吲哚美辛对结肠癌细胞CDK2、CDK4、P21WAF1/CIP1、Bcl-2及Bax蛋白表达的影响

目的：非甾体类抗类药通过环氧合酶途径是抑制肿瘤的机制之一，是否还有其他途径抑制细胞增殖及诱导凋亡。探讨吲哚美辛抗肿瘤的作用机制。为其临床应用实验依据。方法：不同浓度的吲哚美辛作用于结肠癌细胞株HCT116细胞24h，通过Western蛋白印迹技术检测CDK2、CDK4、p21s^WAF1/CIP1、Bcl-2及Bax蛋白表达。结果：吲哚美辛降低细胞周期素依赖蛋白激酶CDK2、CDK4及抗凋亡蛋白Bcl-2的表达上，上调细胞周期依赖蛋白激酶抑制剂p21s^WAF1/CIP1蛋白，而对促凋亡蛋白Bax的表达无影响。结论：吲哚美辛通过降低CDK2、CDK4、Bcl-2蛋白，上调p21s^WAF1/CIP1的表达来抑制细胞增殖和诱导细胞凋亡。     

环氧合酶-2抑制剂对大鼠胃黏膜损伤愈合的影响

目的　环氧合酶 (COX)是合成前列腺素 (PGs)的关键酶 ,传统的非甾体抗炎药 (NSAIDs)抑制COX 1和COX 2活性 ,引起严重的胃肠道不良反应。特异性COX 2抑制剂有望成为不引起胃损伤的新型NSAIDs。本研究探讨特异性和非特异性COX 2抑制剂对盐酸诱导大鼠胃黏膜损伤愈合的影响。方法　雄性SD大鼠胃内给予 0 .6mol/LHCl1ml,Westernblot和免疫组化法分析胃黏膜COX 1和COX 2表达。盐酸灌胃后 10min ,实验组胃内给予NS 3980 .4、4、4 0mg/kg和吲哚美辛 4 0mg/kg ,对照组胃内给予 1%阿拉伯树胶 (AG) 5ml/kg。盐酸灌胃前和灌胃后 1、3、6、12、2 4及 4 8h分别处死大鼠 ,剖腹取胃 ,观察各组动物损伤指数 (LI)及光镜下的胃黏膜病理学改变。结果　盐酸灌胃后COX 2在表层上皮细胞和颈黏液细胞表达显著增加 ,NS 398和吲哚美辛均延迟胃黏膜损伤的愈合。盐酸灌胃后 12h ,NS 398组 (4和 4 0mg/kg)及吲哚美辛组的LI分别为 (1.4 2± 0 .2 3) % ,(1.4 2± 0 .2 9) %和 (1.6 2± 0 .4 4 ) % ,明显高于对照组的 (0 .5 8± 0 .2 4 ) % (P <0 .0 5 )。结论　特异性和非特异性COX 2抑制剂延迟大鼠胃损伤后的愈合 ,提示COX 2表达在胃黏膜再生过程中起重要作用     

紫草素对肺腺癌H1975细胞作用的实验研究

目的 观察紫草素对肺腺癌细胞H1975增殖的影响,并初步探讨其可能的抗癌机制.方法 不同浓度紫草素作用于肺腺癌H1975细胞,MTT实验观察紫草素作用24、48、72 h对肺腺癌细胞增殖的影响,相差显微镜下观察细胞形态,流式细胞术检测细胞凋亡和周期,Western blot检测细胞中EGFR信号通路下游关键分子EGFR、AKT、ERK表达及磷酸化水平以及凋亡相关蛋白Bcl-2表达和DNA修复酶PARP的变化.结果 紫草素能够抑制非小细胞肺癌细胞增殖并呈浓度和时间依赖性;流式细胞术显示紫草素诱导H1975细胞发生凋亡,阻滞细胞于S期;EGFR、AKT和ERK蛋白表达下降,p-EGFR、p-AKT和p-ERK磷酸化水平降低,凋亡相关蛋白Bcl-2表达减少,PARP发生剪切.结论 紫草素能够抑制非小细胞肺癌细胞株H1975增殖、诱导凋亡,其机制可能与其下调EGFR、AKT和ERK的表达及其磷酸化水平和降低凋亡相关蛋白Bcl-2表达和促使PARP发生剪切有关.     

氯吡格雷对大鼠急性胃黏膜损伤愈合的影响及机制

目的:研究氯吡格雷对大鼠急性胃黏膜损伤愈合的影响作用及其机制.方法:40只健康♂SD大鼠随机分为4组,每组10只:阴性对照组、单纯损伤组、10mg/kg氯吡格雷处理组、30mg/kg氯吡格雷处理组;以大剂量阿司匹林灌胃制造大鼠急性胃黏膜损伤模型后,对氯吡格雷处理组的大鼠以相应剂量的氯吡格雷进行灌胃处理,给药3d,每天1次.分别测定各组大鼠的胃黏膜损伤指数(lesionindex,LI);观察大鼠胃黏膜组织学变化;免疫组织化学法检测各组紧密连接蛋白Occludin的表达情况;免疫蛋白印迹法(Westernblot)检测紧密连接蛋白Occludin、ZO-1以及MAPK信号通路中磷酸化P38、磷酸化ERK及磷酸化JNK蛋白的表达量.结果:与损伤组相比,氯吡格雷处理组大鼠胃黏膜损伤加重,且30mg/kg组损伤重于10mg/kg组(39.8±5.05vs35.3±3.86,P<0.05);在阴性对照组、单纯损伤组、10mg/kg氯吡格雷处理组、30mg/kg氯吡格雷处理组中,大鼠胃黏膜中的紧密连接蛋白Occludin、ZO-1蛋白的表达逐渐下降,呈递减趋势(P=0.000),而磷酸化P38、磷酸化ERK蛋白表达则逐渐上升,呈递增趋势(P=0.000).结论:氯吡格雷能够抑制大鼠急性胃黏膜损伤的愈合,其可能是通过激活MAPK中的p38和ERK信号通路,下调胃黏膜上皮细胞间紧密连接蛋白Occludin和ZO-1的表达,破坏大鼠胃黏膜的屏障.     

甲异靛对Jurkat细胞AKT信号通路的影响及其在细胞凋亡中作用的研究

目的:探讨甲异靛对Jurkat细胞AKT信号通路的影响及其在甲异靛诱导Jurkat细胞凋亡中的作用.方法:采用XTT法检测甲异靛对Jurkat细胞的生长抑制作用,应用流式细胞术以及DNA片段分析检测甲异靛诱导Jurkat细胞凋亡的情况.应用Western Blot检测CASPASE家族成员及AKT信号通路相关蛋白在甲异靛作用前后的表达或磷酸化情况.通过电转染方法使Jurkat细胞高表达外源性活化AKT,并进一步分析其对甲异靛诱导细胞凋亡作用的影响.结果:甲异靛抑制Jurkat细胞增殖,随着药物浓度增加抑制作用增强,IC50为10.2 μmol/L;5～20 μmol/L甲异靛诱导Jurkat细胞凋亡且凋亡效应具有浓度依赖性;甲异靛诱导细胞凋亡过程中伴随CASPASE 2,3,8,9的活化,50 μmol/L CASPASE抑制剂z-VAD-fmk 可阻断甲异靛诱导的Jurkat细胞凋亡 .甲异靛降低Jurkat细胞AKT信号通路中AKT,RAF,PDK1,以及ERK1/2 的磷酸化水平;15 μmol/L LY294002)(PI3K-AKT抑制剂)可显著提高甲异靛诱导Jurkat细胞凋亡的作用.甲异靛同样诱导高表达外源性活化AKT的 Jurkat细胞凋亡,但LY294002不能增强甲异靛对高表达外源性活化AKT的 Jurkat细胞的凋亡诱导效应. 结论:甲异靛显著抑制Jurkat细胞增殖,通过活化CASPASE途径诱导Jurkat细胞的凋亡. 甲异靛诱导细胞凋亡过程中伴AKT磷酸化水平的降低,AKT活性的降低并非甲异靛诱导凋亡的惟一因素,但参与甲异靛与PI3K-AKT抑制剂协同诱导Jurkat细胞的凋亡的过程.     

吲哚美辛对受损颈动脉再内皮化的作用及机制

目的研究吲哚美辛对受损颈动脉再内皮化的作用及机制。方法在SD大鼠体内通过球囊法制备颈动脉损伤模型,腹腔注射吲哚美辛,观察其对血管内皮修复的影响;密度梯度离心法获得大鼠单核细胞,应用EGM-2培养基体外诱导培养获得内皮祖细胞(EPCs)。采用不同浓度的吲哚美辛处理晚期EPCs24 h后,MTT法检测细胞的增殖活性,细胞差异贴壁法检测EPCs的粘附能力,改良的Boyden小室检测EPCs的迁移能力,Matrigel基质胶检测EPCs的成血管能力。结果吲哚美辛可明显促进损伤血管内皮的修复,其机制可能与吲哚美辛增强EPCs的增殖、粘附、迁移及成血管能力有关。结论吲哚美辛促进了损伤血管内皮的再内皮化进程。     

二黄糖肾康对糖尿病肾病大鼠肾脏细胞凋亡及PI3 K/AKT信号转导系统的影响

目的 观察二黄糖肾康对糖尿病肾病(DN)大鼠细胞凋亡及PI3 K/AKT信号转导系统的影响. 方法 SD大鼠单侧肾切除加腹腔注射链脲佐菌素(STZ)复制DN模型,每日二黄糖肾康灌胃,8 w后流式细胞术检测细胞凋亡数目及调控因子Bax、Bcl-2、Fas、Fas-L的蛋白表达,采用Western 印迹方法检测细胞内磷酸化Akt蛋白质的表达.结果 二黄糖肾康明显减少DN大鼠肾脏皮质细胞凋亡数目,降低Bax、Fas、Fas-L的的蛋白表达,增加Bcl-2的蛋白表达,激活PI3 K/AKT信号通路.结论 二黄糖肾康能有效降低肾脏细胞凋亡,激活PI3 K/AKT信号通路.     

Toll样受体9在嘌呤霉素氨基核苷导致足细胞损伤中的作用

目的:我们发现Toll样受体9(TLR9)在嘌呤霉素氨基核苷(PAN)处理的足细胞中上调。本研究试图确定TLR9是否参与PAN对足细胞的损伤作用。方法:(1)用PAN诱导体外培养的足细胞损伤模型,以定量逆转录PCR(qRT-PCR)和Western Blot检测足细胞TLR9及该通路其他组分的变化。同时,利用流式细胞术检查足细胞凋亡情况。用PAN诱导大鼠足细胞损伤,以qRT-PCR和免疫组化法检测大鼠肾小球中TLR9表达变化。(2)将TLR9干扰RNA(siRNA)表达质粒和对照质粒分别转染足细胞,用Western Blot检测比较核因子κB(NF-κB)p65和p38丝裂原活化蛋白激酶(p38 MAPK)磷酸化、qRT-PCR比较白细胞介素12(IL-12)的mRNA变化,流式细胞仪比较足细胞凋亡情况。结果:(1)与对照组相比,经PAN刺激的足细胞,其TLR9、丝氨酸/苏氨酸蛋白激酶1(IRAK1)、肿瘤坏死因子受体相关因子6(TRAF6)、IL-12的mRNA水平明显上调,磷酸化p65和磷酸化p38显著增加,细胞凋亡增加。PAN大鼠模型的肾小球中TLR9 mRNA表达上调,免疫组化显示TLR9蛋白显著增加。(2)足细胞转染TLR9干扰质粒后,TLR9的mRNA和蛋白表达水平降低;而经PAN处理后,该细胞与转染对照siRNA的细胞相比,其磷酸化p65和磷酸化p38的水平降低,IL-12 mRNA表达降低,足细胞凋亡减少。结论:TLR9信号通路参与了PAN诱导的足细胞损伤过程,其机制可能是促进炎症因子产生及p38 MAPK依赖的细胞凋亡。     

吲哚美辛对胰腺癌细胞BxPC-3生长的抑制作用及机制

目的探讨环氧合酶抑制剂吲哚美辛体内外对胰腺癌细胞BxPC-3细胞生长的影响及其作用机制。方法用MTT法检测吲哚美辛作用后BxPC-3细胞的增殖情况;用流式细胞分析、透射电镜和原位末端标记(TUNEL)法观察细胞凋亡和细胞周期的变化;建立裸鼠胰腺癌BxPC-3细胞移植瘤模型,用吲哚美辛给荷瘤裸鼠灌胃(3 mg.kg-1.d-1,共4周),观察其对种植瘤生长曲线的影响,TUNEL法检测裸鼠移植瘤组织细胞凋亡。结果吲哚美辛呈剂量和时间依赖性抑制BxPC-3细胞生长。TUNEL、流式细胞仪检测显示药物处理后细胞凋亡增加,细胞阻止于G0/G1。透射电镜可见细胞呈现明显凋亡形态。随着用药时间的增加,吲哚美辛对裸鼠移植瘤的生长抑制作用增加,移植瘤组织凋亡细胞增多。结论吲哚美辛体内外可抑制胰腺癌细胞BxPC-3的生长,其机制可能与促进细胞凋亡,阻滞细胞周期有关。     

前列腺素缺乏条件下促胃动力药胃复安对大鼠胃粘膜的损伤作用与可能机制

目的探讨前列腺素(prostaglandin,PG)缺乏条件下促胃动力药胃复安对大鼠胃粘膜的损伤作用与可能机制。方法 PG缺乏状态由5mg/kg吲哚美辛诱导;雄性SD大鼠随机分组:对照组;胃复安两组(30mg/kg,60mg/kg);吲哚美辛两组(5mg/kg,25mg/kg);吲哚美辛5mg/kg合用胃复安三组(10mg/kg,30mg/kg,60mg/kg);阿托品组(阿托品-吲哚美辛5mg/kg+胃复安60mg/kg),禁食24h后,生理盐水或吲哚美辛灌胃,30min后皮下注射胃复安或生理盐水,阿托品灌胃前10min皮下注射,4h后取血,处死大鼠取胃行损伤测定:放免法测血浆内皮素(Endothelin ET-1);生化法测—氧化氮(nitric oxide NO)、丙二醛(Malondialdhyde MDA)、谷胱甘肽过氧化酶(Glutathioneperoxidase GSH-Px)含量。结果吲哚美辛合用胃复安三组胃粘膜均有明显损伤,ET-1、MDA升高(p<0.05.p<0.01),NO、GSH-Px下降(p<0.05,p<0.01);吲哚美辛25ng/kg组损伤严重,ET-1、MDA升高(p<0.01),NO、GSH-Px下降(p<0.01,P<0.05);胃复安60mg/kg胃有轻微损伤,各指标无显著变化;其余各组未见明显损伤及指标变化。结论(1)PG缺乏条件下促胃动力药胃复安可引起胃黏膜出血性损伤,可能与ET-1升高、NO下降致胃黏膜微循环紊乱有关.MDA升高,GSH-Px减少可能为损伤后的继发反应结果,加剧了黏膜损伤。(32)胃动力有潜在的引起胃黏膜损伤的能力,PG缺乏增加了胃黏膜对胃高动力的敏感性。提示临床上非甾体抗炎药(NSAIDs)服用者应慎用胃动力药,因为合用可能形成或加剧胃黏膜损伤。     

Survivin: a novel target for indomethacin-induced gastric injury

BACKGROUND & AIMS: Nonsteroidal anti-inflammatory drugs (NSAIDs) cause gastrointestinal erosions and ulcers. Apoptosis is one of the mechanisms. The role of survivin, an antiapoptosis protein, in NSAID-induced gastric injury is unknown. We examined the role of survivin in NSAID-induced gastric mucosal and gastric cell injury. METHODS: We examined: (1) the effects of indomethacin (nonselective NSAID), celecoxib and NS-398 (cyclooxygenase [COX]-2-selective NSAIDs), SC-560 (a COX-1-selective NSAID), and SC-560 plus celecoxib on survivin expression and extent of injury in rat gastric mucosa; (2) the effects of indomethacin, NS-398, SC-560, and SC-560 plus NS-398 on survivin expression and injury in gastric epithelial (RGM-1) cells; and (3) the effects of survivin suppression with small interfering RNA (siRNA) on RGM-1 cell integrity at baseline and following indomethacin injury. RESULTS: Indomethacin treatment dose-dependently reduced survivin protein levels and caused severe injury of gastric mucosa and RGM-1 cells. Suppression of survivin expression with siRNA in RGM-1 cells caused cell damage and increased susceptibility to injury by indomethacin. Celecoxib treatment caused exfoliation of the mucosal surface epithelium, but neither caused deep erosions or altered survivin expression. Neither NS-398 nor SC-560 treatment altered survivin levels or produced injury in vivo or in vitro. COX-1 and COX-2 inhibitor combination caused injury in vivo and in vitro but did not decrease survivin expression. CONCLUSIONS: (1) Indomethacin, but not selective COX-1 or COX-2 inhibitors alone or in combination, reduces survivin expression in gastric mucosal cells and (2) significant reduction of survivin precedes greater severity of gastric injury.     

Cellular membrane fluidity measurement by fluorescence polarization in indomethacin-induced gastric cellular injury in vitro

Background Gastric complications of indomethacin involve generation of reactive oxygen species, which induce gastric mucosal injury via lipid peroxidation of cell membranes. Peroxidation by reactive oxygen species alters the amounts of unsaturated fatty acids in the cell membrane and thus affects membrane fluidity. Indomethacin-induced lipid peroxidation can thus be detected by measuring cellular membrane fluidity by the fluorescence polarization (FP) method. The aim of this study was to elucidate the usefulness of the FP method for detecting indomethacin-induced gastric cellular injury in RGM-1 cells. Methods Indomethacin-treated RGM-1 cells were investigated by conventional cytotoxicity assay, fluorometry of diphenyl-1-pyrenylphosphine (DPPP) to detect lipid peroxidation, and FP. The effects of both a radical scavenger and an initiator on membrane fluidity change (MFC) in RGM-1 cells were examined. The sensitivity of FP in detecting cellular injury was compared with those of DPPP fluorometry and conventional cytotoxicity measurements. Results Indomethacin caused an increase in MFC as determined by FP before cytotoxicity was detected by conventional methods. The increase in MFC was associated with increased membrane phospholipid peroxidation (MPP) but not with a prostaglandin deficiency, and the increases in both MFC and MPP were prevented by vitamin E. Conclusions The FP method is potentially useful for detecting cellular injury in vitro.     

Role of active oxygen, lipid peroxidation, and antioxidants in the pathogenesis of gastric mucosal injury induced by indomethacin in rats.

The roles of active oxygen, lipid peroxidation, and the antioxidative defence mechanism in gastric mucosal injury induced by treatment with indomethacin in rats were investigated. The total area of gastric erosions and concentration of lipid peroxides in the gastric mucosa increased with time after administration of indomethacin (20 mg/kg, orally). The alpha-tocopherol:total cholesterol ratio in serum was significantly decreased and the activity of glutathione peroxidase, an important enzyme to scavenger of lipid peroxides, was inhibited by the administration of indomethacin. Treatments with superoxide dismutase and catalase inhibited the increases in gastric mucosal erosions and lipid peroxides in the gastric mucosa, and the reduction of serum alpha-tocopherol. Treatment with these scavengers did not improve the decreased glutathione peroxidase activity. These findings suggest that active oxygen species and lipid peroxidation play an important part in the pathogenesis of gastric mucosal injury induced by indomethacin, and that the decreased glutathione peroxidase activity aggravated the injury due to accelerated accumulation of hydrogen peroxide and lipid peroxides in the gastric mucosal cell.     

Irritant-induced cyclooxygenase-2 is involved in the defense mechanism of the gastric mucosa in mice

Background. Endogenous and exogenous prostaglandins (PGs) have been shown to contribute to reducing the gastric injury caused by irritants given subse-quently. The aim of this study was to clarify whether cyclooxygenase-2 (COX-2) protein induced by pretreatment was involved in the prevention of subsequent ethanol-caused gastric injury in mice. Methods. Mice were pretreated with acidified ethanol or saline and then COX-2 protein expression in the stomach was immunohistochemically determined every 8 h. Mice were administered 95% ethanol 24 h after the acidified ethanol pretreatment, and gastric mucosal damage was evaluated macroscopically and histologically. The effects of NS-398 or indomethacin on the 95% ethanol-caused damage were also examined. Results. Acidified ethanol pretreatment induced COX-2 protein expression in lamina propria macrophages of the gastric mucosa, with a peak level 24 h after the pretreatment. The 95% ethanol treatment caused gastric mucosal damage. The degree of the damage was not different between mice pretreated with acidified ethanol and those pretreated with saline. However, NS-398 aggravated the ethanol-caused damage only in mice pretreated with acidified ethanol, while indomethacin aggravated the damage, evaluated histologically, irrespective of the pretreatment. Conclusions. Pretreatment-induced COX-2, in addition to COX-1, seemed to be involved in the defense mechanism through minimizing the damage caused by a subsequent irritant. Received: October 16, 2000 / Accepted: September 14, 2001     

Rebamipide Reduces Indomethacin-Induced Gastric Injury in Mice via Down-Regulation of ICAM-1 Expression

Non-steroidal anti-inflammatory drugs (NSAIDs) induced gastric mucosal injury occurs through subsequent events following free radical production derived from activated neutrophils. In this study, we hypothesized that rebamipide, a novel anti-ulcer agent, exerts a protective effect on NSAID-induced gastric injury through its antioxidant properties. The protective effect of rebamipide in a mouse model of indomethacin-induced gastric injury and mechanisms for this effect were investigated. Pre-treatment with rebamipide significantly inhibited indomethacin-induced gastric mucosal injury in mice. Gastric thiobarbituric acid reactive substances (TBARS) levels and myeloperoxidase (MPO) activity substantially increased 3 hr after indomethacin administration. These increases were significantly inhibited by pre-treatment with rebamipide. Furthermore, rebamipide pre-treatment notably decreased intercellular adhesion molecule-1 (ICAM-1) expression that was up-regulated in gastric tissue treated with indomethacin. Therefore, rebamipide may reduce indomethacin-induced gastric mucosal injuries through its antioxidant effect, which inhibits the neutrophil activation step following up-regulation of ICAM-1 expression on endothelial cells.     

Rebamipide reduces indomethacin-induced gastric injury in mice via down-regulation of ICAM-1 expression

Non-steroidal anti-inflammatory drugs (NSAIDs) induced gastric mucosal injury occurs through subsequent events following free radical production derived from activated neutrophils. In this study, we hypothesized that rebamipide, a novel anti-ulcer agent, exerts a protective effect on NSAID-induced gastric injury through its antioxidant properties. The protective effect of rebamipide in a mouse model of indomethacin-induced gastric injury and mechanisms for this effect were investigated. Pre-treatment with rebamipide significantly inhibited indomethacin-induced gastric mucosal injury in mice. Gastric thiobarbituric acid reactive substances (TBARS) levels and myeloperoxidase (MPO) activity substantially increased 3 hr after indomethacin administration. These increases were significantly inhibited by pre-treatment with rebamipide. Furthermore, rebamipide pre-treatment notably decreased intercellular adhesion molecule-1 (ICAM-1) expression that was up-regulated in gastric tissue treated with indomethacin. Therefore, rebamipide may reduce indomethacin-induced gastric mucosal injuries through its antioxidant effect, which inhibits the neutrophil activation step following up-regulation of ICAM-1 expression on endothelial cells.     

丙泊酚对小鼠胃缺血/再灌注后细胞增殖及凋亡的影响

目的:观察丙泊酚对小鼠胃缺血/再灌注(ischemia-reperfusion,I/R)后胃黏膜损伤程度及胃黏膜细胞增殖及凋亡的影响,探讨丙泊酚的胃保护作用及可能机制.方法:72只♂昆明小鼠随机分为4组:假手术组(sham,S组)、I/R组、脂肪乳组(fat emulsion,F组)、丙泊酚组(propofol,P组).通过夹闭小鼠腹腔动脉30min后松开动脉夹再灌注1h制作胃I/R模型.取胃观察大体形态变化、计算胃黏膜损伤指数,HE染色光镜下观察病理形态学变化,比色法测定丙二醛(malondialdehyde,MDA)含量和超氧化物歧化酶(superoxide dismutase,SOD)活性,免疫组织化学方法和原位DNA末端标记(TUNEL)染色法分别检测胃黏膜细胞增殖和凋亡的表达情况,蛋白免疫印迹法(Westernblotting)测定胃黏膜组织中Bcl-2、Bax蛋白的表达.结果:腹腔注射25mg/kg丙泊酚后胃黏膜损伤明显减轻,具体表现为胃黏膜及黏膜下层的充血、水肿及糜烂均有明显改善;与I/R组相比,P组细胞内MDA含量明显降低,SOD活性增强(P<0.01);与I/R组相比,丙泊酚可明显抑制胃黏膜细胞凋亡(33.9%±1.3%vs60.8%±6.9%)、促进细胞增殖(16.0%±1.8%vs6.4%±1.2%)、下调Bax(0.453±0.025vs0.268±0.023)及上调Bcl-2蛋白(0.513±0.014vs0.752±0.015)的表达(均P<0.01).结论:丙泊酚能促进小鼠胃I/R后胃黏膜细胞增殖、抑制细胞凋亡,对胃I/R损伤有保护作用,其可能机制与其清除氧自由基、抑制脂质过氧化有关.     

Somatostatin effectively prevents ethanol-and NSAID-induced gastric mucosal damage in rats

The interrelationship between somatostatin and its synthetic analog, sandostatin, with neuropeptides and inflammatory mediators, as well as their protection of gastric mucosal damage, were tested in rats. Rats were treated intragastrically with 1.0 ml of 96% ethanol with or without intravenous or intraperitoneal coadministration of somatostatin (1.0 µM/kg). Mucosal damage was also induced by the administration of either indomethacin (30 mg/kg subcutaneously) with or without intravenous sandostatin (10 µg/rat), given 30 min prior to damage induction. Somatostatin levels in ethanol-damaged gastric mucosa were significantly lower than in control rats. Substance P and vasoactive intestinal peptide (VIP) levels were significantly higher in the damaged mucosa in rats treated with ethanol, as was the mucosal generation of leukotriene B₄ (LTB₄) and cysteinyl-containing leukotrienes. The coadministration of somatostatin with ethanol significantly reduced gastric mucosal injury induced by ethanol alone. The protection of the mucosa was accompanied by reduction of mucosal substance P and VIP levels, as well as the generation of leukotrienes, an effect that was reversed by intraperitoneal or intravenous coadministration of somatostatin antagonist, cyclo-(7-aminoheptanoyl-PH-E-d-Trp-Lys-THR), 1.0 µM/100 g, with somatostatin (1.0 µM/kg) and ethanol. When given by itself somatostatin significantly reduced mucosal leukotriene generation compared with their generation in saline-treated rats. Sandostatin completely abolished gastric mucosal damage induced by indomethacin administration. In rats treated with somatostatin and indomethacin, this effect was accompanied by reduction of mucosal leukotriene generation. Administration of sandostatin to pylorus-ligated rats significantly reduced gastric acid output. It is suggested that somatostatin may be involved in the pathogenesis of acute ethanol- and NSAID-induced gastric mucosal injury and that part of its protective effect involves interrelationships with the neuropeptides, substance P and VIP, as well as inhibition of mucosal leukotriene production.     

Melatonin reduces indomethacin‐induced gastric mucosal cell apoptosis by preventing mitochondrial oxidative stress and the activation of mitochondrial pathway of apoptosis

Abstract: Augmentation of gastric mucosal cell apoptosis due to development of oxidative stress is one of the main pathogenic events in the development of nonsteroidal anti‐inflammatory drug (NSAID)‐induced gastropathy. Identification of a nontoxic, anti‐apoptotic molecule is warranted for therapy against NSAID‐induced gastropathy. The objective of the present study was to define the mechanism of the anti‐apoptotic effect of melatonin, a nontoxic molecule which scavenges reactive oxygen species. Using an array of experimental approaches, we have shown that melatonin prevents the development of mitochondrial oxidative stress and activation of mitochondrial pathway of apoptosis induced by indomethacin (a NSAID) in the gastric mucosa. Melatonin inhibits the important steps of indomethacin‐induced activation of mitochondrial pathway of apoptosis such as upregulation of the expression of Bax and Bak, and the downregulation of Bcl‐2 and BclxL. Melatonin also prevents indomethacin‐induced mitochondrial translocation of Bax and prevents the collapse of mitochondrial membrane potential. Moreover, melatonin reduces indomethacin‐mediated activation of caspase‐9 and caspase‐3 by blocking the release of cytochrome c and finally rescues gastric mucosal cells from indomethacin‐induced apoptosis as measured by the TUNEL assay. Histologic studies of gastric mucosa further document that melatonin almost completely protects against gastric damage induced by indomethacin. Thus, melatonin has significant anti‐apoptotic effects to protect gastric mucosa from NSAID‐induced apoptosis and gastropathy, which makes its use as potential therapy against gastric damage during NSAID treatment.     

Gastroprotective effect of ranitidine bismuth citrate is associated with increased mucus bismuth concentration in rats.

BACKGROUND: Antisecretory and bismuth compounds protect the gastric mucosa from injury resulting from non-steroidal anti-inflammatory drugs. AIM: To study the mechanism underlying the gastroprotective effects of ranitidine bismuth citrate (GG311) in rats. METHODS: Indomethacin rat injury model and in vivo microscopy in which acid output, surface cell intracellular pH (pHi), gastric mucus gel thickness, and mucosal blood flow were measured simultaneously. RESULTS: In injury studies, GG311 dose dependently protected against severe injury induced by indomethacin (60 mg/kg subcutaneously). In in vivo microscopic studies, indomethacin significantly decreased mucus gel thickness and increased the initial rate of acidification of gastric surface cells when the superfusate pH was lowered from 7.4 to 1.0, and impaired pHi during acid exposure. Indomethacin had no effect on mucosal blood flow or acid output. GG311 alone had no effect on gel thickness, blood flow, or pHi homeostasis during acid exposure, but improved the initial acidification rate and pHi during superfusion with pH 1.0 solutions in the presence of indomethacin. In separate experiments, indomethacin pretreatment considerably increased gastric mucus bismuth concentrations in rats given GG311. CONCLUSIONS: The gastroprotective effect of GG311 against indomethacin induced gastric injury is associated with high and prolonged gastric mucus bismuth concentrations, which may impair proton permeation across the mucus gel.