细辛肾毒性与细辛剂型剂量的动物实验研究

目的:研究细辛的肾毒性及其与细辛剂型剂量之间的相关性。方法:以灌服蒸馏水为空白对照,分别以不同剂量的细辛水煎剂、细辛散剂和麻黄附子细辛汤复方为受试药物,连续60天给SD大鼠灌胃给药,通过检测尿蛋白、血清肌酐、血尿素氮等生化指标和观察组织切片,评价细辛不同使用方式对大鼠肾脏的损伤作用。结果:细辛散剂组在3.0 g·kg~(-1)·d~(-1)的给药剂量下,各生化指标与空白组比较P0.05,有显著性差异,大鼠肾脏组织受到严重损伤,并普遍死亡;在1.5 g·kg~(-1)·d~(-1)的给药剂量下,同样引起了大鼠肾组织的明显损伤;在0.3 g·kg~(-1)·d~(-1)的给药剂量下,大鼠肾组织未表现出损伤,且生化指标与空白对照组比较P0.05,均无显著性差异。当细辛生药量达到33.0 g·kg~(-1)·d~(-1)时,细辛水煎剂组方表现出轻微的肾组织损伤,在16.5 g·kg~(-1)·d~(-1)和3.3 g·kg~(-1)·d~(-1)剂量下,细辛水煎剂组未表现出肾组织病理变化,生化指标与空白对照组比较P0.05,均无显著性差异。对麻黄附子细辛汤而言,在细辛生药用量达到16.5 g·kg~(-1)·d~(-1)时,开始出现大鼠轻微肾损伤,而在3.3 g·kg~(-1)·d~(-1)剂量下未表现出肾组织病理变化,生化指标与空白对照组比较P0.05,也均无显著性差异。结论:在大鼠中,肾脏是细辛致毒的靶器官之一,并且大鼠肾损伤与细辛用法用量密切相关,散剂的毒性显著强于水煎剂和复方麻黄附子细辛汤。     

芒果苷通过PI3K/Akt/mTOR通路抑制缺氧缺血性脑损伤大鼠神经细胞凋亡及炎症反应

目的:探讨芒果苷抑制缺氧缺血性脑损伤大鼠神经细胞凋亡的机制。方法:将144只SD新生大鼠分为空白组、模型对照组、阳性对照组(尼莫地平,0.4 mg·kg~(-1)·d~(-1))、芒果苷低、中、高剂量组(50、100、200 mg·kg~(-1)·d~(-1))。检测脑组织中超氧化物歧化酶(SOD)水平、细胞凋亡率、PI3K/Akt/mTOR通路分子表达量。结果:与空白对照组比较,模型组大鼠脑组织中SOD的含量显著降低、细胞凋亡率显著增加,p-PI3K、p-AKT、p-mTOR的表达量显著减少(P0.05);与模型组比较,芒果苷低、中、高剂量组大鼠脑组织中SOD的含量显著增加,细胞凋亡率均显著减少,p-PI3K、p-AKT、p-mTOR的表达量显著增加且芒果苷剂量越大,上述变化越显著(P0.05)。结论:芒果苷对缺氧缺血性脑损伤大鼠的细胞凋亡及炎症反应具有抑制作用且该抑制作用与抑制PI3K/Akt/mTOR通路有关。     

HMGB1对大鼠糖尿病足溃疡炎症的影响及机制分析

目的:分析高迁移率族蛋白1(High mobility group protein 1,HMGB1)对大鼠糖尿病足溃疡炎症的影响及机制。方法:经腹腔注射链脲佐菌素建立糖尿病大鼠模型,并在大鼠的双后足背部做一3 mm×7 mm的全层矩形皮肤缺损,接种质控菌株。将建模成功的大鼠随机分成:模型组(等量生理盐水)、低剂量组(12.5μg·kg~(-1)·d~(-1))、中剂量组(25μg·kg~(-1)·d~(-1))和高剂量组(50μg·kg~(-1)·d~(-1)),每组6只,每天单次腹腔注射,连续给药14 d。另取6只大鼠作为空白组(等量生理盐水)。于规定时间对各组大鼠创面愈合率、微血管密度(Microvascular density,MVD)、组织中血管内皮生长因子(Vascular endothelial growth factor,VEGF)、CD45、Toll样受体4(Toll like receptor 4,TLR4)、核因子κB (Nuclear factor kappa-B,NF-κB)、白介素-1β(Interleukin-1β,IL-1β)、白介素-6 (Interleukin-6,IL-6)、IL-8(Interleukin-8,IL-8)和肿瘤坏死因子-α(Tumor necrosis factor-α,TNF-α)m RNA或蛋白表达量进行检测。结果:与对照组相比,模型组大鼠创面治愈率和微血管密度均较低,VEGF、CD45、TLR4、NF-κB、IL-1β、IL-6、IL-8和TNF-αm RNA或蛋白表达量均较高(P0.05)。与模型组相比,三个剂量组大鼠创面治愈率和微血管密度均明显降低(P0.05),VEGF、CD45、TLR4、NF-κB、IL-1β、IL-6、IL-8和TNF-αm RNA或蛋白表达量均较高(P0.05)。且随着HMGB1注射剂量增大,创面愈合率、血管生成明显减少(P 0.05),炎症因子表达量显著升高(P 0.05)。结论:HMGB1对大鼠糖尿病足溃疡炎症有促进作用,机制可能与HMGB1/TLR4/NF-κB信号通路相关。     

生长抑素在糖尿病大鼠胰腺外分泌功能降低中的作用

本实验观察到,用链佐霉素造成大鼠糖尿病模型,其胰腺组织中生长抑素含量明显升高。大鼠皮下注射生长抑素(100μg·kg~(-1)·d~(-1))5d,其胰腺组织中淀粉酶的含量明显降低。体外胰腺灌流也表明,生长抑素能抑制CCK—8刺激引起的胰腺淀粉酶释放。以上结果提示,糖尿病时胰腺组织中生长抑素含量的增加可能在胰腺外分泌功能降低中有一定的作用。     

黄连素对小鼠心肌梗死后心室重构的作用研究

目的:探讨黄连素(Berberine,BBR)在小鼠心肌梗死(myocardial infarction,MI)后心室重构中的作用,并比较BBR预处理(BBR pre-treatment,preBBR)和BBR后处理(BBR post-treatment,postBBR)给药的效果。方法:将60只C57BL/6小鼠随机分为4组,分别为假手术组、单纯MI对照组、MI+preBBR组及MI+postBBR组,每组15只。MI模型采用前降支结扎法制备。MI+preBBR组在MI模型制备前2周开始用BBR(100 mg·kg~(-1)·d~(-1))每天灌胃,持续至MI后28 d;MI+postBBR组在MI模型制备后4 h开始用BBR(100 mg·kg~(-1)·d~(-1))每天灌胃,持续至MI后28 d。记录实验期间小鼠生存情况。MI后28天采用小动物超声测定左心室收缩功能;取心脏组织,测定心脏大小和重量;ELISA方法测定血浆BNP水平;Masson染色评价心肌纤维化程度。结果:与单纯MI对照组相比,MI+preBBR组及MI+postBBR组小鼠生存率提高、心脏收缩功能增强、心脏变小、心脏重量减轻、血浆BNP水平降低、心肌纤维化明显改善。其中,MI+preBBR组上述指标的改善程度优于MI+postBBR组。结论:BBR可抑制MI后心室重构,且BBR预处理效果优于后处理。     

缺氧大鼠心肌α1,β肾上腺素能受体的变化

为了探讨α_1、β肾上腺素能受体在大鼠缺氧性心脏肥大进程中的作用,本研究应用放射配基结合法观察了不同缺氧时间大鼠心室α_1、β肾上腺素能受体变化的动态过程,同时也观察了α_1、β受体阻断剂在预防缺氧性心肌肥大发生中的作用。缺氧10d后,测定右心室重量及组织学检查未见右心室肥大,但此时心室肌α_1受体数量从对照组的27.49±1.25增加到33.80±0.90fmol/mg蛋白(P<0.05);β受体从对照组的51.80±7.60下降到25.10±2.30fmol/mg蛋白(P<0.01)。缺氧20和30d后α_1受体进一步增加到40.70±1.43和32.30±1.96fmol/mg蛋白(P<0.05);β受体分别为27.90±2.30和42.80±1.70fmol/mg蛋白(P<0.05)。缺氧20和30d后右心室重量指数明显高于对照组,在整个缺氧过程中α_1、β受体的亲和性(K_d)未见明显变化,未见左心室肥大。缺氧同时应用α_1受体阻断剂(哌唑嗪4mg·kg~(-1)·d~(-1))30d,可明显预防缺氧所致的右心肥大;而β受体阻断剂(心得安10mg·kg~(-1)·d~(-1))没有此种作用。由此可见,在缺氧所致右心肥大之前,心肌α_1受体数量即明显升高,α_1受体阻断剂可以预防缺氧引起的右心肥大。     

姜黄素在宫颈癌治疗中对MIF、VEGF-C、P53表达及肿瘤生长的影响

为了揭示姜黄素治疗宫颈癌的实验效果及其作用机制。选取成功建立的宫颈癌Caski细胞移植瘤裸鼠48只,随机分为空白组(等量生理盐水灌胃)、顺铂组(顺铂3 mg·g~(-1)·d~(-1))、高剂量组(100 mg·kg~(-1)·d~(-1))、低剂量组(50 mg·kg~(-1)·d~(-1)),每组12只,连续处理15 d后,对比各组小鼠肿瘤体积、瘤体重量、抑瘤率,采用流式细胞仪技术检测各组小鼠肿瘤组织中Caski细胞周期分布情况、采用RT-PCR技术和Western-blotting技术检测各组小鼠瘤组织中巨噬细胞移动抑制因子(MIF)、血管内皮细胞生长因子-C(VEGF-C)、p53mRNA及蛋白的表达情况。结果显示,顺铂组、高剂量组、低剂量组的小鼠肿瘤体积、肿瘤重量均显著低于空白组(p0.05),顺铂组、高剂量组的小鼠肿瘤体积、肿瘤重量显著低于低剂量组(p0.05),顺铂组、高剂量组的抑瘤率显著高于低剂量组(p0.05);顺铂组、高剂量组、低剂量组的G1期细胞比例低于空白组(p0.05);顺铂组、高剂量组的G1期细胞比例低于低剂量组(p0.05),而S期及G2/M期细胞比例高于低剂量组(p0.05);顺铂组、高剂量的MIF、VEGF-C mRNA表达低于低剂量组(p0.05),顺铂组、高剂量的p53mRNA表达高于低剂量组(p0.05);顺铂组、高剂量组、低剂量组的MIF、VEGF-C蛋白低于空白组(p0.05);顺铂组、高剂量组的MIF、VEGF-C蛋白低于低剂量组(p0.05),而p53蛋白高于低剂量组(p0.05)。姜黄素能有效抑制宫颈癌Caski细胞移植瘤裸鼠肿瘤细胞的生长,可能与下调MIF、VEGF-C及上调p53 mRNA及蛋白有关。     

低氧对高原鼠兔和大鼠血液NO 与ET-1的影响

将Wistar大鼠暴露于3 780 m低氧环境,分别于24 h、2 wk及3 wk后采用酶联免疫法和硝酸还原酶法测定血液中的ET~(-1)和NO的含量,计算NO/ET~(-1)值,并与高原鼠兔比较,探讨低氧条件下大鼠与高原鼠兔血液中NO与ET~(-1)含量的变化趋势。结果表明,低氧24 h后,大鼠血液中NO和ET~(-1)的含量显著高于同海拔的高原鼠兔(P<0·01),而NO/ET~(-1)值无显著差异(P>0·05)。随着大鼠在高海拔停留时间的延长,血液中NO含量呈减少趋势,而ET~(-1)则有上升趋势,二者呈显著的负相关(r2=0·2416,P<0·01)。高原鼠兔NO/ET~(-1)值约为大鼠低氧2 wk和3 wk的2倍(P<0·01)。说明不同低氧暴露时间,高原鼠兔和大鼠的NO、ET~(-1)及NO/ET~(-1)值有显著差异,提示NO/ET~(-1)值可以作为有机体是否适应高原低氧环境的一个指标。     

罗汉果多糖对环磷酰胺所致的免疫 抑制小鼠免疫功能的影响

该研究将小鼠随机分成正常组,模型组,罗汉果多糖低、中、高剂量组(25、50、100 mg·kg~(-1))和左旋咪唑组,采用腹腔注射环磷酰胺(20 mg·kg~(-1))建立免疫抑制小鼠模型,连续灌胃给药14 d后,测定各组小鼠的免疫器官指数、廓清指数(K)、吞噬指数(α)、T和B淋巴细胞增殖水平、耳肿胀度、半数溶血值(HC50)以及免疫球蛋白G(IgG)、免疫球蛋白M(IgM)、IL-2、IL-4、IL-6、TNF-α的含量,并观察脾组织病理形态变化,考察罗汉果多糖对免疫抑制小鼠免疫功能的影响。结果表明:罗汉果多糖各剂量组(25、50、100 mg·kg~(-1))均能显著提高免疫抑制小鼠的免疫器官指数、半数溶血值(HC_(50))、B淋巴细胞增殖能力,明显降低耳肿胀度,显著增加IgG、IgM、IL-2、IL-4、IL-6、TNF-α的含量。罗汉果多糖中、高剂量组(50、100 mg·kg~(-1))能显著增强T淋巴细胞增殖能力,明显增加廓清指数(K)、吞噬指数(α)。脾组织病理学观察结果表明,罗汉果多糖可以减轻免疫抑制小鼠脾脏的病理损伤。这表明罗汉果多糖能明显增强环磷酰胺所致免疫抑制小鼠的免疫功能。     

低分子肝素钙对子痫前期大鼠炎性细胞因子的影响

探讨低分子肝素钙对子痫前期大鼠炎性细胞因子的影响。将Wistar大鼠随机分为A组、B组、C组和D组共4组(n=10),A组和B组大鼠均在妊娠2周后连续5 d注射剂量为200 mg·kg~(-1)·d~(-1)的L-NAME,此后,A组连续5 d注射剂量为50μg·kg~(-1)·d~(-1)的低分子肝素钙注射液,B组连续5 d注射0.5 m L/d生理盐水。C组大鼠为正常妊娠组,妊娠2周后连续10 d注射0.5 m L/d生理盐水。D组大鼠为非妊娠对照组,用药过程中注射0.5 m L/d生理盐水。通过ELISA、免疫组化、荧光定量PCR、Western blotting检测各组大鼠外周血、胎盘、肾脏和脾脏中IFN-γ、IL-2、IL-4和IL-6炎性细胞因子水平的变化。结果显示,B组IFN-γ和IL-2在外周血、胎盘、肾脏和脾脏的表达水平明显高于C组,而IL-4和IL-6的表达水平均明显低于C组(p0.05);A组IFN-γ和IL-2的表达水平均明显低于B组,且IL-4和IL-6表达水平与B组相比,其表达水平明显升高(p0.05)。本研究所建立的动物模型可使Th1/Th2发生Th1方向漂移,可以用来模拟子痫前期的免疫失衡;低分子肝素钙可明显抑制促炎性细胞因子的分泌,促进抗炎细胞因子的分泌,可使Th1/Th2的平衡向Th2方向漂移,从而表现出良好的抗炎作用。     

Resistance to Mercuric Chloride in Pseudomonas K-62

Mercuric ion-resistant mechanism in Pseudomonas K-62 was investigated by isolating a mercuric ion-sensitive mutant strain (H-2 strain) from a resistant wild-type strain (P strain) and comparing the physiological properties of these two strains. Growth curves obtained in mercuric ion-containing medium suggested that P strain constitutively has a resistant mechanism. The capacity of P and H-2 strains to decrease the concentration of mercuric ions in the medium was found to be almost equal; thus, the presence of a resistant mechanism was expected other than MMR-enzyme, which is an inducible system. From the characteristic property of the inhibitory effect of mercuric ions on respiration of the two strains, a resistant mechanism, a permeability barrier mechanism, was proposed. The barrier mechanism in P strain traps mercuric ions with high selectivity to prevent the penetration of ions to the intracellular space where the functional units are located. Finally, the resistance mechanism to mercuric ions in the bacterium was discussed including the MMR-enzyme system and the barrier mechanism.     

Cleavage of Disulfide Bonds of Wheat Glutenin by Mercuric Chloride

The dissociation of wheat glutenin into subunits was observed by treatment with a small amount of mercuric chloride under moderate conditions, suggesting that the cleavage of inter-polypeptide chain disulfide bonds in the glutenin might occur. The dissociation into the subunits was examined by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The electrophoretic patterns of the glutenin treated with mercuric chloride were essentially similar to those of the glutenin treated with 2-mercaptoethanol. Silver nitrate also had the same effects as mercuric chloride, and p-chloromercuribenzoate and N-ethylmaleimide showed no effect on the dissociation of the glutenin. Complete dissociation was achieved when the glutenin solution containing 0.5% SDS and 0.01 m phosphate buffer (pH 7.0) was incubated with 10^?3 m mercuric chloride (about four moles per mole of disulfide groups) at 30°C for 20 hr. Partial dissociation was also observed after 30 min incubation. Increasing temperature and SDS concentration promoted the rate of the dissociation of the glutenin by mercuric chloride.     

Effects of Mercuric Chloride on the Hydraulic Conductivity of Tomato Root Systems (Evidence for a Channel-Mediated Water Pathway)

A pressure-flux approach was used to evaluate the effects of HgCl2 on water transport in tomato (Lycopersicon esculentum) roots. Addition of HgCl2 to a root-bathing solution caused a large and rapid reduction in pressure-induced root water flux; the inhibition was largely reversible upon addition of [beta]-mercaptoethanol. Root system hydraulic conductivity was reduced by 57%. There was no difference between treatments in the K+ concentration in xylem exudate. The results are consistent with the presence of a protein-mediated path for transmembrane water flow in tomato roots.     

Effects of Lycopene and Proanthocyanidins on Hepatotoxicity Induced by Mercuric Chloride in Rats

To evaluate the protective potential of lycopene (Lyc) and proanthocyanidins (PCs) against mercuric chloride (HgCl₂)-induced hepatotoxicity, the study focused on the mechanism of oxidative stress. Firstly, the rats were subcutaneously (s.c.) injected with 0, 2.2, 4.4, and 8.8 μmol/kg HgCl₂. Additionally, 40 mg/kg Lyc and 450 mg/kg PCs were given to the rats intragastrically (i.g.) before exposure to 8.8 μmol/kg HgCl₂. Then, body weight, liver weight coefficient, mercury (Hg) contents, histological feature, ultrastructure, apoptosis, reactive oxygen species (ROS), glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and malondialdehyde (MDA) in the liver were measured. Lactate dehydrogenase (LDH) and alanine transaminase (ALT) in serum were determined. After exposure to different concentrations of HgCl₂,it was found that Hg contents, pathological and ultrastructure injury, activities of LDH and ALT, apoptosis, and levels of ROS, GSH, and MDA increased and the activities of SOD and GSH-Px decreased in a concentration-dependent manner. Further investigation found that pretreatment with Lyc and PCs inhibited ROS production, protected antioxidant enzymes, and reversed hepatotoxicity. We concluded that Lyc and PCs had hepatoprotective effects on HgCl₂-induced toxicity by antagonizing oxidative stress in rat liver.     

Sublethal Cytotoxic Effects of Mercuric Chloride on the Ciliate Tetrahymena pyriformis*

SYNOPSIS. The behavior and ultrastructure of Tetrahymena pyriformis was assessed after exposure to dosages of 8 and 16% of the lethal concentration of HgCl² (TLm 96 hr). The lower dosage caused no abnormal changes in cell motility, activity of the water explusion vesicles, or cell shape; the higher dosage caused deleterious changes in these parameters. The higher sublethal HgCl² concentration (0.50 mg/liter) elicited damage of several cell structures. This damage persisted and accumulated with time up to 24 hr. At the lower HgCl² dosage (0.25 mg liter) there were extensive changes after 1-hr exposure involving primarily mitochondria; however, all major changes were repaired after 24 hr of constant exposure to the HgCl², indicating adaptation to the toxicant. Based solely on cytotoxic evidence an attempt is made to apply the findings defining what constitutes a “safe'’concentration of HgCl₂ in the cell's environment.     

Effects of Mercuric Chloride on Growth and Morphology of Selected Strains of Mercury-Resistant Bacteria

A survey of the comparative cytological effects of growth in the presence of mercury by a group of mercury-resistant bacterial cultures and a characterization of the process of bacterial adaptation to Hg²⁺ ion was accomplished. Mercury resistance was found to be dependent upon the ability to volatilize mercury from the medium and upon the amount of mercury accumulated by the cells. The results indicate that most cultures which adapt to growth in the presence of HgCl₂ exhibit extensive morphological abnormalities. Significant effects are delay in the onset of growth and cell division and numerous structural irregularities associated with cell wall and cytoplasmic membrane synthesis and function. A detailed analysis of the adaptation process and the resulting effects on morphology was performed on an Enterobacter sp. During the period preceding active multiplication, a selection for mercury-resistant mutants occurred. It was also demonstrated that growth commenced only at a specific threshold concentration of Hg²⁺.