is negatively correlated with ALI score and LF,showing a significant role in the development of lung injuries induced by PQ.

Zinc-deficient diet aggravates ventilation-induced lung injury in rats

We investigated the effects of zinc deficiency on acute lung injury （ALI） induced by mechanical ventilation. Male Sprague-Dawley rats were fed with a zinc-deficient or zinc-proficient diet for 4 weeks, and then received mechanical ventilation at normal frequency and pressure for 30 min. Total protein, cell count, the number of poly- morphonuclear neutrophil （PMN） in the bronchoalveolar lavage （BAL）, and vascular endothelial growth factor （VEGF） expression in the lung were determined. Activation of nuclear factor-t^B （NF-~cB） was detected by exam- ining the phosphorylation of NF-kB （pNF-kB p65） and the expression of inhibitor of NF-kB （pI-kBa）. Compared to the controls, total cell count and the number of PMNs were significantly increased to 160% and 140%, respec- tively, in zinc-deficient rats treated with ventilation. Activation of NF-kB was significantly increased and VEGF was also increased to three-folds. Zinc deficiency aggravated the inflammatory response in rats and was associated with the overexpression of VEGF in response to mechanical ventilation. Zinc supplementation may be beneficial to zinc-deficient patients during mechanical ventilation.

Acute lung injury mechanism and therapy induced by paraquat poisoning

Paraquat (PQ, methyl viologen) was widely used in agricultural production throughout the world in 1962 for its efficient herbicidal activity. PQ was also highly toxic drug. About 5 mL medicine including 20% paraquat was life-threatening that can cause poisoning. In 1966, some people died because of PQ poisoning. Most patients had acute respiratory distress syndrome after 2 wk, and 70% of them died due to the lack of effective detoxification drugs. Thus, it was particularly important to understand the pathogenesis of PQ poisoning and give some effective treatments. This article will review the toxicological mechanism and treatment on PQ poisoning of acute lung injury.

The Mechanism of Acute Lung Injury Induced by Nickel Carbonyl in Rats

Nickel carbonyl is a highly toxic metal compound produced from the reaction that occurs between nickel and carbon monoxide under pressure. As previously reported, nickel carbonyl can cause acute aspiration pneumonia, and animal experiments showed it was toxic to animal lung, liver, brain, and other vital organs[1]. However, few studies have investigated nickel carbonyl poisoning in humans.

Functional changes of pulmonary surfactant in rats with lung injury induced by endotoxin

We studied the functional changes of pulmonary surfactant （PS） in acutelung injury models produced by endotoxin injection (E.coli O55B5) in rats.The sur-face properties of the lung lavage liquid and the total phospholipids （TPL） ex-tracted from it were assessed on a modified Wilhelmy film balance.γ-A isothermof the lavage liquid revealed an increase in minimum surface tension and a de-crease in hysteresis area,recruitment index and stability index,whereas that ofTPL extracted from it did not show any change except for hysteresis area.Thesurface activity correlates positively with the TPL content but negatively with thetotal protein content in the lavage liquid.The findings indicated that there was adysfunction of PS in rats with the lung injury induced by endotoxin,suggestingthat the function deficiency of PS might be caused by decreased phospholipidsand increased proteins in the alveoli.

The Role of Oxygen Radicals in Rat Acute Lung Injury Induced by Phorbol Myristate Acetate

We tried to clarify the role of oxygen radicals released from granulocytes stimulated byphorbol myristate acetate(PMA) in rat acute lung injury. It was found that DNA strand-breakdamage(DSBD) in peripheral white blood cells (WBC) was significantly increased 40 min after injec-tion of PMA. DSBD in lung tissue of rats treated with PMA was also markedly increased comparedwith the controls. The PMA-treated rats showed significantly higher lipid-peroxide (LPO) level inplasma and lung tissue hemogenate than the controls did. These results suggest that determination ofDSBD, a simple and sensitive indicator for oxygen radical damaging, might be useful in thediagnosis of adult respiratory distress syndrome (ARDS), when it is used together with themeasurement of plasma LPO.

Effects of Hyperoxia on Mitochondrial Multienzyme Complex Ⅲ and Ⅴ in Premature Newborn Rat Lung

To investigate the effects of hyperoxia on mitochondrial multienzyme complex Ⅲ （cytochrome, Cytb） and Ⅴ （ATPase6, 8） in premature newborn rat lung, the 1-day-old preterm SD rats were randomly assigned to hyperoxia group and air group, The rats in hyperoxia group were continuously exposed to 85% oxygen and those in air group to room air. After 1, 4, 7, 10, 14 day（s） of exposure, these rats were killed, total lung RNA was extracted and Cytb, ATPase6, 8 mRNA were detected by reverse transcription polymerase chain reaction （RT-PCR）. Western blotting was used to detect the expression of Cytb protein in lung tissue. The results showed that compared with air group, Cytb mRNA expression was significantly increased （P〉0,05） after 1, 4 day（s） of exposure. The general tendency decreased after 7 days, and its expression became weak but difference in mRNA expression between the two groups was not significant （P〉0.05）. ATPase6 mRNA expression was significantly increased 1 day after the exposure （P〈0.05） and did not show any significant change 4, 7, 10 days after the exposure （P〉0.05）. At the 14th day, ATPase6 mRNA expression was significantly increased （P〈0.05）, ATPase8 mRNA expression did not show any significant change 1, 4, 10 day（s） after the exposure （P〉0.05）, At the 7th and 14th day, ATPase8 mRNA expression was significantly increased （P〈0.05）. Western blotting showed that Cytb protein expression was increased 1,4 day（s） after the exposure, but the difference between the two groups was not significant （P〉0.05）. The general tendency was decreased after 7 days, and its expression became weak but difference was not significant 7, 10 days after the exposure （P〉0.05）. At day 14 its expression became significantly weak （P〈0.05）. We are led to conclude that exposure to high concentrations of oxygen can significantly change the expression of Cytb and ATPase6, 8, which results in uncoupling of oxidative phosphorylation in mitochondrial respiration chain, and plays an important role in the mechanism of hyperoxia-induced lung injury.

Establishment of Acute Lung Injury Model Induced by Intraperitoneal Injection of Lipopolysaccharide in Rats

The model of acute lung injury(ALI)was established by intraperitoneal administration,but there was no time-point observation and comparison.ALI model was established by intraperitoneal injection of lipopolysaccharide(LPS)at the concentration of 10 mg·kg^-1 (10 mg LPS dissolved in 1 mL normal saline to prepare 1 mL·kg^-1solution)in rats.The control group(CG)was intraperitoneally injected with saline of the same dose.In the LPS group,lung tissues were collected at 4,6,8,12 and 24 h after administration.Then,the morphology changes,the ratio of wet-to-dry weight(W/D),the expression of interleukin-1β(IL-1β)and tumor necrosis factor-α(TNF-α)proteins,the levels of malondialdehyde(MDA),the activities of superoxide dismutase(SOD),glutathione peroxidase(GSH)were measured.To verify the success of the model,the degrees of lung injury via Western blot,RT-PCR,ELISA and other techniques were detected at different time points,and the severe time of the ALI model established was deterimined by intraperitoneal administration,which provided a stable model basis for the study of the pathogenesis of ALI in the future.The results showed that the lung injury occurred in LPS group.W/D and lung pathological changes at 12 and 24 h of LPS group were significantly different from those in the CG.Compared with the CG,the expression of IL-1βand TNF-αproteins and the content of MDA in lung tissues of LPS group increased and most significant difference was found at 12 and 24 h(p<0.01).Compared with the CG,the activities of SOD and GSH in LPS 12 h group decreased significantly(p<0.01).In conclusion,inflammation and oxidative damage were the main causes of the ALI in rats.Lung injury was most obvious 12 h after intraperitoneal injection of 10 mg·kg^-1 LPS.

Effects of methyl palmitate and lutein on LPS-induced acute lung injury in rats

AIM: To investigate the effects of methyl palmitate and lutein on lipopolysaccharide(LPS)-induced acute lung injury(ALI) in rats and explore the possible mechanisms. METHODS: Male Sprague-Dawley rats were divided into 4 groups:(1) control;(2) LPS;(3) Methyl palmitate; and(4) Lutein groups. Methyl palmitate(300 mg/kg, ip) was administered 3 times per week on alternating days while lutein(100 mg/kg, oral) was given once daily. After 1 wk of vehicle/methyl palmitate/lutein treatment, ALI was induced by a single dose of LPS(7.5 mg/kg, iv). After 24 h of LPS injection, animals were sacrificed then biochemical parameters and histopathology were assessed. RESULTS: Treatment with methyl palmitate attenuated ALI, as it significantly decreased the lung wet/dry weight(W/D) ratio, the accumulation of the inflammatory cells in the bronchoalveolar lavage fluid(BALF) andhistopathological damage. However, methyl palmitate failed to decrease lactate dehydrogenase(LDH) activity in BALF. On the other hand, lutein treatment produced significant anti-inflammatory effects as revealed by significant decrease in accumulation of inflammatory cells in lung, LDH level in BALF and histopathological damage. Methyl palmitate and lutein significantly increased superoxide dismutase(SOD) and reduced glutathione(GSH) activities with significant decrease in the lung malondialdehyde(MDA) content. Importantly, methyl palmitate and lutein decreased the level of the inflammatory cytokine tumor necrosis factor-α(TNF-α) in the lung. Lutein also reduced LPS-mediated overproduction of pulmonary nitrite/nitrate(NO-2/NO-3), which was not affected by methyl palmitate pretreatment. CONCLUSION: These results demonstrate the potent protective effects of both methyl palmitate and lutein against LPS-induced ALI in rats. These effects can be attributed to potent antioxidant activities of these agents, which suppress inflammatory cell infiltration and regulated cytokine effects.

Advances in molecular mechanism of lung injury induced by paraquat poisoning

Paraquat is a bipyridine dichloride non-selective herbicide,which was widely used in the world in the last century.Now,paraquat is banned in most countries because of the extremely high lethality and the lack of specific detoxification drugs.However,death due to paraquat poisoning still occurs frequently,thus it is of great clinical significance to explore the molecular mechanism of paraquat poisoning and the detoxification drugs.Paraquat poisoning causes multiple dysfunction of the lung,liver,kidney,heart,and brain through complex molecular mechanisms.About the mechanism there are excessive inflammatory reaction theory,REDOX reaction imbalance theory,oxidative stress free radical damage theory,calcium overload theory,NO molecular damage and cell apoptosis theory,etc.For the treatment of paraquat poisoning,paraquat antibody,pathway target blocker and related factor antibody have been developed in recent years.Although certain effects have been achieved,the treatment efficiency has not been significantly improved.This paper summarized the mechanism of signal transduction pathways involved in lung injury induced by paraquat poisoning in order to provide a theoretical basis for further research.

大蒜素对COPD大鼠肺组织损伤及内质网应激的影响

本研究的目的是探讨大蒜素(ALL)对慢性阻塞性肺疾病(COPD)大鼠肺组织损伤及内质网应激(ERS)的影响。我们采用了烟雾暴露法建立COPD大鼠模型,并将40只大鼠随机分为四组:空气暴露对照组、COPD模型组、COPD+低剂量ALL治疗组以及COPD+高剂量ALL治疗组。ALL的处理剂量分别为50mg/kg和100mg/kg,每天通过腹腔注射给药。治疗持续4周,之后对大鼠进行肺功能测试,并收集肺组织进行组织学分析和生化检测。结果显示,与COPD模型组相比,ALL治疗组的大鼠肺功能显著改善,肺组织病理损伤得到减轻。通过免疫组织化学染色和西方印迹分析,我们发现ALL能够显著降低COPD大鼠肺组织中内质网应激标志物GRP78和CHOP的表达。此外,ALL治疗显著减少了炎症细胞浸润和氧化应激水平,同时提高了抗氧化酶(如SOD和CAT)的活性。低剂量和高剂量ALL治疗组之间的比较显示,高剂量ALL的效果更为显著。由此可见,大蒜素对COPD大鼠模型的肺功能有显著的改善作用,并能减轻肺组织损伤。这可能与其降低内质网应激和抗炎症的作用有关。这为大蒜素在COPD治疗中的应用提供了实验基础。

Expression of bradykinin as a substrate of CD26 /DPP IV in rats ischemia/reperfusion injury following lung transplantation

Objective To investigate the expression of bradykinin as a substrate of CD26 /DPP IV in rats with ischemia/reperfusion injury following lung transplantation ( LTx) . Methods Thirty - six syngeneic male SD rats were randomly allocated into control group and experimental group ( n = 18 each) ,and 36 rats served as do-

百草枯致大鼠肺损伤时内源性CO和NO的变化

目的:探讨内源性CO和NO在大鼠百草枯(PQ)中毒性急性肺损伤中的作用。方法:肺组织常规HE染色和取血测定血浆丙二醛(MDA)含量来评价肺组织损伤情况;检测血浆中肿瘤坏死因子(TNF-α)水平。检测肺组织中CO和NO含量和诱导型一氧化氮合酶(iNOS)活性。Western Blot方法测定HO-1和iNOS表达的变化。结果:PQ中毒后大鼠肺组织损伤明显加重,血浆MDA含量及TNF-α水平明显升高,应用正铁血红素(Hm)后血中CO含量明显升高,iNOS活性和NO水平则降低。结论:大鼠百草枯中毒性急性肺损伤时内源性CO和NO产生增加,在应用CO的供体氯血红素后CO升高更为明显,而NO产生降低,在一定程度上减轻了百草枯所致的大鼠急性肺损伤。

Expression of Angiotensin Ⅱ and Aldosterone in Radiation-induced Lung Injury

Objective Radiation-induced lung injury(RILI) is the most common,dose-limiting complication in thoracic malignancy radiotherapy.Considering its negative impact on patients and restrictions to efficacy,the mechanism of RILI was studied. Methods Wistar rats were locally irradiated with a single dose of 0,16,and 20 Gy to the right half of the lung to establish a lung injury model.Two and six months after irradiation,the right half of the rat lung tissue was removed,and the concentrations of TGF-β1,angiotensinⅡ,and aldosterone were determined via enzyme-linked immunosorbent assay. Results Statistical differences were observed in the expression levels of angiotensinⅡand aldosterone between the non-irradiation and irradiation groups.Moreover,the expression level of the angiotensinⅡ-aldosterone system increased with increasing doses,and the difference was still observed as time progressed. Conclusions AngiotensinⅡ-aldosterone system has an important pathophysiological function in the progression of RILI.

Effects of anisodamine on pulmonary α_1-adrenergic receptor and phospholipase A_2 in acute lung injury

Objective: To imastigate the effects of anisodamine on pulmonary α1- adrenergic receptor andphospholipase A, in acute lung injurg. Methods: Change of α1--adrenergic receptor (al AR ) in lung tissllesduring endotoxin--induced rat acute lung injury was measured with radioligand biding assay. The effects ofanisodamine on pulmonary α1--AR and phospholipase A2 (PLA2 ) were observed. Results: 1. 4 h after theendotoxin injection, there was a significant decrease in the maximal binding capacity of α1--AR by 34% ascompared with the control group. meanwhile elevated activity of PLA2 in rat lung and reduction of thephospholipids content of cell membrane was found. 2. Anisodamine could attenuate endotoxin--induced acutelung injury in rats. Conclusion: This effect might be related to anisodamine’s blockage of α1--AR andsuppression of PLA2, prevention of membranous phospholipids from degradation. and the reduction ofarachidonic acid release.