浅述高蛋白饮食对肾脏产生的影响

高蛋白饮食在肥胖患者及糖尿病患者中非常流行,但其带来的危害却往往被人们忽视。本文主要阐述高蛋白饮食是如何对肾脏产生影响。高蛋白饮食可能通过多种方式产生肾脏损害,括引起肾小球超滤过和肾充血;尿蛋白增加;发生肾结石的风险,以及各种代谢的改变。虽然对于肾脏健康的人没有明确的对高蛋白饮食的禁忌,但我们仍然不能排除理论上的风险。而对于肾脏疾病患者,进食高蛋白饮食可能会引起严重的损害。     

高脂饮食诱导肥胖小鼠白色脂肪组织中IL-33的表达及意义

目的:探讨细胞因子IL-33在高脂饮食诱导的肥胖小鼠体内不同类型白色脂肪组织的表达情况.方法:3T3-L1前脂肪细胞诱导分化10 d,ELISA检测细胞培养上清中IL-33的含量;Western blot和RT-PCR检测细胞中IL-33的表达.6～8周的C57BL/6雄性小鼠随机分为两组,高脂组给予60％高脂饲料饲养...     

慢性阻塞性肺疾病大鼠肺组织中Mdig表达及调控

目的探讨矿物粉尘诱导基因(mineral dust induced gene,Mdig)在慢性阻塞性肺疾病(COPD)模型大鼠肺组织中的表达及其调控机制。方法 12只Wistar雄性大鼠随机分为2组,正常对照组和COPD模型组,利用单纯吸入香烟烟雾的方法,每日2h,连续烟熏16周制造COPD模型大鼠;HE染色观察大鼠肺组织形态学改变;利用Western blot和Real time PCR技术检测COPD模型大鼠肺组织Mdig蛋白和基因的表达情况;利用免疫沉淀技术分析COPD模型大鼠肺组织Mdig蛋白是否存在泛素化修饰及泛素化修饰水平。结果单纯吸入香烟烟雾法连续烟熏16周后,大鼠肺组织出现典型的COPD病理改变;与对照组相比COPD模型大鼠肺组织中Mdig蛋白及基因表达水平均显著升高。免疫沉淀结果显示Mdig蛋白存在泛素化修饰作用,且COPD模型大鼠肺组织中Mdig蛋白泛素化修饰水平高于对照组,通过基因转录调控和翻译后泛素化修饰作用调控COPD病理状态下Mdig表达,导致Mdig蛋白表达增多。结论 Mdig可能是COPD引起肺癌发生的重要机制之一。     

肾脏SK通道的生理调节及分子结构

肾脏分泌性钾通道(secretory K charmel,SK channel)对于肾脏K+分泌有重要作用.分子生物学、微穿刺和微灌注等技术的联合应用使人们对SK通道的生理功能及分子结构有了较深入的认识,并已克隆出ROMK通道.本文就肾脏SK通道的生理特性、高K+摄入或醛固酮等因素对其的影响及其通道的基本分子结构进行简要综述.     

锌转运体-1在小鼠肾脏的表达

目的研究锌转运体-1(zinc transporter1,ZnT-1)在小鼠肾脏的定位分布。方法应用免疫组织化学技术和免疫印迹技术检测小鼠肾脏中ZnT-1的分布。结果 ZnT-1在肾脏内有丰富表达,其主要分布于远曲小管上皮细胞的近腔侧和基底侧的细胞膜上,而在肾小体、肾小管的其它部分以及髓质中的分布较少。结论小鼠肾脏内含有丰富的ZnT-1,ZnT-1可能参与了锌离子在肾脏的排泄和重吸收过程。     

小鼠肾脏发生发育中BAX的表达

目的 探讨小鼠肾脏发育过程中促凋亡蛋白BAX的表达.方法 选取胚龄16、18d和出生后1、3、5、7、14、21d的小鼠共54只,应用免疫组织化学、免疫荧光技术并结合体视学分析方法观察树脂切片上小鼠不同发育时期BAX的表达.结果 BAX的表达主要出现在近端小管,随着发育的不断进行,BAX的表达由皮质的近髓质区逐渐发展到中层皮质区,最后出现在浅层皮质区.BAX的面数密度从E16d到P3d逐渐升高,随后下降,在P7d又逐渐升高.结论 小鼠肾脏发育过程中BAX的表达与近端小管的发育密切相关,可能影响近端小管的存活、分化和成熟.     

饮食模式对大鼠糖尿病早期肾脏病变的影响及其机制

目的：使用不同饮食模式联合链脲佐菌素（STZ）诱导建立大鼠糖尿病模型,确认模型结果并探索饮食模式对大鼠糖尿病早期肾脏病变的影响及其可能的机制。方法：将147只SD大鼠分别以正常饮食（维持饲料且自由摄食,n=25）、控制饮食（维持饲料但减量20%,n=25）和高脂饮食（高脂饲料且自由摄食,n=97）分组喂养后注射低剂量STZ,以空腹血糖是否达到糖尿病造模标准再分为未成模大鼠和成模大鼠,追踪动物的摄食、饮水和体重,通过组织病理学分析各组大鼠肾脏病变,采集各阶段的血浆样品并检测内源性代谢产物进而开展代谢组学分析。结果：不同饮食模式联合低剂量STZ可不同程度诱发大鼠糖尿病早期肾脏病变,主要表现为肾小管空泡变性,累及部分近曲小管和远曲小管。高脂饮食组的糖尿病成模率（89.2%）和肾脏病变率均最高（造模前期7/10,造模后期57/59）,控制饮食组肾脏病变率最低（造模前期0/12,造模后期3/13）。相比正常饮食组,控制饮食组能量代谢和糖异生作用有关的代谢产物[如L-肉毒碱,不饱和脂肪酸二十四碳四烯酸（24:4n-6）,氨基酸及其衍生物L-胱硫醚、4-氯-L-苏氨酸、L-酪氨酸等]有显著差异（P&...     

蛋白酶体抑制剂处理神经细胞系后Nicastrin的表达变化及其与Aβ的关系

目的 探讨蛋白酶体抑制剂处理后神经细胞内Nicastrin(NCT)的表达变化,及其与γ-分泌酶活性和Aβ生成的关系.方法 运用亚细胞器分级分离技术、免疫共沉淀、Western blot和ELISA等检测神经细胞内NCT的表达及Aβ水平.结果 正常情况下NCT主要分布于内质网和高尔基复合体,极少量分布于溶酶体,蛋白酶体抑制剂Lactacystin处理后NCT水平升高(P<0.001),且细胞内增多的NCT也主要聚集在内质网和高尔基复合体;NCT与泛素在细胞内共存;NCT的蛋白降解不受PS的影响;NCT降解受阻可引起细胞内γ-分泌酶的底物C99、C83显著减少,而γ-分泌酶的产物Aβ40、Aβ42的生成显著增多(P<0.01).结论 NCT的降解可通过泛素-蛋白酶体途径实现,蛋白酶体抑制剂处理后神经细胞内NCT水平升高,且增多的NCT可促进APP的代谢及Aβ的生成.     

小泛素样修饰蛋白对α-突触核蛋白线粒体亚细胞定位及α-突触核蛋白经泛素系统降解的影响

目的 探讨α-突触核蛋白(α-synuclein)的小泛素样修饰蛋白1(small ubiquitin-like modifier1,SUMO-1)化修饰对α-synuclein蛋白亚细胞线粒体定位及α-synuelein蛋白经泛素系统降解的影响.方法 构建野生型、A53T突变型和缺失SUMO-1互作氨基酸的K96R突变型α-synuclein真核表达质粒.将野生型、A53T突变型和K96R突变型α-synuclein真核表达质粒分别转染HEK293细胞;在转染后48 h通过应用线粒体染色剂和激光共聚焦技术,观察野生型、A53T突变型及缺失SUMO-1修饰的α-synuclein蛋白的亚细胞线粒体定位和蛋白聚集情况.在转染后48 h应用anti-ubiquitin抗体进行Western印迹分析,明确野生型、A53T突变型及缺失SUMO-1修饰的α-synuclein蛋白泛素化程度有无差别.结果 将构建所得EGFP-α-synuclein-WT、EGFP-α-synuclein-A53T、EGFP-α-synuclein-K96R真核表达质粒经双酶切鉴定及DNA测序证实;激光共聚焦结果显示野生型、A53T突变型、K96R突变型α-synuclein蛋白均广泛分布于细胞质和细胞核中,以细胞质为主,野生型、A53T型细胞可见绿色荧光物质在胞质积聚,形成强荧光斑块,K96R型胞质内绿色荧光物质聚集少;野生型、A53T突变型、K96R突变型α-synuclein均与线粒体存在共定位,A53T突变型、K96R突变型α-synuclein在SUMO-1修饰或缺失的情况下对α-synuclein蛋白的线粒体亚细胞定位无明显影响.Western印迹结果显示转染缺失SUMO-1互作氨基酸的K96R突变型α-synuclein真核表达质粒组的细胞泛素蛋白的含量与转染空质粒组相比无明显变化,转染野生型、A53T突变型α-synuclein真核表达质粒组HEK293细胞中泛素蛋白的含量减少.结论 α-synuclein基因过度表达及致病突变A53T对α-synuclein蛋白的线粒体亚细胞定位无明显影响;SUMO-1修饰对α-synuclein蛋白的线粒体亚细胞定位也无明显影响;SUMO-1对a-αsynuclein基因过度表达及A53T突变型α-synuclein细胞内泛素化蛋白数量产生影响.     

增殖细胞核抗原在小鼠生后肾脏发育中的表达

目的：观察小鼠出生后肾脏发育过程中增殖细胞核抗原（PCNA）的表达特征,探讨出生后小鼠肾脏发育过程中细胞增殖的规律。方法：应用免疫组织化学技术检测小鼠出生后1、3、7、14、21、28和70d肾脏PCNA的表达。结果：小鼠出生后1～70d,皮质中的生肾区、肾小体、肾小管、髓放线以及髓质中的肾小管和集合管PCNA阳性细胞的表达具有一定的规律,早期PCNA阳性表达丰富,随着肾脏发育逐渐成熟而表达减弱直至消失。在70d成年小鼠肾脏中,没有检测到PCNA阳性细胞。结论：出生后小鼠肾脏皮质中的生肾区、肾小体、肾小管、髓放线以及髓质中小管的细胞增殖规律是由高逐渐降低的,直至成年完全停止。     

Decreased osteopontin expression in the rat kidney on a sodium deficient diet

Osteopontin (OPN) is a secreted phosphoprotein that is constitutively expressed in the normal kidney and is induced by various experimental and pathologic conditions. Several possible functions of OPN have been suggested, however the mechanism and significance of OPN expression are still uncertain. Since high salt concentration or salt crystal have been known to enhance OPN expression in intact kidney or cultured renal cells, in the present study we examined whether or not a low salt condition had an effect on OPN expression in the kidney. Adult male Sprague-Dawley rats were fed either a normal sodium or a sodium deficient diet for 1 week. Kidneys were processed for in situ hybridization using a digoxigenin-labeled riboprobe and for immunohistochemistry using antibodies to OPN, renin, and Na-K-ATPase. In rats fed a normal sodium diet, OPN mRNA and protein were expressed only in the descending thin limbs of Henle's loop (DTL) and in the papillary and pelvic surface epithelium (PSE). In rats fed a sodium deficient diet, there was a marked decrease in OPN immunoreactivity in the DTL, but no changes in PSE. In contrast, no changes were observed in OPN mRNA expression in the DTL by in situ hybridization, indicating that decreased OPN protein expression was a result of translational regulation. As expected, rats fed a sodium deficient diet were associated with increased immunoreactivity for Na-K-ATPase and renin compatible with activation of the renin-angiotensin system. These results suggest that dietary sodium may be involved in the regulation of OPN expression in the DTL of the rat kidney.     

Aldosterone and high-NaCl diet modulate ClC-2 chloride channel gene expression in rat kidney

It is well known that Na+ reabsorption in the kidney can be regulated by aldosterone. Although Cl- is the most abundant anion present in the extra cellular fluids the involvement of aldosterone in the regulation of Cl- conductance through Cl- channels at the molecular level is unknown. In this study, the effects of aldosterone and high-Na+ diet on the expression of ClC-2, a cell volume-, pH- and voltage-sensitive Cl- channel, was examined in the rat kidney. Total RNA isolated from Wistar rats fed a high-Na+ diet for 5 days, furosemide treatment, adrenalectomy and adrenalectomy with replacement of normal plasma levels of aldosterone were compared by the use of ribonuclease protection assay (RPA), and/or a semi-quantitative RT-PCR. The high-Na+ diet reduced renal mRNA and protein ClC-2 expression. The renal expression of ClC-2 mRNA decreased in adrenalectomized rats and was restored by plasma aldosterone replacement. In addition, the semi-quantitative RT-PCR in different segments of the nephron showed that these changes were secondary to the modulation of ClC-2 mRNA expression by aldosterone in the cortical and medullary segments of thick ascending limbs of Henle's loop. These results suggest that ClC-2 may be involved with aldosterone-induced Cl- transport in the kidney.     

Altered mRNA expression of basement membrane components in a murine model of polycystic kidney disease

Basement membranes surround the renal tubules and have been shown to limit their distension in vitro. Therefore, it has been postulated that a defect in a basement membrane component(s) underlies the pathogenesis of polycystic kidney disease. Here we have studied a murine model of congenital polycystic kidney disease and found by immunohistology, that the components of the peri-cyst basement membrane appeared to diminish with time. We also measured mRNA levels for collagen IV and laminin, and found a different pattern than in the normal mouse kidney. In normal kidneys, mRNA levels for the B1 and B2 chains of laminin were maximal at birth, and at 1 week for the alpha 1(IV) chain of collagen IV. With all three chains, the levels then rapidly declined. In contrast, mRNA for the alpha 1(IV) chain in congenital polycystic kidneys was half normal 1 week after birth and then increased. Laminin B1 and B2 chain mRNA's were 80% of normal at 1 week but were maintained at that level. As a control, beta-actin mRNA was examined and found to remain constant in both normal and diseased kidneys. In situ hybridization of cRNA probes for the alpha 1(IV) chain confirmed that cells associated with cysts were the principal source of expression of these basement membrane mRNAs. Thus, there exists an abnormal regulation of basement membrane gene expression in congenital polycystic kidney disease. The first stage is characterized by reduced levels of expression. In the second stage, the levels are abnormally high, perhaps representing a compensatory synthesis of basement membrane as cysts enlarge.     

高脂饮食对大鼠胸主动脉瘤形成过程中细胞黏附分子表达的影响

目的 探讨高脂饮食对胸主动脉瘤形成过程中细胞黏附分子包括血管细胞黏附分子-1(VCAM-1)和细胞间黏附分子-1(ICAM-1)表达的影响.方法 将30只成年雄性Wistar大鼠随机分为3组,即对照组、手术组和高脂饮食组,采用氯化钙(CaCl2)诱导法制备胸主动脉瘤模型,于术后4周取外敷CaCl2段胸主动脉.采用地衣红染色和HE染色观察胸主动脉形态学改变;免疫组织化学技术检测CD45、VCAM-1和ICAM-1的表达.结果 高脂饮食组动脉管径较手术组扩张明显,动脉管壁破坏更广泛,伴有更多的炎性细胞浸润;VCAM-1、ICAM-1较手术组表达升高.结论 高脂饮食可促进胸主动脉瘤管壁VCAM-1和ICAM-1的表达.     

Effect of moloney murine leukemia virus on the carcinogenicity of 3-methylcholanthrene in normal rat kidney cells

Summary Normal rat kidney (NRK) cell were found to be resistant to neoplastic transformation by diverse carcinogenic chemicals. To study chemical-retroviral co-carcinogenesis in this cells they were infected with a low multiplicity of Moloney murine leukemia virus (M-MLV). Using a single cell cloning procedure, a virus-producing clone was isolated from the infected cells, which was shown to carry only one integrated M-MLV provirus per cell. It was found that this single provirus was sufficient to render the clone susceptible to transformation by 3-methylcholanthrene (3-MC). However this clone responded differently to the carcinogen at different passages after infection. When exposed to 3-MC at a low passage postinfection (passage 5), cell transformation was evident only after 11 subsequent subcultures. On the other hand when it was chemically treated at a high passage postinfection (passage 29), cell transformation could clearly be detected already at the next subculture after the chemical treatment. It is suggested that an M-MLV-mediated cumulative effect is necessary to complement the action of the carcinogen in order to complete the carcinogenic process in these cells. This cumulative viral effect appeared to be associated with a change in the control of the virus expression, since 3-MC was found to stimulate virus replication in this clone also only at the high passage postinfection. Indeed virus release by cells of isolated transformed foci, produced by the chemical-M-MLV co-carcinogenesis, was extremely higher than by untransformed cells.With 4 Figures     

The effect of a high-fat diet on murine macrophage activity

The phagocytic, oxygen free radical generating and cytotoxic activities of macrophages from C57BL/6J mice fed either a normal or an atherogenic high-fat diet have been investigated. Phagocytosis of aggregated low density lipoprotein (LDL) was only slightly inhibited by the high-fat diet although phorbol myristate acetate (PMA)-induced hydrogen peroxide (H2O2) and superoxide anion (O2-) production was significantly reduced. Activation of tumoricidal activity against L929 target cells by lipopolysaccharide (LPS) or lymphocyte-derived macrophage-activating factor (MAF), but not N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP), was also significantly reduced in macrophages from mice fed the high-fat diet. These results indicate that an atherogenic diet is capable of significantly affecting the responsiveness of macrophages to a number of stimulatory agents which act via specific membrane receptors.     

母源性甲亢对仔鼠肾甲状腺素受体表达的影响

目的:研究母源性甲亢对新生仔鼠肾的影响。方法:建立妊娠合并甲亢模型,取新生1、5、10和15 d仔鼠肾。分别进行解剖学及组织病理检查,采用实时定量PCR法检测甲状腺激素受体(TR)TRα_1、TRα_2、TRβ_1在肾组织中mRNA水平表达量的变化。结果:母源性甲亢仔鼠与同期对照仔鼠相比,光镜结构未见明显异常;甲亢组TRα_1的表达量略高于对照组(仔鼠1 d上调约50%,仔鼠5 d上调约32%,仔鼠15 d上调约48%);甲亢组TRα_2的表达量略高于对照组(仔鼠1 d上调约36%,仔鼠10 d上调约33%);TRβ_1的表达差异无统计学意义。结论:母源性甲亢引起甲状腺激素受体的差异表达,以TRα_1、TRα_2的变化为主,可能在甲亢引起的子代肾损伤中扮演重要角色。     

Effect of tunicamycin on expression of epitopes on Japanese encephalitis virus glycoprotein E in porcine kidney cells

The effect of tunicamycin (Tm), a glycosylation inhibitor, on the epitopes expressed on Japanese encephalitis virus (JEV) glycoprotein E (gpE) in porcine kidney stable (PS) cells was studied. At Tm concentration of 2 micrograms/ml, the virus-infected cells showed markedly reduced or no reactivity with any of the monoclonal antibodies (MAbs) directed against JEV gpE except NHs-2 and also with polyclonal antibodies (PAbs) directed against JEV. With the increase in Tm concentration to 3 micrograms/ml, a complete loss of the conventionally detected reactivity of the MAbs except NHs-2 was recorded, while the Pabs showed no decrease in their reactivity. However, the MAb NHs-2 and PAbs lost their reactivity when the cells treated with 3 micrograms/ml Tm were stained for epitopes expressed on their surface indicating that glycosylation plays a role in this phenomenon. Tissue culture fluid (TCF) displayed a low virus content in the presence of 3 micrograms/ml Tm, indicating probably a down-regulation of virus maturation inside the cells. Since preM and NS-1 proteins possess besides gpE conserved N-glycosylation sites and play a role in the maturation of JEV, their expression in nascent, i.e. non-glycosylated form might be responsible for the observed low virus content of TCF. Thus, the glycosylation of JEV gpE seems essential for the acquisition of native conformation of its epitopes and their expression in cells.