The ameliorative effect of nanoselenium on histopathological and biochemical alterations induced by melamine toxicity on the brain of adult male albino rats

Melamine is a chemical substance used as a food adulterant because of its high nitrogen content; it is known to induce neurotoxicity, thereby adversely affecting the central nervous system. The biocompatibility, bioavailability, lower toxicity, and the large surface area of nanosized selenium relative to its other forms indicate that selenium nanoparticles (SeNPs) have a potential ameliorative effect against melamine-induced neurotoxicity. In this study, we tested this hypothesis using 40 adult male albino rats that were randomly assigned into four groups (n = 10 per group): group I rats served as the untreated negative controls and were fed with standard diet and distilled water; group II rats were orally treated with melamine (300 mg/kg body weight/d); group III rats orally received melamine (300 mg/kg body weight/d) and SeNPs (2 mg/kg body weight/d); and group IV rats received SeNPs only (2 mg/kg body weight/d) for 28 days. Blood and brain samples were collected from all rats and processed for biochemical, histopathological, and immunohistochemical investigations. SeNPs were encapsulated in starch as a natural stabilizer and a size-controlling agent (SeNP@starch). The prepared SeNPs were characterized using different techniques. Inductively coupled plasma-optical emission spectrometry (ICP-OES) indicated that the percentage of selenium loaded in starch was 1.888 %. Powder x-ray diffractometer (XRD) was used to investigate the crystalline structure of the Se-NP@starch, to be tubular and composed of amorphous starch as well as metallic selenium. Thermogravimetric analysis confirmed the thermal stability of the product and determined the interactions among the different components. Transmission electron microscope demonstrated the spherical shape of SeNPs and their dispersion into starch surface as well as evaluating their size in nanoscale (range 20−140 nm). Our results revealed that the melamine- exposed rats had significantly elevated in malondialdehyde levels, significantly reduced in total antioxidant capacity, down-regulated expression of the antioxidant related genes Nrf2 (nuclear factor erythroid 2–related factor 2) and GPx (glutathione peroxidase), as well as up-regulated expression of the apoptosis-related gene Bax (B-cell lymphoma 2–associated X protein), with down regulation of Bcl-2 (B-cell lymphoma 2). Histopathological examination exhibited several alterations in the cerebrum, cerebellum, and hippocampus of the treated rats compared with the controls. Neuronal degeneration, vacuolation of the neuropils, and pericellular and perivascular spaces were observed. In addition, the pyramidal and granular cell layers of the hippocampus and cerebellum, respectively, were found to have significantly reduced thickness. Furthermore, a significant decrease in the percentage area of the glial fibrillary acidic protein and a significant increase in the percentage area of caspase-3 were noted. On the other hand, co-treatment with SeNPs partially ameliorated these alterations. A significant reduction in malondialdehyde levels; a non- significant elevation in total antioxidant capacity; up-regulation, upregulation of Nrf2, GPx, and Bcl-2 and downregulation of Bax were recorded. Neuronal degeneration, vacuolation of neuropils, and pericellular spaces were reduced. The pyramidal and granular cell layers restored their normal thickness. The percentage area of the glial fibrillary acidic protein significantly increased, whereas that of caspase-3 significantly decreased. In conclusion, SeNPs have an ameliorative effect against melamine-induced neurotoxicity in albino rats.     

甲酚紫高氯酸盐-共振荧光光谱法测定三聚氰胺

目的:建立一种高灵敏度的共振荧光光谱法测定奶粉中三聚氰胺的新方法。方法:对B-R缓冲溶液-CPC表面活性剂介质中的甲酚紫高氯酸盐进行同步扫描,应用三维荧光和吸收光谱分析同步扫描光谱峰的共振荧光特性;基于三聚氰胺对甲酚紫高氯酸盐的共振荧光强度的抑制作用,建立阻抑共振荧光测定三聚氰胺的分析方法。结果:在9.6×10-8～2.8×10-6mol/L浓度范围内,体系的△F值与三聚氰胺浓度(c,10-6mol/L)之间具有良好的线性关系,线性回归方程为△F=106.59c-5.44,相关系数r=0.9993。检出限为2.87×10-8mol/L。奶粉样品测定的相对标准偏差为1.9%～2.7%,加标回收率为95.0%～103.1%。结论:方法灵敏,操作简便,分析成本低,用于奶粉中三聚氰胺的测定,结果满意。     

三聚氰胺致肾结石患儿的诊治

目的探讨三聚氰胺奶粉导致婴幼儿肾结石的临床诊断治疗效果。方法对该院2010年9月—2011年12月收治的43例三聚氰胺奶粉导致泌肾结石患儿的临床资料进行回顾性分析,患儿接受保守治疗,每日对患儿尿液pH值进行监测,观察尿结晶是否排出。结果 43例肾结石患儿超声检查结果显示大多数患儿结石大小为0.4～1.0cm,部分患儿伴有肾积水、输尿管扩张、集合系统分离。经过15～30d内科保守治疗后,患儿肾结石体积逐渐变小直至消失,患儿肾积水症状出现明显好转,肾功能恢复正常。结论采用内科保守治疗三聚氰胺奶粉导致泌肾结石患儿,溶石效果良好,临床治愈率高。     

巴马香猪Toll样受体4基因cDNA的克隆及生物信息学分析

目的观察三聚氰胺急性毒性及中药三金汤对三聚氰胺的清除作用。方法昆明小鼠90只,分为7组灌胃三聚氰胺,2组对照,观察其对小鼠的毒性。昆明小鼠70只分为7组,三金汤预防高、中、低剂量组,三金汤治疗组、三聚氰胺模型组、2组对照,一次性给予三聚氰胺后,观察三金汤对小鼠肾和肺三聚氰胺的清除作用。结果昆明小鼠灌胃三聚氰胺的LD50为9366mg／kg,肾脏未见结晶,肾、肝、肺有炎性细胞浸润。三聚氰胺灌胃后在肾、肺含量分别为327ng／g、177．5ng／g,三金汤预防高剂量组清除三聚氰胺效果最佳,肾、肺三聚氰胺含量分别降低至58ng／g、28．2ng／g。结论本实验条件下,初步认定三聚氰胺属微毒或无毒;中药三金汤对小鼠体内三聚氰胺的清除作用以三金汤预防高剂量组的效果最佳。     

婴幼儿泌尿系三聚氰胺结石影像检查特点

目的探讨婴幼儿泌尿系三聚氰胺结石的影像特点,总结不同影像检查的诊断价值。方法回顾分析17例婴幼儿泌尿系三聚氰胺结石的腹部平片、螺旋CT平扫和泌尿系超声检查表现,与7例非三聚氰胺结石病例的影像表现进行对照分析。结果17例三聚氰胺结石病例中,多发结石者8例,形态多不规则,CT值较对照组低,超声声像图显示结石强回声光团后方多伴淡声影或无声影。同时行腹部螺旋CT平扫和超声检查的病例中,2例CT发现的结石数量多于超声检查。结论三聚氰胺结石的影像特点为多发、体积小、密度低且形态不规则;腹部螺旋CT平扫对结石性状、数量及并发症的检出高于超声检查。     

三聚氰胺和三聚氰酸混合物所致肾结石的实验研究

目的评价枸橼酸和金钱草治疗三聚氰胺-三聚氰酸所致大鼠肾脏结石和急性肾功能损害的实验效果。方法40只sD幼龄鼠被随机分成4组。正常对照组（NC组）10只,常规喂养。三聚氰胺-三聚氰酸加自来水组（Mc组）、三聚氰胺-三聚氰酸加枸橼酸治疗组（CA组）、三聚氰胺-三聚氰酸加金钱草治疗组（HL组）各10只,三聚氰胺三聚氰酸悬浮液每日400／400mg／kg连续灌胃3d后,分别用自来水2mL／d、枸橼酸溶液每日1g／kg、金钱草溶液每日1g／kg连续灌胃10d。评价各组大鼠的平均体重、平均双侧肾重、肾重／体重、肾功能、肾脏组织病理学结果。结果MC组、CA组和HL组在三聚氰胺-三聚氰酸喂养期间平均体重进行性下降;停止喂养后分别用自来水、枸橼酸和金钱草溶液灌胃处理,平均体重逐渐上升。处理结束后3组平均体重显著低于NC组,平均双侧肾重、肾重／体重均明显高于NC组,肾功能明显受损,肾脏中均存在大量晶体。但MC组、CA组和HL组三组间平均体重、平均双侧肾重、肾重／体重、肾功能比较无统计学意义。结论三聚氰胺-三聚氰酸在大鼠肾脏中产生不溶性晶体并导致急性肾功能损害;短期的枸橼酸和金钱草治疗不能促进晶体排出或溶解晶体,不能改善肾功能。     

成都地区食用含三聚氰胺奶粉儿童泌尿系统结石发病情况调查

目的调查成都地区食用含三聚氰胺超标奶粉儿童泌尿系统结石的发病情况。方法对2008年9月17日～12月9日前来四川省人民医院进行“问题奶粉”筛查的5795例儿童进行泌尿系统B超检查,用SPSS13．0软件包对数据进行处理。结果调查期间筛查的5795例儿童中,患有泌尿系统结石者24例,发生率为0．41％。其中男12例,女12例;平均发病年龄2．35-1．68岁。调查结果显示,成都地区儿童泌尿系统结石的发病与性别无关（P〉0．05）,婴幼儿（≤3岁）组泌尿系统结石发生率高于学龄前和学龄期年龄（〉3岁）组（P〈0．05）。结论成都及周边地区食用“问题奶粉”的0—3岁婴幼儿泌尿系统结石发生率较高,远期后遗症尚待随访。     

婴幼儿三聚氰胺相关泌尿系结石并发急性肾衰竭诊疗分析

目的 探讨食用受三聚氰胺污染的婴幼儿配方奶粉致泌尿系结石并发急性肾衰竭患儿的临床特点、诊断和治疗措施.方法 回顾性分析首都医科大学附属北京儿童医院和徐州市儿童医院2008年收治的34例因食用三聚氰胺污染的婴幼儿配方奶粉致泌尿系结石、梗阻发生急性肾衰竭的患儿.分析其流行病学、临床表现及影像学特点,总结4种不同的治疗方法 及疗效.结果 34名患儿均存在急性肾衰竭,血尿素氮(24.1±8.2)mmol/L,血肌酐(384.2±201.2)μmol/L.对留取的14例结石标本分析证实,结石是三聚氰胺和尿酸的合成体.膀胱镜治疗组血肌酐降至正常的平均时间为(3.5±1.9)d;切开取石组(2.7±1.1)d;透析组(3.8±2.3)d;内科保守治疗组(2.7±1.6)d.四组肾功能恢复时间差异无统计学意义(P=0.508),组问差异无统计学意义(P=0.803～1).经治疗34例患儿急性肾衰竭全部治愈,泌尿系结石完全或部分排出.肾功能恢复时间为(3.0±1.8)d.结论 三聚氰胺污染婴幼儿配方奶粉可以导致婴幼儿泌尿系结石引发的梗阻性急性肾衰竭,治疗首选药物或透析方法 纠正电解质紊乱,特别是高钾血症,尽快通过内、外科方法 解除梗阻引流尿液.患儿近期预后良好.     

三聚氰胺及其类似物致大鼠肾结石动物模型建立

目的探讨三聚氰胺及其类似物（三聚氰酸）致肾结石动物模型的建立方法.方法雌性SD大鼠48只（167～206 g）随机分为对照组和实验组.根据每只大鼠每日进食三聚氰胺和三聚氰酸量的不同,将实验组又随机分为A、B、C三组.将计算出的每只大鼠每日进食三聚氰胺和三聚氰酸的量,溶于2 mL1%羧甲基纤维素钠内配制成混悬液予实验组灌胃,灌胃1周.对照组每日予2 mL1%羧甲基纤维素钠灌胃1周.灌胃结束时检测大鼠血肌酐、尿素氮并观察肾脏病理切片.结果给予不同剂量三聚氰胺其类似物后观察肾脏病理切片均有结晶形成,但181 mg组动物死亡率高,32 mg组结石形成率低.结论采用121 mg/（kg.day）（2 mL/day,共1周）三聚氰胺和三聚氰酸灌胃,能成功建立三聚氰胺及其类似物（三聚氰酸）肾结石动物模型.     

三聚氰胺对大鼠肾脏的毒性损害

目的观察三聚氰胺对大鼠肾脏的毒性损害。方法实验动物随机分为2组,每组20例,第1组为正常对照组,给予正常维持鼠料20d;第2组为研究组（亚急性损害组）,喂食掺有三聚氰胺的鼠料20d。完成饲养后先做超声检查,观察大鼠肾脏的形态、大小、皮质厚度、实质回声情况及肾内是否有结石形成,然后留取尿液、静脉血做相关检验,最后解剖大鼠,留取双侧肾脏标本,福尔马林浸泡,待病理切片观察。结果正常对照组病理所见、生化结果、超声表现未见异常改变。研究组超声显示,20只大鼠的40个肾脏实质部回声增强,肾内均可见散在多发的细小强回声结石影,较大者位于集合系统内,伴有声影,8个肾脏出现集合系统分离;实验室检查14只大鼠出现结晶尿,其中8只出现三聚氰胺结晶,20只大鼠尿素升高,10只肌酐增高,14只出现二氧化碳结合率降低;研究组有不同程度病理损害,典型表现有肾组织广泛淤血伴灶性出血,肾小管伴有点状坏死及成纤维细胞增生,数个肾小管（以皮质肾小管为多）内可见黄绿色针状扇形排列结晶体,相应肾小管扩张,部分区域间质内可见数个淋巴细胞浸润。结论三聚氰胺可引起大鼠肾脏病理损害,并可导致结石形成,沉积于肾脏,造成肾损害。