N-乙酰半胱氨酸对大鼠肝脏缺血再灌注损伤NF-κ B和ICAM-1表达的影响

目的：探讨大鼠肝脏缺血再灌注损伤NF-κB和ICAM-1表达情况及NAC的保护作用机制。方法：45只雄性SD大鼠随机分成三组：假手术组（Sham组,n=5）;缺血再灌注损伤组（I/R组,n=20）缺血60min后分别再灌注1、3、6、12h;N-乙酰半胱氨酸组（NAC组,n=20）：先自阴茎背静脉给大鼠注射溶于生理盐水的NAC,20min后再按I/R组处理。在各规定的再灌注时间点,分别采用western-blot和免疫组化方法测定肝组织中NF-κB和ICAM-1的表达。结果：I/R组和NAC组再灌注1、3、6、12h后,NF-κB的表达均明显高于Sham组（p〈0.01）,于再灌注3h达到高峰;ICAM-1的表达均明显高于Sham组（p〈0.01）,于再灌注6h达到高峰。NAC组再灌注1、3、6h与I/R组相同时间点比较：NF-κB和ICAM-1的表达均低于I/R组（p〈0.05）。NAC组再灌注12h与I/R组相同时间点比较：NF-κB和ICAM-1的表达虽然在数值上有所减少,但统计学上无差异（p〉0.05）。结论：大鼠肝脏缺血再灌注后NF-κB和ICAM-1表达增加,NAC可抑制NF-κB激活,减少ICAM-1表达减轻大鼠肝脏缺血再灌注损伤。     

姜黄素对沙土鼠脑缺血/再灌注损伤的海马CA1区细胞凋亡和即早基因c-fos、c-jun、NF-κB表达变化的关系

目的探讨姜黄素对沙土鼠海马CA1区缺血/再灌注损伤的影响及与即早基因c-fos、c-jun、NF-κB在海马CA1区表达的关系及意义。方法采用沙土鼠双侧颈总动脉阻断缺血/再灌注损伤模型。动物随机分为假手术组(SH)、脑缺血/再灌注组(I/R)、姜黄素组(CU)、溶剂对照组(SC);每组据再灌注时间点的不同又分多个亚组,每组6只动物。在预定时间点行开阔法行为学检查、TUNEL法海马CA1区凋亡细胞检测,免疫组织化学ABC法测定c-fos、c-jun、NF-κB蛋白在海马CA1区的动态变化。结果姜黄素可显著减少沙土鼠探索活动及海马CA1区凋亡锥体细胞数量(P<0.01)、诱导Fos蛋白及抑制Jun和NF-KB蛋白的表达(P<0.01)。结论姜黄素具有脑保护作用,调控即早基因c-fos、c-jun和NF-κB的表达可能是作用机制之一。     

缺血后低压灌注处理对兔脊髓缺血/再灌注损伤的保护及ERK传导通路在其中的作用

目的 评价细胞外信号调节激酶 (ERK)传导通路对低压灌注缺血后处理兔缺血/再灌注损伤脊髓的保护作用及机制.方法 84只日本大耳白兔随机分为7组,分别为C组(对照组,不给予缺血后处理)、PB组(缺血后处理组)、D、PD1、PD3、PD9组分别于腹主动脉开放前1min鞘内注射DMSO 20μl、PD98059 1μg(20μl)、PD98059 3μg(20μl)、PD98059 9μg(20μl)之后进行缺血后处理及PD组(腹主动脉开放前1min鞘内注射PD98059 3μg(20μl),之后不行缺血后处理).分别于再灌注1、3、7、28d时采用Tarlov评分评价后肢运动功能.每组于再灌注1d时处死6只动物,取L3～5节段脊髓组织,采用Western blot技术测定p-ERK1/2 及Bcl-2,Bax蛋白表达.结果 1、3、7、28d,PB组Tarlov评分明显高于其它各组(P<0.05),缺血后处理可以明显上调p-ERK1/2及凋亡抑制基因Bcl-2的表达,下调凋亡促进基因Bax的表达(P<0.05),而这些调节作用可以被ERK1/2阻断剂PD98059抑制.结论 p-ERK1/2在低压灌注缺血后处理对缺血再灌注损伤脊髓的保护中起重要作用.     

西比灵干预对沙鼠脑缺血再灌注后核因子-κB、单核细胞趋化蛋白-1表达的影响

目的：研究西比灵对沙鼠脑缺血再灌注后核因子-κB、单核细胞趋化蛋白-1表达的影响。方法：52只健康蒙古沙鼠随机分为正常对照组、假手术组、脑缺血再灌注（I/R）组、西比灵干预组,I/R组及西比灵干预组再分为6h、1d、3d、7d四个亚组。通过夹闭双侧颈总动脉10 min后松夹,建立沙鼠全脑缺血再灌注模型。采用免疫组化的实验方法检测各组脑组织中NF-κBp65、MCP-1的表达。结果：缺血再灌注后各时间点I/R组及西比灵干预组,NF-κBp65的表达量显著高于正常对照组及假手术组（均P〈0.01）,且出现MCP-1阳性表达。与I/R组比较,西比灵干预组在I/R后6h、1d,NF-κBp65、MCP-1表达下调（均P〈0.05）。结论：在脑缺血再灌注早期,西比灵能够下调NF-κBp65、MCP-1的表达,减轻局部炎症反应及脑缺血再灌注损伤。     

姜黄素对自发性高血压大鼠脑缺血/再灌注后海马神经元损伤及RANTES表达的影响

目的：探讨姜黄素对自发性高血压大鼠（SHR）脑缺血/再灌注后认知功能及海马神经元损伤和调解活化正常T细胞表达和分泌的趋化因子（RANTES）表达的影响。方法：雄性Wistar-Kyoto大鼠（WKY）和SHR,随机分为5组：假手术组（W-Sham、S-Sham）、缺血/再灌注组（W-I/R、S-I/R）和姜黄素组（S-Cur）,各组按再灌注时间分为3h、12 h、1 d、3 d、7 d 5个亚组（n=6）。采用四血管阻断法制备全脑缺血/再灌注模型,HE染色观察海马CA1区神经细胞形态,Nissl染色计数海马CA1区平均锥体细胞密度,ELISA法检测海马RANTES表达,于再灌注后7 d观察行为学。结果：与假手术组大鼠比较,缺血/再灌注组大鼠学习和记忆能力下降,海马CA1区神经元损伤加重,海马RANTES蛋白表达上调（P〈0.05）;与W-I/R大鼠比较,S-I/R大鼠学习和记忆能力下降,海马CA1区神经元损伤加重,海马RANTES蛋白表达上调（P〈0.05）;姜黄素组大鼠学习和记忆能力明显改善,海马CA1区神经元损伤减轻,海马RANTES蛋白表达下调（P〈0.05）。结论：缺血/再灌注更易导致SHR海马神经元损伤。姜黄素减轻SHR脑缺血/再灌注海马神经元损伤,其机制可能与抑制RANTES蛋白的表达有关。     

姜黄素对沙土鼠脑缺血／再灌注损伤的海马CAl区细胞凋亡和即早基因c-fos、c-jun、NF-κB表达变化的关系

目的：探讨姜黄素对沙土鼠海马CAl区缺血／再灌注损伤的影响及与即早基因c-fos、c-jun、NF-κB在海马CAl区表达的关系及意义。方法：采用沙土鼠双侧颈总动脉阻断缺血佴灌注损伤模型。动物随机分为假手术组（SH）、脑缺血佴灌注组（VR）、姜黄素组（CU）、溶剂对照组（SC）;每组据再灌注时间点的不同又分多个亚组,每组6只动物。在预定时间点行开阔法行为学检查、TUNEL法海马CAl区凋亡细胞检测,免疫组织化学ABC法测定c-fos、c-jun、NF-κB蛋白在海马CAl区的动态变化。结果：姜黄素可显著减少沙土鼠探索活动及海马CAl区凋亡锥体细胞数量（P〈0.01）、诱导Fos蛋白及抑制Jun和NF-κB蛋白的表达（P〈0.01）。结论：姜黄素具有脑保护作用,调控即早基因c-fos、c-jun和NF-κB的袁达可能是作用机制之一。     

虎杖甙抗肺缺血/再灌注损伤作用及其机制初探

目的：探讨虎杖甙（PD）抗肺缺血/再灌注损伤作用及其机制。方法：采用在体兔单肺原位缺血/再灌注损伤模型。健康日本大耳白兔40只随机均分成4组（n=10）：假手术对照组（C组）;肺缺血/再灌注组（I/R组）;肺缺血/再灌注＋虎杖甙组（PD组）,缺血前20 min和再灌注即刻按2.5 mg/kg静脉注射0.2%PD溶液;肺缺血/再灌注＋PD＋多粘菌素B组（PMB组）,给PD同时按24 mg/kg静注PMB。各组分别在缺血前20 min,缺血1 h即刻,再灌注1 h、2 h、3 h各时点颈动脉抽血检测丙二醛（MDA）含量,超氧化物歧化酶（SOD）活性。实验结束时,取肺组织测湿干重比（W/D）,计算肺泡损伤率（IAR）,电镜观察细胞超微结构改变。结果：①I/R组和PMB组血清SOD活性随着缺血和再灌注时间的延长而逐渐下降,且两组间无差异;PD组则显著改善（均P〈0.01）。②I/R组、PD组、PMB组血清MDA浓度均随着缺血和再灌注时间的延长而逐渐上升,但PD组上升明显缓慢（均P〈0.01）。③I/R组、PD组和PMB组的W/D与IAR均高于C组（P〈0.05或P〈0.01）,但PD组显著低于I/R组和PMB组（均P〈0.01）。④I/R组及PMB组肺组织的超微结构损伤严重,PD组损伤程度明显较轻。结论：PD对肺缺血/再灌注损伤具有拮抗作用,其机制除抗氧化损伤外可能还有PKC参与。     

大鼠肢体缺血预处理对肝缺血/再灌注损伤的保护作用

目的：研究肢体缺血预处理对大鼠肝缺血/再灌注损伤是否具有保护作用。方法：雄性SD大鼠32只,随机分为对照组（S组）;缺血/再灌注组（I/R组）;经典缺血预处理组（IPC组）;肢体缺血预处理组（远端缺血预处理组,RPC组）。S组仅行开腹,不作其他处理;IPC组以肝缺血5min作预处理;RPC组以双后肢缺血5min,反复3次作预处理,2个预处理组及I/R组均行肝缺血1h再灌注3h。取血用于血清谷丙转氨酶（ALT）与血清谷草转氨酶（AST）检测。切取肝组织用于测定湿干比（W/D）、中性粒细胞（PMN）计数及观察显微、超微结构的变化。结果：与I/R组比较,IPC组,RPC组ALT,AST,W/D值,及PMN计数均明显降低（P〈0.01）,肝脏的显微及超微结构损伤减轻。结论：肢体缺血预处理对大鼠肝脏I/R损伤有明显的保护作用,强度与经典缺血预处理相当,其机制可能与抑制肝脏炎症反应、减轻肝脏水肿、改善肝组织微循环有关。     

缺血后适应对局灶性脑缺血/再灌注大鼠p38表达的影响

目的：探讨缺血后适应对大鼠局灶性脑缺血/再灌注损伤后p38表达的影响。方法：将30只雄性SD大鼠随机分为3组（n=10）：假手术组（sham组）、缺血/再灌注（I/R）组和缺血后适应（IP）组。利用TUNEL法观察神经细胞凋亡的变化,应用Westernblot检测大鼠局灶性脑I/R损伤后p38蛋白表达水平的变化。结果：大鼠脑缺血/再灌注后凋亡细胞数量和p38蛋白表达水平均显著升高,而IP组凋亡细胞数量和p38蛋白表达水平均显著低于IR组（P〈0.01）。结论：缺血后适应可抑制大鼠脑缺血/再灌注后细胞凋亡的发生,此作用可能与下调p38蛋白表达有关。     

N-乙酰半胱氨酸对大鼠肝脏缺血再灌注损伤NF-κB和ICAM-1表达的影响

目的:探讨大鼠肝脏缺血再灌注损伤NF-κB和ICAM-1表达情况及NAC的保护作用机制.方法:45只雄性SD大鼠随机分成三组:假手术组(Sham组,n=5);缺血再灌注损伤组(I/R 组,n=20)缺血60min后分别再灌注1、3、6、12h;N-乙酰半胱氨酸组(NAC组,n=20):先自阴茎背静脉给大鼠注射溶于生理盐水的NAC,20min后再按I/R组处理.在各规定的再灌注时间点,分别采用western-blot和免疫组化方法测定肝组织中NF-κB和ICAM-1的表达.结果:I/R组和NAC组再灌注1、3、6、12h后,NF-k B的表达均明显高于Sham组(p＜0.01),于再灌注3h达到高峰;ICAM-1的表达均明显高于Sham组(p＜0.01),于再灌注6h达到高峰.NAC组再灌注1、3、6h与VR组相同时间点比较:NF-k B和ICAM-1的表达均低于I/R组(p＜0.05).NAC组再灌注12h与I/R组相同时间点比较:NF-K B和ICAM一1的表达虽然在数值上有所减少,但统计学上无差异(p＞0.05).结论:大鼠肝脏缺血再灌注后NF-κB和ICAM-1表达增加,NAC可抑制NF-k B激活,减少ICAM-1表达减轻大鼠肝脏缺血再灌注损伤.     

Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

Scurvy in capybaras bred in captivity in Argentine

In order to determine if the absence of vitamin C in the diet of capybaras (Hydrochoerus hydrochaeris) causes scurvy, a group of seven young individuals were fed food pellets without ascorbic acid, while another group of eight individuals received the same food with 1 g of ascorbic acid per animal per day. Animals in the first group developed signs of scurvy-like gingivitis, breaking of the incisors and death of one animal. Clinical signs appeared between 25 and 104 days from the beginning of the trial in all individuals. Growth rates of individuals deprived of vitamin C was considerably less than those observed in the control group. Deficiency of ascorbic acid had a severe effect on reproduction of another population of captive capybaras. We found that the decrease in ascorbic acid content in the diet affected pregnancy, especially during the first stages. The results obtained suggest that it is necessary to supply a suitable quantity of vitamin C in the diet of this species in captivity.     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.     

2016年中国植物科学若干领域重要研究进展

2016年中国植物科学持续稳步发展, 表现在中国植物科学家在国际主流高影响力学术期刊发表文章的数量稳中有升, 中国植物科学领域的期刊逆风出行, 进入研究性期刊世界前三甲行列。中国科学家在植物学诸多领域取得了丰硕的成果。水稻(Oryza sativa)产量性状杂种优势的分子遗传机制解析入选2016年中国科学十大进展; 植物受精过程中雌雄配子体信号识别机制的研究和独脚金内酯的受体感知机制入选2016年生命科学十大进展。我国植物科学, 特别是以水稻为代表的作物研究在国际学术界已占有一席之地。例如, 在水稻组学(如基因组和转录组等)资源和技术平台的建立、重测序的开发及功能基因的克隆和调控网络的解析方面取得了系列重要成果(如揭示了独脚金内酯信号转导的“去抑制化激活”机制、从分子水平上阐释了水稻籼粳杂种不育和广亲和性基因S5的作用机理及发现了控制水稻耐冷的基因组位点), 已经引领世界水稻乃至作物科学研究。该文对2016年中国本土植物科学若干领域取得的重要研究进展进行了概括性评述, 旨在全面追踪当前中国植物科学领域的发展前沿和研究热点, 与读者共享我国科学家所取得的杰出成就。