N-乙酰半胱氨酸对小鼠免疫性肝损伤的影响

目的研究N-乙酰半胱氨酸(NAC)对卡介苗(BCG)与细菌脂多糖(LPS)引起小鼠免疫性肝损伤的影响。方法建立BCG/LPS引起的小鼠免疫性肝损伤模型。采用两种处理方式给予NAC:方式A,于LPS处理前4h和15min分别经腹腔注射给予NAC(预处理);方式B,于LPS处理后0h和4h分别经腹腔注射NAC(后处理)。LPS处理后8h剖杀动物,取血和肝脏,并检测血清丙氨酸氨基转移酶(ALT)活性与一氧化氮(NO)水平、肝脏组织谷胱甘肽(GSH)与丙二醛(MDA)含量以及肿瘤坏死因子α(TNF-α) mRNA表达水平。结果与模型组比较,NAC预处理组小鼠血清ALT活性下降,肝脏TNF-α mRNA表达明显减少,而体内NO生成和肝脏脂质过氧化水平无改变;NAC后处理组与模型组相比,小鼠死亡率升高,血清NO生成增加,肝脏GSH含量进一步下降,而小鼠血清ALT活性未见明显改变。结论NAC对小鼠免疫性肝损伤有双重效应,NAC预处理对抗BCG/LPS引起的小鼠免疫性肝脏损伤,NAC后处理加重BCG/LPS引起的氧化应激并升高动物死亡率。     

低剂量细菌脂多糖预处理对其诱导宫内胎儿死亡和早产的影响

目的 研究低剂量细菌脂多糖(LPS)预处理对高剂量LPS诱导宫内胎儿死亡(IUFD)和早产的影响.方法 实验1:孕鼠随机分为4组,LPS组和对照组分别于孕15 d腹腔注射LPS(120μug/kg)和等容积NS;LPS(4 h) LPS组和LPS(24 h) LPS组孕鼠分别在给予低剂量LPS(10 μg.kg,i.P.)4、24 h后再腹腔注射高剂量LPS(120μg/kg).高剂量LPS处理后密切观察各组孕鼠早产迹象,第18 d剖杀各组非早产孕鼠,记录活胎数、死胎数、吸收胎数和着床腺数.实验2:随机分成4组(同实验1).每组12只孕鼠在高剂量LPS处理1.5 h后被刮杀,取孕鼠血清和羊水,并测定其肿瘤坏死因子α(TNF-α)和白细胞介素10(IL-10)含量;另外每组12只孕鼠于高剂量LPS处理6 h后被剖杀,留取孕鼠血清、羊水和胎盘,并检测母血和羊水中-氧化氮(NO)水平,测定胎盘组织还原性谷胱甘肽(GSH)和丙二醛(MDA)含量.结果 在高剂量LPS处理前24 h给予的低剂量LPS显著降低高剂量LPS诱导的宫内胎鼠死亡、减少孕鼠血清和羊水中TNF-α含量和降低小鼠胎盘MDA含量.与单纯LPS组比较,LPS(4 h) LPS组宫内胎鼠死亡率进一步升高、孕鼠血清和羊水中TNF-α与NO含量明显增加、小鼠胎盘MDA含量和GSH损耗也明显提高.结论 低剂量LPS预处理对高剂量LPS引起发育毒性的影响取决于两次LPS处理的时距.在高剂量LPS处理孕鼠前24 h给予的低剂量LPS可保护高剂量LPS引起IUFD和早产,主要通过抑制TNF-α产生和对抗机体氧化应激;而在高剂量LPS处理前4 h给予的低剂量LPS却加重高剂量LPS引起的发育毒性.     

地昔帕明对小鼠内毒素急性肺损伤的影响

目的探讨地昔帕明(DP)对脂多糖(LPS)引起的急性肺损伤的作用并初步探讨其作用机制。方法昆明种小鼠随机分为生理盐水对照组(NS组)、地昔帕明对照组(DP组)、模型组(LPS组)及地昔帕明处理组(DP+LPS组)。腹腔注射LPS建立小鼠急性肺损伤模型。造模6h后测定肺湿/干重比值(W/D)、肺泡灌洗液(BALF)中白细胞数和蛋白含量、肺组织匀浆中髓过氧化物酶(MPO)活性和丙二醛(MDA)水平,同时用ELISA法检测肺匀浆中肿瘤坏死因子-α(TNF-α)含量。结果LPS可提高小鼠肺W/D、BALF中白细胞数和蛋白含量、肺匀浆MPO活性、MDA和TNF-α含量(P<0.01),DP处理组可有效减轻LPS所引起的上述变化(P<0.05)。结论DP对LPS导致的小鼠急性肺损伤有保护作用,其保护机制可能与抑制肺TNF-α的产生,进而减轻中性粒细胞的肺部扣押和肺组织脂质过氧化损伤的程度有关。     

参麦、丹参注射液治疗全身炎症反应综合征

目的 研究参麦、丹参注射液治疗全身炎症反应综合征(SIRS)的作用机理.方法 以脂多糖(LPS)腹腔注射Wistar大鼠制备SIRS动物模型,观察参麦、丹参注射液治疗后血常规、血清肿瘤坏死因子α(TNF-α)和白细胞介素6(IL-6)水平变化,并进行肝、肺及肾脏组织的病理组织学检查.结果 参麦注射液及丹参注射液均能明显降低LPS腹腔注射后的血清TNF-α和IL-6水平,减轻肝、肺、肾等器官的损害,使SIRS大鼠48 h存活率明显提高.结论 参麦、丹参注射液可通过抑制大鼠炎症反应发挥抗SIRS作用.     

脂多糖加速饮食所致非酒精性脂肪肝小鼠的炎症和氧化应激

目的本研究旨在探讨脂多糖在非酒精性肝炎(NASH)模型中的作用。方法采用胆碱蛋氨酸缺乏(Methionine choline deficient,MCD)饮食诱导的小鼠NASH模型。18只雄性C57BL/6小鼠分为3组,MCS+Saline组给予正常饮食+腹腔生理盐水,MCD+Saline组给予胆碱蛋氨酸缺乏饮食+腹腔注射生理盐水,MCD+LPS组给予胆碱蛋氨酸缺乏饮食+腹腔注射1 mg/kg脂多糖,共2周。在最后一次注射的6 h之后处死小鼠,取血清和肝组织。进行肝脏HE染色和Sirius Red染色,观察肝组织病理学变化。并测定血清中血清丙氨酸氨基转移酶(ALT)和肿瘤坏死因子-α(TNF-α)的含量。结果 MCD造成小鼠肝脏中大量脂肪滴的沉积和炎症细胞浸润,血清ALT升高,脂多糖注射进一步加重肝细胞凋亡,肝脏中TBARS进一步升高,血清TNF-α含量显著增加。结论在MCD所致非酒精性脂肪肝炎模型小鼠中,腹腔注射脂多糖引起血清中TNF-α升高,进一步加重细胞凋亡,因此,脂多糖在非酒精性脂肪肝炎的进程中具有重要作用,提示临床预防或治疗非酒精性脂肪肝炎需要关注患者肠道菌群失调症状。     

褪黑素对大鼠肝纤维化的影响及部分机制研究

目的探讨褪黑素(melatonin,MEL)对大鼠肝纤维化的影响及部分机制。方法 111只雄性SD大鼠随机分为6组:正常对照组、模型对照组、N-乙酰-L-半胱氨酸组(N-ac-etyl-L-cysteine,NAC)组、褪黑素低、中、高剂量组(剂量分别为2.5、5、10 mg.kg-1)。采用四氯化碳(carbon tetrachloride,CCl4)制备大鼠肝纤维化模型,同时腹腔注射褪黑素,HE染色和VG胶原纤维染色观察肝脏病理改变;生化法测定肝脏丙二醛(malondialdehyde,MDA)含量和谷胱甘肽过氧化物酶(glutathione peroxidase,GPx)、超氧化物歧化酶(superox-ide dismutase,SOD)活性;RT-PCR法测定肝组织中α1(I)前胶原(α1(I)procollagen)mRNA表达;原位灌注加密度梯度离心法分离正常SD大鼠肝脏星状细胞,在培养的肝星状细胞中加入脂多糖(lipopolysaccharide,LPS)进行刺激,用MTT法测定不同浓度的MEL对肝星状细胞增殖的抑制作用。结果和模型组比较,MEL(10 mg.kg-1)组肝纤维化评分较低(P<0.05),MEL能明显降低肝匀浆MDA含量,升高SOD、GPx活性,MEL(10 mg.kg-1)组、NAC组大鼠肝组织α1(I)型前胶原mRNA表达明显减少(P<0.05);培养的肝星状细胞经LPS刺激后A值增大,与LPS组相比,LPS+NAC组和LPS+MEL(0.1 mmol·L-1)组A值明显减小(P<0.05)。结论 MEL对大鼠肝纤维化具有改善作用,其机理可能与抗氧化、抑制前胶原基因转录和抑制肝星状细胞增殖有关。     

ROS在LPS下调鼠胎盘pxr等基因表达中的作用

目的研究活性氧(ROS)在细菌脂多糖(LPS)下调小鼠胎盘孕烷X受体(pxr)及其靶基因细胞色素P-4503a11(cyp3 a11)和多药耐药基因1a(mdr1 a)表达中的作用。方法小鼠妊娠第17天分别注射不同剂量LPS(0.1~0.5mg/kg,ip);LPS PBN组在注射LPS(0.2 mg/kg,ip)前30 min和后3 h给予2-苯叔丁基硝酮(PBN);LPS NAC组在注射LPS(0.2 mg/kg,ip)前30 min和后3 h给予N-乙酰半胱氨酸(NAC);对照组给予等容量生理盐水或PBN/NAC。孕鼠分别于LPS处理后6和12 h处死。结果LPS显著下调小鼠胎盘pxr,cyp3 a11和mdr1 amRNA表达,进一步研究发现,妊娠晚期给予LPS后,胎盘组织MDA水平明显升高且GSH含量显著降低。PBN和NAC处理显著抑制LPS对胎盘pxr,cyp3 a11和mdr1 amRNA表达的下调作用,且显著对抗LPS引起的氧化应激。结论LPS下调小鼠胎盘pxr、cyp3 a11和mdr1 amRNA表达;ROS至少部分参与了LPS对小鼠胎盘pxrc、yp3 a11和mdr1 amRNA表达的下调作用。     

二硫代氨基甲酸吡咯烷对小鼠免疫性肝损伤的抑制作用

目的探讨二硫代氨基甲酸吡咯烷(PDTC)对免疫性肝损伤的抑制作用及其机制。方法设正常对照、脂多糖(LPS)、卡介苗(BCG)、BCG+LPS、PDTC和BCG+PDTC+LPS组。除正常对照、LPS和PDTC组外,其余各组小鼠经尾静脉注射BCG(每只2.5mg)。10d后,LPS和BCG+LPS组分别给予LPS(0.2mg·kg-1,ip),PDTC和BCG+PDTC+LPS组在给予LPS前24和2h分别给予PDTC(100mg·kg-1,ip),对照组给予等体积生理盐水。每组15只小鼠用于观察LPS处理后72h的死亡率;每组6只小鼠于LPS处理后1.5h处死,取肝脏,用RT-PCR检测肝脏组织肿瘤坏死因子α(TNF-α)和白细胞介素1β(IL-1β)mRNA表达水平,用凝胶电泳迁移率分析法测定肝脏核因子κB(NF-κB)结合活性;每组12只小鼠于LPS处理后6h取血,处死,留取肝脏,测定血清谷丙转氨酶(GPT)活性、一氧化氮(NO)水平和肝组织还原型谷胱甘肽(GSH)含量,制备肝组织切片进行HE染色,观察组织病理变化。结果与正常对照组比较,BCG和LPS组小鼠肝脏炎症细胞明显增加,血清GPT活性升高,肝脏GSH含量显著下降,肝脏TNF-α与IL-1β mRNA表达增强,各组均未见小鼠死亡;PDTC组除血清GPT活性升高外,上述其他指标均未发生明显改变。与BCG和LPS组比较,BCG+LPS组血清GPT活性进一步升高,并伴有大面积肝脏坏死和大量炎症细胞浸润,肝脏NF-κB结合活性显著升高,TNF-α和IL-1β表达进一步增强,GSH水平下降,血清NO水平增加,小鼠死亡率40%。与BCG+LPS组比较,PDTC预处理明显抑制BCG+LPS引起的肝脏NF-κB活性、TNF-α及IL-1β mRNA表达增强,升高肝脏GSH含量,降低血清GPT活性和NO水平,减轻BCG+LPS引起的肝脏炎症和坏死,未见小鼠死亡。结论PDTC可抑制BCG+LPS引起的小鼠免疫性肝损伤,其机制可能与其抗炎和抗氧化作用有关。     

核因子-κB特异性抑制剂小白菊内酯在大鼠心肌组织的药效时间

目的观察核因子-κB(NF-κB)特异性抑制剂小白菊内酯(PTN)在大鼠心肌组织中的药效作用时间。方法健康雄性SD大鼠40只随机分为5组:空白对照组、PTN组、二甲亚砜(DMSO)组、脂多糖(LPS)组和PTN+LPS组。第1天:PTN组、DMSO组和PTN+LPS组大鼠分别腹腔内注射PTN(500μg/kg)和PTN溶剂DMSO(相等容量);其余各组腹腔内注射相等容量的生理盐水。第2天(即PTN注射后24 h):LPS组和PTN+LPS组大鼠经皮下注射LPS(12.5 mg/kg);其余各组经皮下注射相等容量的生理盐水。每组在相当于注射LPS后1 h时取出心脏,采用Westernblot法分析心肌细胞细胞核内NF-κB p50和细胞浆中抑制蛋白(IκBα)、磷酸化抑制蛋白(p-IκBα)表达变化。结果与空白对照相比,PTN组和DMSO组NF-κB p50I、κBα和p-IκBα表达差异无统计学意义,而LPS组和PTN+LPS组NF-κBp50表达上调(P<0.05),IκBα表达下调(P<0.05),p-IκBα表达上调(P<0.05)。结论LPS刺激可在1 h内激活NF-κB,PTN(500μg/kg)在大鼠体内代谢24 h后未见明显药效。     

蛇床子素对脂多糖诱导的小鼠急性肺损伤的保护作用及机制研究

目的探讨蛇床子素(Osthole,Ost)对脂多糖(Lipopolysaccharide,LPS)诱导的急性肺损伤的作用及其机制。方法 45只雄性C57小鼠随机分为3组:正常对照组(对照组),LPS组,Ost+LPS组(Ost组),每组15只。各组小鼠于腹腔注射LPS或生理盐水(50 mg/kg)6 h后,测定PaO2、PaCO2、pH,IL-6、IL-1β、TNF-α表达,JAK2、STAT3、p-JAK2和p-STAT3蛋白表达量,观察肺组织病理变化和湿干比(W/D)。结果与LPS组比较,Ost组PaCO2、W/D,IL-6、IL-1β和TNF-α表达,p-JAK2和p-STAT3蛋白表达量和肺组织病理改变均明显降低,但PaO2和pH增高,而JAK2和STAT3表达无明显变化。结论 Ost预处理可通过抑制JAK2/STAT3信号通路激活而减轻LPS诱导的急性肺损伤。     

Effect of N-acetylcysteine on lipopolysaccharide-induced intra-uterine fetal death and intra-uterine growth retardation in mice.

Lipopolysaccharide (LPS) has been associated with adverse developmental outcome, including embryonic resorption, intra-uterine fetal death (IUFD), intra-uterine growth retardation (IUGR), and preterm delivery. Reactive oxygen species (ROS) have been associated with LPS-induced developmental toxicity. N-acetylcysteine (NAC) is a glutathione (GSH) precursor and direct antioxidant. The present study investigated the effects of NAC on LPS-induced IUFD and IUGR. All pregnant mice except controls were injected with LPS (75 microg/kg, ip) on gestational day (GD) 15-17. NAC was administered in two different modes. In mode A, the pregnant mice were pretreated with two doses of NAC (either 50 plus 25 mg/kg or 200 plus 100 mg/kg) before LPS, one (either 50 or 200 mg/kg) at 12 h before LPS and the other (either 25 or 100 mg/kg) at 15 min before LPS. In mode B, the pregnant mice were administered with two doses of NAC (either 50 plus 25 mg/kg or 200 plus 100 mg/kg) in 24 h, one (either 50 or 200 mg/kg) injected immediately after LPS and the other (either 25 or 100 mg/kg) injected 3 h after LPS. The number of live fetuses, dead fetuses and resorption sites was counted on GD 18. Live fetuses in each litter were weighed. Crown-rump and tail lengths were measured and skeletal development was evaluated. Results showed that pretreatment with NAC significantly alleviated LPS-induced fetal mortality and reversed LPS-induced growth and skeletal development retardation. Correspondingly, pretreatment with NAC significantly attenuated LPS-induced elevation in TNF-alpha concentration in maternal serum and amniotic fluid and lipid peroxidation in maternal and fetal livers. By contrast to pretreatment, posttreatment with NAC had no effect on LPS-induced TNF-alpha production and lipid peroxidation. When administered after LPS, NAC did not protect against LPS-induced IUFD and IUGR and in fact aggravated LPS-induced preterm labor. All these results indicate that NAC had a dual effect on LPS-induced IUFD and IUGR. Pretreatment with NAC improves fetal survival and reverses LPS-induced fetal growth and skeletal development retardation, whereas posttreatment with NAC aggravates LPS-induced preterm labor.     

Ascorbic acid protects against lipopolysaccharide-induced intra-uterine fetal death and intra-uterine growth retardation in mice

Lipopolysaccharide (LPS) has been associated with adverse developmental outcomes including embryonic resorption, intra-uterine fetal death (IUFD), intra-uterine growth retardation (IUGR) and preterm labor. Reactive oxygen species (ROS) mediate LPS-induced developmental toxicity. Ascorbic acid is an antioxidant. In the present study, we investigated the effect of ascorbic acid on LPS-induced IUFD and IUGR in mice. All ICR pregnant mice except controls received an intraperitoneal (75 microg/kg, i.p.) injection of LPS daily on gd 15-17. The experiment was carried out in three different modes. In mode A, the pregnant mice were pretreated with a single dose (500 mg/kg, i.p.) of ascorbic acid before LPS. In mode B, the pregnant mice were administered with a single dose (500 mg/kg, i.p.) of ascorbic acid at 3h after LPS. In mode C, the pregnant mice were administered with 500 mg/kg (i.p.) of ascorbic acid at 30 min before LPS, followed by additional dose (500 mg/kg, i.p.) of ascorbic acid at 3h after LPS. The number of live fetuses, dead fetuses and resorption sites was counted on gd 18. Live fetuses in each litter were weighed. Crown-rump and tail lengths were examined and skeletal development was evaluated. Results showed that maternally administered LPS significantly increased fetal mortality, decreased fetal weight and crown-rump and tail lengths of live fetuses, and retarded skeletal ossification in caudal vertebrae, anterior and posterior phalanges, and supraoccipital bone. LPS-induced IUFD and IUGR were associated with lipid peroxidation and GSH depletion in maternal liver, placenta and fetal liver. Pre-treatment with ascorbic acid significantly attenuated LPS-induced lipid peroxidation, decreased fetal mortality, and reversed LPS-induced fetal growth and skeletal development retardation. By contrast to pre-treatment, post-treatment with ascorbic acid had less effect on LPS-induced IUFD, although post-treatment significantly attenuated LPS-induced lipid peroxidation and reversed LPS-induced fetal growth and skeletal development retardation. Furthermore, post-treatment with ascorbic acid reduced the protective effects of pre-treatment on LPS-induced IUFD. All these results suggest that pre-treatment with ascorbic acid protected against LPS-induced fetal death and reversed LPS-induced growth and skeletal development retardation via counteracting LPS-induced oxidative stress, whereas post-treatment had less effect on LPS-induced IUFD.     

Effects of low-dose lipopolysaccharide (LPS) pretreatment on LPS-induced intra-uterine fetal death and preterm labor

Lipopolysaccharide (LPS) has been associated with adverse developmental outcome, including embryonic resorption, intra-uterine fetal death (IUFD), intra-uterine growth retardation (IUGR) and preterm delivery in rodents. The purpose of the present study was to investigate whether administration of a low-dose LPS to the pregnant mice induce a reduced sensitivity to subsequent high-dose LPS-induced IUFD and preterm labor. We found that LPS-induced IUFD was obviously attenuated when the pregnant mice were pretreated with low-dose LPS (10 microg/kg, i.p.) 24h before high-dose LPS (120 microg/kg, i.p.). Consistent with its protective effect, when administered 24h before high-dose LPS, low-dose LPS pretreatment obviously inhibited the releases of tumor necrosis factor alpha (TNF-alpha) in maternal serum and amniotic fluid and attenuated LPS-induced placental lipid peroxidation and GSH depletion. However, when administered 4h before high-dose LPS, low-dose LPS pretreatment did not induced a reduced sensitivity to subsequent high-dose LPS-induced release of TNF-alpha in maternal serum and amniotic fluid. Actually, low-dose LPS pretreatment 4h before high-dose LPS worsened LPS-induced oxidative stress in mouse placenta and increased nitric oxide production in maternal serum and amniotic fluid. Correspondingly, low-dose LPS pretreatment 4h before high-dose LPS aggravated LPS-induced IUFD. Taken together, these results indicate that whether a low-dose LPS exposure during pregnancy produce LPS hyporesponsiveness depends on the interval between the two doses of LPS. When administered 24h before high-dose LPS, a low-dose LPS pretreatment induces a reduced sensitivity to subsequent high-dose LPS-induced IUFD, TNF-alpha production and oxidative stress.     

Maternally-administered lipopolysaccharide (LPS) increases tumor necrosis factor alpha in fetal liver and fetal brain: its suppression by low-dose LPS pretreatment

Lipopolysaccharide (LPS) has been associated with adverse developmental outcome, including intra-uterine fetal death (IUFD), intra-uterine growth retardation (IUGR) and neurological injury. In the LPS model, tumor necrosis factor alpha (TNF-alpha) is the major mediator leading to IUFD, IUGR and neurological injury. In the present study, we investigated the effect of maternally-administered LPS on TNF-alpha in maternal serum, amniotic fluid, fetal liver and fetal brain. The timed pregnant mice were intraperitoneally (i.p.) injected with a single dose of LPS (500microg/kg) on gestational day 17. As expected, TNF-alpha was obviously increased in maternal serum and amniotic fluid in response to LPS. Although maternally-administered LPS also increased the level of TNF-alpha protein in fetal liver and brain, no significant difference in TNF-alpha mRNA level in fetal liver and brain was observed among different groups, suggesting that the increased TNF-alpha protein in fetal liver and brain may be transferred from either the maternal circulation or amniotic fluid or placenta. When the pregnant mice were pretreated with a low-dose LPS (10microg/kg, i.p.) at 4, 12, 24 or 48h before LPS (500microg/kg, i.p.), LPS-evoked TNF-alpha in maternal serum and amniotic fluid was significantly inhibited. Importantly, low-dose LPS pretreatment also greatly attenuated LPS-induced increases in TNF-alpha protein in fetal liver and fetal brain. Taken together, these results indicate that perinatal exposure to low-dose LPS induces a reduced sensitivity to subsequent LPS challenge.     

Tumor necrosis factor alpha partially contributes to lipopolysaccharide-induced intra-uterine fetal growth restriction and skeletal development retardation in mice

Maternal infection is a cause of adverse developmental outcomes. Lipopolysaccharide (LPS)-induced embryonic resorption, intra-uterine fetal death (IUFD) and preterm labor have been well characterized. In the present study, we investigated the effects of maternal LPS exposure on intra-uterine fetal growth and skeletal development. All pregnant mice except controls received an intraperitoneal injection of LPS (75 microg/kg) on gestational days (GD) 15-17. The number of live fetuses, dead fetuses and resorption sites was counted on GD 18. Live fetuses in each litter were weighed. Crown-rump and tail lengths were examined and skeletal development was evaluated. As expected, perinatal LPS exposure resulted in 63.2% fetal death. LPS significantly lowered fetal weight, reduced crown-rump and tail lengths, and retarded skeletal ossification in caudal vertebrae, anterior and posterior phalanges, and supraoccipital bone. Additional experiment showed that a single dose of LPS (75 microg/kg, i.p.) on GD 15 increased the expression of TNF-alpha mRNA in maternal liver and placenta and TNF-alpha concentration in maternal serum and amniotic fluid. Furthermore, pentoxifylline, an inhibitor of TNF-alpha synthesis, significantly inhibited TNF-alpha production, reduced fetal mortality, and reversed LPS-induced fetal intra-uterine growth restriction and skeletal development retardation. Taken together, these results suggest that TNF-alpha is, at least in part, involved in LPS-induced intra-uterine fetal death, intra-uterine growth restriction and skeletal development retardation.     

Reactive oxygen species contribute to lipopolysaccharide-induced teratogenesis in mice.

Lipopolysaccharide (LPS) has been associated with adverse developmental outcome, including embryonic resorption, fetal death and growth retardation, and preterm delivery. In the present study, we showed that an ip injection with LPS daily from gestational day (gd) 8 to gd 12 resulted in the incidence of external malformations. The highest incidence of malformed fetuses was observed in fetuses from dams exposed to 20 microg/kg LPS, in which 34.9% of fetuses per litter were externally malformed. In addition, 17.4% of fetuses per litter in 30 microg/kg group and 12.5% of fetuses per litter in 10 microg/kg group were externally malformed. Importantly, external malformations were also observed in fetuses from dams exposed to only two doses of LPS (20 microg/kg, ip) on gd 8, in which 76.5% (13/17) of litters and 39.1% of fetuses per litter were affected. LPS-induced teratogenicity seemed to be associated with oxidative stress in fetal environment, measured by lipid peroxidation, nitrotyrosine residues, and glutathione (GSH) depletion in maternal liver, embryo, and placenta. alpha-Phenyl-N-t-butylnitrone (PBN, 100 mg/kg, ip), a free radical spin-trapping agent, abolished LPS-induced lipid peroxidation, nitrotyrosine residues, and GSH depletion. Consistent with its antioxidant effects, PBN decreased the incidence of external malformations. Taken together, these results suggest that reactive oxygen species might be, at least partially, involved in LPS-induced teratogenesis.     

Postnatal Outcomes In Term And Preterm Lambs Following Fetal Growth Restriction

1. Epidemiological evidence indicates that low birthweight increases the risk of a number of adult-onset diseases. It is now apparent that many babies with a low birthweight may have been subjected to a combination of reduced growth rates in utero as well as preterm birth. However, the long-term effects of preterm birth following intra-uterine growth restriction (IUGR) are unknown. Thus, our objectives were: (i) to identify prenatal factors associated with preterm birth in IUGR fetuses; and (ii) to characterize postnatal effects of preterm birth following IUGR. 2. We studied pregnant sheep and their offspring, in which fetal growth was restricted by umbilico-placental embolization during late gestation. Some of these animals were born at term (146 +/- 1 days) and some were born prematurely (139 +/- 1 days). In both groups, we have conducted longitudinal studies of postnatal respiratory function, cardiovascular function and learning ability up to 6-8 weeks of age. 3. Before birth, IUGR fetuses born prematurely (P-IUGR) were more hypoxaemic and acidaemic and had higher haemoglobin concentrations than both control fetuses and IUGR fetuses born at term (T-IUGR). In P-IUGR fetuses, plasma cortisol concentrations increased earlier than in the two other groups. The P-IUGR lambs had lower birthweights than T-IUGR lambs and both groups of IUGR lambs remained lighter than controls for 8 weeks. 4. After birth, P-IUGR lambs were hypoxaemic compared with T-IUGR and control lambs. Pulmonary diffusing capacity (adjusted for lung volume) was significantly lower in both groups of IUGR lambs than in controls, with P-IUGR lambs having lower values than T-IUGR lambs. Lung compliance (adjusted for lung volume), was not different between P-IUGR and control lambs, but values were higher in T-IUGR lambs than in control and P-IUGR lambs. Chest wall compliance (adjusted for lung volume) was higher in both groups of IUGR lambs than in controls. 5. During the 8 week postnatal study period, both groups of IUGR lambs had lower mean arterial pressures than control lambs; this relative hypotension was greatest in P-IUGR lambs. 6. In tests of learning ability, P-IUGR lambs took longer to complete a simple maze task at all ages and, in the second postnatal week, made a greater number of errors compared with controls. In an obstacle course, P-IUGR lambs recorded longer trial durations; they also made more errors than control lambs. 7. We conclude that preterm birth in the presence of late- gestational placental insufficiency and IUGR can result in specific effects on respiratory and cardiovascular development after birth, in addition to the effects of IUGR alone.     

N-acetylcysteine attenuates lipopolysaccharide-induced apoptotic liver damage in D-galactosamine-sensitized mice

Aim： To investigate the effects of N-acetylcysteine on D-galactosamine （GAIN）/ lipopolysaccharide （LPS）-induced apoptotic liver injury in mice. Methods： When given together with a low dose of LPS, GaIN highly sensitizes animals to produce apoptotic liver injury with severe hepatic congestion, resulting in rapid death. In the GalN/LPS model, TNF-α is the major mediator leading to apoptotic liver injury. Reactive oxygen species （ROS） are involved in GaiN-induced sensitization to TNF-α-evoked hepatocyte apoptosis. N-acetylcysteine （NAC） is an antioxidant and a glutathione （GSH） precursor. In this study, we investigated the effects of NAC on LPS-induced apoptotic liver injury in GaiN-sensitized mice. Results： Pretreatment with NAC significantly reduced GalN/LPS-induced elevation of serum alanine aminotransferase levels. In parallel, GalN/LPS-induced hepatic necrosis and congestion were obviously improved by NAC. Furthermore, NAC pretreatment significantly alleviated GalN/LPS-induced hepatic apoptosis, measured by the inhibition of hepatic caspase-3 activity and attenuation of DNA laddering. NAC pretreatment had no effect on LPS-evoked nitric oxide production in GaiN-sensitized mice. Increases in serum TNF-α concentration, which were observed in GalN/LPS-treated mice, were not significantly reduced by NAC. Although NAC pretreatment significantly alleviated LPS-induced hepatic GSH depletion, DL-buthionine-（SR）-sulfoximine, an inhibitor of GSH synthesis, did not influence the protective effect of NAC on GalN/LPS-induced apoptotic liver injury. Conclusion： NAC attenuates GalN/LPS-induced apoptotic liver injury via its strong ROS scavenging and anti-apoptotic effects.