N-乙酰半胱氨酸对肺微血管内皮细胞核因子κB活性影响的体外研究

目的探讨N-乙酰半胱氨酸（NAC）对人肺微血管内皮细胞（HPMEC）核岗子κB（NF—κB）结合活性和环氧合酶-2（COX-2）表达的影响机制。方法体外培养HPMEC细胞株,采用四甲基偶氮唑盐（MTT）检测NAC对HPMEC增殖活化的抑制作用,分别采用NAC（1mmol／L）处理1h,肿瘤坏死因子α（TNF-α）（100ng／mL）处理1h。NAC＋TNF-α联合处理。凝胶电泳移动抑制实验检测HPMECNF—κB的结合活性;免疫蛋白质印迹检测相应的HPMEC胞质内NF—κB抑制蛋白（IKB—α）的表达;免疫细胞化学观察HPMECNF—κB表达的核内转移;激光共聚焦检测NAC对HPMEC中COX-2表达的影响。结果NAC对HPMEC的增殖活化有明显抑制作用,NAC＋TNF-α联合处理组吸光度值明显低于TNF-α处理组,差异均有统计学意义（均P〈0．05）。TNF—α刺激后具有诱导HPMECNF—κB结合活性．且IKB-α表达明显减弱,NAC处理组IKB-α表达高于TNF—α处理组,差异有高度统计学意义（P〈0．01）。TNF—α处理1h后．HPMECNF—κB的主要表达从细胞质转移至细胞核内;NAC预处理后联合TNF—α刺激,HPMECNF—κB表达主要位于细胞质．出现核内转移极少。HPMEC经TNF-α处理后细胞内COX-2表达明显高于NAC＋TNF—α联合处理组以及正常对照组．差异均有统计学意义（均P〈0．05）;而NAC＋TNF-α联合处理组与正常对照组比较。差异无统计学意义（P〉0．05）。结论NAC可抑制HPMEC增殖活化;NAC可抑制HPMECNF—κB结合活性、减少核内转移发生和COX-2的表达。     

N-乙酰半胱氨酸联合甲基强的松龙治疗放射性肺损伤临床研究

目的探讨使用N-乙酰半胱氨酸(NAC)治疗放射性肺损伤的临床效果和应用价值。方法将100例放射性肺损伤患者随机平均分为甲基强的松龙治疗组(对照组)和甲强龙+N-乙酰半胱氨酸治疗组(治疗组),每组50例,疗程14天。4周后观察2组临床疗效。并分别于第1天和第14天观察血浆TNF-α、IL-6、TGF-β1和CRP水平变化。结果 4周后甲强龙治疗组总有效率为78%,甲强龙+N-乙酰半胱氨酸治疗组为88%,两组间临床疗效的差异有统计学意义(χ2=4.461,P<0.05)。2治疗组在第1天时血浆TNF-α、IL-6、TGF-β1和CRP水平无统计学差异(P均>0.05)。在第14天时,2治疗组血浆TNF-α、IL-6、TGF-β1和CRP水平较前明显下降,各指标差异均有统计学意义(P均<0.05)。同时,与甲强龙治疗组相比甲强龙+N-乙酰半胱氨酸组血浆TNF-α、IL-6、TGF-β1和CRP水平下降更明显,差异均有统计学意义(P均<0.05)。结论本研究发现在常规使用甲强龙治疗的基础上加用N-乙酰半胱氨酸进行辅助治疗,能有效减轻放射性肺损伤的临床症状,同时降低血浆TNF-α、IL-6、TGF-β1和CRP水平。N-乙酰半胱氨酸对于放射性肺损伤有保护作用,可常规应用于临床治疗。     

MMP-9/TIMP-1在脂多糖和N-乙酰半胱氨酸干预体外孵育胎膜中的表达及意义

目的探讨感染引发早产的可能机制及N-乙酰半胱氨酸(NAC)预防感染引发早产的可行性。方法取20例正常择期剖宫产孕妇(无妊娠合并症及临产征兆)的胎膜在体外进行孵育,共分成5组:0 h组(取下后未经孵育的胎膜),24 h组,48 h组,72 h细菌内毒素脂多糖组(LPS组),72 h LPS NAC组(LPS NAC组)。首先评价体外孵育胎膜的存活力,然后应用逆转录聚合酶链反应(RT-PCR)分别测定5组胎膜的基质金属蛋白酶-9(MMP-9)及金属蛋白酶组织抑制因子-1(TIMP-1)mRNA表达水平的变化,最后比较LPS组和LPS NAC组MMP-9/TIMP-1比值的变化。结果体外孵育胎膜的存活力达到83%±1.9%,RT-PCR可见0 h组及48 h组的MMP-9表达微弱,24 h组的表达较前两组增强(P<0.05),LPS组的表达最强(与24 h组比较P<0.01),LPS NAC组的表达低于LPS组(P<0.01),各组TIMP-1的表达无明显区别(P>0.05),LPS NAC组较LPS组MMP-9/TIMP-1比值明显降低(P<0.01)。结论MMP-9/TIMP-1比值升高可能是感染引发早产的机制之一,NAC有望在预防和治疗早产中发挥作用。     

糖尿病大鼠SOD活性及蛋白表达水平抗氧化剂N-乙酰半胱氨酸对糖尿病大鼠心、肺、肝、肾组织中的组织差异性及抗氧化剂治疗对机体抗氧化状态SOD活性及蛋白表达的影响

摘 要 目的 探究糖尿病大鼠主要脏器SOD活性及蛋白表达水平的变化,并观察抗氧化剂N-乙酰半氨胺酸（N-acetylcysteine,NAC）短期治疗（4周）后对机体抗氧化状态的影响。方法 STZ诱导的糖尿病大鼠（D组,n＝8）每天给予NAC 1.5g/kg灌胃治疗（D T组,n＝8）,正常对照组（C组,n＝8）同时给予同体积生理盐水。4周后,获取心、肺、肝、肾组织,试剂盒检测血浆总SOD、总抗氧化物浓度、脂质过氧化特异性标志物15-F2t-isoprostane及各组织总超氧化物歧化酶（superoxide dismutase,SOD）活性,Western blotting分析SOD亚型Cu/Zn-SOD及Mn-SOD蛋白表达水平。结果 与C组相比,D组大鼠血浆15-F2t-isoprostane与总抗氧化物浓度及心肌组织中总SOD活性显著升高,其它组织显著降低而血浆、肺、肝、肾组织总SOD活性显著降低;心、肺组织中Cu/Zn-SOD蛋白表达水平明显升高,而肝、肾组织中明显降低;肺、肾组织中Mn-SOD蛋白表达水平明显降低,而肝组织明显升高,但心肌组织变化不明显。NAC干预能不同程度逆转上述改变,但进一步降低肾组织Mn-SOD表达。结论 糖尿病大鼠各组织中抗氧化剂NAC对总SOD活性、Cu/Zn-SOD及Mn-SOD蛋白表达水平具有组织差异性,抗氧化剂NAC的影响程度与组织种类相关,能不同程度恢复糖尿病大鼠各组织总SOD活性抗氧化水平,从而起到阻止或延缓糖尿病相关的靶器官功能损害的作用。     

7-b, a novel amonafide analogue, cause growth inhibition and apoptosis in Raji cells via a ROS-mediated mitochondrial pathway

Previous studies have shown that 7-b (6-(dodecylamino)-2-(3-(4-methylpiperazin-1-yl)propyl)-1H-benzo-[de]isoquinoline-1,3(2H)-dione), a novel amonafide-based DNA intercalator, was generated as a new anticancer candidate. However, the effects induced by 7-b and the molecular mechanisms involved remain poorly understood in Burkitt's lymphoma. To shed light on these issues, we have investigated the effects of 7-b on proliferation, cell cycle progression, apoptosis activity and oxidative stress levels of lymphoma Raji cells in vitro. Our results showed that 7-b inhibited the proliferation of Raji cells and induced G1 cell cycle arrest in a dose-dependent manner. Moreover, 7-b treatment triggered programmed cell death, production of reactive oxygen species (ROS) and alteration of the mitochondrial membrane potential (Δψm). Altogether our results showed that 7-b mediated its growth inhibitory effects on Raji cells via the activation of a ROS-mediated mitochondrial pathway and cell cycle checkpoint signaling pathway which subsequently targeted p21.     

Refining the level for anticipated hepatotoxicity in acetaminophen poisoning

Treatment of an acetaminophen overdose with N-acetyl cysteine usually is based on the position of the 4-h acetaminophen (APAP) level on the Rumack-Matthew nomogram; however, there is disagreement on the level at which clinically relevant hepatotoxicity occurs. A retrospective review of all acute adult formulation APAP exposures reported to our poison center between 1986 and 1993 was performed and cases corresponding to the “possible risk or toxicity” range on the nomogram were identified. Our current poison center protocol for APAP poisoning does not recommend treatment with N-acetylcysteine (NAC) in low-risk patients if the 4-h serum APAP level or the extrapolated equivalent falls within the possible toxicity range on the nomogram. Seventeen cases met the inclusion criteria for the study and received no NAC; six additional patients met inclusion criteria but received one or two doses of NAC before therapy was discontinued. No patients in either group demonstrated clinical evidence of hepatotoxicity. This pilot study suggests that patients with no risk factors and APAP levels in the “possible risk” range may not require NAC therapy.     

谷胱甘肽与N-乙酰半胱氨酸对谷氨酸诱导海马神经元损伤的影响

目的观察还原型谷胱甘肽(reducedglutathione,GSH)与N-乙酰半胱氨酸(N-Acetylcysteine,N-NAC)对不同浓度谷氨酸(glutamate,Glu)诱导的海马神经元损害的影响。方法选用新生Wistar大鼠原代培养海马神经元谷氨酸细胞毒性模型,采用台盼蓝活细胞拒染及TUNEL细胞凋亡原位检测等方法比较GSH与NAC对100μmol/L及500μmol/LGlu细胞毒性损伤的影响,并与MK-801比较。结果GSH与NAC能够降低100μmol/LGlu作用下神经元死亡率与凋亡率,NAC组细胞存活率高于同条件下GSH组,其中1mmol/LNAC组神经元存活率达到90.4%±5.2%,与10μmol/LMK-801组相比,差异无统计学意义;在500μmol/LGlu作用下,GSH与NAC则不能增加神经元的存活率,但1mmol/LNAC抗500μmol/LGlu诱导调亡的作用与MK-801相比无明显差异。结论GSH及NAC对轻度Glu细胞毒性神经损伤有保护作用。     

N-acetylcysteine and serum concentrations of lipoprotein(a).

A high plasma concentration of lipoprotein(a) [Lp(a)], a complex of low-density lipoprotein linked by disulphide bridges to apoprotein(a), is correlated with premature atherosclerosis. We determined whether the serum Lp(a) concentration could be decreased in vitro and in vivo by the reducing agent N-acetylcysteine (NAC), a drug used as a mucolytic agent, which acts by cleaving disulphide bonds. High concentrations of NAC (greater than or equal to 8 mg ml-1) resulted in dissociation of the Lp(a) antigen in vitro. However, the plasma level of Lp(a) was not changed by administration of NAC 1.2 g d-1 for 4 weeks in 7 subjects with a median Lp(a) concentration of 14.3 mg dl-1 (range 2.1-21.0 mg dl-1) or by doubling the dose to 2.4 g d-1 for a further 2 weeks. In 12 subjects with a high plasma level of Lp(a), median 87.0 mg dl-1 (range 42.0-201.6 mg dl-1), a small but significant decrease in Lp(a) concentration of 7% (P = 0.02) was observed after administration of NAC in a dose of 1.2 g d-1 for 6 weeks. These results indicate that NAC has only a limited capacity to reduce the concentration of Lp(a), which is not clinically significant.     

Effect of N-acetylcysteine(NAC) treatment on HIV-1 infection: a double-blind placebo-controlled trial

Objective: In a double-blind placebo-controlled trial, human immunodeficiency virus (HIV)-seropositive patients with a CD4 lymphocyte cell count of more than 200 × 10⁶⋅l⁻¹ were randomised to receive either 800 mg N-acetylcysteine (NAC) or placebo for 4 months. Before treatment low plasma cysteine levels, high free radical activity in neutrophils in the presence of autologous plasma – measured by the nitroblue tetrazolium (NBT) test – and increased tumor necrosis factor (TNF)-α levels were found in the HIV positive patients. Results: After treatment the low plasma cysteine level in the NAC group increased to normal, and the decline of the CD4+ lymphocyte count before the study start, was less steep in the NAC group than in the placebo group after treatment. There was also a reduction in TNF-α level. However, NAC had no effect on the radical production by neutrophils, and although it did not increase the CD4+ cell count, it may have decreased the decline in CD4+ cells. Conclusion: Further controlled trials with NAC are needed to devermine whether it has a beneficial effect in the treatment of asymptomatic HIV-infected individuals. Received: 25 October 1995/Accepted in revised form: 15 February 1996     

N-Acetylcysteine ameliorates lithium-induced renal failure in rats.

BACKGROUND: Prolonged lithium treatment may induce progressive deterioration of renal function in humans and experimental animals. N-Acetylcysteine (NAC) has been shown to be effective in the prevention of hypoperfusion and toxin-induced renal failure, but its effect on lithium nephrotoxicity has not been evaluated yet. The purpose of this study was to examine a possible renoprotective effect of NAC against lithium-induced renal failure in a rat model. METHODS: Moderate renal failure was induced in 40 Sprague-Dawley rats using a 5 week protocol including 3 weeks of lithium chloride administration in the drinking water. The animals were divided randomly into two equal groups receiving either 10 mg/kg NAC or saline by two daily intraperitoneal injections. In week 6, the glomerular filtration rate (GFR) was assessed by 99mTechnetium diethylene triaminepentaacetic acid, and serum creatinine, blood urea nitrogen (BUN) and 24 h urinary protein and osmolarity were measured. Kidneys were excised for pathological evaluation. RESULTS: At the end of the lithium protocol, the GFR was significantly higher in the NAC-treated group compared with the control group, 0.92+/-0.35 vs 0.56+/-0.25 ml/min/100 g, respectively, P = 0.002. Serum creatinine and BUN were also significantly lower in the NAC-treated group 1.009+/-0.107 vs 1.143+/-0.118 mg/dl, P = 0.001, and 83.9+/-6.8 vs 88.95+/-7.1 mg/dl, P = 0.28, respectively. The percentages of tubular necrosis and tubular lumen obstruction, evaluated by light microscopy, were significantly lower in the NAC-treated group, P = 0.002 and P = 0.007, respectively. CONCLUSIONS: NAC treatment has a renoprotective effect against lithium-induced renal failure in a rat model.