烫伤后IL-6和IL-1α对大鼠外周血中性粒细胞凋亡的影响

目的:研究严重烫伤后血IL-6和IL-1α对中性粒细胞(PMN)凋亡的影响。方法:复制30%体表面积Ⅲ度烫伤大鼠模型;分离PMN,TUNEL荧光标记,流式细胞仪分析细胞凋亡;PMNcaspase3活性以荧光免疫吸附酶法测定;血清IL-6和IL-1α水平以酶联免疫法测定。结果:血清IL-6水平(μg/L)在伤后各组(3、6、12、24、48h依次分别为9.14±1.16、12.49±1.14、3.01±0.75、1.41±0.28和1.56±0.43)和IL-1α水平(ng/L)在伤后3、6、12h组(90.08±8.39、320.93±14.48和47.84±5.19)均分别显著高于伤前对照组IL-6(0.24±0.07)和IL-1α(27.65±4.86)水平(P<0.05);伤后各组PMN凋亡率(%)按时点依次为9.89±2.00、4.98±1.35、1.31±0.72、2.49±1.87和6.88±1.13显著少于伤前组13.66±3.88(P<0.05);PMNcaspase-3的活性测定结果与PMN的凋亡表现相一致。结论:大鼠烫伤后外周血PMN凋亡明显延迟;IL-6和IL-1α等细胞因子是重要的影响因素,减少细胞内caspase-3的激活可能是其机制之一。     

丙戊酸钠通过激活内源性凋亡途径诱导乳腺癌细胞凋亡的实验研究

目的探讨丙戊酸钠（VPA）诱导乳腺癌细胞凋亡的作用。方法乳腺癌细胞株MCF-7细胞分为0.75～4.0 mmoL/L VPA实验组、对照组（不加VPA）及VPA与caspase抑制剂共同作用组。Annexin V-PI双染法流式细胞术检测细胞凋亡,间接免疫荧光法定量分析及分光光度法检测caspase- 3、caspase-8、caspase-9蛋白丰度和活性,探讨VPA诱导凋亡的机制,同时检测VPA与caspase-3、caspase- 8、caspase-9特异性抑制剂协同作用后细胞凋亡的变化来加以验证。结果各浓度VPA干预MCF-7细胞48 h后,细胞凋亡率显著增加,caspase-3、caspase-9活性升高、蛋白表达明显上调,与对照组相比有显著差异（F=552.1、610.9、312.8、222.8、70.3,均P〈0.001）;而caspase-8活性及蛋白表达未见明显改变;1.5、3.0 mmol/L VPA与caspase-3、caspase-9相应特异性抑制剂共同作用组,细胞凋亡率均较VPA组显著降低（t=109.0、28.7、18.7、32.3,均P〈0.005）;VPA与caspase-8特异性抑制剂共同作用组细胞凋亡率与VPA组比较无明显改变（t=1.03、2.32,均P〉0.05）。结论VPA可通过激活caspase-9介导的内源性凋亡途径,明显诱导乳腺癌细胞凋亡,具有较好的临床应用价值。     

c-FLIP(S) reduces activation of caspase and NF-kappaB pathways and decreases T cell survival

Effective stimulation of NF-kappaB in T cells following TCR ligation requires the activity of caspase-8. The active caspase-8 complex includes the paracaspase, MALT1, and Bcl-10, which connect to the NF-kappaB pathway. It has been less clear what regulates the level of caspase-8 activity during T cell activation. A likely candidate is cellular FLIP (c-FLIP), an enzymatically inert caspase-8 homologue. Two alternatively spliced forms of c-FLIP exist, a long form (c-FLIP(L)) and a short-form (c-FLIP(S)). The latter lacks the C-terminal caspase-like domain. c-FLIP(L) can heterodimerize with and activate caspase-8 through an activation loop in the C terminus of c-FLIP(L). Here we show that, in contrast to c-FLIP(L), c-FLIP(S) inhibits activation of caspase-8 in T cells, and consequently reduces recruitment of MALT1 and Bcl-10 to the active caspase complex. This results in reduced activity of NF-kappaB. Consequently, T cells from c-FLIP(S)-transgenic mice undergo more rapid cell death both spontaneously and after activation. The findings suggest that c-FLIP(S) functions to reduce the expansion of T cells during an immune response.     

生精细胞凋亡与男性不育症

近年来,随着对细胞凋亡认识的不断加深,医疗及科研工作者越来越关注细胞凋亡与疾病之间的联系,并为此展开了一系列的试验。现已明确凋亡是人体正常生长发育所必需的,但其失衡也与许多疾病的发生关系密切。生精细胞凋亡过度可能是导致男性不育的重要原因之一。而caspases是细胞凋亡末期的共同通道,对细胞凋亡起着关键性的作用。因此,对caspases家族的活性调控研究可能为治疗男性不育提供新的诊断标准及治疗途径。     

Cadmium exposure induces mitochondria-dependent apoptosis in oligodendrocytes

Cadmium toxicity has been associated with learning disabilities and Parkinsonian symptoms in humans. We have previously shown that cultured oligodendrocytes are directly damaged by cadmium exposure. Here, we characterized the molecular mechanisms underlying cadmium-induced cell death in oligodendrocyte progenitors (OLP). Cadmium caused a concentration-dependent decrease in cell viability as assessed by mitochondrial dehydrogenase activity and by the cellular release of lactate dehydrogenase (LDH). A short exposure (1 h) to cadmium (25–100 μM), followed by several hours of recovery, produced a predominant apoptotic mechanism of cell death, involving the mitochondrial intrinsic pathway, as evidenced by nuclear condensation, DNA fragmentation, bax integration into the outer mitochondrial membrane, cytochrome c release, and activation of caspases-9 and -3. Pretreatment of OLPs with the pan-caspase inhibitor, zVAD-fmk, prevented caspase-3 activation but only slightly reduced cell death 11 h after cadmium exposure and failed to prevent cadmium-induced bax insertion into the mitochondrial membrane. In contrast, the anti-oxidant N-acetyl cysteine blocked caspase-3 activation and significantly protected OLPs from cadmium-induced cell death. Continuous exposure (18–48 h) of OLPs to low micromolar concentrations (0.001–25 μM) of cadmium significantly decreased mitochondrial metabolic activity, increased LDH leakage starting at 5 μM and maximally activated caspase-3. These results suggest that cadmium induces OLP cell death mainly by apoptosis, and at higher concentrations or with prolonged exposure to the heavy metal there is an increase in cytoplasmic membrane damage, an index of necrosis. More importantly, transient exposure to cadmium is sufficient to damage OLPs and could in principle impair myelination in the neonate.     

The pyranoxanthone inophyllin A induces oxidative stress mediated-apoptosis in Jurkat T lymphoblastic leukemia cells

Inophyllin A (INO-A), a pyranoxanthone isolated from the roots of Calophyllum inophyllum represents a new xanthone with potential chemotherapeutic activity. In this study, the molecular mechanism of INO-A-induced cell death was investigated in Jurkat T lymphoblastic leukemia cells. Assessment of phosphatidylserine exposure confirmed apoptosis as the primary mode of cell death in INO-A-treated Jurkat cells. INO-A treatment for only 30 min resulted in a significant increase of tail moment which suggests that DNA damage is an early apoptotic signal. Further flow cytometric assessment of the superoxide anion level confirmed that INO-A induced DNA damage was mediated with a concomitant generation of reactive oxygen species (ROS). Investigation on the thiols revealed an early decrease of free thiols in 30 min after 50 μM INO-A treatment. Using tetramethylrhodamine ethyl ester, a potentiometric dye, the loss of mitochondrial membrane potential (MPP) was observed in INO-A-treated cells as early as 30 min. The INO-A-induced apoptosis progressed with the simultaneous activation of caspases-2 and -9 which then led to the processing of caspase-3. Taken together, these data demonstrate that INO-A induced early oxidative stress, DNA damage and loss of MMP which subsequently led to the activation of an intrinsic pathway of apoptosis in Jurkat cells.     

依达拉奉对大鼠急性脊髓损伤后Caspase-3、Bcl-xl表达影响

目的:研究依达拉奉对大鼠急性脊髓损伤后Caspase-3、Bcl-xl表达影响,探讨其对脊髓损伤后神经细胞的保护作用机制。方法:80只SD大鼠,随机分为假手术组(n=16),ASCI盐水组(n=32)和ASCI治疗组(n=32),采用改良的Allen法,制成中度脊髓损伤大鼠模型;各组按术后3h、6h、24h、48h随机分为4个亚组;检测各亚组脊髓组织MDA的含量;以免疫组化检测各亚组脊髓组织Caspase-3表达和Bcl-xl基因表达。结果:ASCI盐水组MDA含量、Caspase-3阳性细胞表达和Bcl-xl蛋白表达水平均明显高于假手术组;与盐水组相比,依达拉奉治疗组MDA含量和Caspase-3阳性细胞表达水平均下降,而Bcl-xl蛋白表达水平显著增高。结论:依达拉奉可抑制脊髓损伤后神经细胞凋亡,此作用可能与其减轻氧化激化、减弱Caspase-3表达和增强Bcl-xl表达水平有关。     

放射治疗对大鼠新月体性肾炎进程的影响

目的 探讨放射治疗对大鼠新月体性肾炎进程的影响.方法 雄性SD大鼠随机分成:(1)对照组(n=12);(2)新月体性肾炎组(n=23),肾毒性血清(NTS)静脉注射;(3)放射治疗组(n=55),NTS注射后第6、13、20、27天双肾接受0.5Gy X射线单次局部照射.照射后不同时间点处死各组动物,分别以NTS7dRa1d、NTS14dRa1d、NTS21dRa1d、NTS28dRa1d来命名NTS注射后第6、13、20、27天接受肾脏局部照射的治疗组动物.结果 与相同时间点新月体性肾炎组比较,放射治疗组中NTS7dRa1d、NTS14dRa1d大鼠血清肌酐水平、肾小球细胞增殖度、新月体比例和肾小球硬化率在照射后第8天明显降低(P<0.05),第15、22天显著性降低(P<0.01),肾小管间质病变亦明显减轻.免疫组化表明,与相同时间点新月体性肾炎组比较,NTS7dRa1d、NTS14dRa1d大鼠肾内增殖细胞核抗原(PCNA)阳性细胞及巨噬细胞标识ED-1阳性的巨噬细胞明显减少(P<0.05),TUNEL阳性凋亡细胞显著增加(P<0.05),半胱氨酸蛋白酶3(caspase 3)及半胱氨酸蛋白酶7(caspase 7)肾内表达亦明显增强.连续切片提示:ED-1阳性的巨噬细胞同时具有TUNEL阳性表达.免疫印迹(Western blot)表明,放射治疗组caspase 3及caspase 7蛋白水平明显升高,并且p53基因蛋白水平亦显著性升高.结论 放射治疗通过p53依赖性途径诱导细胞凋亡有效抑制大鼠新月体性肾炎进程.     

c-Jun氨基末端激酶与caspase在细胞凋亡中的作用及相互关系

丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)是信号从细胞表面转导到细胞核内部的重要传递者.在真核细胞中,已确定出4条MAPK信号转导通路[1],即细胞外调节蛋白激酶(extracellular regulated protein kinases,ERK) 通路、c-Jun 氨基末端激酶(c-Jun N-terminal kinase,JNK)通路、P38通路及ERK5通路.JNK也称为应激蛋白激酶,参与应激反应和细胞死亡[2].     

Activation of several concurrent proapoptic pathways by sulforaphane in human colon cancer cells SW620

Despite the reported cytotoxicity and apoptosis-inducing properties of sulforaphane (SF) in colon cancer cells, the details concerning individual mechanisms and signaling cascades underlying SF-mediated apoptosis remain unclear. To understand different aspects of SF-induced proapoptic signaling in advanced colon carcinoma, we investigated its mechanisms in metastatic SW620 cell line. Our results indicate that in SW620 cells SF acts to induce multivariate cascades including DNA-damage response pathway whose proapoptotic signaling is nevertheless reduced owing to the mutant status of p53 and caspase-2-JNK pathway which seems to complement and enhance p53-dependent signaling, however only in wild-type p53. Furthermore, both pathways require the active role of mitochondria and do not depend on generation of ROS, making SF an attractive chemopreventive agent whose antitumor properties should be further investigated in colon cancer.