褪黑素治疗重症急性胰腺炎的机制研究

褪黑素是一种高效的内源性抗氧化剂,不仅可以有效清除氧自由基,还可通过抑制NF-κB的激活而发挥抗炎作用。最新研究表明,针对急性重症胰腺炎的两个重要发病学说,褪黑素具有靶向治疗作用。     

褪黑素对大鼠急性坏死性胰腺炎的干预作用及机制

目的: 观察褪黑素前干预对急性坏死性胰腺炎(ANP)大鼠的胰腺和肺组织的保护作用与硫氧还蛋白-1(Trx-1)表达的关系.方法: 72只♂SD大鼠随机分成ANP模型组(A组)、褪黑素前干预组(M组)、对照组(C组). A组的大鼠腹腔注射6%左旋精氨酸(25 mL/kg体质量), 每次间隔1 h, 共3次, 诱发ANP, 且在诱发ANP前、后0.5 h腹腔注射生理盐水(20mL/kg体质量)各1次;M组的大鼠诱发ANP的方法同A组, 但在诱发ANP前0.5 h腹腔注射0.25%褪黑素(20 mL/kg体质量)1次, 替代生理盐水;C组的大鼠腹腔注射相当于A组各次注射用量的等容积生理盐水. 每组术后6 h、12 h及24 h时点分批处置大鼠. 抽血测定Trx-1、白介素-6(IL-6)、谷胱甘肽(GSH)、总超氧化物歧化酶(T-SOD)、丙二醛(MDA)的含量;取胰腺和肺组织做病理学检查.结果: 大鼠胰腺组织的病理变化和病理学评分证实左旋精氨酸导致A组的ANP. 与A组比较, M组胰腺和肺组织的病理损伤显著减轻. 与C组比较, A组的大鼠血清的Tr x-1的量在6 h、12 h时点显著降低, 24 h时点显著升高, 呈现出先降低后升高的趋势;与A组比较,M组的大鼠血清的Trx-1的量在6 h、12 h时点显著增高, 他们表达的峰值前移. 与C组比较,A组的大鼠血清的IL-6、MDA水平显著增高,血清的T-SOD活力、GSH的含量显著降低;与A组比较, M组的大鼠血清的IL-6、MDA水平显著降低, 血清的T-SOD活力、GSH的含量显著增高.结论: ANP可诱导Trx-1的表达;而褪黑素前干预可进一步促进Trx-1的表达, 提高T-SOD活力和GSH水平, 降低IL-6、MDA水平, 故能显著减轻大鼠胰腺和肺组织的病理损伤, 发挥其对胰腺和肺组织的保护作用.     

褪黑素前后干预对左旋精氨酸诱导的实验性急性坏死性胰腺炎大鼠肺胰组织损伤的保护作用

目的探讨褪黑素前、后干预对急性坏死性胰腺炎(acute necrotizing pancreatitis,ANP)大鼠肺和胰腺组织的保护作用。方法将96只SD大鼠随机分成对照组(C组,n=24)、急性坏死性胰腺炎组(A组,n=24)、褪黑素前干预组(M1组,n=24)和后干预组(M2组,n=24)。A组用6%的左旋精氨酸(L-Arginine,L-Arg)腹腔内注射,每次25mL/kg体质量,共3次,注射间隔1h,诱导ANP模型,在首次注射L-Arg前0.5h腹腔注射生理盐水20mL/kg体质量1次;C组同法注射相当于A组各次注射用量的等容积生理盐水;M1和M2组分别在诱导胰腺炎前和后0.5h腹腔内注射0.25%褪黑素(20mL/kg体质量)干预。在末次注射L-Arg后的第6h、第12h和第24h3个时点分批处死大鼠,观察各组对应各时点胰腺和肺组织病理学改变的变化。结果 A组大鼠胰腺和肺组织病理损伤在各时点较C组明显加重(P0.01);M1组胰腺和肺组织病理损伤较A组减轻,尤以第6h、第12h显著(P0.01或0.05)。M2组上述改变介于A组和M1组之间。M1组较M2组病变轻;在第24h,A组血清淀粉酶较C组显著升高(P0.01);M2组淀粉酶较A组降低(P0.05);M1较A组低。结论在ANP肺组织损伤程度与胰腺组织损伤程度密切相关。褪黑素在一定程度上减轻ANP的胰腺和肺损伤。M1组对肺和胰腺组织的保护作用明显强于M2组。     

褪黑素对急性坏死性胰腺炎并肝损伤的保护作用及肝Ghrelin的表达

目的观察在大鼠急性坏死性胰腺炎并肝损伤时肝组织中ghrelin的表达,探讨ghrelin在肝脏损伤中的作用及抗氧化剂褪黑素对其的影响和可能机制。方法72只雄性SD大鼠随机分为对照组(C组,n=24)、急性坏死性胰腺炎组(A组,n=24)、褪黑素干预组(M组,n=24)。A组、M组分3次腹腔注射6%左旋精氨酸(L-Arg)1.5 g/kg,诱发急性坏死性胰腺炎,M组在首次注射L-Arg前0.5 h腹腔注射1%褪黑素50μg/kg,C组同法注射等量生理盐水。各组大鼠在末次腹腔注射后6、12、24 h分批处死。光镜下观察胰腺及肝脏病理改变并进行评分,测定血清淀粉酶水平,RT-PCR检测肝脏ghrelin mRNA水平,并检测肝组织中SOD、MDA含量。结果A组各时点胰腺及肝脏病理评分、血清淀粉酶显著高于C组,ghrelin mRNA表达较C组明显降低(P均0.05),SOD较C组降低,而MDA升高(P均0.05)。M组各时点胰腺及肝脏病理评分、血清淀粉酶较A组降低,ghrelin mRNA较A组升高(P0.05),SOD较A组升高,MDA降低(P均0.05)。结论Ghrelin在急性胰腺炎并肝损伤时的表达可能与病变严重程度有关;外源性褪黑素通过对抗氧化应激,可减轻急性胰腺炎的胰腺和肝脏损伤。     

褪黑素对胰腺炎损伤的剂量依赖性保护作用的研究进展

褪黑素是一种具有抗氧化作用和免疫调节作用的吲哚类激素,它可以下调急性炎性反应过程中多种炎性介质的表达,从而减轻各个脏器的急性炎性反应.实验研究表明,褪黑素不仅在急性胰腺炎(AP)及相关性脏器损伤中发挥着保护作用,而且这一作用具有剂量依赖性和昼夜节律性.此文对这一方面的研究进展作一综述.     

硫氧还蛋白-1在急性坏死性胰腺炎大鼠肺组织中的表达及褪黑素干预的影响

目的:探讨内源性硫氧还蛋白-1(Trx-1)在急性坏死性胰腺炎(ANP)大鼠模型肺组织中的表达:观察褪黑素对ANP胰和肺脏的保护作用和对肺组织Trx-1表达的影响.方法:将72只SD大鼠随机分成对照组(C组,n=24)、急性胰腺炎组(A组,n=24)、褪黑素前干预组(M组,n=24).A组用6%的左旋精氨酸(L-Arginine,L-Arg)腹腔内注射,每次25 mL/kg体质量,共3次,注射间隔1 h,诱导ANP模型,在首次注射L-Arg前30 min腹腔注射生理盐水20mL/kg体质量1次;C组同法注射相当于A组各次注射用量的等容积生理盐水:M组在诱导胰腺炎前30 min腹腔内注射0.25%褪黑素(20mL/kg体质量)干预.在注射完L-Arg后的6、12、24 h三个时点分批处死大鼠.应用免疫组织化学技术检测各组ANP肺组织Trx-1的表达.并观察各组对应各时点胰腺、肺组织病理学和肺免疫组织化学的改变;抽取动脉血测定Trx-1和淀粉酶.结果:A组大鼠胰腺和肺组织病理损伤在6、12、24 h时点比C组明显加重(均P＜0.01);M组胰腺和肺组织病理损伤在6、12、24 h时点较A组明显减轻(P＜0.01或0.05).A组、M组肺组织表达Trx.1量在6、12、24 h时点较C组显著升高(均P<0.01).在24 h,A组血清淀粉酶较C组显著升高(4 598 U/L±2 274 U/L vs2 033U/L±863 U/L,P＜0.01);M组较A组低(3 990U/L±1 146 U/L vs 4 598 U/L±2 274 U/L,P＜0.05).A组大鼠血清Trx-1含量在6、12 h时点显著降低,24 h时点显著升高,呈前低后高趋势;与A组比较,M组血清Trx-1在6、12 h时点显著升高,24 h时点显著降低,量的峰值前移.结论:Trx-1在ANP肺损伤组织中的过度表达与急性胰腺炎相关性肺损伤关系密切.褪黑素影响Trx-1表达,并可能在一定程度上减轻ANP的胰、肺组织损伤.     

褪黑素对重症急性胰腺炎相关性肺损伤保护作用的研究

在重症急性胰腺炎（SAP）引起的多器官功能衰竭中,呼吸功能衰竭占SAP第1周病死率60％,肺功能障碍是除腹部脏器功能障碍外最突出的表现,因此同时着眼于胰腺和肺组织是治疗SAP的新策略。     

急性胰腺炎的研究进展

本文对2010年美国DDW会议报告的急性胰腺炎(acute pancreatitis,AP)的研究进展做一总结,主要集中在AP的临床特征以及指导临床治疗的危险分层.对于AP患者,临床医生有必要对其进行危险因素分层,鉴定出高危患者以进行早期干预如大量补液、早期肠内营养,并且适时进行内镜下逆行胰胆管造影术(ERCP).最近的临床指南、文献和去年发表的高质量调查研究均表明这些措施可以有效地降低AP的临床死亡率.     

褪黑素对心肌细胞抗过氧化氢损伤的实验研究

目的 :观察 H2 O2 对心肌细胞内活性氧 （ROS）和游离钙 （[Ca2 + ]i）的影响及褪黑素 （MT）的保护作用。方法 :酶消化法原代分离培养乳鼠心肌细胞 ,分别用荧光探针 DCFH- DA和 Fluo- 3- AM标记 ,H2 O2 和 MT处理后 ,流式细胞仪检测细胞荧光强度的变化。结果 :低浓度的 H2 O2 （10 0 μm ol/ L）随着时间的延长可使心肌细胞内的 ROS呈上升趋势 ,30 m in,6 0 m in与 0 min或对照组相比均明显增高 （P<0 .0 1） ;MT干预后上升趋势均明显减弱 ,在 30 ,6 0 min两组均差异显著 （P<0 .0 1）。 [Ca2 + ]i 亦呈显著上升趋势 ,30 min时与 0 min或对照组相比有差异 （P<0 .0 5 ） ,6 0min时与 30 m in,0 min或对照组相比差异显著 （P<0 .0 1） ;MT干预后其上升明显减少 ,两者差异显著 （P<0 .0 1）。结论 :MT有很好的抗氧化效果 ,能起到保护心肌的作用。     

重症急性胰腺炎实验动物模型的研究进展

为探讨重症急性胰腺炎(seve re acutepancreatitis,SAP)的病因、发病机制、病理生理变化及其治疗方法,已用多种方式建立了活体动物SAP模型.鉴于各种活体SAP模型能在不同侧面模拟人类SAP病变过程,但操作及控制各异、部分便于动态观察各项指标变化及治疗效果,可根据不同的实验目的选择合适、操作简单、重复性好的建模方案进行研究.本文简述目前SAAP究现状,启迪未来探索方向.     

Effect of melatonin on the severity of L-arginine-induced experimental acute pancreatitis in rats

AIM: To determine the effect of melatonin pre- and post-treatment on the severity of L-arginine (L-Arg) -induced experimental pancreatitis in rats. METHODS: Male Wistar rats (25) were divided into five groups. Those in group A received two injections of 3.2 g/kg body weight L-Arg i.p. at an interval of 1 h. In group MA, the rats were treated with 50 mg/kg body weight melatonin i.p. 30 min prior to L-Arg administration. In group AM, the rats received the same dose of melatonin 1 h after L-Arg was given. In group M, a single dose of melatonin was administered as described previously. In group C the control animals received physiological saline injections i.p. All rats were exsanguinated 24 h after the second L-Arg injection. RESULTS: L-Arg administration caused severe necrotizing pancreatitis confirmed by the significant elevations in the serum amylase level, the pancreatic weight/body weight ratio (pw/bw), the pancreatic IL-6 content and the myeloperoxidase activity, relative to the control values. Elevation of the serum amylase level was significantly reduced in rats given melatonin following L-Arg compared to rats injected with L-Arg only. The activities of the pancreatic antioxidant enzymes (Cu/Zn-superoxide dismutase (Cu/Zn-SOD) and catalase (CAT)) were significantly increased 24 h after pancreatitis induction. Mela- tonin given in advance of L-Arg significantly reduced the pancreatic CAT activity relative to that in the rats treated with L-Arg alone. In the liver, L-Arg significantly increased the lipid peroxidation level, and the glutathione peroxi-dase and Cu/Zn-SOD activities, whereas the Mn-SOD activity was reduced as compared to the control rats. Melatonin pre-treatment prevented these changes. CONCLUSION: Melatonin is an antioxidant that is able to counteract some of the L-Arg-induced changes during acute pancreatitis, and may therefore be helpful in the supportive therapy of patients with acute necrotizing pancreatitis.     

急性坏死性胰腺炎胰腺组织中褪黑激素受体表达及褪黑激素干预作用

目的 探讨急性坏死性胰腺炎(ANP)胰腺组织中褪黑激素受体MT1表达及褪黑激素(MT)干预作用.方法 54只SD大鼠随机分为假手术组(SO组)、急性坏死性胰腺炎组(ANP组)、MT干预组(MT组),每组18只.应用胰胆管逆行注射牛磺胆酸钠的方法诱导ANP模型,MT组于诱导模型前30 min腹腔注射MT.术后4 h、8 h和12 h分批处死大鼠(每个时间点6只),以免疫组化和实时定量PCR分别检测胰腺组织中MT1蛋白及MT1 mRNA的表达;检测血清淀粉酶、胰腺组织中丙二醛(MDA)、超氧化物歧化酶(SOD)及TNFα的含量,并行胰腺病理检查.结果 (1)ANP组胰腺病理损伤呈进行性加重,MT组胰腺病理损伤较ANP组明显减轻(P＜0.05).(2)淀粉酶、MDA、TNFα水平在ANP组较S0组明显增高(P＜0.05或P＜0.01),而MT组较相应时间点ANP组显著降低[12 h,(2348.00±278.90)U/L比(3194.83±538.10)U/L,(2.255±0.472)μmol/L比(2.960±0.722)μmol/L,(102.929±29.399)ng/L比(378.544±183.454)ng/L,P＜0.05].SOD水平在ANP组各时点较SO组显著降低(P＜0.01),而MT组较ANP组显著升高[12 h,(11.448±1.594)U/L比(8.427±1.950)U/L,P＜0.05].(3)与SO组相比,MT1蛋白及MT1 mRNA表达在ANP组胰腺组织中明显下降(P＜0.05),且随ANP病变加重表达减弱,而MT组表达较ANP组明显增多.结论 MT干预可提高SOD活力,降低MDA、TNFα水平,故能显著减轻ANP时胰腺病理损伤,MT1在ANP发病机制中可能具有重要作用,MT对ANP中的干预作用可能与上调胰腺组织中MT1的表达有关.     

Hormonal protection in acute pancreatitis by ghrelin,leptin and melatonin

Acute pancreatitis is a nonbacterial disease of the pancreas.The severe form of this ailment is characterized by high mortality.Whether acute pancreatitis develops as the severe type or resolves depends on the intensity of the inflammatory process which is counteracted by the recruitment of innate defense mechanisms.It has been shown that the hormones ghrelin,leptin and melatonin are able to modulate the immune function of the organism and to protect the pancreas against inflammatory damage.Experimental studies have demonstrated that the application of these substances prior to the induction of acute pancreatitis significantly attenuated the intensity of the inflammation and reduced pancreatic tissue damage.The pancreatic protective mechanisms of the above hormones have been related to the mobilization of non-specific immune defense,to the inhibition of nuclear factor kappa B and modulation of cytokine production,to the stimulation of heat shock proteins and changes of apoptotic processes in the acinar cells,as well as to the activation of antioxidant system of the pancreatic tissue.The protective effect ofghrelin seems to be indirect and perhaps dependent on the release of growth hormone and insulin-like growth factor 1.Leptin and ghrelin,but not melatonin,employ sensory nerves in their beneficial action on acute pancreatitis.It is very likely that ghrelin,leptin and melatonin could be implicated in the natural protection of the pancreatic gland against inflammatory damage because the blood levels of these substances increase in the initial phase of pancreatic inflammation.The above hormones could be a part of the innate resistance system which might remove noxious factors and could suppress or attenuate the inflammatory process in the pancreas.     

Exogenous melatonin treatment reduces hepatocyte damage in rats with experimental acute pancreatitis

Background/purpose

The hormone melatonin affects cellular immunity in particular and the immune system in general both directly and indirectly. We report our evaluation of the effects of decreasing and increasing serum melatonin levels on hepatocyte damage in rats with experimental acute pancreatitis.

Methods

Winstar Albino rats with experimentally induced acute pancreatitis were divided into three groups of ten rats each: (1) control (induced acute pancreatitis only); (2) rats with induced acute pancreatitis plus surgical pinealectomy (no melatonin injections); (3) rats with induced acute pancreatitis plus injections of exogenous melatonin. The effects of melatonin levels were evaluated using biochemical and histopathological parameters.

Results

Rats undergoing the pinealectomy had increased amylase and lactate dehydrogenase (LDH) levels, while those receiving injections of exogenous melatonin had decreased amylase, aspartate transaminase, LDH, and bilirubin levels but increased levels of alanine transferase levels.

Conclusion

Melatonin may have a therapeutic or protective effect on acute pancreatitis and obstructive jaundice.     

硫氧还蛋白-1在急性坏死性胰腺炎并急性胃黏膜损伤中的作用

目的探讨硫氧还蛋白-1（TRX-1）在实验性急性坏死性胰腺炎（ANP）并急性胃黏膜损伤发病机制中的作用以及抗氧化剂褪黑素对其的影响。方法72只大鼠随机分为对照组（C组,n=24）、ANP组（A组,n=24）和褪黑素干预组（M组,n=24）。A组分3次腹腔内注射6％L-精氨酸（L—Arg）1．5g／kg建立ANP模型;C组同法注射等量生理盐水;M组于首次注射L—Arg前0．5h腹腔内注射1％褪黑素50μg／kg。各实验组大鼠于末次腹腔内注射后6h、12h和24h分批处死。光镜下观察胰腺和胃组织并进行病理学评分,采用免疫组化检测TRX-1在胃黏膜的表达,并检测胃黏膜中MDA、MPO的含量。结果A组各时点胃黏膜TRX-1的染色积分及MDA、MPO的含量明显高于C组（P均〈0．05）;M组各时点胃黏膜中TRX一1的染色积分及MDA、MPO的含量明显低于A组（P均〈0．05）,胰腺和胃组织病理改变较A组明显减轻（P均〈0．05）。结论内源性的TRX-1可能是胃黏膜组织抵御氧化应激损伤的重要因子之一,TRX-1的表达量可能与组织氧化应激损伤的严重程度有关。外源性的褪黑素在ANP时可能通过其抗氧化作用,减轻胃黏膜氧化应激损伤的程度,对胃黏膜有一定的保护作用。     

Myocardial ischemia-reperfusion injury: Possible role of melatonin

Our knowledge and understanding of the pathophysiology of coronary atherosclerosis has increased enormously over the last 20 years. Reperfusion through thrombolysis or percutaneous coronary angioplasty is the standard treatment for preventing acute myocardial infarction. Early reperfusion is an absolute prerequisite for survival of the ischemic myocardium, but reperfusion itself may lead to accelerated and additional myocardial injury beyond that generated by ischemia alone. These outcomes, in a range of reperfusion-associated pathologies, are collectively termed "reperfusion injuries". Reactive oxygen species are known to be produced in large quantities in the first few minutes of the post-ischemia reperfusion process. Similarly, scientific evidence from the last 15 years has suggested that melatonin has beneficial effects on the cardiovascular system. The presence of vascular melatoninergic receptor binding sites has been demonstrated; these receptors are functionally linked to vasoconstrictor or vasodilatory effects of melatonin. It has been shown that patients with coronary heart disease have a low melatonin production rate, especially those with higher risk of cardiac infarction and/or sudden death. Melatonin attenuates molecular and cellular damage resulting from cardiac ischemia-reperfusion in which destructive free radicals are involved.