D-半乳糖诱导大鼠脑损伤的糖基化机制

目的D-半乳糖（D-galactose）诱导大鼠体内不同糖基化水平,研究其脑损伤发生的机理。方法采用不同剂量D-半乳糖[150、75、37．5mg／（kg·d）]分别腹腔注射（ip）处理大鼠8周,诱导糖基化状态和脑损伤。采用硫代巴比妥酸（TBA）比色法测定糖化血红蛋白,硝基四氮唑蓝（NBT）比色法测定血清果糖胺;按文献方法分别测定血红细胞醛糖还原酶活性和晚期糖基化终末产物（AGEs）含量及脑组织中AGEs含量,羟胺法和比色法分别测定SOD和GSH-Px活性,硫代巴比妥酸法测定MDA含量;以Fura-2／AM作为钙荧光指示剂,双波长荧光分光光度法检测脑海马神经细胞胞质[Ca^2＋]i的变化;透射电镜观察脑海马神经细胞线粒体的变化。结果D-半乳糖处理8周后,大鼠血红细胞醛糖还原酶活性升高,糖化产物形成增多;脑组织中AGEs及脑细胞胞质[Ca^2＋]i含量明显升高,SOD及GSH-Px活性下降,MDA含量升高（P〈0．01,P〈0．05）,海马神经细胞线粒体出现病理性改变。结论D-半乳糖通过诱导体内蛋白糖基化和脑组织AGEs大量生成,降低抗氧化能力及胞质[Ca^2＋]i超负荷等,导致脑细胞损伤。     

D-半乳糖建造老年性聋动物模型

目的研究D-半乳糖建造老年性聋模型的理想方式。方法健康wistar大鼠50只,随机分为5组,即对照组和四个不同剂量D-半乳糖（50、100、200、500mg/kg）建造的老年性聋模型组。观察各组动物行为检测（兴奋性实验）、ABR反应阈、血清中丙二醛（MDA）含量和超氧化物歧化酶（SOD）活性、听皮层中的神经元形态和数量。结果各模型组较对照组探究能力明显下降,但紧张度无明显改变。血清中MDA含量和SOD活性与对照组比较有显著性升高（P〈0.05）,但ABR阈值和Ⅰ、Ⅲ波潜伏期仅500mg/kg组显著升高延长,其他模型组与对照组均无显著性差异。并且模型组中仅500mg/kg组听皮层出现明显的神经细胞稀少、肿胀,尼氏小体减少的现象。结论 D-半乳糖（500mg/kg）腹腔注射每天一次持续10周造模是建造老年性聋动物模型的有效方法。     

苯并[a]芘对小鼠肝脏和肾脏中丙二醛和过氧化氢酶的影响

目的探讨苯并[a]芘（B（a）P）对小鼠肝脏和肾脏脂质过氧化及抗氧化能力的影响。方法采用B（a）P口腔灌胃连续染毒3 d后,取肝、肾组织作匀浆,采用TBA比色法测定鼠肝脏和肾脏内的丙二醛（MDA）的含量,钼酸铵比色法测定鼠肝脏和肾脏内的过氧化氢酶（CAT）的含量。结果肝中各剂量染毒组的MDA含量增加,其中5 mg/kg、10 mg/kg剂量组与油剂对照组比较差异有显著性（P〈0.05）。肾脏中各剂量染毒组的MDA含量均有所增加,其中10 mg/kg剂量组与对照组比较差异有显著性（P〈0.05）。肝脏中各剂量染毒组的CAT的含量低剂量增加高剂量减少,肾脏中各剂量染毒组的CAT的含量增加。结论B（a）P可引起MDA含量增加诱导小鼠肝肾的脂质过氧化损伤。     

人参皂苷Rg1对衰老模型大鼠骨髓造血功能的影响及其机理

目的:探讨人参皂苷Rg1对衰老模型大鼠骨髓造血功能的影响及其机理。方法:SD大鼠随机分为4组,每组10只。衰老模型组,皮下注射D-半乳糖120mg/kg qd×42;Rg1衰老模型组,注射D-半乳糖剂量与时间同衰老模型组,第15d起腹腔注射Rg1 20mg/kg qd×28;正常对照组,皮下注射生理盐水qd×42;Rg1正常对照组,注射生理盐水qd×14,第15d起腹腔注射Rg1(同Rg1衰老模型组)。模型复制或药物注射完成后第2d,采外周血检测血白细胞总数与分类计数和晚期糖基化终产物(AGEs),骨髓单个核细胞(BMNCs)计数,衰老相关β-半乳糖苷酶(SA-β-Gal)染色检测BMNCs衰老百分率,多向造血祖细胞集落(CFU-Mix)培养检测BMMCs形成集落能力;Western blotting检测BMMCs衰老相关蛋白P21和P53的变化;提取腹腔巨噬细胞进行培养,比色法检测巨噬细胞吞噬功能。结果:与衰老模型组比较,Rg1衰老模型组外周血白细胞数量增多,淋巴细胞比例升高,粒细胞比例降低,CD8+T细胞所占比例降低,CD4+T细胞所占比例升高,外周血AGEs水平降低,每根股骨的BMMCs细胞数增多,SA-β-Gal染色阳性的BMMCs明显降低,BMMCs形成CFU-Mix能力提高,P21和P53的表达下调,腹腔巨噬细胞吞噬中性红指数上升。结论:D-半乳糖复制的衰老模型大鼠骨髓造血功能损伤明显,人参皂苷Rg1对其致衰损伤有明确的保护作用,可能机理与调控p53/p21信号通路有关。     

外源性硫化氢减轻D-半乳糖诱导的亚急性衰老大鼠血管老化

本文旨在观察亚急性衰老大鼠血管壁结构和功能的改变,探讨硫化氢(hydrogen sulfide,H2S)对血管老化的影响。雄性SD大鼠40只,随机分为溶剂组、D-半乳糖组、NaHS(H2S的供体)低、中、高剂量组,每组8只。D-半乳糖组每日背部皮下注射125 mg/kg D-半乳糖,连续8周;溶剂组每日背部皮下注射等体积生理盐水;NaHS低、中、高剂量组每日背部皮下注射125 mg/kg D-半乳糖,同时分别按1、10、100μmol/kg腹腔注射NaHS,连续8周。HE和Masson染色法观察各组大鼠主动脉形态学改变;硫代巴比妥酸(TBA)法和黄嘌呤氧化酶法检测大鼠主动脉超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量以及抗超氧阴离子含量;生化方法测定大鼠血清H2S浓度的变化;酶联免疫法(ELISA)检测血浆血管紧张素II(AngII)浓度变化;免疫印迹法测定大鼠主动脉血管紧张素II型1类受体(AT1R)蛋白的表达。结果显示,与溶剂组相比,D-半乳糖组大鼠血清H2S的浓度降低(P0.05);而给予NaHS处理后,NaHS各剂量组大鼠血清H2S的浓度较D-半乳糖组明显升高(P0.05)。血清H2S浓度的增高能够改善D-半乳糖引起的亚急性衰老大鼠主动脉形态学的变化。HE染色结果中,溶剂组主动脉内膜较薄,结构完整,中膜平滑肌排列规则;D-半乳糖组主动脉内膜增厚、隆起,内皮细胞部分脱落,中膜明显增厚,平滑肌增生、紊乱;与D-半乳糖组相比,NaHS各剂量组内皮细胞脱落减少,平滑肌细胞增生减少。Masson染色结果表明:与溶剂组相比,D-半乳糖组胶原纤维增多,平滑肌细胞增生(P0.05);与D-半乳糖组相比,NaHS各剂量组胶原纤维减少,平滑肌细胞增生减少(P0.05)。ELISA检测结果显示:与溶剂组相比,D-半乳糖组大鼠血浆AngII浓度明显升高(P0.05);而给予NaHS处理后,NaHS各剂量组大鼠血浆AngII浓度较D-半乳糖组明显降低(P0.05)。与溶剂组相比,D-半乳糖组大鼠主动脉SOD活性下降、MDA含量升高、抗超氧阴离子含量降低(P0.05);而给予NaHS处理后,血管组织氧化应激水平得到明显改善:与D-半乳糖组相比,NaHS各剂量组主动脉SOD活性升高、MDA含量降低、抗超氧阴离子含量升高(P0.05)。免疫印迹法测定显示,与溶剂组相比,D-半乳糖组大鼠主动脉血管AT1R蛋白表达上调(P0.05),给予NaHS处理能下调主动脉AT1R蛋白的表达。以上结果提示,外源性H2S能够改善亚急性衰老大鼠主动脉形态学变化,降低血浆AngII的浓度、下调主动脉AT1R蛋白的表达,提高血管组织抗氧化应激的能力,延缓血管老化的发生。     

杭白菊总黄酮对衰老小鼠学习记忆的影响

目的：探讨杭白菊总黄酮（TFCM）对衰老小鼠学习记忆能力及胆碱能系统的影响。方法：采用皮下注射D-半乳糖的方法制备衰老小鼠模型。ICR小鼠随机分为5组（n=10）：正常对照组,模型组,低、中、高剂量TFCM处理组。TFCM处理组于造模后第2周开始每天给予TFCM（50、100或150mg／kg）灌胃。用Morris水迷宫法检测小鼠学习记忆能力,用比色法测定血清和大脑组织中丙二醛（MDA）含量,以及超氧化物歧化酶（SOD）和乙酰胆碱酯酶（Ach E）活性。结果：与正常对照组相比,模型组学习记忆能力减退,MDA含量和Ach E活性增加,SOD活性降低。与模型组相比,中高浓度TFCM处理组（100、150mg／kg）小鼠学习记忆能力明显改善,MDA含量和Ach E活性明显降低,SOD活性增高。结论：TFEM能显著改善D-半乳糖衰老小鼠学习记忆能力,其机制可能与TFCM的抗氧化特性以及提高中枢胆碱能系统功能有关。     

核桃低聚肽对亚急性肾衰老大鼠肾损伤的改善作用

目的：探讨核桃低聚肽（WOPs）对D-半乳糖诱导的亚急性肾衰老大鼠肾损伤的改善作用。方法：将108只雄性SD大鼠随机分为生理盐水组、模型对照组、3个WOPs剂量组（220、440、880 mg/kg）和乳清蛋白组（440 mg/kg）,每组18只。各组每日分别腹腔注射D-半乳糖生理盐水溶液300 mg/kg,生理盐水组注射等量灭菌生理盐水,连续6 w,造成亚急性肾衰老模型。造模成功后继续进行腹腔注射并灌胃给予干预物,8 w后记录体重、计算肾脏系数,检测肾组织SOD、GSH-Px活性、GSH、MDA含量,检测血清肌酐、胱抑素C水平,检测尿微量白蛋白、尿肌酐并计算尿微量白蛋白/肌酐比值（UACR）。结果：与生理盐水组相比,模型对照组肾脏系数［（4.91±0.36）mg/g］、GSH-Px活性［（24.41±2.10）U/mg prot］显著下降,血清肌酐［（41.50±7.27）μmol/L］、UACR［（1.37±0.24）mg/g］、 MDA水平［（3.09±0.35）nmol/L］显著提高（P＜0.05）。与模型对照组相比,WOPs低剂量组血清胱抑素C水平［（0.31±0.04）mg/L］显著下降（P＜0.05）,WOPs中剂量组大鼠UACR［（0.99±0.34）mg/g］显著下降（P＜0.05）,WOPs高剂量组体重［（616.0±44.2）g］、肾脏脏器系数［（5.25±0.39）mg/g］显著提高,肌酐水平［（34.50±6.58）μmol/L］显著下降（P＜0.05）;WOPs中、高剂量组大鼠肾组织SOD活性［（71.18±7.71）、（71.95±9.56）U/mg prot］及GSH水平［（4.51±0.28）、（4.37±0.23）μmol/g prot］显著提高（P＜0.05）;WOPs低、中、高剂量组大鼠肾组织GSH-Px活性［（26.49±2.08）、（26.56±2.17）、（26.29±1.87）U/mg prot］均显著提高,MDA水平［（2.88±0.36）、（2.51±0.21）、（2.36±0.26）nmol/L］显著下降（P＜0.05）。结论：WOPs对D-半乳糖诱导的肾脏损害具有改善作用。     

马齿苋多糖对衰老小鼠肠道微生态调节作用的研究

目的探讨中药马齿苋多糖对衰老小鼠微生态调节作用。方法皮下注射D-半乳糖建立衰老小鼠模型,用马齿苋多糖进行治疗,同时设正常对照组、阳性对照组和阴性对照组,用药30d后处死小鼠,进行肠道微生态指标检测。结果用D-半乳糖造模以后,小鼠肠道双歧杆菌及乳酸杆菌数量降低（P〈0．05）,而肠杆菌及肠球菌数量增加说明模型建立,血内毒素含量也升高（P〈0．05）。用马齿苋治疗后,益生菌数量升高而肠杆菌和肠球菌数量减少,血内毒素含量也降低（P〈0．05）。结论马齿苋多糖对衰老小鼠的肠道菌群和血内毒素具有调节作用。     

两面针提取物(S-O)对小鼠镇痛、抗炎和止血作用的研究

本研究对两面针根的提取物S-O进行了镇痛、止血和抗炎药理实验,每种作用选用两种实验方法来评价。镇痛作用采用热板法和扭体法。热板法实验显示,S-O在150mg/kg剂量时,小鼠痛阈值明显提高（P〈0．01）;扭体法实验显示,S-O在150mg/kg剂量为时,对冰醋酸致痛的小鼠扭体反应次数减少了70．96％（P〈0．01）。抗炎实验采用二甲苯致小鼠耳廓肿胀法及腹腔染料渗出法。二甲苯致炎剂实验表明,S-O在150mg/kg剂量时,对二甲苯所致小鼠耳廓肿胀有明显抑制作用,抑制率为63．45％（P〈0．01）;冰醋酸所致的腹腔毛细血管通透性实验中,S-O在150mg/kg和75mg/kg两个剂量组时,对小鼠的抗炎效果分别为52．94％（P〈0．01）和52．00％（P〈0．01）。止血实验采用毛细玻璃管法和载玻片法。毛细玻璃管实验表明S-O在150mg/kg和75mg/kg两个剂量时,凝血时间明显缩短（P〈0．01）;载玻片实验表明S-O在150mg/kg剂量时,凝血时间明显缩短（P〈0．01）。总之,两面针中提取物S-O对小鼠具有显著的镇痛、止血和抗炎作用。     

D-半乳糖亚急性中毒拟衰老模型鼠免疫功能及生化指标变化的研究

目的研究D-半乳糖慢性中毒所致衰老模型鼠免疫功能与生化指标变化。方法制备D-半乳糖亚急性中毒导致的衰老鼠模型;给药第8周时以P815细胞腹腔注射免疫小鼠,诱导特异性CTL细胞并用MTT法检测CTL细胞杀伤活性;间隔1周后以10％淀粉腹腔注射,诱导腹腔巨噬细胞,吞噬中性红法检测腹腔巨噬细胞（Mφ）功能;给药第10周杀鼠,取胸腺计算胸腺指数;采用流式细胞术检测胸腺细胞凋亡情况;MTT法检测T淋巴细胞转化增殖功能与NK细胞杀伤活性;取脾细胞48h培养上清,检测IL-2、INF-γ、TNF三种TH1型细胞因子的活性;硫代巴比妥酸（TBA）法检测血清中丙二醛（MDA）含量,黄嘌呤氧化酶法检测血清中总超氧化物歧化酶（SOD）活性;ISP半自动生化分析仪检测血清中血糖（Glu）、总胆固醇（CHO）、甘油三酯（TG）的含量。结果衰老鼠胸腺指数低于对照组（P〈0．05）;胸腺细胞凋亡高于对照组（P〈0．05）;T淋巴细胞增殖率显著低于对照组（P〈0．05）;IL-2、INF-γ、TNF三种TH1型细胞因子的活性较对照组均显著降低（P〈0．05）;与对照组比较VE衰老鼠腹腔Mφ细胞吞噬功能明显降低（P〈0．05）、NK细胞杀伤活性也有所降低（P〈0．05）,但CTL细胞的杀伤活性变化不明显（P〉0．05）。衰老模型鼠血清中MDA含量显著高于正常对照组（P〈0．05）,衰老模型鼠血清总SOD含量显著低于正常对照组（P〈0．05）。模型鼠血清中的血糖、总胆固醇、甘油三酯含量显著高于正常对照组（P〈0．05）。结论D-半乳糖慢性中毒所致衰老模型鼠免疫功能明显减退,氧自由基MDA、SOD的改变及生化学指标血糖、血脂改变趋势与自然衰老的动物模型相一致。     

Effects of Andrographis paniculata (Burm. F.) Extract on Diabetic Nephropathy in Rats

Background:Hyperglycemia and accumulation of advanced glycation end products (AGEs) play a significant role in the development of diabetic nephropathy. Andrographis paniculata (AP) is a plant with high flavonoid content with the potential to suppress oxidative stress activity in cells and tissue. This study was aimed to investigate the role of Andrographis paniculata extract (APE) in protecting kidney damage due to the formation of AGEs in the renal glomerulus in diabetic rats.Methods:A total of 30 male Sprague Dawley rats were randomly divided into five groups as follows: normal control group, streptozocin (STZ) induced diabetic group, STZ-induced diabetic group with AP extract (100 mg/kg BW), STZ-induced diabetic rats with AP extract (200 mg/kg BW), and STZ-induced diabetic rats with APE (400 mg/ kg BW). Blood glucose levels were measured before treatment and after treatment. Serum and urine parameters were determined. Antioxidant enzymes and lipid peroxide levels were determined in the kidney along with histopathological examination.Results:The finding of this study showed that treatment APE at the dose of 200 mg/kg and 400 mg/kg ameliorated kidney hypertrophy index. SOD, catalase, and GSH activities significantly decreased in the kidney of STZ-diabetic rats compared to the normal control rats. Treatment with APE significantly decreased malondialdehyde level at the dose of 200 and 400 mg/kg BW.Conclusion:This study revealed evidence for improving diabetic retinopathy in male rats treated with Andrographis paniculata extract. APE significantly decreased oxidative stress activities in kidney of diabetic rats.Key Words: Andrographis, Diabetic Nephropathies, Streptozocin, Rats, Oxidative Stress     

Early and advanced glycation end-products are increased in dietary copper deficiency

The hypothesis that nonenzymatic glycosylation of proteins (glycation) contributes to damage associated with dietary copper deficiency has depended largely on indirect evidence. Thus far, the observation of an elevated percentage of glycated hemoglobin in copper-deficient rats has provided the only direct evidence of an increase in glycation. We sought further direct evidence of increased glycation in copper deficiency. Male weanling rats were fed a copper-adequate (CuA, 6.4 mg Cu/kg diet) or copper-deficient diet (CuD, 0.4 mg Cu/kg diet) for 5 weeks. Rats fed the CuD diet were copper deficient as judged by depressed organ copper concentrations and a variety of indirect indices. Measurements of hemoglobin A(1) and serum fructosamine (both early glycation end-products) as well as serum pentosidine (an advanced glycation end-product) indicated that all three compounds were elevated in CuD rats relative to CuA rats. This finding further supports the view that glycation is enhanced and thus may contribute to defects associated with dietary copper deficiency.     

Ceftriaxone ameliorates cyclosporine A-induced oxidative nephrotoxicity in rat

A growing body of evidence now suggested that cyclosporine A (CycA)‐induced nephrotoxicity is a crucial clinical problem and oxidative stress is importantly responsible for its toxicity. Ceftriaxone induced antioxidant effect in brain and neuronal tissues against oxidative damage although its antioxidant potential effect on kidney has not been clarified. The aim of this study was to evaluate whether ceftriaxone protects CycA‐induced oxidative stress kidney injury in rats. Twenty‐four rats were equally divided into four groups. First group was used as control. Ceftriaxone (200 mg/kg) and CycA (15 mg/kg) were administrated to second and third groups for 10 days, respectively. The ceftriaxone and CycA combination was given to rats constituting the fourth group for 10 days. Lipid peroxidation (LP), urea nitrogen and lactate dehydrogenase (LDH) levels were higher in CycA group than in control and ceftriaxone groups although LP, urea nitrogen and LDH levels were lower in ceftriaxone + CycA group than in control and ceftriaxone groups. Glutathione peroxidase and catalase activities were lower in CycA group than in control whereas their activities were increased in control and ceftriaxone groups. Superoxide dismutase activity did not change by the treatments. Ceftriaxone administration recovered also CycA‐induced atrophy, vacuolization and exfoliations of tubular epithelium and glomerular collapse in histopathological evaluation of kidney. In conclusion, we observed that ceftriaxone is beneficial on CycA‐induced oxidative stress in kidney of rats by modulating oxidative and antioxidant system. Copyright © 2011 John Wiley & Sons, Ltd.     

Back-regulation of six oxidative stress proteins with grape seed proanthocyanidin extracts in rat diabetic nephropathy

Diabetic nephropathy (DN) is a major cause of morbidity and mortality in diabetic patients. To prevent the development of this disease and to improve advanced kidney injury, effective therapies directed toward the key molecular target are required. Grape seed proanthocyanidin extracts (GSPE) have been reported to be effective in treating DN, while little is known about the functional protein changes. In this study, we used streptozotocin (STZ) to induce diabetic rats. GSPE (250 mg/kg body weight/day) were administrated to diabetic rats for 24 weeks. Serum glucose, glycated hemoglobin, and advanced glycation end products were determined. Consequently, 2-D difference gel electrophoresis and mass spectrometry were used to investigate kidney protein profiles among the control, untreated and GSPE treated diabetic rats. Twenty-five proteins were found either up-regulated or down-regulated in the kidneys of untreated diabetic rats. Only nine proteins in the kidneys of diabetic rats were found to be back-regulated to normal levels after GSPE therapy. These back-regulated proteins are involved in oxidative stress, glycosylation damage, and amino acids metabolism. Our findings might help to better understanding of the mechanism of DN, and provide novel targets for estimating the effects of GSPE therapy.     

Edaravone inhibits acute renal injury and cyst formation in cisplatin-treated rat kidney

Background: Although cis-diamminedichloroplatinum (II) (cisplatin) is an effective anticancer agent, its clinical use is highly limited predominantly due to its adverse effects on renal functions. The present work examined the therapeutic potential of edaravone, a free radical scavenger, for inhibiting cisplatin-induced renal injury.

Methods: Edaravone, 3-methyl-1-phenyl-pyrazolin-5-one, was administrated intravenously at a dose of 30 mg/kg of body weight to male Wistar rats (200-220 g). After 30 min, cisplatin was injected intraperitoneally at a dose of 5 mg/kg of body weight. At the indicated times after the treatment, functions and histological changes of the kidney were analyzed. To test the therapeutic potential of edaravone in chemotherapy, its effect on the anticancer action of cisplatin was examined in ascites cancer-bearing rats.

Results: We found that cisplatin rapidly impaired the respiratory function and DNA of mitochondria in renal proximal tubules, thereby inducing apoptosis of tubular epithelial cells within a few days and chronic renal dysfunction associated with multiple cysts one-year after the administration. Administration of edaravone inhibited the cisplatin-induced acute injury of mitochondria and their DNA and renal epithelial cell apoptosis as well as the occurrence of chronic renal dysfunction and multiple cyst formation. The anticancer effect of cisplatin remained unaffected by intravenous administrating of edaravone.

Conclusions: These results indicate that edaravone may have therapeutic potential for inhibiting the acute and chronic injury of the kidney induced by cisplatin.     

Effect of dietary fluoride on selenite toxicity in the rat

Three factorial experiments were conducted to determine if high dietary fluoride (F) would inhibit selenite toxicity in rats. Initially, three levels of selenite (0.05, 3, and 5 mg/kg diet) were matched against three levels of F (2, 75, and 150 mg/kg diet). Fluoride failed to prevent the depressive effect of selenite on 8-wk food intake and body wt gain. Selenium (Se) concentration of plasma and kidney and enzymatic activity of whole blood glutathione peroxidase (GSH-Px) were also unaffected by F. Liver Se concentration, however, was slightly (12%) but significantly (p<0.025) reduced when the highest F and Se levels were combined. Fluoride (150 mg/kg) appeared to reduce liver selenite toxicity (5 mg/kg). Therefore, further study focused on liver histology with treatments that eliminated the middle levels of selenite and F. Fluoride prevented the hepatic necrosis seen in selenite-toxic rats. Similar histological lesions were not observed for kidney or heart. Fluoride partially (26%) but significantly (p<0.025) reduced thiobarbituric-reactive substances in selenite-toxic rats, but there was no F effect on intracellular distribution of liver Se, glutathione levels in liver and kidney, or on liver xanthine oxidase activity. Overall, the protective effect of F on selenite toxicity appears to be confined to liver pathology. The exact mechanism for this effect, however, remains unclear. Oregon Agricultural Experiment Station Technical Paper No. 9728.     

Effects of Grape Seed Proanthocyanidin Extracts on Aortic Pulse Wave Velocity in Streptozocin Induced Diabetic Rats

Grape seed proanthocyanidin extracts (GSPEs) have been reported to be effective in treating arteriosclerosis, while little is known about therapeutic agents against diabetic macrovascular complications. We used streptozocin to induce diabetic rats. GSPEs (250 mg/kg of body weight) were administrated to diabetic rats for 24 weeks. Aortic blood pressure and pulse wave velocity (PWV) were determined in anesthetized rats. Serum glycated hemoglobin and advanced glycation end products (AGEs) were determined. An electronic microscope was used to observe the changes in aortic ultrastructure. Immunohistochemistry was used to evaluate the receptor of advanced glycation end product (RAGE) protein expression in aortic tissue. GSPEs significantly decreased aortic PWV, blood pressure, and aortic medial thickness (P<0.05), and inhibited the migration of vascular smooth muscle cells. GSPEs significantly reduced the AGEs (P<0.05) and the expression of RAGE in aortas of diabetic rats. GSPEs play an important role against diabetic macrovascular complications. This study may provide a new recognition of natural medicine for the treatment of diabetic macrovascular complications.     

Beneficial Effect of Metformin on Nerve Regeneration and Functional Recovery After Sciatic Nerve Crush Injury in Diabetic Rats

Neuroprotective effects of metformin have been increasingly recognized in both diabetic and non-diabetic conditions. Thus far, no information has been available on the potential beneficial effects of metformin on peripheral nerve regeneration in diabetes mellitus. The present study was designed to investigate such a possibility. Diabetes was established by a single injection of streptozotocin at 50 mg/kg in rats. After sciatic nerve crush injury, the diabetic rats were intraperitoneally administrated daily for 4 weeks with metformin (30, 200 and 500 mg/kg), or normal saline, respectively. The axonal regeneration was investigated by morphometric analysis and retrograde labeling. The functional recovery was evaluated by electrophysiological studies and behavioral analysis. It was found that metformin significantly enhanced axonal regeneration and functional recovery compared to saline after sciatic nerve injury in diabetic rats. In addition, metformin at 200 and 500 mg/kg showed better performance than that at 30 mg/kg. Taken together, metformin is capable of promoting nerve regeneration after sciatic nerve injuries in diabetes mellitus, highlighting its therapeutic values for peripheral nerve injury repair in diabetes mellitus.     

Resistance to renal damage by chronic nitric oxide synthase inhibition in the Wistar-Furth rat

Chronic nitric oxide synthase inhibition (NOSI) causes chronic kidney disease (CKD) in the Sprague Dawley (SD) rat. We previously showed that the Wistar-Furth (WF) rats are resistant to several models of CKD and maintain renal nitric oxide (NO) production compared with SD rats, whereas low-dose NOSI caused progression of CKD in WF rats. Here, we evaluate the impact of high-dose chronic NOSI in WF and SD rats, as well as intrarenal responses to an acute pressor dose of NOSI in the normal WF. Rats were given N(G)-nitro-l-arginine methyl ester (l-NAME) (150 and 300 mg/l for 6-10 wk) in the drinking water after an initial bolus tail vein injection. Both strains showed significant reductions in total NO production with chronic l-NAME. SD given 150 mg/l l-NAME for 6 wk developed proteinuria and renal injury, whereas WF rats receiving 150 mg/l l-NAME for 6-10 wk or 300 mg/l for 6 wk developed no proteinuria and minimal renal injury. Blood pressure was significantly elevated with chronic NOSI in both strains but was higher in the SD rat. There was little impact on renal nitric oxide synthase expression with l-NAME, except that cortical endothelial nitric oxide synthase abundance increased in WF after 6 wk (150 mg/l). Micropuncture experiments with acute pressor NOSI resulted in similar increases in systemic blood pressure in SD and WF rats, whereas WF rats showed a much smaller increment in glomerular blood pressure compared with SD rats. In conclusion, WF rats do not develop renal injury after chronic NOSI at, or above, a dose that causes significant injury in the SD rat. This protection may be associated with protection from glomerular hypertension.