下丘脑弓状核损毁对大鼠某些组织Se—GSH—Px活性和LPO水平的影响

本研究证实,弓状核损伤后大鼠睾丸和肾上腺谷胱甘肽过氧化酶(Se—GSH—Px)活性明显降低(P<0.05),而脂质过氧化物(LPO)水平在两种组织中都不同程度增高;肝脏中两种物质都非常明显增高(P<0.01);脾脏中两者变化不明显。提示,下丘脑弓状核损毁可影响大鼠睾丸、肾上腺和肝脏Se—GSH—Px活性和LPO水平变化,而对脾脏无影响。     

年龄相关性黄斑变性血清过氧化脂质水平与超氧化物歧化酶活性的相关性研究

对３５例年龄相关性黄斑变性（ＡＭＤ）和３４例健康对照者进行过氧化脂质（ＬＰＯ）水平和血清超氧化物歧化酶（ＳＯＤ）活性的测定。ＬＰＤ检测采用测定其最终产物之一丙二醛（ＭＤＡ）含量。结果显示ＡＭＤ组ＭＤＡ高于对照组，差异显著（Ｐ＜０．０５）。ＳＯＤ在ＡＭＤ组偏低，但无统计学意义（Ｐ＞０．０５）。正常对照组ＭＤＡ与ＳＯＤ呈负相关（ｒ＝－０．４１３９，Ｐ＜０．０５），而ＡＭＤ组则否。说明ＡＭＤ患者抗氧化能力减弱，导致脂质过氧化损害。低锌可能是ＳＯＤ降低原因，应用抗氧化剂治疗是有益的。     

针刺对主动脉粥样硬化兔自由基系统的影响

对家兔用免疫损伤加高胆固醇喂食造成主动脉粥样硬化模型，针刺内关等腧穴并观察其血中过氧化脂质（ＬＰＯ）、超氧化物岐化酶（ＳＯＤ）、谷胱苷肽过氧化物酶（ＧＳＨ－ｐｘ）等变化。疗程效应表明，针刺内关等穴可显著提高血中ＳＯＤ、ＧＳＨ－ｐｘ活性，并使主动脉病变减轻；针刺前后ＳＯＤ、ＧＳＨ－ｐｘ的即刻变化，同样显示其活性迅速提高。提示针刺内关等穴对冠心病的治疗作用与其增强氧自由基系统的酶类活性有关。     

Ovariectomy induces oxidative stress and impairs bone antioxidant system in adult rats

BACKGROUND: There is increasing evidence suggesting the role of free radicals in bone resorption and bone loss. Ovariectomized rats have been used as the animal model for the study of osteoporosis. Oxidative stress due to reactive oxygen species (ROS) can cause oxidative damage to cells. Cells have a number of defense mechanisms to protect themselves from the toxicity of ROS. Even though, there are studies portraying the role of free radicals in bone loss, the defense mechanism adapted by bone in ovariectomized animals remains obscure. We investigated the impact of ovariectomy (OVX) on the bone antioxidant system in rats. METHODS: Sixty days after bilateral OVX, the rats were killed and the femora were removed, the tissue homogenates were made and used for the estimation of superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S transferase (GST), lipid peroxidation (LPO) and hydrogen peroxide (H(2)O(2)). RESULTS: The levels of LPO and H(2)O(2) were increased and enzymatic antioxidants like SOD, GPx, GST were decreased in ovariectomized animals when compared to sham-operated control rats. The calculated correlation coefficient demonstrated strong correlation (0.905) between the production of H(2)O(2) and LPO in the femur bone. A strong inverse (-0.945) correlation was observed between H(2)O(2) production and SOD activity. CONCLUSIONS: OVX induces oxidative stress in the femur bone of rats.     

5-HT、自由基在蛛网膜下腔出血时致脑血管痉挛的实验研究

本实验将血液与脑脊液(CSF)孵育5天,5-HT无明显减少。5-HT对基底动脉与股动脉均具有强烈的收缩作用(+++)。电镜检查产生痉挛动脉的内皮细胞与中膜平滑肌细胞,发现有空泡变性。5-HT引起痉挛动脉壁的6-酮-PGF_1、血栓烷B_2(TXB_2)、前列腺素E_2(PGE_2)、过氧化脂质(LPO)均无变化。放射免疫测定发现正常情况下,基底动、静脉6-酮-PGF_1含量明显高于其他部位血管,而TXB_2、PGE_2各血管无明显差异。氧合血红蛋白(OxyHb)可诱发基底动脉强烈收缩(+++)。电镜检查痉挛动脉的内皮细胞与中膜平滑肌细胞,见有空泡变性;LPO升高,6-酮-PGF_1下降。但OxyHb不诱发股动脉的收缩(一)或只引起轻微收缩(±);LPO升高,6-酮-PGF_1无变化;电镜检查动脉壁正常。应用不同的自由基清除剂与OxyHb混合,然后作用于基底动脉。只有羟自由基(·OH)清除剂甘露醇有缓解脑血管痉挛的作用。     

几种药物对血流再通后缺血脑组织代谢的影响

本实验利用改良的Pulsinelli“大鼠模型,研究葡萄糖、胰岛素及山莨菪碱对血流再通后,缺血脑组织中的乳酸、葡萄糖、LPO、TXB_2及6-酮-PGF_(1α)含量的影响。结果:投用葡萄糖后,乳酸、LPO及TXB_2均明显增加,6-酮-PGF_(1α)明显减少;而投用胰岛素后,乳酸、LPO则明显减少,6-酮-PG_(1α)。明显增加;投用山茛菪碱后LPO及TXB_2明显减少。电镜检查发现,投用葡萄糖组的缺血性脑损害最为严重,而在其它组损害较轻。上述资料提示,葡萄糖可加重缺血性脑损害,而胰岛素及山莨菪碱对缺血脑组织具有保护作用。本文也讨论了这些药物的作用机制。     

急性脑中风并多脏器功能衰竭患者红细胞SOD和血浆LPO测定

对32例急性脑中风，26例急性脑中风并多器官功能衰竭（MOF）和40例同年龄健康者的红细胞SOD和血浆LPO进行测定。结果：健康对照组、急性脑中风组和急性脑中风并MOF组的红细胞SOD活性依次降低（P＜0．01），血浆LPO水平依次升高（P＜0．01）。结果提示：氧自由基参与急性脑中风和急性脑中风并MOF的病理生理过程。故血中SOD和LPO的动态变化，可作为判断患者病情发展及预后的指标。     

黄芪防风药对耐缺氧及抗氧化的实验研究

实验结果显示：黄芪防风药对水煎液能显著提高断头小鼠急性脑缺氧的耐缺氧能力；能显著抑制体外ＮＡＤＰＨ－ＶｉｔＣ诱发的大鼠肝微粒体脂质过氧化物的形成     

Radiomodulatory influence of Rajgira (Amaranthus paniculatus) leaf extract in Swiss albino mice

Radiomodulatory effect of Rajgira leaf extract against 6, 8 and 10 Gy gamma radiation has been evaluated by 30 day survival of Swiss albino mice. Animals of control groups (untreated irradiated) showed diarrhoea, ruffled hairs, epilation, facial edema and consistent decrease in body weight. These signs were less severe/absent in experimental groups (Rajgira treated irradiated), and recovery in body weight was also early and faster. Thirty day survivability was 66 per cent in control group, exposed to 6 Gy, whereas no animal survived beyond 14 and 10 days after irradiation with 8 and 10 Gy gamma rays respectively. However, 100, 60 and 25 percent survivability was observed in experimental groups at 6, 8 and 10 Gy respectively. Regression analysis of survival data showed that the LD50/30 values were 6.33 and 8.62 Gy for control and experimental animals respectively. The dose reduction factor (DRF) was computed as 1.36. A significant decrease in GSH content and increase in LPO level was observed in control animals, whereas in Rajgira pretreated irradiated animals the level of GSH was recorded significantly higher but LPO level decreased significantly. The results from the present study suggest that Rajgira pretreatment provide protection against gamma irradiation in mice.     

Antioxidant, prooxidant and cytotoxic activity of hydroxylated resveratrol analogues: structure-activity relationship

Resveratrol (trans-3,4',5-trihydroxystilbene), a naturally occurring hydroxystilbene, is considered an essential antioxidative constituent of red wine possessing chemopreventive properties. However, resveratrol and even more its metabolite piceatannol were reported to have also cytostatic activities. In order to find out whether this is related to antioxidative properties of those compounds, we synthesized five other polyhydroxylated resveratrol analogues and studied structure-activity relationships between pro-/antioxidant properties and cytotoxicity. Radical scavenging experiments with O(2)(*-) (5,5-dimethyl-1-pyrroline-N-oxide/electron spin resonance (DMPO/ESR)) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) (photometry) revealed that 3,3',4',5-tetrahydroxystilbene (IC(50): 2.69microM; k(9): 443000M(-1)s(-1)), 3,4,4',5-tetrahydroxystilbene (IC(50): 41.5microM; k(9): 882000M(-1)s(-1)) and 3,3',4,4',5,5'-hexahydroxystilbene (IC(50): 5.02microM), exerted a more than 6600-fold higher antiradical activity than resveratrol and its two other analogues. Furthermore, in HL-60 leukemic cells hydroxystilbenes with ortho-hydroxyl groups exhibited a more than three-fold higher cytostatic activity compared to hydroxystilbenes with other substitution patterns. Oxidation of ortho-hydroxystilbenes in a microsomal model system resulted in the existence of ortho-semiquinones, which were observed by ESR spectroscopy. Further experiments revealed that these intermediates undergo redox-cycling thereby consuming additional oxygen and forming cytotoxic oxygen radicals. In contrast to compounds with other substitution patterns hydroxystilbenes with one or two resorcinol groups (compounds 1 and 3) did not show an additional oxygen consumption or semiquinone formation. These findings suggest that the increased cytotoxicity of ortho-hydroxystilbenes is related to the presence of ortho-semiquinones formed during metabolism or autoxidation.