中药泽泻中提取的化合物对尿草酸钙结石形成的影响

目的 通过乙二醇与氯化铵诱导的大白鼠肾草酸钙结石模型观察从中药泽泻中提取的三种化合物对尿草酸钙结石形成的影响,并探讨其抑制尿草酸钙结石形成的有效成分.方法 中药泽泻饮片,经药理学方法得到化合物Ⅰ、化合物Ⅱ、化合物Ⅲ.50只Wistar雄性健康大白鼠,随机分为5组,A组:正常空白对照组;B组:草酸钙结石成石组;C组:化合物Ⅰ实验组,在给予诱石剂的同时,每只大鼠每天灌胃化合物Ⅰ 1 ml,其他各实验组以此类推;D组:化合物Ⅱ实验组;E组:化合物Ⅲ实验组.各组在相同条件下饲养4周后,用代谢笼收集大鼠的24 h尿液检测24 h尿草酸(OX),Ca2+含量,断颈处死大鼠检测肾组织Ca2+含量,偏光显微镜下观察肾组织Von-Kossa's染色切片中草酸钙结晶大小,形态分布和肾小管损害程度.结果 C组24 h尿Ca2+(61.49±2.06)含量高于B组(37.23±1.84),差异有统计学意义(P<0.05);肾Ca2+(10.35±6.45)含量明显低于B组(49.20±9.63),差异有统计学意义(P<0.01);切片可见少量草酸钙晶体沉积和肾小管轻度扩张.结论 从中药泽泻中提取的化合物I能显著降低肾组织Ca2+含量和增加草酸钙结石大白鼠24 h尿Ca2+的分泌量,明显降低草酸钙晶体在肾脏的沉积和减轻肾小管的损害程度,因而化合物Ⅰ是泽泻抑制尿草酸钙结石形成的重要成分.     

草酸钙结石形成对肾组织bikunin和IαI表达的影响

目的研究肾草酸钙结石形成对肾组织bikunin基因和间α胰蛋白酶抑制物(IαI)蛋白表达的影响,探讨bikunin在尿结石形成中的意义。方法诱导实验性大鼠肾草酸钙结石模型,收集结石大鼠、正常大鼠、临床肾结石和非结石患者每组各8例的肾组织标本。采用免疫组化、逆转录聚合酶链反应(RT-PCR)和计算机图像分析技术分别检测所有大鼠和人肾组织中bikuninmRNA和IαI蛋白的表达水平。结果正常大鼠和非结石患者肾组织均存在bikuninmRNA和IαI蛋白的表达。肾草酸钙结石形成后,结石大鼠肾组织IαI蛋白的灰度值和bikuninmRNA的相对表达水平分别为198.43±15.17、0.70±0.14;肾结石患者肾组织IαI蛋白的灰度值和bikuninmRNA的相对表达水平分别为263.25±17.41、1.27±0.13,分别和对照组相比,均显著增加(P<0.05)。结论Bikunin作为构成IαI的轻链结构,在肾草酸钙结石形成后,bikuninmRNA的表达迅速增强,提示机体通过肾脏合成更多的bikunin来抑制肾草酸钙结石的形成。     

草酸钙结石形成对肾组织bikunin和ⅠαⅠ表达的影响

目的研究肾草酸钙结石形成对肾组织bikunin基因和间α胰蛋白酶抑制物(ⅠαⅠ)蛋白表达的影响,探讨bikunin在尿结石形成中的意义.方珐诱导实验性大鼠肾草酸钙结石模型,收集结石大鼠、正常大鼠、临床肾结石和非结石患者每组各8例的肾组织标本.采用免疫组化、逆转录聚合酶链反应(RT-PCR)和计算机图像分析技术分别检测所有大鼠和人肾组织中bikuninmRNA和ⅠαⅠ蛋白的表达水平.结果正常大鼠和非结石患者肾组织均存在bikunin mRNA和IαI蛋白的表达.肾草酸钙结石形成后,结石大鼠肾组织ⅠαⅠ蛋白的灰度值和bikunin mRNA的相对表达水平分别为198.43士15.17、0.70士0.14;肾结石患者肾组织IαI蛋白的灰度值和bikunin mRNA的相对表达水平分别为263.25士17.41、1.27±0.13,分别和对照组相比,均显著增加(P＜0.05).结论Bikunin作为构成IαI的轻链结构,在肾草酸钙结石形成后,bikunin mRNA的表达迅速增强,提示机体通过肾脏合成更多的bikunin来抑制肾草酸钙结石的形成.     

草酸钙结石形成对肾组织bikunin和IαⅠ表达的影响

目的研究肾草酸钙结石形成对肾组织bikunin基因和间α胰蛋白酶抑制物(ⅠαⅠ)蛋白表达的影响,探讨bikunin在尿结石形成中的意义.方珐诱导实验性大鼠肾草酸钙结石模型,收集结石大鼠、正常大鼠、临床肾结石和非结石患者每组各8例的肾组织标本.采用免疫组化、逆转录聚合酶链反应(RT-PCR)和计算机图像分析技术分别检测所有大鼠和人肾组织中bikuninmRNA和ⅠαⅠ蛋白的表达水平.结果正常大鼠和非结石患者肾组织均存在bikunin mRNA和IαI蛋白的表达.肾草酸钙结石形成后,结石大鼠肾组织ⅠαⅠ蛋白的灰度值和bikunin mRNA的相对表达水平分别为198.43士15.17、0.70士0.14;肾结石患者肾组织IαI蛋白的灰度值和bikunin mRNA的相对表达水平分别为263.25士17.41、1.27±0.13,分别和对照组相比,均显著增加(P＜0.05).结论Bikunin作为构成IαI的轻链结构,在肾草酸钙结石形成后,bikunin mRNA的表达迅速增强,提示机体通过肾脏合成更多的bikunin来抑制肾草酸钙结石的形成.     

高血糖在高草酸尿环境下促进肾草酸钙结石形成的机制研究

目的通过细胞及动物实验,探究高血糖促进草酸钙结石形成的机制。方法八周龄Wistar雄性大鼠(共40只)随机分为4组:阴性对照组、高草酸尿模型组,高血糖模型组,高血糖合并高草酸尿模型组;每组10只。采用q RT-PCR检测在含有不同浓度葡萄糖培养基下HK2细胞中OPN、MCP-1、Cbfa1、BMP-2 m RNA的表达;酶联免疫吸附测定(ELISA)检测OPN与MCP-1在培养基中的浓度;钙盐染色检测各组大鼠肾组织中草酸钙结石晶体;细胞凋亡试验检测各组大鼠肾组织中肾小管上皮细胞凋亡。免疫组织化学染色法(IHC)检测OPN在各组大鼠肾组织中的表达;ELISA检测MCP-1在各组大鼠24小时尿液中的含量。结果高浓度葡萄糖环境中,HK-2细胞的OPN与MCP-1表达上调。高血糖合并高草酸尿模型组肾组织中有大量草酸钙沉积,大量肾小管上皮细胞凋亡,OPN表达显著增加,其尿液中MCP-1总量明显增加,与其他组相比有统计学差异(P0.05)。结论高血糖能促使肾小管上皮细胞炎症趋化因子OPN、MCP-1表达增加。在高草酸尿环境中,高血糖能促进肾小管上皮细胞凋亡及草酸钙结石形成。高血糖可能是通过炎症趋化因子加重局部炎症反应,促进肾小管上皮细胞凋亡及草酸钙结石形成。     

尿凝血酶原片断1在肾结石模型大鼠肾组织的表达及其意义

目的　研究尿液中尿凝血酶原片段 1(UPTF1)的来源和UPTF1在肾结石模型大鼠肾组织的表达 ,探讨尿结石形成对肾组织UPTF1表达的影响及其在尿结石形成中的意义。方法用乙二醇和 1α 羟基维生素D3 灌胃制作大鼠肾草酸钙结石模型。采用半定量逆转录聚合酶链反应(RT PCR)检测UPTF1mRNA在结石模型大鼠和正常对照大鼠肾组织中的表达及水平变化。结果　偏光显微镜下结石模型大鼠肾乳头和肾皮质内布满草酸钙晶体 ,肾钙含量、2 4h尿草酸和尿钙分泌量分别为 13 8.3 9mg/g、82 .89μmol和97.3 5 μmol;对照组肾钙含量、2 4h尿草酸和尿钙分泌量分别为 1.5 4mg/g、2 4.2 2 μmol和3 .14 μmol,组间差异均有统计学意义(P <0 .0 1)。UPTF1mRNA在所有大鼠肾组织和肝组织中都有表达 ,但在正常大鼠和肾结石大鼠肾组织中的相对表达量分别为 1.73± 0 .2 5、1.86± 0 .19,两组差异无统计学意义意义 (P >0 .0 5 )。结论　尿液中的UPTF1来源于大鼠肾组织的生物合成 ,可能是草酸钙结石形成的生理性抑制因子 ,从而可以借助实验动物模型为研究UPTF1在尿结石形成中的作用提供了依据。     

苄丙酮香豆素对实验性大鼠肾草酸钙结石形成的影响

目的：探讨Vit．K拮抗剂苄丙酮香豆素(商品名华法令)对大鼠肾草酸钙结石形成的影响。方法：采用乙二醇饮水和氯化铵灌胃作成石剂，30只Wistar大鼠随机分为对照组(A组)、成石组(B组)、华法令组(C组)。饲养4周后，检测大鼠肾组织钙含量和草酸钙晶体形成、24h尿钙、尿草酸含量及血生化指标。结果：成石组和华法令组肾组织中钙、镁含量，24h尿草酸及尿钙、镁排泄量差异无显著性意义；镜下观察发现：华法令组大鼠肾脏草酸钙结晶形成多于成石组，但组间比较差异无显著性意义。结论：苄丙酮香豆素对大鼠肾草酸钙结石的形成无显著影响。     

泽泻提取物对大鼠尿结石形成和间α胰蛋白酶抑制物表达的影响

目的　观察中药泽泻的有效部位提取物对实验性大鼠尿草酸钙结石形成和间α胰蛋白酶抑制物 (IαI)表达的影响。方法　采用乙二醇和氯化铵诱导形成大鼠肾草酸钙结石模型 ,将健康成年雄性Wistar大白鼠随机分成对照组 (A组 )、成石组 (B组 )、泽泻组 (C组 )。用免疫组织化学和计算机图像分析技术检测IαI在肾组织的表达情况 ,并测定血、尿生化和草酸钙晶体在肾组织的分布。结果　泽泻组大鼠肾组织草酸钙晶体分布、血生化等指标均明显低于结石模型组 ;泽泻组大鼠肾组织IαI的灰度值为 2 18.3 2± 7.5 8、肾钙含量 (7.3 2± 1.5 9)mg/g、2 4h尿钙分泌量 (5 .3 4±1.10 ) μmol/2 4h ,模型组大鼠IαI的灰度值为 2 0 3 .40± 14 .69、肾钙含量 (12 .63± 2 .2 9)mg/g、2 4h尿钙分泌量 (8.5 3± 1.73 ) μmol/2 4h ,两组间差异均有显著性 (P <0 .0 5 )。 结论　泽泻的乙酸乙酯浸膏的乙酸乙酯洗脱液提取物可能通过抑制肾组织内草酸钙晶体的形成和减少肾IαI的表达 ,从而能抑制尿结石的形成。     

中药泽泻提取物对尿草酸钙结石形成影响的实验研究

目的　探讨中药泽泻对尿草酸钙结石形成的影响。　方法　采用种晶技术检测泽泻水溶性提取物 (C1、C2 组 )、5 0 %甲醇提取物 (D1、D2 组 )和 10 0 %甲醇提取物 (E1、E2 组 )对体外一水草酸钙晶体生长的抑制指数 (I .I)。 80只Wistar大鼠随机分为 8组 ,对照组 (A组 )、成石组 (B组 )、泽泻水溶性提取物组 (CL、CH 组 )、5 0 %甲醇提取物组 (DL、DH 组 )、10 0 %甲醇提取物组 (EL、EH 组 ) ,分别予不同浓度的泽泻水溶性提取物和甲醇提取物。饲养 4周后 ,检测各组大鼠血生化 ,2 4h尿草酸(Ox)、Ca2 + 、Mg2 + 分泌量和肾组织Ca2 + 、Mg2 + 含量。镜下观察肾组织切片中草酸钙结晶及肾小管扩张情况。　结果　C1、C2 、D1、D2 、E1、E2 组I.I分别为 90 .5 6 %、76 .4 7%、74 .38%、86 .4 1%、6 1.17%和 11.89%。动物实验A组血BUN、Cr明显低于其他各组 ,差异有显著性意义 (P <0 .0 5 ) ;各组间血Ca2 + 、P浓度无显著性差异 ;2 4h尿Ox、Ca2 + 和Mg2 + 分泌量各泽泻实验组与B组差异无显著性意义(P >0 .0 5 ) ;CH、DL、DH 组肾组织Ca2 + 含量明显低于B组 ,差异有显著性意义 (P <0 .0 5 ) ,各组间肾组织Mg2 + 含量差异无显著性 (P均 >0 .0 5 )。A组肾小管正常 ,B组肾小管腔可见大量成片草酸钙结晶存在 ,管腔明显扩张     

钙敏感受体活性改变对大鼠泌尿系草酸钙结石形成的影响

目的探讨钙敏感受体（CaSR）活性改变对草酸钙结石形成的影响。方法在实验期间给予乙二醇和氯化铵诱导雄性SD大鼠产生泌尿系草酸钙结石。在造模期间给予不同剂量的CaSR抑制剂（NPS-2390）。实验结束时检测各组大鼠血尿素氮（BUN）、肌酐（Cr）、血磷、血钙、血镁、PTH的含量、24h尿量、尿pH值、尿钙、镁、尿草酸的分泌量,显微镜下观察肾组织切片中草酸钙结晶沉积及病理变化情况及肾脏中CaSR表达情况。从而评价CaSR活性的改变对泌尿系结石形成的影响。结果成石对照组大鼠血BUN、Cr、尿草酸、尿钙较空白组明显升高并且有大量结晶形成,表明建模成功。CaSR抑制剂组较成石对照组甲状旁腺激素（PTH）的分泌增加并且血Ca2＋升高尿钙升高。肾组织病理学检查显示CaSR抑制组的肾脏组织中的草酸钙结晶较成石对照组明显增加,组织病理损伤也较重。结论肾脏中及甲状旁腺中CaSR的表达下降可以导致草酸钙结晶的形成增加。     

Expression of inter-alpha inhibitor related proteins in kidneys and urine of hyperoxaluric rats

PURPOSE: To investigate the involvement of the inter-alpha inhibitor family of proteins in calcium oxalate stone formation we determined immunohistochemical distribution in the kidneys and excretion in the urine of these proteins in normal and hyperoxaluric rats. Various members of the family have been shown to inhibit the formation and retention of calcium oxalate crystals in the kidneys. MATERIALS AND METHODS: Hyperoxaluria was induced in male Sprague-Dawley rats by administering 0.75% ethylene glycol. The inter-alpha inhibitor family consists of inter-alpha inhibitor, pre-alpha inhibitor, the so-called heavy chains H1, H2 and H3, and the light chain bikunin. Antibodies against these molecules were used to localize various proteins in rat kidneys by immunohistochemical techniques. Urine was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis to determine the expression of various members of the inter-alpha inhibitor family. RESULTS: In normal kidneys staining for inter-alpha inhibitor and other members of the family was mostly limited to the proximal tubules and generally to their luminal contents. Eight weeks after the induction of hyperoxaluria various sections of renal tubules stained positive for inter-alpha inhibitor, bikunin and H3. Positive staining was observed in the tubular lumina as well as in the cytoplasm of epithelial cells. Crystal associated material was heavily stained. Western blot analysis recognized 7 protein bands in the urine. The urinary expression of H1, H3 and pre-alpha-inhibitor was significantly increased. CONCLUSIONS: Apparently hyperoxaluria and renal calcium oxalate crystal deposition result in the increased expression of crystallization inhibitors, such as inter-alpha-inhibitor related proteins, in the kidneys and urine. Results indicate that kidneys respond to nephrolithic challenges by producing proteins that inhibit crystal formation and retention.     

Role of Oxalobacter formigenes in preventing calcium oxalate kidney stones

Objective To screen Oxalobacter formigenes (OxF) from fresh feces of healthy adults, and study its effect on the the prevention of calcium oxalate kidney stones. Methods OxF was screened and cultured from fresh feces of healthy adults. The rat model of calcium oxalate stone was established by esophageal gavage of 0.8% of ethylene glycol. Rats were divided into a control group and four groups of rats with ethylene glycol-induced calcium oxalate kidney stones according to random number table. Three groups were treated with 106 CFU, 107 CFU, 108 CFU viable OxF every day, respectively, for 4 weeks. The blood and 24-hour urine samples were collected to detect the serum creatinine, urea nitrogen, serum and urine calcium, phosphorus, magnesium and urine oxalate every week. At the end of the 4th week, the rats were sacrificed and the kidney tissues were stained with HE and Yasue. The deposition and content of calcium oxalate crystals were observed under a light microscope. Results The bacteria strain isolated from fresh feces of healthy adults was 100% as same as the known ATCC35274 bacteria strain, which means the strain screened is OxF. Among the 5 groups, there were no significant differences in body weight, Scr, BUN, serum calcium, blood magnesium, blood phosphorus, urinary magnesium and urinary phosphorus. The 24-hour urinary calcium excretion in the model group was significantly lower than that of the control group (P＜0.05). After intervention with OxF solution, the 24-hour urinary calcium excretion in the 108 CFU OxF group was significantly higher than that in the model group (P＜0.05), while there was no significant difference between the other intervention groups and the model. The oxalic acid excretion of 106 CFU OxF group and 107 CFU OxF group was lower than that of the model, but the difference did not reach statistical significance (P＞0.05). The 24 h oxalic acid excretion in the 108 CFU OxF group was significantly lower than that of the model at the end of first week (P＜0.05), and continued to decrease for the next 3 weeks. After 4 weeks of intervention, no crystal formation was observed in the control group under the deflection microscope, but a large amount of calcium oxalate crystals were formed in the renal cortex and renal medulla. The crystals were piled up and connected to each other. Yasue staining coincided with the calcium oxalate crystal in the same part of the kidneys. Compared with the model, there was no significant change in the score of calcium oxalate crystal in the kidneys of 106 CFU OxF group and 107 CFU OxF group, while the score of calcium oxalate crystal in the kidneys of 108 CFU OxF group was significantly lower (P＜0.05). Conclusions OxF are successively screened from healthy adults. Daily administration of 108 CFU OxF can safely and effectively reduce the urinary oxalic acid excretion, prevent the formation of calcium oxalate crystals and inhibit the formation of stones in kidneys of rats.     

The influence of sex hormones on renal osteopontin expression and urinary constituents in experimental urolithiasis

PURPOSE: To our knowledge the influence of sex hormones on urinary stone formation remains undetermined. We investigated the effect of castration on urinary lithogenic factors and renal osteopontin expression in rats previously treated with ethylene glycol. MATERIALS AND METHODS: Sprague-Dawley rats were divided normal males, castrated males, males with 2 weeks of 0.75% ethylene glycol treatment, castrated males with 2 weeks of 0.75% ethylene glycol treatment, normal females, castrated females, females with 2 weeks of 0.75% ethylene glycol treatment and castrated females with 2 weeks of 0.75% ethylene glycol treatment. We analyzed 24-hour urine samples for urinary constituents, such as calcium, oxalate, citrate, uric acid, phosphate, magnesium, sodium, potassium and creatinine. The kidneys were examined for osteopontin expression by Northern blot analysis and for crystal deposition by histological examination. RESULTS: In intact male rats calcium and citrate excretion decreased and oxalate excretion increased significantly after ethylene glycol treatment. Castrated male rats with ethylene glycol had greater calcium and less oxalate excretion than male intact rats with ethylene glycol. In intact female rats uric acid excretion decreased and only calcium excretion increased significantly after ethylene glycol treatment. Castrated female rats with ethylene glycol excreted significantly more oxalate and less calcium than intact female rats with ethylene glycol. Renal osteopontin expression was the same in male intact and castrated rats, and in female intact and castrated rats. In males with ethylene glycol expression was stronger in castrated than in intact rats. In females with ethylene glycol expression was weaker in castrated than in intact rats. No crystal deposits were found in the kidneys in any group. CONCLUSIONS: Testosterone appears to promote stone formation by suppressing osteopontin expression in the kidneys and increasing urinary oxalate excretion. Estrogen appears to inhibit stone formation by increasing osteopontin expression in the kidneys and decreasing urinary oxalate excretion.     

Dietary oxalate and calcium oxalate nephrolithiasis

PURPOSE: Patients with calcium oxalate kidney stones are advised to decrease the consumption of foods that contain oxalate. We hypothesized that a cutback in dietary oxalate would lead to a decrease in the urinary excretion of oxalate and decreased stone recurrence. We tested the hypothesis in an animal model of calcium oxalate nephrolithiasis. MATERIALS AND METHODS: Hydroxy-L-proline (5%), a precursor of oxalate found in collagenous foods, was given with rat chow to male Sprague-Dawley rats. After 42 days rats in group 1 continued on hydroxy-L-proline, while those in group 2 were given chow without added hydroxy-L-proline for the next 21 days. Food and water consumption as well as weight were monitored regularly. Once weekly urine was collected and analyzed for creatinine, calcium, oxalate, lactate dehydrogenase, 8-isoprostane and H(2)O(2). Urinary pH and crystalluria were monitored. Rats were sacrificed at 28, 42 and 63 days, respectively. Renal tissue was examined for crystal deposition by light microscopy. RESULTS: Rats receiving hydroxy-L-proline showed hyperoxaluria, calcium oxalate crystalluria and nephrolithiasis, and by day 42 all contained renal calcium oxalate crystal deposits. Urinary excretion of lactate dehydrogenase, 8-isoprostane and H(2)O(2) increased significantly. After hydroxy-L-proline was discontinued in group 2 there was a significant decrease in urinary oxalate, 8-isoprostane and H(2)O(2). Half of the group 2 rats appeared to be crystal-free. CONCLUSIONS: Dietary sources of oxalate can induce hyperoxaluria and crystal deposition in the kidneys with associated degradation in renal biology. Eliminating oxalate from the diet decreases not only urinary oxalate, but also calcium oxalate crystal deposits in the kidneys and improves their function.     

Effect of angiotensin II receptor blockage on osteopontin expression and calcium oxalate crystal deposition in rat kidneys

Hyperoxaluria leads to calcium oxalate (CaOx) crystallization and development of tubulointerstitial lesions in the kidneys. Treatment of hyperoxaluric rats with angiotensin II (Ang II) type I receptor blocker (ARB) reduces lesion formation. Because Ang II mediates osteopontin (OPN) synthesis, which is involved in both macrophage recruitment and CaOx crystallization, it was hypothesized that ARB acts via OPN. Hyperoxaluria was induced in 10-wk-old male Sprague-Dawley rats, and they were treated with ARB candesartan. At the end of 4 wk, kidneys were examined for crystal deposits, ED-1-positive cells, and expression of OPN mRNA. PCR was used to quantify OPN, renin, and angiotensin-converting enzyme (ACE) mRNA in kidneys. RIA was used to determine renal, plasma, and urinary OPN; plasma renin; Ang II and ACE; and renal Ang II. For evaluating oxidative stress, malondialdehyde was measured. Urinary calcium, oxalate, creatinine, and albumin were also determined. Despite similar urinary calcium and oxalate levels, kidneys of hyperoxaluric rats on candesartan had fewer CaOx crystals, fewer ED-1-positive cells, reduced OPN expression, and reduced malondialdehyde than hyperoxaluric rats. Urinary albumin excretion and serum creatinine levels improved significantly on candesartan treatment. mRNA for OPN, renin, and ACE were significantly elevated in hyperoxaluric rats. OPN synthesis and production increased with hyperoxaluria but to a lesser extent in candesartan-treated hyperoxaluric rats. These results show for the first time that oxalate can activate the renal renin-angiotensin system and that oxalate-induced upregulation of OPN is in part mediated via renal renin-angiotensin system.     

Effect of etidronate disodium (EHDP) on calcium oxalate renal stones induced by synthetic 1 alpha(OH) vitamin D3 and ethylene glycol in rats

Combination of 1 alpha(OH) D3(vit D) and ethylene glycol induced renal or ureteral stones or both consisting of calcium oxalate in male Wistar rats. This study investigates the effect of EHDP on calcium oxalate stone using the rat model. EHDP reduced the frequency of renal stone and calcium content in the kidney, and reduced the size of the stones in the renal pelvis and ureter. EHDP biochemically ameliorated renal injury induced by vit D and ethylene glycol. EHDP suppressed urinary excretion of calcium even though serum calcium slightly increased. EHDP had a phosphaturic action. EHDP elevated urinary excretion of magnesium. However, the severity of hypermagnesuria decreased in the rat which was not given EHDP concomitantly. Although EHDP slightly elevated urinary excretion of oxalate in the control rat, it did not affect the high level of urinary oxalate in the vit D/ethylene glycol rat. EHDP did not produce any histological change in the kidney or femoral bone. These data indicate that EHDP can suppress renal stone formation in the vit D/ethylene glycol rat. It is speculated that firstly, EHDP may physicochemically inhibit stone formation in the process of nidus, aggregation and crystal growth of calcium oxalate, under the supersaturated condition of calcium oxalate in the urine, and secondly, EHDP may endocrinologically inhibit production of 1,25 (OH)2 vit D in the kidney or inhibit 1, 25 (OH)2 vit D-mediated intestinal calcium absorption. It is suggested that in order to prevent stone recurrence, EHDP may be clinically applied not only to calcium phosphate stones but also to calcium oxalate stones and hypercalciuria mediated by an active form of vitamin D.     

Characterization of Tamm-Horsfall protein in a rat nephrolithiasis model

PURPOSE: The role of Tamm-Horsfall protein in calcium oxalate stone formation is controversial. It is unclear whether Tamm-Horsfall protein has a role in crystallization. If it does, does it act as an inhibitor or promoter of crystallization? To elucidate the nature of its involvement we characterized Tamm-Horsfall protein in a rat model of calcium oxalate nephrolithiasis by in vivo and in vitro techniques. MATERIALS AND METHODS: Calcium oxalate nephrolithiasis was induced in male Sprague-Dawley rats. The amino acid and carbohydrate composition of Tamm-Horsfall protein from normal rats and those with nephrolithiasis was determined. The Tamm-Horsfall protein gene and protein expression in the kidneys were examined by in situ hybridization and immunohistochemistry. Furthermore, the interaction of Tamm-Horsfall protein and calcium oxalate crystals was assessed by an in vitro crystal aggregation assay. RESULTS: Tamm-Horsfall protein from rats with nephrolithiasis was biochemically similar to that from normal rats. Although Tamm-Horsfall protein was associated with crystal deposits in the renal papillae of rats with nephrolithiasis, Tamm-Horsfall protein messenger RNA expression in the kidneys remained unchanged. In each group Tamm-Horsfall protein inhibited calcium oxalate crystal aggregation by 47%, indicating no change in functional capabilities. CONCLUSIONS: The results of this study indicate that urinary excretion, and the biochemical nature and functional capabilities of Tamm-Horsfall protein remain unchanged during experimental calcium oxalate nephrolithiasis. Although staining for Tamm-Horsfall protein was evident in the papillae of rats with nephrolithiasis, the site of Tamm-Horsfall protein synthesis remained cells of the thick ascending limbs of the loop of Henle.     

Role of inter-α-inhibitor and its related proteins in experimentally induced calcium oxalate urolithiasis. Localization of proteins and expression of bikunin gene in the rat kidney

Summary Our earlier studies indicated that members of the inter-α-inhibitor (IαI) family of glycoproteins may play an important role in urolithiasis. Indeed bikunin, the light chain of IαI is a potent inhibitor of calcium oxalate crystallization. In order to understand this role, the distribution of IαI and its related proteins, as well as the expression of bikunin, were studied in normal and nephrolithic rats. In normal rats, IαI immunoreactivity was located mainly in proximal tubules. However, in nephrolithic rats, in addition to proximal tubules, the staining was intensively extended to tubules in the corticomedullary junction. Furthermore, by using polymerase chain reaction technique, we demonstrated that gene encoding for bikunin was activated in kidneys of nephrolithic rats. We have previously demonstrated increased staining for osteopontin in association with calcium oxalate crystal deposition in rat kidneys. Others have shown an increase in osteopontin production by renal epithelial cells on exposure to calcium oxalate crystals. Based on these observations we conclude that kidney cells possess an auto-defense system against calcium oxalate crystallization and stone formation in which members of the IαI family may be closely involved. Received: 18 February 1998 / Accepted: 9 July 1998