梗阻性黄疸大鼠肾细胞凋亡及bcl-2表达的作用

目的探讨梗阻性黄疸引起肾损伤过程中细胞凋亡的意义。方法32只雄性SD大鼠随机均分为2组，假手术组（SO组）只暴露腹腔但不结扎胆管，胆总管结扎组（BDL组）以双重结扎胆管中间离断方法制成梗阻性黄疸大鼠模型。于术后行光镜下肾脏病理学检查，琼脂糖凝胶电泳检测肾细胞DNA的断裂形式，测定血清中D-Bil、TBA、GOT、GPT、Cr和BUN的含量，检测尿β2-微球蛋白，流式细胞术检测肾脏细胞凋亡率，免疫组化法检测肾组织凋亡抑制基因bcl-2蛋白的表达。结果BDL组大鼠肾脏细胞凋亡率明显高于SO组（P〈0．05），出现细胞凋亡特征性DNA梯状带；其肾脏细胞bcl-2蛋白的表达阳性细胞率明显高于SO组（P〈0．01），并于术后7d达高峰，14d时bcl-2表达阳性细胞率开始下降。结论梗阻性黄疸大鼠肾功能损害过程中存在肾脏细胞凋亡，梗阻性黄疸可反馈性启动肾小管上皮细胞凋亡抑制基因bcl-2的表达。     

还原型谷胱甘肽在预防糖尿病大鼠勃起功能障碍中的研究

目的探讨还原型谷胱甘肽(GSH)在预防糖尿病大鼠勃起功能障碍中的作用。方法通过腹腔注射链脲佐菌素65mg/kg建立糖尿病大鼠模型,然后随机分成DM组和DM+GSH组,DM+GSH组每天肌肉注射GSH200mg/kg。10周后观察大鼠勃起功能,并获取海绵体组织检测其谷胱甘肽、一氧化氮合酶(NOS)与丙二醛(MDA)水平,用TUNEL法检测细胞凋亡。结果成功建立糖尿病大鼠模型。与未注射GSH的DM组相比,DM+GSH组和正常对照组(C组)勃起功能更好,勃起率分别是20%,62.5%和100%。GSH水平DM+GSH组和C组明显比DM组高,其3组含量每克蛋白分别是(75.83±15.62)、(61.47±8.65)和(35.03±12.29)mg(P<0.05);NOS水平在DM+GSH组每毫克蛋白为(133.9±31.9)U,与正常对照组每毫克蛋白为(142.2±31.2)U相当,但较DM组每毫克蛋白为(58.4±18.9)U高(P<0.05);MDA含量在DM组每毫克蛋白为(3.71±0.62)nmol,明显高于正常对照组和DM+GSH组(P<0.05),这两组每毫克蛋白为(2.08±0.34)nmol和(2.44±0.28)nmol;细胞凋亡率在DM组、DM+GSH组和C组的分别是(22.6±3.6)%、(10.8±1.7)%和(7.2±2.1)%(P<0.05)。结论还原型谷胱甘肽对糖尿病大鼠阴茎组织有较好的抗氧化作用,能减少细胞凋亡,对延缓糖尿病性ED的发生有一定的作用。     

精液FSH、LH、PRL和T水平与精子质量关系的研究

目的探讨人精液中性激素水平与精子质量的关系。方法参照WHO标准方法,进行精子密度、活动率检测,按不同密度和活动率分为4个组。采用ELISA法分析FSH、LH、PRL和T水平。用脱氧核苷酸末端转移酶(TdT)介导的缺口末端标记(TUNEL)法检测生殖细胞的凋亡。结果68例不育者精子密度和活动率随精液性激素水平减少而下降,呈显著性正相关(P均<0.01),生育组精液中FSH、LH、PRL和T水平分别为(1.73±0.15)mIU/ml、(2.28±0.21)mIU/ml、(6.44±0.30)ng/ml、(1.95±0.11)ng/ml,生殖细胞凋亡率为(4.71±1.23)%,与不育组(1.35±0.18)mIU/ml、(1.86±0.32)mIU/ml、(5.96±0.31)ng/ml、(1.55±0.13)ng/ml和(19.36±2.04)%相比有显著性差异(P<0.01)。不育组FSH、LH、PRL、T水平与生殖细胞的凋亡率呈显著性负相关(r分别为-0.89、-0.94、-0.91、-0.98)。结论精液低性激素水平可使睾丸生殖细胞凋亡率增加,精子密度和活率下降而致男性不育。     

Androgen-insensitive prostate cancer cells transiently respond to castration treatment when growing in an androgen-dependent prostate environment

BACKGROUND: Castration-induced involution of the normal prostate is caused by primary effects in the prostate stroma and vasculature, but if this is the case also in tumors is unknown. METHODS: Androgen-independent AT-1 prostate tumor cells were therefore injected into the ventral prostate (VP) in Copenhagen rats. Seven days later when the growing tumor was surrounded by normal VP tissue the rats were castrated and the effect examined 3 and 7 days later. RESULTS: Castration reduced vascular density in the surrounding VP tissue and this was accompanied by tumor cell hypoxia, apoptosis, and temporarily retarded tumor growth. Castration-induced VP tissue regression occurred more rapidly in the contra-lateral than in the tumor-bearing lobe. CONCLUSIONS: Androgen-independent tumor cell respond to castration when growing in an androgen-dependent environment. The presence of a tumor influences the castration response in the surrounding normal tissue. The microenvironment determines how prostate epithelial cells respond to castration.     

The HDAC inhibitor trichostatin A inhibits growth of small cell lung cancer cells

BACKGROUND: An estimated 162,460 people will die of lung cancer in the United States in 2006, making it the leading cause of cancer deaths. Small cell lung cancer (SCLC) accounts for 20% of all lung cancers and exhibits aggressive behavior with early metastases. Current treatments yield five-year survival rates of 5 to 10%, indicating a need for novel therapeutic approaches. Histone deacetylase inhibitors (HDACIs) represent a new class of anticancer agents. Trichostatin A (TSA), an HDACI, has been shown to inhibit growth in several cancers. We hypothesized that TSA may inhibit proliferation of SCLC cells. MATERIALS AND METHODS: Human SCLC DMS53 cells were treated with TSA (0 to 400 nM). Light microscopy was used to assess changes in cell morphology. Western analysis was performed for acetylated histone 4 to confirm HDAC inhibition. The effect of TSA treatment on cellular growth was measured by the MTT assay. Finally, levels of BCL-2, cleaved poly(ADP-ribose) polymerase, p21, and p27 proteins were measured to look for induction of cell cycle arrest and/or apoptosis. RESULTS: DMS53 cells treated with TSA underwent dramatic changes in cell appearance. Treated cells assumed round and spindle shapes with distinct cellular borders. Western analysis demonstrated increased levels of acetylated histone 4. TSA treatment resulted in a dose-dependent inhibition of growth. Lastly, elevated p21, p27, and cleaved poly(ADP-ribose) polymerase along with decreased BCL-2 protein levels were observed. CONCLUSIONS: TSA causes morphological differentiation and dose-dependent inhibition of cell growth via cell cycle arrest and subsequent apoptosis. This suggests that TSA and other HDACIs may represent a new potential therapy for patients with SCLC.     

Effect of the XIAP inhibitor Embelin on TRAIL-induced apoptosis of pancreatic cancer cells

BACKGROUND: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potent inducer of apoptosis in a wide variety of tumor cells, while it has no toxicity for the majority of normal cells.Therefore, TRAIL may be a suitable agent for anticancer therapy. We previously reported that a number of pancreatic cancer cell lines show resistance to TRAIL-induced apoptosis via overexpression of XIAP and FLIP. The present study was conducted to further examine TRAIL-based therapeutic strategies by aiming to restore functional apoptotic pathways in resistant pancreatic cancer cells. METHODS: In various pancreatic cancer cell lines, TRAIL-induced apoptosis was evaluated in the presence or absence of an XIAP-inhibitor (Smac peptide). Second, TRAIL-induced apoptosis was evaluated in TRAIL-resistant AsPC-1 cells with or without FLIP antisense. Third, the combined effect of Smac peptide and FLIP antisense was tested, and the activation of apoptosis-related caspases and poly (ADP-ribose) polymerase was evaluated. Finally, TRAIL-induced apoptosis was evaluated in the presence or absence of FLIP antisense and an XIAP inhibitor (embelin). RESULTS: Smac peptide enhanced TRAIL-induced apoptosis in a dose-dependent manner for several pancreatic cancer cell lines, but showed no effect on TRAIL-resistant AsPC-1 cells. Smac peptide alone had no influence on cell viability. TRAIL-induced apoptosis was restored in TRAIL-resistant AsPC-1 cells by exposure to FLIP antisense, which suppressed the expression of FLIP. The effect of TRAIL was augmented by the combination of FLIP antisense and Smac peptide. Similarly, TRAIL-induced apoptosis was restored by the combination of FLIP antisense and embelin. Activation of apoptotic caspases and cleavage of poly (ADP-ribose) polymerase was observed after sensitization of TRAIL-resistant pancreatic cancer cells. CONCLUSIONS: Pancreatic cancer cells gain resistance to TRAIL-induced apoptosis via expression of the antiapoptotic proteins XIAP and FLIP. Smac peptide and FLIP antisense could restore the apoptotic effect of TRAIL. An XIAP inhibitor, embelin, enhanced the effect of TRAIL in the presence of FLIP antisense. These findings may provide useful information for the development of TRAIL-based therapeutic strategies by restoring functional apoptotic pathways in resistant pancreatic cancer cells. In addition, a low molecular weight XIAP inhibitor like embelin could be a lead compound for the development of effective XIAP inhibitors.     

大鼠急性胰腺炎细胞凋亡与Notch-1表达关系的研究

目的探讨大鼠急性胰腺炎时Notch-1的表达及其与胰腺细胞凋亡的关系。方法用不同浓度的牛磺胆酸钠逆行胆胰管注射分别建立急性轻型胰腺炎（MAP）及急性重型胰腺炎模型（SAP），采用TUNEL、Westernblot以及实时定量PCR的方法分别检测不同类型急性胰腺炎在不同时相的细胞凋亡指数、Notch-1蛋白以及Notch-lmRNA的表达水平变化。结果MAP组在建模后4～24h内细胞凋亡指数均明显升高，但各时点之间细胞凋亡指数相差不大；SAP组在建模4h后细胞凋亡指数最高，其后逐渐下降，两组之间细胞凋亡指数有显著性差异。建模后4h开始，各时点SAP组和MAP组的Notch1表达均有上升，但在SAP组的Notch-l表达明显高于MAP组，两组之间相比有显著差异；MAP组Notch-l表达的峰值时问是建模后12h，而SAP组Notch-1表达的峰值时间是建模后8h。结论不同类型急性胰腺炎细胞凋亡指数及Notch1的表达均有明显差异，Notch-1的过度表达可能通过抑制细胞凋亡而加重急性胰腺炎的病情。     

不同放射剂量的^125I粒子对人低分化胃癌细胞影响的动物实验研究

目的探讨不同放射剂量的^125I粒子对BGC823人低分化胃癌细胞的影响。方法将BGC823人低分化胃癌细胞悬液种植于64只BLAB nu/nu裸鼠的皮下,以制备荷瘤鼠模型。待荷瘤鼠模型饲养3周左右、肿瘤生长至0.7-1.2 cm时,将其随机分为4组：空白对照组、低剂量组、中剂量组及高剂量组（n=16）。其中,空白对照组裸鼠植入空白粒子,低、中及高剂量组分别植入放射剂量为1.48×10^-7、2.22×10^-7及2.96×10^-7 Bq的^125I粒子。分别于粒子植入前、植入后7、14、21及28 d,4组均随机抽取4只荷瘤鼠处死,剥取瘤体称重,并计算肿瘤体积;分别于植入粒子后14d和28d,测量4组荷瘤鼠肿瘤组织的细胞凋亡率和细胞周期因子E（cyclinE）mRNA的表达水平。结果①除空白对照组外（空白对照组的变化不大）,低、中及高剂量组的肿瘤体积和肿瘤质量随时间延长均呈下降趋势。粒子植入后7、14、21及28d,低、中及高剂量组的肿瘤体积和肿瘤质量均小于（轻于）空白对照组（P〈0.05）,且在28 d时,低剂量组的肿瘤体积和肿瘤质量均小于（轻于）中剂量组和高剂量组（P〈0.05）。②14d和28d时,低、中及高剂量组的凋亡率均高于空白对照组（P〈0.05）,而cyclinE mRNA的表达水平均低于空白对照组（P〈0.05）。28d时,低剂量组的凋亡率高于中剂量组和高剂量组（P〈0.05）,而cyclinE mRNA的表达水平却低于该2组（P〈0.05）。同组内与14d比较,28 d时除空白对照组的差异无统计学意义外（P〉0.05）,其余3组的凋亡率均较高（P〈0.05）,而cyclinE mRNA的表达水平均较低（P〈0.05）。结论 ^125I粒子组织间植入可有效抑制人低分化胃癌组织的生长,可抑制其cyclinE mRNA的表达;与其他剂量相比（2.22×10^-7 Bq及2.96×10^-7 Bq）,低剂量（1.48×10-7 Bq）的125I粒子持续照射可诱导BGC823人低分化胃癌细胞的凋亡增加。     

自噬与前列腺癌

自噬作用被认为具有高度复杂性及环境依赖性,在有些肿瘤中表现为肿瘤抑制和促进相对立两方面影响,比如乳腺癌和前列腺癌。本文综述了自噬对前列腺癌的发生、发展及治疗的最新研究进展。重点突出自噬调节在雄激素剥夺期间的影响,讨论了雄激素对前列腺癌细胞自噬作用所产生的调节效应。通过对一些研究的报道结果进行评价、分析,我们认为:自噬抑制并结合抗雄激素治疗对于前列腺癌是非常有前景的新型治疗方法。     

Glutamine downregulates TLR-2 and TLR-4 expression and protects intestinal tract in preterm neonatal rats with necrotizing enterocolitis

Background/Purpose

Toll-like receptor (TLR)-4 and TLR-2 play an essential role in the pathogenesis of necrotizing enterocolitis (NEC). In this study, we investigated the protective effect of glutamine (Gln) in an NEC neonatal rat model, and the potential association with TLR-4 and TLR-2 expression in local intestinal tissues.

Methods

Preterm neonatal rats were randomly divided into 3 groups: normal control; NEC model; and NEC plus Gln intervention. NEC was induced by feeding with artificial milk substitutes, plus exposure to hypoxia and cold stress. All preterm rats were sacrificed at 3 days after birth. The intestinal tissues were taken for pathological analysis. Protein and mRNA expression of TLR-2, TLR-4, and caspase-3 was examined by immunohistochemistry and real-time RT-PCR, respectively.

Results

Compared with the normal control, the NEC neonatal rats showed mucosal injury and upregulated mRNA and protein expression of TLR-2, TLR-4, and caspase-3 in ileum and colon. Gln intervention significantly reduced the mucosal injury and suppressed the upregulated expression of TLR-2, TLR-4, and caspace-3 in the ileum and colon of NEC neonatal rats.

Conclusions

Gln protects the intestinal tract of NEC neonatal rats, which may be associated with the reduction of TLR-2 and TLR-4 expression in intestines