大鼠肝细胞线粒体周围内质网的三维重建

目的：研究肝细胞线粒体与内质网的空间结构关系。 方法：通过连续超薄切片重建线粒体与其周围内质网的三维模型,结果：连续超薄切片和三维模型显示：除极少量的线粒体与脂滴直接接触外,几乎每个线粒体都被内质网所包裹,大多数线粒体周围既有RER又有小囊泡状SER,少数线粒体则仅有小的SER。这些内质网与线粒体紧贴如同线粒体外壳,二者的间隙小于30nm,其间无任何其它细胞器。结论：肝细胞线粒体通常在内质网包绕下执行生理功能,二者形成的结构和功能紧系的整体。     

辅酶Q_(10)和复方丹参对心肌线粒体呼吸链的保护作用

目的　制备异丙基肾上腺素对心肌损伤模型 ,探讨辅酶Q10 和复方丹参对心肌线粒体呼吸链的保护作用。方法　采用In cheolKim法和Lucile Smith法分别测定对照组 ,异丙肾损伤组 ,丹参保护组和辅酶Q10 保护组的琥珀酸脱氢酶比活力 ,心肌线粒体辅酶Q10 含量等多项指标。结果　复方丹参组和辅酶Q10 组心肌线粒体琥珀酸脱氢酶比活力 ,心肌线粒体辅酶Q10 含量都显著高于异丙肾组。结论　辅酶Q10 和复方丹参对心肌线粒体呼吸链有明显地保护作用。     

Differential effects of zidovudine and zidovudine triphosphate on mitochondrial permeability transition and oxidative phosphorylation

1. The effects of zidovudine (ZDV) and zidovudine triphosphate (ZDV-3P) on Ca²⁺-induced mitochondrial permeability transition (MPT), respiratory control ratio (RCR) and ATP synthesis have been investigated on isolated rat liver mitochondria.
2. ZDV slightly but significantly decreased RCR and ATP synthesis but was ineffective in inhibiting MPT. In contrast, ZDV-3P did not alter RCR and ATP synthesis but strongly inhibited MPT (IC₅₀=3.0±0.9 μM).
3. The effect of ZDV-3P on mitochondrial swelling required a preincubation time. When incubated 10 min with mitochondria, ZDV-3P (8 μM) totally inhibited the rate of swelling.
4. ADP, ATP and atractyloside, which are agents known to interact with the mitochondrial adenine nucleotide carrier (ANC), antagonized the effect of ZDV-3P on mitochondrial swelling. Indeed, the IC₅₀ value of ZDV-3P increased from 3.0 to 17.4, 93.6 and 66.5 μM, in the presence of 20 μM, ADP, ATP or atractyloside, respectively.
5. ZDV-3P did not displace [³H]-ATP from its mitochondrial binding site(s) whereas ADP and atractyloside did, suggesting that ZDV-3P and [³H]-ATP do not share the same binding sites.
6. ZDV-3P did not affect either mitochondrial respiration or ATP synthesis but inhibited Ca²⁺-dependent mitochondrial swelling. It was concluded that mitochondrial toxic effects observed during the chronic administration of ZDV cannot be related to its active metabolite (ZDV-3P).

     

大鼠肝细胞线粒体三维结构的观察与重建

为深入研究大鼠肝细胞线粒体形态特征,本研究以钻石刀连续超薄切片,通过电子显微观察大鼠肝细胞线粒体的三维结构,对特殊形态的线粒体进行三维结构重组。结果表明：球形,椭球形,盘状及杆状等小型线粒体约占线粒体总数的５３．８％,而分枝形及各种不规则形的线粒体约占４１．６％。     

Endogenous and exogenous nitric oxide enhance the DNA strand scission induced by tert-butylhydroperoxide in PC12 cells via peroxynitrite-dependent and independent mechanisms, respectively

A short-term exposure to tert-butylhydroperoxide (tB-OOH) promoted a concentration-dependent formation of DNA single-strand breaks in PC12 cells. These events were paralleled by an increase in the cytosolic concentration of Ca2+ that was in part cleared by the mitochondria. Unlike the extent of Ca2+ mobilization and/or mitochondrial Ca2+ clearance, the DNA strand scission evoked by the hydroperoxide was markedly reduced by the nitric oxide (NO) scavenger 2-phenyl-4,4,5,5-tetramethylimidazolin-1-oxyl-3-oxide (PTIO) or by the NO synthase inhibitor N-nitro-L-arginine methylester (L-NAME). Inhibitors of electron transport (rotenone and myxothiazol), ruthenium red (RR, a polycation which inhibits the calcium uniporter of mitochondria), or peroxynitrite scavengers (Trolox and L-methionine) were as effective as PTIO or L-NAME in inhibiting the DNA-damaging response mediated by tB-OOH. Rotenone, RR or peroxynitrite scavengers did not further reduce the residual DNA cleavage observed following treatment with tB-OOH in L-NAME-supplemented cells. Exogenous NO also increased the DNA damage caused by tB-OOH in L-NAME-supplemented cells and this response was blunted by RR or by inhibitors of electron transport but was insensitive to peroxynitrite scavengers. We conclude that both endogenous and exogenous NO enhance the DNA cleavage generated by tB-OOH in PC12 cells. However, only endogenous NO set the bases for an involvement of peroxynitrite in this DNA-damaging response.     

三七皂苷Rg1对失血性休克大鼠肠上皮细胞线粒体损伤保护作用的研究

 目的观察大鼠失血性休克后肠上皮细胞线粒体编码基因细胞色素氧化酶(COXⅠ，COXⅡ，COXⅢ)mRNA的表达变化，并探讨三七皂苷Rg1(Rg₁)对其保护作用的分子机制，为休克的防治提供实验依据。方法采用失血性休克模型，分离肠上皮细胞后进行RNA的提取，应用RT-PCR检测大鼠失血性休克后及用Rg₁治疗后COXⅠ，COXⅡ，COXⅢ mRNA的表达变化情况。结果大鼠失血性休克1h，COXⅠ，COXⅡ基因表达开始增强，2h表达最强，以后随着休克时间延长，表达又逐渐减弱，失血性休克晚期5 h表达显著低于正常对照鼠(P＜0.01)；Rg1(5 mg·kg^-1)治疗后，可使COXⅠ，COXⅡ mRNA表达显著增强(P＜0.01)。结论失血性休克可引起大鼠肠上皮细胞线粒体编码基因COXⅠ，COXⅡ mRNA的明显改变，Rg1可提高其表达,对失血性休克肠上皮细胞线粒体损伤有明显的保护作用。     

CBN对脑缺血再灌注小鼠线粒体损伤的影响

目的：观察CBN对脑缺血再灌注小鼠的线粒体损伤的影响。方法：分离提纯脑缺血再灌注小鼠脑的线粒体。用分光光度法检测线粒体的膜肿胀度，用激光拉曼光谱检测脑线粒体的生物大分子的变化。结果：小鼠脑缺血再灌注后。其线粒体出现膜肿胀，CBN50、100mg／kg iv对此有明显的抑制作用。各组脑线粒体的Raman和IR光谱基本一致。CBN组与假手术组比较接近。模型组只是在量上有一些差异。结论：CBN对脑缺血再灌注小鼠的线粒体损伤的有一定的保护作用。     

当归总多糖对小鼠肝脏药物代谢酶活性具有调节作用

目的:观察当归总多糖(ASP)对正常及泼尼松龙(PSL)所致肝损伤小鼠肝脏药物代谢酶活性的影响。方法:PSL皮下注射15mg·kg^-1,连续5d造成小鼠肝损伤。酶学测定Ⅱ相酶谷胱甘肽相关酶活性;测定细胞色素P450(CYP)含量、NADPH-细胞色素C还原酶、氨基比林N-脱甲基酶(AMD)及苯胺羟化酶(ANH)活性。结果:ASPig使正常小鼠肝微粒体及线粒体谷胱甘肽S-转移酶(GST)活性升高,肝线粒体谷胱甘肽(GSH)含量、谷胱甘肽还原酶活性无明显改变,对肝微粒体细胞色素P450酶系统有诱导作用。大剂量PSL使小鼠血清ALT明显升高,肝线粒体GSH含量明显下降,上述各项酶活性升高。ASP对PSL所致酶活性及GSH含量改变有恢复作用。结论:ASP具有调节肝脏药物代谢酶活性作用。     

卡托普利对病毒性心肌炎小鼠心肌线粒体结构及其酶活性的影响

目的　研究卡托普利对病毒性心肌炎小鼠心肌线粒体结构和三磷酸腺苷 (ATP)酶活性变化的影响。方法　将雄性Balb/c小鼠随机分为柯萨奇病毒B3 (CVB3 )感染组、CVB3 感染加卡托普利治疗组和对照组。以d3、d14为两个时相点 ,比较线粒体超微结构 ,线粒体Na+ K+ ATP酶、Ca2 + ATP酶活性变化。结果　感染组心肌细胞线粒体结构破坏 ,线粒体Na+ K+ ATP酶、Ca2 + ATP酶活性较对照组显著下降 (P均 <0 .0 1)。卡托普利治疗组各时相点线粒体结构破坏较轻 ,线粒体Na+ K+ATP 酶、Ca2 + ATP酶活性较感染组明显增高 (P均 <0 .0 5 )。结论　病毒性心肌炎早期即可见心肌线粒体结构破坏 ,ATP酶活性下降。卡托普利可有效保护心肌线粒体结构和功能     

心肌线粒体ATP敏感性钾通道开放保护线粒体结构和功能

目的　评价线粒体ATP敏感性钾通道 (mitoKATP)开放剂二氮嗪对缺氧心肌线粒体结构和功能的影响。方法　异丙肾上腺素 (ISO)皮下注射诱发大鼠心肌缺氧损伤 ,观察二氮嗪对线粒体呼吸控制比 (RCR)、膜流动性、磷脂酶A2 和磷脂含量的影响。结果　ISO皮下注射诱发大鼠心肌缺氧损伤后 ,与对照组比较线粒体RCR降低了 2 0 8% (P <0 0 1) ,膜流动性降低了 9 1% (P <0 0 5 ) ,磷脂酶A2 活性增加了14 4 5 % (P <0 0 1) ,磷脂含量下降了 37 5 % (P <0 0 5 ) ,二氮嗪预防性给药后可改善RCR、膜流动性和磷脂含量。结论　二氮嗪可保护心肌缺氧损伤后线粒体膜结构和功能的完整