氨基胍对大鼠脊髓压迫伤后后肢运动功能的影响

目的观察诱导型一氧化氮合酶抑制剂-氨基胍(AG)对大鼠脊髓损伤后运动功能的影响。方法大鼠脊髓压迫伤后给予AG进行治疗,24 h后用分光光度法测定脊髓组织中一氧化氮(NO)含量和NOS活性;72 h后用流式细胞仪检测神经细胞凋亡情况;4周后用电生理和动物行为学等指标评价运动功能的恢复情况。以正常大鼠和损伤未治大鼠为对照。结果AG可以抑制组织中的NO含量和NOS活性,同时降低神经细胞的凋亡比率,提高动物后肢运动功能评分,恢复运动诱发电位的振幅和潜伏期,与对照及损伤未治大鼠相比均有显著差异(P<0.05)。结论脊髓损伤后应用NOS抑制剂可以使伤后运动功能得到改善,提示iNOS活性变化可能对脊髓损伤的恢复更具决定作用,其作用机制与抑制伤后细胞凋亡有关。     

氨基胍对去卵巢大鼠主动脉晚期糖化终末产物及血脂的影响

将 6月龄雌性SD大鼠随机分为假手术组 (sham)、去卵巢组 (OVX)和去卵巢 +氨基胍组 (OVX +AG)。去除双侧卵巢 2周后用氨基胍治疗 13周。禁食 2 4h ,放血处死动物 ,取血和主动脉 ,分别测定主动脉AGEs、血脂和血清过氧化物含量。结果表明 ,与假手术组比较 ,去卵巢组主动脉AGEs、甘油三脂 (TG)、氧化低密度脂蛋白 (OX LDL)、丙二醛 (MDA)均明显升高 (分别为P <0 0 1,P <0 0 5 ,P <0 0 5和P <0 0 1) ;高密度脂蛋白 胆固醇 (HDL C)、载脂蛋白AⅠ (apo AⅠ )和超氧化物歧化酶 (SOD)活性均显著降低 (均P <0 0 1)。氨基胍组与病理组比较 ,主动脉AGEs、血清TG、MDA和OX LDL均明显降低 (分别为P <0 0 1,P <0 0 5、P <0 0 5和P <0 0 1) ;HDL C、apo AⅠ和SOD活性均显著升高 (均P <0 0 1)。提示氨基胍通过降低去卵巢大鼠主动脉AGEs含量 ,降低大鼠血清OX LDL和TG水平 ,升高HDL C、apo AⅠ水平和SOD活性 ,发挥其对心血管的保护作用     

Nitric oxide mediates the inhibition of neutrophil migration induced by systemic administration of LPS

To investigate the role of NO in the inhibition of neutrophil migration by circulating endotoxin, mice were pretreated with NO synthase inhibitors or with a free radical scavenger (D-penicillamine), before intravenous LPS injection. LPS dose-dependently inhibited the thioglycollate-induced neutrophil migration into the peritoneal cavities. Aminoguanidine, a selective inducible NO synthase inhibitor, abolished the inhibition of neutrophil migration and the increase in serum nitrate levels induced by a nonlethal dose of LPS. During lethal endotoxemia aminoguanidine partially abolished the neutrophil migration inhibition. Additionally, D-penicillamine prevented the inhibition of neutrophil migration caused by LPS. However, Nitro-L-Arginine, a selective constitutive NO synthase inhibitor, did not prevent neutrophil migration inhibition. Aminoguanidine treatment did not affect the systemic increased levels of TNF-, IL-1, and IL-10, suggesting that NO is the final mediator involved in the inhibition of neutrophil migration. Our results suggest that NO released by the inducible NO synthase mediates the inhibition of neutrophil migration mediated by circulating LPS.     

Effect of advanced glycosylation end products on activity of protein kinase C in human peripheral blood mononuclear cells

Objectives To investigate the effect of advanced glycosylation end products (AGEs) on the a ctivity of protein kinase C (PKC) in human peripheral blood mononuclear cells (P BMC) and to observe whether aminoguanidine (AG) can influence the effect of AGEs .Methods After PBMC were isolated from human peripheral blood and incubated with differen t concentrations of AGEs-BSA for various periods, total PKC activity in PBMC wa s determined by measuring the incorporation of (32)P from ［γ-(32) P］ ATP into a special substrate using Promega PKC assay kit.Results AGEs-BSA increased the total PKC activity in PBMC from 83.43±6.57 pmol/min/ mg protein to 116.8±13.82 pmol/min/mg protein with a peak at 15 min. AGEs -BSA also increased the total PKC activity in a concentration-dependent manner fro m 83.1±6.4 pmol/min/mg protein (control) to 119.1±13.3 pmol/min/mg prote in (control vs AGEs-BSA 400 mg/L, P&lt;0.01).Furthermore, AGEs-BSA induc ed an elevation of PKC activity in a glycosylating time-related manner, from 80 .9±8.2 (control) to 118.3±11.5 pmol/min/mg protein (glycosylation for 12 wk, P&lt;0.01).The total PKC activity stimulated by AGEs-BSA pretreated wi th AG (100, 200 mg/L) was markedly lower than that of AGEs-BSA group not pretr eated with AG (P&lt;0.05, P&lt;0.01).Conclusions AGEs-BSA increased the total PKC activity in PBMC in a concentration and incuba tion time dependent manner. The ability of AGEs-BSA to stimulate PKC activity was markedly decreased by pretreatment of AGEs-BSA with AG.     

Advanced glycosylation end products, protein kinase C and renal alterations in diabetic rats

Objective To study the relationship between advanced glycosylation end products (AGE) an d protein kinase C (PKC), and their effects on renal alteration in diabetic rats .
Methods Insulin or aminoguanidine was administered to diabetic rats. Blood glucose, hem oglobin A_1C (HbA_1C), glomerular tissue extracts AGE (GTE-AGE), PKC, glomerular basement membrane thickness (GBMT) and urine protein/creatinine ( Pr/Cr) ratio in diabetic rats were measured and analysed.
Results Levels of blood glucose, HbA_1C and AGE, PKC activity, the Pr/Cr ratio an d GBMT were all significantly increased (P values all less than 0.01) in di abetic rats. Insulin could decrease the formation of HbA_1C and AGE, and improve PKC activity. Aminoguanidine had no influence on PKC activity (P >0.05) although it decreased the formation of AGE. Both drugs could delay t he increase of urine Pr/Cr ratio and GBMT (P<0.05 or P<0.01).
Conclusions Chronic hyperglycemia may lead to an increase of PKC activity. HbA_1Cand AGE may not directly contribute to alterations of PKC activity, but the increa se of PKC activity could promote the action of AGE on GBM thickening. It is imp ortant t o inhibit the formation of AGE and reduce the PKC activity so as to prevent or d elay the development of diabetic nephropathy.     

氨基胍对大鼠急性肺栓塞后肺组织细胞凋亡的影响

目的　观察氨基胍对大鼠急性肺栓塞后肺组织细胞凋亡的影响。方法　将大鼠随机分为对照组、模型组、治疗(AG)组,采用改良的导管方法将体外已凝的大鼠血栓注入右心房制备大鼠急性肺栓塞模型。AG组于制成肺栓塞后立即腹腔注射氨基胍,模型组给等容量的生理盐水,对照组只通过导管注入血清。于肺栓塞后1h放血处死大鼠,迅速取肺组织,流式细胞仪(FCM)测定肺组织细胞凋亡率,免疫组化法检测Caspase - 3蛋白的表达。结果　肺栓塞后,肺组织细胞凋亡率明显上升,Caspase - 3蛋白表达阳性细胞明显增多,给予氨基胍后细胞凋亡率明显下降,Caspase- 3蛋白表达阳性细胞数明显减少。结论　氨基胍可降低急性肺栓塞后肺组织细胞凋亡率及Caspase - 3蛋白表达,对急性肺栓塞大鼠有保护作用。     

氨基胍对糖尿病大鼠心脏功能及心肌超微结构的影响

目的 :探讨非酶糖化抑制剂 氨基胍 (amin oguanidine ,AG)对链尿佐菌素 (streptozotocin ,STZ)糖尿病大鼠心肌的保护作用 ,为糖尿病心肌病的防治提供参考。方法 :建立STZ糖尿病大鼠模型 ,随机分为对照组、糖尿病组和氨基胍治疗组 ,AG剂量为15 0mg·kg-1·d-1。 12周时测定大鼠血清果糖胺含量、心脏重量指数、左室内压最大上升和下降率 (±dp dtmax)值 ,电镜观察心肌超微结构 ,测量心肌毛细血管基底膜厚度。结果 :糖尿病组大鼠血清果糖胺含量、心脏重量指数明显增高 ,±dp dtmax降低 ;超微结构显示心肌肌原纤维排列紊乱 ,线粒体肿胀变性 ,间质胶原增生 ,微血管内皮细胞肿胀、基底膜明显增厚。氨基胍治疗组血清果糖胺含量降低、心脏重量指数明显下降、±dp dtmax 值上升 ,微血管基底膜增厚减轻 ,间质胶原减少 ,心肌细胞超微结构异常减轻。结论 :糖尿病时存在心脏功能异常、心肌肥厚和超微结构的改变 ,早期应用AG在一定程度上可阻抑糖尿病心肌病变的发展。     

银杏叶及葡萄籽提取物体外抑制蛋白糖化终末产物生成作用的研究

 目的 应用体外蛋白糖化反应系统,确定银杏叶及葡萄籽提取物抑制蛋白糖化终末产物生成的作用。方法 对照组将葡萄糖与牛血清白蛋白分别在STUOX；条件下共同孵育，实验组则加入不同剂量的银杏叶及葡萄籽提取物或氨基胍。利用荧光分光光度计对不同温度和时间培养条件下的样品测定，根据荧光强度确定蛋白糖化终末产物的生成量。结果 在本体外系统中，蛋白糖化终末产物的生成与孵育温度及时间呈正相关。银杏叶提取物及葡萄籽提取物在1.0~2.0 g.L_-1剂量范围内均可有效抑制蛋白糖化终末产物的生成，当药物浓度达2.0 g·L_-1时其抑制作用相当于同剂量的氨基胍。结论 具有明确 抗氧化作用的银杏叶提取物及葡萄籽提取物在体外可有效抑制蛋白糖化终末产物的生成。     

Isoproterenol disperses distribution of NADPH oxidase,MMP-9, and pPKCε in the heart,which are mitigated by endothelin receptor antagonist CPU0213

Aim： Spatial dispersion of bioactive substances in the myocardium could serve as pathological basis for arrhythmogenesis and cardiac impairment by β-adrenoceptor stimulation. We hypothesized that dispersed NADPH oxidase, protein kinase Cε （PKCε）, early response gene （ERG）, and matrix metalloproteinase 9 （MMP-9） across the heart by isoproterenol （ISO） medication might be mediated by the endothelin （ET） - ROS pathway. We aimed to verify if ISO induced spatially heterogeneous distribution of pPKCε, NAPDH oxidase, MMP-9 and ERG could be mitigated by either an ET receptor antagonist CPU0213 or iNOS inhibitor aminoguanidine. Methods：Rats were treated with ISO （1 mg/kg sc） for 10 days, and drug interventions （mg/kg） either CPU0213 （30 sc） or aminoguanidine （100 ip） were administered on days 8-10. Expression of NADPH oxidase, MMP-9, ERG, and PKCε in the left and right ventricle （LV, RV） and septum （S） were measured separately. Results： Ventricular hypertrophy was found in the LV, S, and RV, in association with dispersed QTc and oxidative stress in ISO-treated rats. mRNA and protein expression of MMP-9, PKCε, NADPH oxidase and ERG in the LV, S, and RV were obviously dispersed, with augmented expression mainly in the LV and S. Dispersed parameters were re-harmonized by either CPU0213, or aminoguanidine. Conclusion： We found at the first time that ISO-induced dispersed distribution of pPKCε, NADPH oxidase, MMP-9, and ERG in the LV, S, and RV of the heart, which were suppressed by either CPU0213 or aminoguanidine. It indicates that the ET-ROS pathway plays a role in the dispersed distribution of bioactive substances following sustained β-receptor stimulation.     

吡格列酮和厄贝沙坦对糖基化终产物诱导血管平滑肌细胞增殖的影响

目的：观察吡格列酮和厄贝沙坦对糖基化终产物诱导的血管平滑肌细胞增殖的影响。方法：组织块贴壁法培养大鼠主动脉血管平滑肌细胞,6～10代的细胞用于实验,糖基化终产物(50,100,200,400 mg·L~(-1))干预血管平滑肌细胞不同时间(0,8,16,24,48 h)后,分别用氨基胍(阳性对照组)、吡格列酮、厄贝沙坦与200 mg·L~(-1)基化终产物共同孵育24 h,四甲基偶氮唑盐微量酶比色(MTT)法检测血管平滑肌细胞增殖。结果：各浓度的糖基化终产物对血管平滑肌细胞作用8 h,细胞增殖不明显,200 mg·L~(-1)糖基化终产物作用48 h,细胞增殖最明显；氨基胍、吡格列酮、厄贝沙坦均能抑制糖基化终产物诱导的血管平滑肌细胞增殖(P＜0．05)。结论：吡格列酮与厄贝沙坦可明显抑制糖基化终产物诱导的血管平滑肌细胞增殖。