癌痛消方对DEN诱癌大鼠不同时间点凋亡相关蛋白的影响

目的 通过分析癌痛消方(AP)干预二乙基亚硝胺(DEN)诱癌大鼠模型在不同时间点的肝脏组织病理变化、细胞凋亡的相关蛋白表达变化,来探讨癌痛消方治疗原发性肝癌的机制.方法 将50只♂ Wistar大鼠随机分为预防组、模型组(每组20只)和空白对照组(10只),预防组和模型组的大鼠以64 ppm DEN饮水饲养,连续16周.同时,自诱癌之日起,预防组大鼠予以AP灌胃0.2 g·(100 g)-1,qd,每周连续用药6d,给药周期为18周;模型与空白对照组正常饮食,饮水(自来水).分别在4、8、12、16、18周时,随机各取预防组和模型组的4只大鼠、2只空白对照组的,断颈处死,取肝组织(阳性部位)免疫组化法检测Bax、Bcl-2、survivin、Fas、Fasl、caspase-3蛋白的表达情况.结果 空白对照组未见survivin、casepase-3、Fas/Fasl、Bax、Bcl-2蛋白的表达;模型组各时间点均可见凋亡相关蛋白的表达,以凋亡抑制蛋白Bcl-2、survivin表达量较多;AP干预过程可以全程下调survivin、Bcl-2蛋白的表达,上调Fas、casepase、Bax蛋白的表达.结论 AP可以促进受损肝细胞或癌细胞凋亡,其预防和治疗肝癌机理是上调促凋亡蛋白、下调抑凋亡蛋白的表达,促进炎症细胞或肿瘤细胞凋亡.     

苦参碱和氧化苦参碱对二乙基亚硝胺诱发大鼠肝癌作用的影响

目的　研究苦参碱和氧化苦参碱对二乙基亚硝胺诱发大鼠肝癌作用的影响。方法　采用二乙基亚硝胺法诱发大鼠肝癌 ,观察腹腔注射苦参碱 2 5mg·kg-1和氧化苦参碱10 5mg·kg-130d后 ,大鼠肝表面癌结节数、肝 /体重比和血清中丙氨酸氨基转移酶 (ALT)、γ 谷氨酰转肽酶 (γ GT)、碱性磷酸酶 (ALP)的变化。结果　氧化苦参碱组大鼠肝表面癌结节数、肝 /体重比和血清ALT、γ GT明显低于模型组 (P<0 0 5 ) ;苦参碱组大鼠肝表面癌结节数和血清γ GT明显低于模型组 (P <0 0 5 )。结论　苦参碱和氧化苦参碱 ,尤其是氧化苦参碱 ,不仅能保护肝细胞免受损伤 ,而且能抑制肿瘤细胞增长     

蛇葡萄素与苯并芘合用对大鼠肝组织内CYP和GST基因表达的影响

目的观察蛇葡萄素与苯并芘合用对♂SD大鼠肝组织内CYP(cytochrome P450,CYP)和GST(glutathione S-transferase,GST)基因表达的影响。方法♂SD大鼠,蛇葡萄素(二氢杨梅素)250、500mg·kg-1,每日1次连续灌胃15d,d15模型组和2个给药组分别腹腔注射(ip)苯并芘100mg·kg-1。用逆转录-实时荧光定量PCR法检测肝组织内的CYP基因CYP1A1、CYP1A2、CYP1B1和GST基因GST-m1、GST-pi的表达情况。结果与空白组相比,苯并芘组(模型组)可明显诱导肝组织内的CYP1A1、CYP1A2、CYP1B1基因表达(P<0.01),分别是空白对照组的121倍、11倍、684倍,对谷胱甘肽-S转移酶基因GST-m1和GST-pi的表达有抑制趋势,分别是空白对照组的0.79倍和0.82倍;蛇葡萄素(二氢杨梅素)组+苯并芘组可明显诱导肝组织内的CYP1A1、CYP1A2、CYP1B1基因表达(P<0.01),分别是空白对照组的189和289倍、16.9和44.5倍、914和804倍,蛇葡萄素500mg.kg-1+苯并芘组明显诱导谷胱甘肽-S转移酶基因GST-m1和GST-pi的表达,分别是空白对照组的2.18倍(P<0.01)和2.12倍(P<0.05)。与苯并芘组(模型组)相比,蛇葡萄素250mg·kg-1+苯并芘组和蛇葡萄素500mg·kg-1+苯并芘组不影响CYP1B1的基因表达,但明显诱导CYP1A1的基因表达,分别是苯并芘组(模型组)的1.56倍(P>0.05)和2.39倍(P<0.05);明显诱导CYP1A2的基因表达,分别是苯并芘组(模型组)的1.53倍(P<0.05)和4.04倍(P<0.05);蛇葡萄素500mg.kg-1+苯并芘组明显诱导谷胱甘肽-S转移酶基因GST-m1和GST-pi的表达,分别是苯并芘组(模型组)的2.78倍(P<0.01)和2.57倍(P<0.05)。结论与苯并芘合用,蛇葡萄素(二氢杨梅素)可明显诱导CYP1A1、CYP1A2基因和谷胱甘肽-S转移酶基因GST-m1和GST-pi的表达。对CYP1B1基因无影响。表明蛇葡萄素与苯并芘合用可加速苯并芘代谢形成非致癌物而解毒和加速排泄。提示蛇葡萄素可对抗苯并芘的致癌作用。     

低剂量邻苯二甲酸二(2-乙基)己酯对老年大鼠前列腺的促增生作用

目的评价环境暴露剂量的邻苯二甲酸二(2-乙基)己酯(DEHP)对老年大鼠前列腺的促增生作用及机制。方法 32只1.5岁龄老年雄性SD大鼠随机分成4组,每组8只,分别ig给予DEHP(30,90和270μg·kg~(-1))或溶媒,每天1次,连续4周。于末次给药24 h后将大鼠麻醉,而后(1)腹主动脉采血,采用ELISA检测血清中睾酮(T)、雌二醇(E2)和泌乳素(PRL)水平;(2)处死后取前列腺,分叶,称重、测量体积,计算脏器系数;(3)制作前列腺组织病理切片,HE染色后用显微镜观察组织形态改变,并利用显微图像分析软件分析前列腺上皮高度变化。结果与溶媒对照组比较,DEHP 270μg·kg~(-1)组前列腺系数、背侧前列腺质量和背侧前列腺系数均显著增加(P<0.05);DEPH各剂量组腹侧前列腺上皮高度明显升高(P<0.01);DEHP 270μg·kg~(-1)组背侧前列腺上皮高度明显升高(P<0.01);DEHP各剂量组E2,PRL和T水平均无显著改变,但DEHP 30和270μg·kg~(-1)组E2/T比值显著增加(P<0.05)。结论低剂量DEHP对老年大鼠前列腺具有促增生作用,该作用可能与其影响内源性激素的相对水平有关。     

Tumor promoting and co-carcinogenic effects in medium-term rat hepatocarcinogenesis are not modified by co-administration of 12 pesticides in mixture at acceptable daily intake

The purpose of this investigation was to evaluate the possible influence of a mixture of pesticides on medium-term carcinogenesis using improved hepatocarcinogenesis protocols. We performed a 12 commercially available pesticides combination with alachlor, atrazine, carbofuran, chlorpyrifos, diazinon, dicofol, endosulfan, iprodione, mancozeb, maneb, procymidone and rotenone. The mixture was given at 1-fold and 10-fold the acceptable daily intake (ADI) level in a set of Solt–Farber-derived protocols involving diethylnitrosamine, 2-acetylaminofluorene treatments and a partial hepatectomy. Co-carcinogenic effect and promoting activity were evaluated using γ-glutamyl transpeptidase (GGT) positive altered hepatocyte foci, as well, protein and mRNA levels of glutathione S-transferase P (GSTP) in liver extracts as molecular biomarkers of carcinogenic effects. The pesticide treatments when compared to vehicle treatments always produced the same number of hepatocyte lesions and an equal GSTP expression on liver extracts independently of carcinogenic-protocol utilized. On this base, we concluded that the pesticide mixture evaluated in this report does not have tumor promoting activity or co-carcinogenic effect in the rat medium-term liver carcinogenesis. Altogether these data contribute to the confidence that the ADI represents a safe intake level to mixture of pesticides at dietary exposure.     

A study on possible modulating and direct effects of γ2-MSH and ACTH-(1–24) on the cardiovascular system of the rat

In conscious rats, γ₂-melanocyte-stimulating hormone (γ₂-MSH) dose-dependently increases blood pressure and heart rate, whereas adrenocorticotropin-(1–24) [ACTH-(1–24)] dose-dependently decreases blood pressure, an effect which was accompanied by a reflectory tachycardia. As the exact mechanism involved in these cardiovascular effects of the two melanocortins is as yet not known, we undertook a series of experiments to investigate the possibility that these peptides have modulating or direct effect on the cardiovascular system of the rat. In pithed rats γ₂-MSH, administered intravenously (i.v.) in doses of 5–200 nmol/kg, had no significant effect on systolic and diastolic blood pressure and on heart rate, whereas ACTH-(1–24), 5–500 nmol/kg, i.v., dose-dependently decreased blood pressure and increased heart rate. Infusion of γ₂-MSH, 10^–8 M, or ACTH-(1–24), 10^–6 M, in the isolated perfused rat heart did not significantly affect left ventricular pressure or coronary flow. Pretreatment with either γ₂-MSH or ACTH-(1–24) did not modify the responsiveness of the myocardium and coronary vasculature to salbutamol and phenylephrine. Neither γ₂-MSH nor ACTH-(1–24) did affect the vascular contractile machinery of skinned vascular smooth muscles of the rabbit with respect to Ca²⁺ handling in the cell, as measured by its sensitivity to exogenously applied Ca²⁺. γ₂-MSH had no effect on blood pressure and heart rate in pithed rats in which postganglionic sympathetic outflow was stimulated by 1,1-dimethyl-4-phenylpiperazinium (DMPP), nor in pithed rats in which preganglionic sympathetic outflow was stimulated electrically. A dose of 15 nmol/kg ACTH-(1–24) had no significant influence on preganglionic outflow to the cardiac and vascular structures in pithed rats. These data show that γ₂-MSH does not exert its cardiovascular effects via a peripheral site of action at the level of the vascular system and the heart, nor directly on pre- or postganglionic sympathetic outflow. These results are in support for the notion that the peptide acts via a brain region localised outside the blood-brain barrier. The acute depressor effect of ACTH-(1–24), however, seems to be due to a direct effect on the vasculature in the periphery. Received: 28 October 1997 / Accepted: 23 April 1998     

Evaluation of cytotoxicity and oxidative DNA damaging effects of di(2-ethylhexyl)-phthalate (DEHP) and mono(2-ethylhexyl)-phthalate (MEHP) on MA-10 Leydig cells and protection by selenium

Di(2-ethylhexyl)-phthalate (DEHP) is the most abundantly used phthalate derivative, inevitable environmental exposure of which is suspected to contribute to the increasing incidence of testicular dysgenesis syndrome in humans. Oxidative stress and mitochondrial dysfunction in germ cells are suggested to contribute to phthalate-induced disruption of spermatogenesis in rodents, and Leydig cells are one of the main targets of phthalates’ testicular toxicity. Selenium is known to be involved in the modulation of intracellular redox equilibrium, and plays a critical role in testis, sperm, and reproduction. This study was aimed to investigate the oxidative stress potential of DEHP and its consequences in testicular cells, and examine the possible protective effects of selenium using the MA-10 mouse Leydig tumor cell line as a model. In the presence and absence of selenium compounds [30 nM sodium selenite (SS), and 10 μM selenomethionine (SM)], the effects of exposure to DEHP and its main metabolite mono(2-ethylhexyl)-phthalate (MEHP) on the cell viability, enzymatic and non-enzymatic antioxidant status, ROS production, p53 expression, and DNA damage by alkaline Comet assay were investigated. The overall results of this study demonstrated the cytotoxicity and genotoxicity potential of DEHP, where MEHP was found to be more potent than the parent compound. SS and SM produced almost the same level of protection against antioxidant status modifying effects, ROS and p53 inducing potentials, and DNA damaging effects of the two phthalate derivatives. It was thus shown that DEHP produced oxidative stress in MA-10 cells, and selenium supplementation appeared to be an effective redox regulator in the experimental conditions used in this study, emphasizing the critical importance of the appropriate selenium status.