PAF受体拮抗剂对内毒素血症幼年大鼠胃黏膜NO含量及iNOS表达的影响

目的:探讨一氧化氮(NO)、诱导型一氧化氮合酶(iNOS)及PAF受体拮抗剂在内毒素(LPS)腹腔注射诱导的幼年大鼠急性胃黏膜损伤中的作用.方法:Wistar大鼠, 随机分为对照组、LPS组、PAF受体拮抗剂预防组和治疗组. 用内毒素(O55:B5脂多糖)5 mg/kg ip制备幼年大鼠内毒素血症模型. 预防组和治疗组分别于内毒素ip前及ip后0.5 h, 应用血小板活化因子(PAF)受体拮抗剂BN52021(GinkgolideB)5 mg/kg ip, 同等量生理盐水ip为对照组. 于LPS注射后1.5,3, 6, 24, 48, 72 h处死动物, 大体及光学显微镜下观察胃黏膜损伤情况, 采用硝酸还原酶的化学比色法测定胃黏膜NO含量;免疫组织化学S-P方法测定胃黏膜iNOS蛋白的表达, 半定量RT-PCR法测定胃黏膜iNOS mRNA的表达.结果:LPS组6 h胃黏膜损伤最重, 黏膜内有出血, 核碎裂、固缩, 凋亡小体出现;预防组和治疗组改变轻微. LPS组腹腔注射内毒素后6 h胃黏膜NO含量最高, 此时LPS组较对照组NO含量明显增高(84.37±5.44 vs 37.37±1.90,P<0.01), 预防组和治疗组(40.07±3.42, 48.63±3.24)较LPS组明显降低( P<0.01);预防组与治疗组较对照组明显增高( P<0.05). 对照组胃黏膜组织未见iNOS蛋白及mRNA的表达;LPS组腹腔注射内毒素后1.5 h胃黏膜组织胞质iNOS蛋白表达, 6 h明显增高, 24 h最高, 48 h下降, 72 h仍未恢复正常;预防组和治疗组3 hiNOS蛋白表达, 6 h明显增高, 48 h下降, 72 h同对照组. iNOS mRNA水平的表达变化与iNOS蛋白表达变化趋势相同.结论:PAF受体拮抗剂可下调iNOS mRNA表达水平, 减少iNOS蛋白表达, 使NO含量下降.从而使NO和iNOS对胃黏膜发挥保护作用.     

血小板活化因子受体拮抗剂对幼年大鼠肠黏膜上皮细胞间紧密连接蛋白的影响

目的:探讨血小板活化因子(platelet activating factor,PAF)受体拮抗剂对肠黏膜上皮细胞间紧密连接蛋白ZO-1的影响．方法:18日龄Wistar大鼠,随机分为对照组,内毒素组(LPS组)和PAF受体拮抗剂组(预防组和治疗组)．LPS组和对照组分别腹腔注射内毒素 (5 mg/kg)和生理盐水(1 mL/kg)．预防组和治疗组分别于每一时相点注射LPS前、后30 min 腹腔注射PAF受体拮抗剂BN52021(5 mg/kg)．按时间点分别处死动物,取回肠用于电镜观察,免疫组化及RT-PCR检测ZO-1．结果:电镜下对照组肠微绒毛及细胞间紧密连接未见异常．实验组上皮细胞连接增宽;微绒毛变细、稀疏,部分断裂、脱落;细胞器受损．拮抗剂组改变较实验组减轻．紧密连接蛋白ZO-1正常时均匀一致地分布于小肠上皮细胞连接处的尖端,呈蜂巢状,实验组ZO-1 分布不均,染色变淡．免疫组化平均光密度值及RT-PCR结果可见LPS组ZO-1表达明显低于对照组,6 h表达最低,光密度从对照组 0．224 7降至LPS组0．198 5,ZO-1 mRNA从1．18 降至0．16(P<0．01)．预防组及治疗组变化趋势同LPS组,6 h预防组及治疗组光密度分别为 0．199 2和0．203 8,ZO-1 mRNA分别为0．47和 0．53,与对照组相比均有显著差异(P<0．01)．各时相点ZO-1较LPS组高,预防组较治疗组 ZO-1略低,无统计学差异．结论:PAF可降低肠道紧密连接蛋白ZO-1,从而损害肠道的屏障功能,而PAF受体拮抗剂可减轻肠道屏障功能损伤的程度．     

基质金属蛋白酶-9及其抑制物在急性冠状动脉综合征中的意义

目的测定急性冠状动脉综合征患者血浆基质金属蛋白酶-9(matrix metalloproteinase-9,MMP-9) 和组织金属蛋白酶抑制因子-1(tissue inhibitor metalloproteinase-1,TIMP-1)的变化,探讨MMP-9和TIMP-1 在急性冠状动脉综合征中的作用。方法急性冠状动脉综合征患者30例,稳定型心绞痛患者29例,正常对照17例,用酶联免疫法测定MMP-9和TIMP-1的血浆水平,血脂水平用比浊法测定。结果急性冠状动脉综合征组MMP．9(13±10)μg／L,TIMP-1(1．4±0．2)μg／L,MMP-9／TIMP-1(10±7);稳定型心绞痛组MMP-9 (2．2±0．5)μg／L,TIMP-1(0．7±0．4)μg／L和MMP-9／TIMP-1(3．2±2．0);正常对照组MMP-9(1．7±1．3)μg／L、 TIMP-1(0．6±0．4)μg／L和MMP-9／TIMP-1(5．2±0．9),急性冠状动脉综合征组与稳定型心绞痛组及对照组差异有统计学意义(P<0．01)。三组血脂水平差异无统计学意义。结论 MMP-9、TIMP-1和MMP-9／TIMP-1 在急性冠状动脉综合征患者中显著升高,他们有可能成为ACS患者易损斑块的预测指标。     

内毒素对气管上皮细胞损伤的实验研究

目的观察不同浓度内毒素（LPS）作用不同时程对气管上皮细胞（HBE）的损伤作用。方法取处于对数生长期的HBE,加入LPS的终浓度分别为0．02μg/ml、0．04μg／ml、0．06μg／ml、0．08μg／ml、0．1μg／ml、0．2μg／ml、0．4μg／ml、0．6μg／ml、0．8μg/ml、1．0μg／ml,在培养箱内分别孵育24h、48h后,采用MTT比色法于酶联免疫测定仪490nm波长处测定OD值。结果作用24h后,各浓度LPS对HBE具有不同程度的损伤作用,其中以0．1μg／ml作用最为明显（0．4080±0．0217 vs 0．3800±0．0100,P〈0．01）;作用48h后,各浓度LPS对HBE具有不同程度的损伤作用,其中以0．1μg／ml作用最为明显（0．3900±0．0122 vs 0．3060±0．0230,P〈0．01）。结论根据LPS致气管上皮细胞损伤的量效及时效关系,选择0．1μg／ml作用24h作为细胞刺激条件较为适宜。     

银杏苦内酯B对重症急性胰腺炎大鼠血浆细胞因子的影响

目的:观察重症急性胰腺炎(SAP)大鼠血浆中TNF-α,血小板活化因子(PAF),IL-10, IL-12,sTNFR的水平变化及其银杏苦内酯B(BN52021)的影响.方法:实验选用Wistar♂大鼠45只,随机分成SAP模型组(SAP,n=15),BN52021治疗组(BN,n=15)和阴性对照组(NC,n=15)．前两组以50 g／L牛磺胆酸钠逆行注入主胰管制成SAP模型,NC组开腹后仅翻动十二指肠并触摸胰腺数次关腹．制模15 min后,SAP组经股静脉以5 mL／mg注射生理盐水;BN组以BN52021(5 mg／kg)代替生理盐水静注．制模后分别于1,6,12 h采血,应用ELISA技术测定血浆TNF-α,PAF,IL-10,IL-12和sTNFR水平．结果:SAP组,NC组和BN组大鼠血浆TNF-α和PAF水平相比,具有显著性差异,SAP组(746．2±374．1,82．5±35．4 ng／L)显著高于NC组(385．1±86．3．1．1±1．9 ng／L),BN组(503．7±177．9,39．9±29．9 ng／L)显著低于SAP组(P<0．05)．血浆sTNFR水平三组相比存在明显差异,SAP组(488．7±363．8 ng／L)显著高于NC组(50．0±21．0 ng／L),BN组(883．4±552．5 ng／L)显著高于SAP组(488．7±363．8 ng／L)(P<0．05)．血浆IL-12三组相比存在明显差异,SAP组(97．1±55．9 ng／L)显著高于NC组(20．4±19．4 ng／L),BN组在1 h时相点(133．5±33．4 ng／L)显著高于SAP组(55．9±14．7 ng／L)(P<0．05)．血浆IL-10三组相比不存在明显差异(P>0．05)．结论:SAP大鼠促炎细胞因子和抗炎细胞因子均显著升高．BN52021能降低血浆促炎因子含量,提高IL-12和细胞因子拮抗剂sTNFR含量．     

孤束核、脊髓损毁后艾灸预处理对急性胃黏膜损伤大鼠PGE2与EGF含量的影响

目的:损毁大鼠中枢神经通路中的孤束核和脊髓,观察艾灸预处理对胃黏膜内源性保护物质前列腺素E2(prostaglandin E2,PGE2)和表皮生长因子(epidermal growth factor,EGF)含量的影响,进而探讨艾灸启动内源性保护信息与中枢神经通路的关系.方法:50只SD大鼠随机分5组,即A:空白对照组;B:模型对照组;C:温和灸+模型组;D:温和灸+模型组+孤束核损毁组;E:温和灸+模型组+脊髓损毁组.预先按要求对D、E组大鼠分别实施孤束核、脊髓的损毁手术,再对相应组别进行艾灸处理,最后用无水酒精灌胃造成急性胃黏膜损伤模型.运用酶联免疫吸附法(enzyme linked immunosorbent assay,ELISA)法检测胃黏膜组织中PGE2和EGF的含量.结果:艾灸预处理有上调胃黏膜中PGE2、E G F含量的作用(338.82g/L±19.87g/Lvs279.52g/L±16.53g/L,P<0.01;4037.12g/L±300.20g/L vs2923.73g/L±251.23g/L,P<0.05),孤束核和脊髓被损毁的2组大鼠胃黏膜PGE2和EGF的含量明显低于神经通路未损伤的温和灸组(298.65g/L±12.89g/L,317.56g/L±16.60g/Lvs338.82g/L±19.87g/L;3176.21g/L±242.35g/L,3337.43g/L±249.86g/L vs4037.12g/L±300.20g/L,均P<0.01),且孤束核损毁的大鼠胃黏膜中PGE2的含量较脊髓损毁的低(P<0.05).结论:损毁大鼠中枢神经通路中的孤束核和脊髓对艾灸预处理提高胃黏膜组织中PGE2、EGF含量有影响,提示孤束核和脊髓均参与了艾灸保护胃黏膜信号的传导.其中,艾灸诱导胃黏膜PGE2的产生可能主要受控于孤束核,而其对胃黏膜EGF表达调控则与孤束核和脊髓均有关.     

大鼠急性胰腺炎早期肺损伤机制及前列腺素E1的保护作用

目的:探讨实验性急性胰腺炎(acute pancreatitis,AP)合并肺损伤的发生机制及前列腺素E1(PGE1)的保护作用．方法:健康成年SD大鼠78只,随机平均分为假手术组(SO组)、AP组和PGE1组,采用十二指肠闭袢法建立大鼠AP模型．PGE1组制模后即刻经颈静脉持续每分钟输入PGE160 ng／kg．观察胰腺和肺组织的病理组织学改变,测定血清淀粉酶、肺组织中性粒细胞髓过氧化物酶 (MPO)活性、脂质过氧化产物(LPO)水平及肺毛细血管通透性(LCP),免疫组织化学ABC法检测肺组织细胞黏附分子-1(ICAM-1)的表达．结果:制模后12和24 h,AP组大鼠胰腺和肺组织病理损伤持续加重,肺组织MPO(12 h: 5．65±0．80 vs 1．22±0．71 kat／g,P<0．01;24 h: 7．22±1．05 vs 1．48±0．57 kat／g,P<0．01)和 LPO(12 h:1．44±0．63 vs 0.38±0．07μmol／g． P<0．01;24 h:3．64±0．83 vs 0．44±0．15 μmol／ g,P<0．01)水平以及LCP(12 h:145．4±23．0 vs 47．3±5．5 μg／g组织湿重,P<0．01)明显高于SO组,AP组大鼠肺组织ICAM-1表达呈阳性或强阳性,而SO组呈阴性;与AP组比较, PGE1组的胰腺病理损伤虽未减轻,但肺组织 MPO(12 h:2．96±1．04 vs 5．65±0．80 kat／g, P<0．05;24 h:3．68±1．15 vs 7．22±1．05 kat／g, P<0．05)和LPO (12 h:0．86±0.34 vs 1．44± 0．63 μmol／g,P<0．05;24 h:1．69±0．45 vs 3．64 ±0．83 μmol／g,P<0．05)水平以及LCP(12 h: 105．9±23．9 vs 145．4±23．0 μg／g组织湿重, P<0．05)明显降低,ICAM-1表达下调．肺间质出血、水肿和中性粒细胞(PMN)浸润明显减轻．结论:肺组织ICAM-1过度表达、PMN浸润和氧自由基大量释放与AP早期肺损伤的发生关系密切．PGE1通过降低肺组织ICAM-1表达, 抑制PMN活化和氧自由基释放,从而减轻AP 早期肺损伤．     

复方中药安胃汤提高大鼠胃溃疡愈合质量的机制

目的:通过实验性乙酸大鼠胃溃疡模型,研究复方中药安胃汤提高慢性胃溃疡愈合质量机制．方法:40只Wistar大鼠随机平均分为正常对照组、模型组、安胃汤组和雷尼替丁．采用乙酸浸渍法建立胃溃疡模型,造模3 d后前两组分别用生理盐水灌胃,后两组分别用安胃汤和雷尼替丁灌胃．采用放射免疫方法和免疫组织化学方法观察复方中药安胃汤对大鼠胃溃疡模型愈合时血清表皮生长因子(EGF)和胃黏膜 EGF,表皮生长因子受体(EGFR)及转化生长因子-β1(TGF-β1)表达的影响．结果:模型组相比,安胃汤组和雷尼替丁组可提高血清EGF(1．12±0．24,0．99±0．15μg／L vs0．52±0．13μg／L,P<0．01),安胃汤组与雷尼替丁组相比差异也有显著意义(P<0．05)．与模型组相比,安胃汤组和雷尼替丁组可显著增强胃黏膜EGF、EGFR及TGF-β1表达(EGF: 29．7％±1．9％,26．5％±1．6％vs18．4％±2．0％, P<0．01:EGFR:29．6％±2．6％,25．9％±1．0％vs 20．4％±1．8％,P<0．01;TGF-β1:67．0％±2．0％, 49．5％±1．1％vs27．3％±1．0％,P<0．01),安胃汤组强于雷尼替丁组(均P<0．01)．结论:安胃汤可能通过提高血清EGF和增强胃黏膜EGF,EGFR及TGF-β1表达,增强胃黏膜保护作用而提高溃疡愈合质量．     

PGE2对胃癌MKN28细胞VEGF表达的影响

目的:观察前列腺素E2(PGE2)对胃癌MKN28细胞血管内皮生长因子(VEGF)mRNA转录、蛋白表达水平的影响．方法:对胃癌MKN28细胞分别给予0．1,1,5, 10μmol／L浓度的PGE2处理3 h,分别以实时PCR,Western blot检测VEGF mRNA转录水平及VEGF蛋白表达水平的变化．结果:胃癌MKN28细胞经用不同浓度的PGE2作用3 h,VEGF mRNA表达呈剂量依赖性增加,其表达在PGE2浓度为0．1,1,5,10μmol／L时与对照组之间的差异均有统计学意义(0．67±0．093,0．74±0．13,0．87±0．07,1．49±0．15 vs 0．42±0．10．P<0．05或P<0．01)．VEGF蛋白表达量与PGE2浓度存在正相关,其表达在PGE2浓度为1,5,10μmol／L组与对照组之间的差异均有统计学意义(51．02±2．16,66．69±9．85,136．49±6．89 vs 26．87±3．98,P<0．05或P<0．01)．结论:外源性PGE2可显著增加胃癌MKN28细胞VEGF的表达．     

苦参碱对大鼠原位肝移植冷缺血再灌注损伤的保护作用

目的:探讨苦参碱对大鼠原位肝移植中供肝冷缺血再灌注损伤的保护作用及其机制方法:应用延长保存的大鼠原位肝移植模型, 大鼠224只随机分为对照组、低剂量(40 mg／ kg)、高剂量苦参碱治疗组(80 mg／kg)和假手术组,将供肝在4℃林格液中保存5 h后植入受体,分别观察移植术后1 wk生存率,并且检测移植术后1,2,4,24 h血ALL TNF-α,内毒素 (ET),透明质酸(HA),一氧化氮(NO)及肝组织丙二醛(MDA),超氧化物歧化酶(SOD),细胞间黏附分子-1(ICAM-1)的含量,并观察移植肝脏病理形态学的改变．结果:与对照组比较,苦参碱低剂量、高剂量治疗组术后1 wk生存率显著增加(75％,75％ vs 0,P<0．01),肝功能改善,血清HA(277．62 ±29．06,406．84±95．04 μg／L vs 1109．42± 110．28 μg／L,P<0．01)和肝组织ICAM-1表达均显著减少,血清NO含量增加(53．1±5．1,54．2 ±4．9 μmol/L vs 30．2±2.3 μmol／L,P<0．01), TNF-α(1．69±0．22,1．29±0．33 U／L vs 5．96 ±0．59 U／L,P<0．01)、ET(0．343±0．111, 0_302±0．059 kEU／L vs 0．643±0．110 kEU／L． P<0．01)以及肝组织MDA(0．87±0．41,0．69± 0．22 μmol／g vs 2．35±0．54 μmol／g,P<0．01) 水平均明显降低,肝组织SOD(19．89±1．84, 21．04±1．86 kU／g vs 13．39±0．85 kU／g,P<0．01) 水平均明显升高,肝细胞和肝窦内皮细胞形态也发生改善．结论:苦参碱可以通过减轻再灌注后内毒素血症,抑制库氏细胞激活及释放TNF-α, ICAM-1等炎症性细胞因子,清除氧自由基,促进NO合成等途径,减轻肝细胞及肝窦内皮细胞的损伤．     

Distribution of prostaglandin E2 and prostaglandin F2 alpha receptors in human myometrium

Human myometrium was studied for specific binding of PGE2 and PGF2 alpha. PGF2 alpha-binding was almost undetectable, but specific binding sites for PGE2 with high affinity (KD = 2.7 +/- 0.4 x 10(-9) M were demonstrated. The binding capacity for PGE2 exhibited a topically different distribution pattern with the highest values in the central parts and low to undetectable levels in the cervical region. Binding characteristics were analyzed by receptor kinetics, revealing a homogeneous receptor population. Binding capacity in uteri obtained from post-menopausal women was of the order of 900-940 fmol/mg protein. Oestrogen pre-treatment and pregnancy were associated with a 3-fold reduction of the PGE2-binding capacity.     

Roles of prostaglandin E2 in cardiovascular diseases

Prostaglandin E2 (PGE(2)) is produced in inflammatory responses and regulates a variety of immunological reactions through 4 different receptor subtypes; EP1, 2, 3 and 4. However, the precise role of each receptor in cardiovascular disease has not yet been elucidated. Enhanced expression of some EPs has been observed in clinical and experimental cardiovascular diseases. EP agonists have been developed to clarify the role of each receptor. Recently, we developed a novel selective agonist to examine the effects of EP4 on cardiac transplantation, myocardial ischemia, and myocarditis. Of note, a selective EP4 agonist attenuated inflammatory cytokines and chemokines via attenuation of macrophage activation in inflammatory heart diseases. In this review article, we discuss the effects of PGE(2) receptor agonists on the development of cardiovascular diseases.     

Microparticles stimulate the synthesis of prostaglandin E2 via induction of cyclooxygenase 2 and microsomal prostaglandin E synthase 1

Objective

Microparticles are small vesicles that are released from activated or dying cells and that occur abundantly in the synovial fluid of patients with rheumatoid arthritis (RA). The goal of these studies was to elucidate the mechanisms by which microparticles activate synovial fibroblasts to express a proinflammatory phenotype.

Methods

Microparticles from monocytes and T cells were isolated by differential centrifugation. Synovial fibroblasts were cocultured with increasing numbers of microparticles. Gene expression was analyzed by real‐time polymerase chain reaction and confirmed by Western blotting and enzyme immunoassay. Arachidonic acid labeled with tritium was used to study the transport of biologically active lipids by microparticles. The roles of NF‐κB and activator protein 1 (AP‐1) signaling were analyzed with electrophoretic mobility shift assay and transfection with small interfering RNA and IκB expression vectors.

Results

Microparticles strongly induced the synthesis of cyclooxygenase 2 (COX‐2), microsomal prostaglandin E synthase 1 (mPGES‐1), and prostaglandin E₂ (PGE₂). In contrast, no up‐regulation of COX‐1, mPGES‐2, cytosolic PGES, or phospholipase A₂ was observed. The induction of PGE₂ was blocked by selective inhibition of COX‐2. Microparticles activated NF‐κB, AP‐1, p38, and JNK signaling in synovial fibroblasts. Inhibition of NF‐κB, AP‐1, and JNK signaling reduced the stimulatory effects. Arachidonic acid was transported from leukocytes to fibroblasts by microparticles. Arachidonic acid derived from microparticles was converted to PGE₂ by synovial fibroblasts.

Conclusion

These results demonstrate that microparticles up‐regulate the production of PGE₂ in synovial fibroblasts by inducing COX‐2 and mPGES‐1. These data provide evidence for a novel mechanism by which microparticles may contribute to inflammation and pain in RA.

     

Oral antisecretory activity of prostaglandin E2 in man

We studied the oral gastric antisecretory activity of prostaglandin E₂ in three groups of six normal volunteers. Each volunteer was studied twice, once after receiving prostaglandin E₂ (0.5, 1.0, or 2.0 mg) and the other time after receiving placebo administered in a double-blind, randomized fashion. Gastric acid secretion was stimulated with a liquid protein meal from 1/2 to 1 1/2hr after drug administration. Acid secretion was quantitated using the technique of intragastric titration. Acid secretion after 0.5 mg of prostaglandin E₂ was no different than after placebo administration, but 1.0 mg and 2.0 mg of prostaglandin E₂ inhibited 58% (6.68±7.64 meq vs 14.67±6.75 meq, P<0.02) and 76% (2.38±2.38 meq vs 11.50±3.51, P<0.01) respectively, of gastric acid production compared to placebo therapy. After oral administration, prostaglandin E₂ in man is antisecretory with an ED₅₀ of 1.1 mg.     

前列腺素E 2在特发性肺纤维化中的作用

特发性肺纤维化(IPF)是一种慢性、进行性且最终致命的肺纤维化疾病,其病理特征包括肌成纤维细胞的积累和肺组织中细胞外基质沉积的增加。前列腺素E 2(PGE 2)是一种生物活性类二十烷酸,可以参与许多重要的生物学过程,并已显示出抑制成纤维细胞增殖、迁移、分化和细胞外基质产生,以及促进肌成纤维细胞凋亡的...     

Modulation of prostaglandin E2 synthesis in rabbit synoviocytes

Prostaglandin E2 (PGE2) production by rabbit synoviocytes was markedly stimulated by hydroxyapatite only after a 60-minute delay. Release of 3H-arachidonic acid (C20:4) and 3H-PGE2 from cells with phospholipids that were prelabeled with 3H-C20:4 did not occur in parallel. At 240 minutes, phospholipase activity in sonicated cell suspensions had increased only 38%, while cyclooxygenase activity had doubled (109%). This doubling, as well as the production of synoviocyte PGE2, was prevented by inhibiting the synthesis of protein. Cyclooxygenase is an inducible enzyme, and as such, it is a rate-controlling step in PGE2 production.     

Attenuation of acetaminophen hepatitis by prostaglandin E2

Acute acetaminophen hepatitis was produced in three groups of five rats given 1600 mg/kg by gavage. The protective effect of 16,16-dimethyl prostaglandin E₂, 200 µg/kg administered subcutaneously 30 min later, was compared to the protective effect ofN-acetylcysteine 1 g/kg similarly administered. All animals were killed at 24 hr, and liver tissues were compared histologically to the damage found in acetaminophen-treated controls and untreated anatomic controls. Serum transaminase values at 24 hr exceeded 1000 units in the acetaminophen control group, averaged 658 units in the acetylcysteine treated group, and were near normal (75 units) in the prostaglandin treated group (P<0.02). Liver samples (1 cm³) were removed terminally at 24 hr. Liver damage was assessed without reference to precedent history. Histopathologically, damage was most severe in the acetaminophen control group, mainly in pericentral lobular zones. The prostaglandin-treated group showed considerably less damage, which was confined to the hepatic vein area. The acetylcysteine-treated group showed an intermediate degree of damage. We conclude that dmPGE₂, given 30 min after ingestion of acetaminophen was found to be more effective in limiting liver damage than NAC in this rat model.     

Simultaneous infusion of prostaglandin E2 antagonizes the luteolytic action of prostaglandin F2alpha in vivo

Corpora lutea of ewes bearing ovarian autotransplants were infused for 4 h with prostaglandin F2alpha (PGF2alpha) (10 microng/h), PGF2alpha+PGE2 (10microng/h of each), PGE2 (10 microng/h) or saline on day 10 of the cycle. Ovarian venous blood obtained before, during, and up to 12 h after the infusion period, was assayed for progesterone. Prostaglandin F2alpha produced an immediate, rapid and sustained decline in progesterone secretion, but infusion of PGE2 together with PGF2alpha prevented the decline until after the infusion. Progesterone secretion was unaffected by infusion of PGE2 alone. Oestrous behaviour was observed in four out of seven animals infused with PGF2alpha but in only one out of six infused with PGF2Alpha+PGE2. None of the animals infused with PGE2 alone or saline only came into heat.